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5184 Commits

Author SHA1 Message Date
Radim Krčmář
9ea369b032 KVM: x86: fix mixed APIC mode broadcast
Broadcast allowed only one global APIC mode, but mixed modes are
theoretically possible.  x2APIC IPI doesn't mean 0xff as broadcast,
the rest does.

x2APIC broadcasts are accepted by xAPIC.  If we take SDM to be logical,
even addreses beginning with 0xff should be accepted, but real hardware
disagrees.  This patch aims for simple code by considering most of real
behavior as undefined.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-3-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08 10:47:00 +02:00
Eugene Korenevsky
5a4f55cde8 KVM: x86: cache maxphyaddr CPUID leaf in struct kvm_vcpu
cpuid_maxphyaddr(), which performs lot of memory accesses is called
extensively across KVM, especially in nVMX code.

This patch adds a cached value of maxphyaddr to vcpu.arch to reduce the
pressure onto CPU cache and simplify the code of cpuid_maxphyaddr()
callers. The cached value is initialized in kvm_arch_vcpu_init() and
reloaded every time CPUID is updated by usermode. It is obvious that
these reloads occur infrequently.

Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Message-Id: <20150329205612.GA1223@gnote>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08 10:46:56 +02:00
Denys Vlasenko
3304c9c37b x86/asm/entry/irq: Simplify interrupt dispatch table (IDT) layout
Interrupt entry points are handled with the following code,
each 32-byte code block contains seven entry points:

		...
		[push][jump 22] // 4 bytes
		[push][jump 18] // 4 bytes
		[push][jump 14] // 4 bytes
		[push][jump 10] // 4 bytes
		[push][jump  6] // 4 bytes
		[push][jump  2] // 4 bytes
		[push][jump common_interrupt][padding] // 8 bytes

		[push][jump]
		[push][jump]
		[push][jump]
		[push][jump]
		[push][jump]
		[push][jump]
		[push][jump common_interrupt][padding]

		[padding_2]
	common_interrupt:

And there is a table which holds pointers to every entry point,
IOW: to every push.

In cold cache, two jumps are still costlier than one, even
though we get the benefit of them residing in the same
cacheline.

This change replaces short jumps with near ones to
'common_interrupt', and pads every push+jump pair to 8 bytes. This
way, each interrupt takes only one jump.

This change replaces ".p2align CONFIG_X86_L1_CACHE_SHIFT" before
dispatch table with ".align 8" - we do not need anything
stronger than that.

The table of entry addresses (the interrupt[] array) is no
longer necessary, the address of entries can be easily
calculated as (irq_entries_start + i*8).

   text	   data	    bss	    dec	    hex	filename
  12546	      0	      0	  12546	   3102	entry_64.o.before
  11626	      0	      0	  11626	   2d6a	entry_64.o

The size decrease is because 1656 bytes of .init.rodata are
gone. That's initdata, though. The resident size does go up a
bit.

Run-tested (32 and 64 bits).

Acked-and-Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428090553-7283-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-08 09:02:13 +02:00
Denys Vlasenko
fc3e958a2b x86/asm/entry: Clear EXTRA_REGS for all executable formats
On failure, sys_execve() does not clobber EXTRA_REGS, so we can
just return to userpsace without saving/restoring them.

On success, ELF_PLAT_INIT() in sys_execve() clears all these
registers.

On other executable formats:

  - binfmt_flat.c has similar FLAT_PLAT_INIT, but x86 (and everyone
    else except sh) doesn't define it.

  - binfmt_elf_fdpic.c has ELF_FDPIC_PLAT_INIT, but x86 (and most
    others) doesn't define it.

  - There are no such hooks in binfmt_aout.c et al. We inherit
    EXTRA_REGS from the prior executable.

This inconsistency was not intended.

This change removes SAVE/RESTORE_EXTRA_REGS in stub_execve,
removes register clearing in ELF_PLAT_INIT(),
and instead simply clears them on success in stub_execve.

Run-tested.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428173719-7637-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-06 09:24:08 +02:00
Brian Gerst
6a3713f001 x86/signal: Remove pax argument from restore_sigcontext
The 'pax' argument is unnecesary.  Instead, store the RAX value
directly in regs.

This pattern goes all the way back to 2.1.106pre1, when restore_sigcontext()
was changed to return an error code instead of EAX directly:

  https://git.kernel.org/cgit/linux/kernel/git/history/history.git/diff/arch/i386/kernel/signal.c?id=9a8f8b7ca3f319bd668298d447bdf32730e51174

In 2007 sigaltstack syscall support was added, where the return
value of restore_sigcontext() was changed to carry the memory-copying
failure code.

But instead of putting 'ax' into regs->ax directly, it was carried
in via a pointer and then returned, where the generic syscall return
code copied it to regs->ax.

So there was never any deeper reason for this suboptimal pattern, it
was simply never noticed after being introduced.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1428152303-17154-1-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-06 09:06:39 +02:00
Borislav Petkov
dbe4058a6a x86/alternatives: Fix ALTERNATIVE_2 padding generation properly
Quentin caught a corner case with the generation of instruction
padding in the ALTERNATIVE_2 macro: if len(orig_insn) <
len(alt1) < len(alt2), then not enough padding gets added and
that is not good(tm) as we could overwrite the beginning of the
next instruction.

Luckily, at the time of this writing, we don't have
ALTERNATIVE_2() invocations which have that problem and even if
we did, a simple fix would be to prepend the instructions with
enough prefixes so that that corner case doesn't happen.

However, best it would be if we fixed it properly. See below for
a simple, abstracted example of what we're doing.

So what we ended up doing is, we compute the

	max(len(alt1), len(alt2)) - len(orig_insn)

and feed that value to the .skip gas directive. The max() cannot
have conditionals due to gas limitations, thus the fancy integer
math.

With this patch, all ALTERNATIVE_2 sites get padded correctly;
generating obscure test cases pass too:

  #define alt_max_short(a, b)    ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))

  #define gen_skip(orig, alt1, alt2, marker)	\
  	.skip -((alt_max_short(alt1, alt2) - (orig)) > 0) * \
  		(alt_max_short(alt1, alt2) - (orig)),marker

  	.pushsection .text, "ax"
  .globl main
  main:
  	gen_skip(1, 2, 4, 0x09)
  	gen_skip(4, 1, 2, 0x10)
  	...
  	.popsection

Thanks to Quentin for catching it and double-checking the fix!

Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150404133443.GE21152@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-04 15:58:23 +02:00
Borislav Petkov
6b51311c97 x86/asm/entry/64: Use a define for an invalid segment selector
... instead of a naked number, for better readability.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03 15:29:13 +02:00
Borislav Petkov
78cac48c04 x86/mm/KASLR: Propagate KASLR status to kernel proper
Commit:

  e2b32e6785 ("x86, kaslr: randomize module base load address")

made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:

  f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")

In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.

Originally-From: Jiri Kosina <jkosina@suse.cz>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03 15:26:15 +02:00
Borislav Petkov
47091e3c5b x86/asm/entry: Drop now unused ENABLE_INTERRUPTS_SYSEXIT32
Commit:

  4214a16b02 ("x86/asm/entry/64/compat: Use SYSRETL to return from compat mode SYSENTER")

removed the last user of ENABLE_INTERRUPTS_SYSEXIT32. Kill the
macro now too.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1428049714-829-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03 10:34:19 +02:00
Andy Lutomirski
cf9328cc99 x86/asm/entry/32: Stop caching MSR_IA32_SYSENTER_ESP in tss.sp1
We write a stack pointer to MSR_IA32_SYSENTER_ESP exactly once,
and we unnecessarily cache the value in tss.sp1.  We never
read the cached value.

Remove all of the caching.  It serves no purpose.

Suggested-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/05a0163eb33ef5208363f0015496855da7cebadd.1428002830.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03 08:30:44 +02:00
Ross Zwisler
d9dc64f30a x86/asm: Add support for the CLWB instruction
Add support for the new CLWB (cache line write back)
instruction.  This instruction was announced in the document
"Intel Architecture Instruction Set Extensions Programming
Reference" with reference number 319433-022.

  https://software.intel.com/sites/default/files/managed/0d/53/319433-022.pdf

The CLWB instruction is used to write back the contents of
dirtied cache lines to memory without evicting the cache lines
from the processor's cache hierarchy.  This should be used in
favor of clflushopt or clflush in cases where you require the
cache line to be written to memory but plan to access the data
again in the near future.

One of the main use cases for this is with persistent memory
where CLWB can be used with PCOMMIT to ensure that data has been
accepted to memory and is durable on the DIMM.

This function shows how to properly use CLWB/CLFLUSHOPT/CLFLUSH
and PCOMMIT with appropriate fencing:

void flush_and_commit_buffer(void *vaddr, unsigned int size)
{
	void *vend = vaddr + size - 1;

	for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
		clwb(vaddr);

	/* Flush any possible final partial cacheline */
	clwb(vend);

	/*
	 * Use SFENCE to order CLWB/CLFLUSHOPT/CLFLUSH cache flushes.
	 * (MFENCE via mb() also works)
	 */
	wmb();

	/* PCOMMIT and the required SFENCE for ordering */
	pcommit_sfence();
}

After this function completes the data pointed to by vaddr is
has been accepted to memory and will be durable if the vaddr
points to persistent memory.

Regarding the details of how the alternatives assembly is set
up, we need one additional byte at the beginning of the CLFLUSH
so that we can flip it into a CLFLUSHOPT by changing that byte
into a 0x66 prefix.  Two options are to either insert a 1 byte
ASM_NOP1, or to add a 1 byte NOP_DS_PREFIX.  Both have no
functional effect with the plain CLFLUSH, but I've been told
that executing a CLFLUSH + prefix should be faster than
executing a CLFLUSH + NOP.

We had to hard code the assembly for CLWB because, lacking the
ability to assemble the CLWB instruction itself, the next
closest thing is to have an xsaveopt instruction with a 0x66
prefix.  Unfortunately XSAVEOPT itself is also relatively new,
and isn't included by all the GCC versions that the kernel needs
to support.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1422377631-8986-3-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03 06:56:38 +02:00
Alexander Shishkin
52ca9ced3f perf/x86/intel/pt: Add Intel PT PMU driver
Add support for Intel Processor Trace (PT) to kernel's perf events.
PT is an extension of Intel Architecture that collects information about
software execuction such as control flow, execution modes and timings and
formats it into highly compressed binary packets. Even being compressed,
these packets are generated at hundreds of megabytes per second per core,
which makes it impractical to decode them on the fly in the kernel.

This driver exports trace data by through AUX space in the perf ring
buffer, which is zero-copy mapped into userspace for faster data retrieval.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1422614392-114498-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 17:14:20 +02:00
Alexander Shishkin
ed69628b3b x86: Add Intel Processor Trace (INTEL_PT) cpu feature detection
Intel Processor Trace is an architecture extension that allows for program
flow tracing.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-11-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 17:14:18 +02:00
Boris Ostrovsky
3f85483bd8 x86/cpu: Factor out common CPU initialization code, fix 32-bit Xen PV guests
Some of x86 bare-metal and Xen CPU initialization code is common
between the two and therefore can be factored out to avoid code
duplication.

As a side effect, doing so will also extend the fix provided by
commit a7fcf28d43 ("x86/asm/entry: Replace this_cpu_sp0() with
current_top_of_stack() to x86_32") to 32-bit Xen PV guests.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1427897534-5086-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02 12:06:41 +02:00
Christoph Hellwig
ec776ef6bb x86/mm: Add support for the non-standard protected e820 type
Various recent BIOSes support NVDIMMs or ADR using a
non-standard e820 memory type, and Intel supplied reference
Linux code using this type to various vendors.

Wire this e820 table type up to export platform devices for the
pmem driver so that we can use it in Linux.

Based on earlier work from:

   Dave Jiang <dave.jiang@intel.com>
   Dan Williams <dan.j.williams@intel.com>

Includes fixes for NUMA regions from Boaz Harrosh.

Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-nvdimm@ml01.01.org
Link: http://lkml.kernel.org/r/1427872339-6688-2-git-send-email-hch@lst.de
[ Minor cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01 17:02:43 +02:00
Ingo Molnar
84a87c628a * Fixes and cleanups for SMBIOS 3.0 DMI code - Ivan Khoronzhuk
* A new efi=debug command line option that enables debug output in the
    EFI boot stub and results in less verbose EFI memory map output by
    default - Borislav Petkov
 
  * Disable interrupts around EFI calls and use a more standard page
    table saving and restoring idiom when making EFI calls - Ingo Molnar
 
  * Reduce the number of memory allocations performed when allocating the
    FDT in EFI boot stub by retrieving size from the FDT header in the
    EFI config table - Ard Biesheuvel
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 -----END PGP SIGNATURE-----

Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into core/efi

Pull EFI updates from Matt Fleming:

 - Fixes and cleanups for SMBIOS 3.0 DMI code. (Ivan Khoronzhuk)

 - A new efi=debug command line option that enables debug output in the
   EFI boot stub and results in less verbose EFI memory map output by
   default. (Borislav Petkov)

 - Disable interrupts around EFI calls and use a more standard page
   table saving and restoring idiom when making EFI calls. (Ingo Molnar)

 - Reduce the number of memory allocations performed when allocating the
   FDT in EFI boot stub by retrieving size from the FDT header in the
   EFI config table. (Ard Biesheuvel)

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01 15:10:25 +02:00
Ingo Molnar
744937b0b1 efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction
Currently x86-64 efi_call_phys_prolog() saves into a global variable (save_pgd),
and efi_call_phys_epilog() restores the kernel pagetables from that global
variable.

Change this to a cleaner save/restore pattern where the saving function returns
the saved object and the restore function restores that.

Apply the same concept to the 32-bit code as well.

Plus this approach, as an added bonus, allows us to express the
!efi_enabled(EFI_OLD_MEMMAP) situation in a clean fashion as well,
via a 'NULL' return value.

Cc: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-04-01 12:46:22 +01:00
Bandan Das
4399c03c67 x86/apic: Remove verify_local_APIC()
__verify_local_APIC() is detritus from the early APIC days.
Its return value isn't used anywhere and the information it
prints when debug is enabled is already part of APIC
initialization messages printed to syslog. Off with it!

Signed-off-by: Bandan Das <bsd@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/jpgy4mcsxsq.fsf@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01 10:47:57 +02:00
Joe Perches
1d804d079a x86: Use bool function return values of true/false not 1/0
Use the normal return values for bool functions

Signed-off-by: Joe Perches <joe@perches.com>
Message-Id: <9f593eb2f43b456851cd73f7ed09654ca58fb570.1427759009.git.joe@perches.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-31 18:05:09 +02:00
Ingo Molnar
55474c48b4 x86/asm/entry: Remove user_mode_ignore_vm86()
user_mode_ignore_vm86() can be used instead of user_mode(), in
places where we have already done a v8086_mode() security
check of ptregs.

But doing this check in the wrong place would be a bug that
could result in security problems, and also the naming still
isn't very clear.

Furthermore, it only affects 32-bit kernels, while most
development happens on 64-bit kernels.

If we replace them with user_mode() checks then the cost is only
a very minor increase in various slowpaths:

   text             data   bss     dec              hex    filename
   10573391         703562 1753042 13029995         c6d26b vmlinux.o.before
   10573423         703562 1753042 13030027         c6d28b vmlinux.o.after

So lets get rid of this distinction once and for all.

Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150329090233.GA1963@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-31 11:45:19 +02:00
Hector Marco-Gisbert
4e26d11f52 x86/mm: Improve AMD Bulldozer ASLR workaround
The ASLR implementation needs to special-case AMD F15h processors by
clearing out bits [14:12] of the virtual address in order to avoid I$
cross invalidations and thus performance penalty for certain workloads.
For details, see:

  dfb09f9b7a ("x86, amd: Avoid cache aliasing penalties on AMD family 15h")

This special case reduces the mmapped file's entropy by 3 bits.

The following output is the run on an AMD Opteron 62xx class CPU
processor under x86_64 Linux 4.0.0:

  $ for i in `seq 1 10`; do cat /proc/self/maps | grep "r-xp.*libc" ; done
  b7588000-b7736000 r-xp 00000000 00:01 4924       /lib/i386-linux-gnu/libc.so.6
  b7570000-b771e000 r-xp 00000000 00:01 4924       /lib/i386-linux-gnu/libc.so.6
  b75d0000-b777e000 r-xp 00000000 00:01 4924       /lib/i386-linux-gnu/libc.so.6
  b75b0000-b775e000 r-xp 00000000 00:01 4924       /lib/i386-linux-gnu/libc.so.6
  b7578000-b7726000 r-xp 00000000 00:01 4924       /lib/i386-linux-gnu/libc.so.6
  ...

Bits [12:14] are always 0, i.e. the address always ends in 0x8000 or
0x0000.

32-bit systems, as in the example above, are especially sensitive
to this issue because 32-bit randomness for VA space is 8 bits (see
mmap_rnd()). With the Bulldozer special case, this diminishes to only 32
different slots of mmap virtual addresses.

This patch randomizes per boot the three affected bits rather than
setting them to zero. Since all the shared pages have the same value
at bits [12..14], there is no cache aliasing problems. This value gets
generated during system boot and it is thus not known to a potential
remote attacker. Therefore, the impact from the Bulldozer workaround
gets diminished and ASLR randomness increased.

More details at:

  http://hmarco.org/bugs/AMD-Bulldozer-linux-ASLR-weakness-reducing-mmaped-files-by-eight.html

Original white paper by AMD dealing with the issue:

  http://developer.amd.com/wordpress/media/2012/10/SharedL1InstructionCacheonAMD15hCPU.pdf

Mentored-by: Ismael Ripoll <iripoll@disca.upv.es>
Signed-off-by: Hector Marco-Gisbert <hecmargi@upv.es>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan-Simon <dl9pf@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-fsdevel@vger.kernel.org
Link: http://lkml.kernel.org/r/1427456301-3764-1-git-send-email-hecmargi@upv.es
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-31 10:01:17 +02:00
Nadav Amit
b32a991800 KVM: x86: Remove redundant definitions
Some constants are redfined in emulate.c. Avoid it.

s/SELECTOR_RPL_MASK/SEGMENT_RPL_MASK
s/SELECTOR_TI_MASK/SEGMENT_TI_MASK

No functional change.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427635984-8113-3-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-30 16:46:42 +02:00
Nadav Amit
0efb04406d KVM: x86: removing redundant eflags bits definitions
The eflags are redefined (using other defines) in emulate.c.
Use the definition from processor-flags.h as some mess already started.
No functional change.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427635984-8113-2-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-30 16:46:37 +02:00
Ingo Molnar
4bfe186dbe Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:

  - Documentation updates.

  - Changes permitting use of call_rcu() and friends very early in
    boot, for example, before rcu_init() is invoked.

  - Miscellaneous fixes.

  - Add in-kernel API to enable and disable expediting of normal RCU
    grace periods.

  - Improve RCU's handling of (hotplug-) outgoing CPUs.

    Note: ARM support is lagging a bit here, and these improved
    diagnostics might generate (harmless) splats.

  - NO_HZ_FULL_SYSIDLE fixes.

  - Tiny RCU updates to make it more tiny.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 10:04:06 +01:00
Denys Vlasenko
aa6d9a128b x86/irq/tracing: Do not save callee-preserved registers around lockdep_sys_exit_thunk
Internally, lockdep_sys_exit_thunk saves callee-clobbered
registers, and calls a C function, lockdep_sys_exit. Thus,
callee-preserved registers won't be mangled, there is no need to
save them.

Patch was run-tested.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1427314468-12763-4-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 10:01:49 +01:00
Denys Vlasenko
7dc7cc0780 x86/irq/tracing: Fold ARCH_LOCKDEP_SYS_EXIT defines into their users
There is no need to have an extra level of macro indirection
here.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1427314468-12763-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 10:01:49 +01:00
Denys Vlasenko
40e2ec657d x86/irq/tracing: Move ARCH_LOCKDEP_SYS_EXIT defines closer to their users
This change simply moves defines around (even if it's not
obvious in a patch form). Nothing is changed.

This is a preparation for folding ARCH_LOCKDEP_SYS_EXIT defines
into their users.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1427314468-12763-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 10:01:48 +01:00
Ingo Molnar
936c663aed Merge branch 'perf/x86' into perf/core, because it's ready
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27 09:46:19 +01:00
Jan Kiszka
b3a2a9076d KVM: nVMX: Add support for rdtscp
If the guest CPU is supposed to support rdtscp and the host has rdtscp
enabled in the secondary execution controls, we can also expose this
feature to L1. Just extend nested_vmx_exit_handled to properly route
EXIT_REASON_RDTSCP.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-26 22:33:48 -03:00
Greg Kroah-Hartman
ff85f707ac Merge 4.0-rc5 into char-misc-next
We want those fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-25 10:51:53 +01:00
Ingo Molnar
72d64cc769 x86/asm: Further improve segment.h readability
- extend/clarify explanations where necessary

 - move comments from macro values to before the macro, to
   make them more consistent, and to reduce preprocessor overhead

 - sort GDT index and selector values likewise by number

 - use consistent, modern kernel coding style across the file

 - capitalize consistently

 - use consistent vertical spacing

 - remove the unused get_limit() method (noticed by Andy Lutomirski)

No change in code (verified with objdump -d):

 64-bit defconfig+kvmconfig:

   815a129bc1f80de6445c1d8ca5b97cad  vmlinux.o.before.asm
   815a129bc1f80de6445c1d8ca5b97cad  vmlinux.o.after.asm

 32-bit defconfig+kvmconfig:

   e659ef045159ddf41a0771b33a34aae5  vmlinux.o.before.asm
   e659ef045159ddf41a0771b33a34aae5  vmlinux.o.after.asm

Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 21:13:38 +01:00
Ingo Molnar
dca5b52ad7 x86/asm/entry/64: Rename THREAD_INFO() to ASM_THREAD_INFO()
The THREAD_INFO() macro has a somewhat confusingly generic name,
defined in a generic .h C header file. It also does not make it
clear that it constructs a memory operand for use in assembly
code.

Rename it to ASM_THREAD_INFO() to make it all glaringly
obvious on first glance.

Acked-by: Borislav Petkov <bp@suse.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/20150324184442.GC14760@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 20:57:31 +01:00
Ingo Molnar
f9d71854b4 x86/asm/entry/64: Merge the field offset into the THREAD_INFO() macro
Before:

   TI_sysenter_return+THREAD_INFO(%rsp,3*8),%r10d

After:

   movl    THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d

to turn it into a clear thread_info accessor.

No code changed:

 md5:
   fb4cb2b3ce05d89940ca304efc8ff183  ia32entry.o.before.asm
   fb4cb2b3ce05d89940ca304efc8ff183  ia32entry.o.after.asm

   e39f2958a5d1300158e276e4f7663263  entry_64.o.before.asm
   e39f2958a5d1300158e276e4f7663263  entry_64.o.after.asm

Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/20150324184411.GB14760@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 20:57:31 +01:00
Ingo Molnar
1ddc6f3c60 x86/asm/entry/64: Improve the THREAD_INFO() macro explanation
Explain the background, and add a real example.

Acked-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/20150324184311.GA14760@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 20:57:30 +01:00
Denys Vlasenko
84f5378845 x86/asm: Deobfuscate segment.h
This file just defines a number of constants, and a few macros
and inline functions. It is particularly badly written.

For example, it is not trivial to see how descriptors are
numbered (you'd expect that should be easy, right?).

This change deobfuscates it via the following changes:

Group all GDT_ENTRY_foo together (move intervening stuff away).

Number them explicitly: use a number, not PREV_DEFINE+1, +2, +3:
I want to immediately see that GDT_ENTRY_PNPBIOS_CS32 is 18.
Seeing (GDT_ENTRY_KERNEL_BASE+6) instead is not useful.

The above change allows to remove GDT_ENTRY_KERNEL_BASE
and GDT_ENTRY_PNPBIOS_BASE, which weren't used anywhere else.

After a group of GDT_ENTRY_foo, define all selector values.

Remove or improve some comments. In particular:
Comment deleted as stating the obvious:
    /*
     * The GDT has 32 entries
     */
    #define GDT_ENTRIES 32

"The segment offset needs to contain a RPL. Grr. -AK"
    changed to
"Selectors need to also have a correct RPL (+3 thingy)"

"GDT layout to get 64bit syscall right (sysret hardcodes gdt
offsets)" expanded into a description *how exactly* sysret
hardcodes them.

Patch was tested to compile and not change vmlinux.o
on 32-bit and 64-bit builds (verified with objdump).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 20:47:07 +01:00
Denys Vlasenko
ef593260f0 x86/asm/entry: Get rid of KERNEL_STACK_OFFSET
PER_CPU_VAR(kernel_stack) was set up in a way where it points
five stack slots below the top of stack.

Presumably, it was done to avoid one "sub $5*8,%rsp"
in syscall/sysenter code paths, where iret frame needs to be
created by hand.

Ironically, none of them benefits from this optimization,
since all of them need to allocate additional data on stack
(struct pt_regs), so they still have to perform subtraction.

This patch eliminates KERNEL_STACK_OFFSET.

PER_CPU_VAR(kernel_stack) now points directly to top of stack.
pt_regs allocations are adjusted to allocate iret frame as well.
Hopefully we can merge it later with 32-bit specific
PER_CPU_VAR(cpu_current_top_of_stack) variable...

Net result in generated code is that constants in several insns
are changed.

This change is necessary for changing struct pt_regs creation
in SYSCALL64 code path from MOV to PUSH instructions.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426785469-15125-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 19:42:38 +01:00
Denys Vlasenko
b3fe8ba320 x86/asm/entry/64: Change the THREAD_INFO() definition to not depend on KERNEL_STACK_OFFSET
This changes the THREAD_INFO() definition and all its callsites
so that they do not count stack position from
(top of stack - KERNEL_STACK_OFFSET), but from top of stack.

Semi-mysterious expressions THREAD_INFO(%rsp,RIP) - "why RIP??"
are now replaced by more logical THREAD_INFO(%rsp,SIZEOF_PTREGS)
- "calculate thread_info's address using information that
rsp is SIZEOF_PTREGS bytes below top of stack".

While at it, replace "(off)-THREAD_SIZE(reg)" with equivalent
"((off)-THREAD_SIZE)(reg)". The form without parentheses
falsely looks like we invoke THREAD_SIZE() macro.

Improve comment atop THREAD_INFO macro definition.

This patch does not change generated code (verified by objdump).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426785469-15125-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-24 19:42:37 +01:00
Aravind Gopalakrishnan
43eaa2a1ad x86/mce: Define mce_severity function pointer
Rename mce_severity() to mce_severity_intel() and assign the
mce_severity function pointer to mce_severity_amd() during init on AMD.
This way, we can avoid a test to call mce_severity_amd every time we get
into mce_severity(). And it's cleaner to do it this way.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Suggested-by: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1427125373-2918-3-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Borislav Petkov <bp@suse.de>
2015-03-24 12:14:15 +01:00
Aravind Gopalakrishnan
bf80bbd7dc x86/mce: Add an AMD severities-grading function
Add a severities function that caters to AMD processors. This allows us
to do some vendor-specific work within the function if necessary.

Also, introduce a vendor flag bitfield for vendor-specific settings. The
severities code uses this to define error scope based on the prescence
of the flags field.

This is based off of work by Boris Petkov.

Testing details:
Fam10h, Model 9h (Greyhound)
Fam15h: Models 0h-0fh (Orochi), 30h-3fh (Kaveri) and 60h-6fh (Carrizo),
Fam16h Model 00h-0fh (Kabini)

Boris:
Intel SNB
AMD K8 (JH-E0)

Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/1427125373-2918-2-git-send-email-Aravind.Gopalakrishnan@amd.com
[ Fixup build, clean up comments. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
2015-03-24 12:13:34 +01:00
Rusty Russell
2f921b5bb0 lguest: suppress interrupts for single insn, not range.
The last patch reduced our interrupt-suppression region to one address,
so simplify the code somewhat.

Also, remove the obsolete undefined instruction ranges and the comment
which refers to lguest_guest.S instead of head_32.S.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-24 11:52:08 +10:30
Marcelo Tosatti
0a4e6be9ca x86: kvm: Revert "remove sched notifier for cross-cpu migrations"
The following point:

    2. per-CPU pvclock time info is updated if the
       underlying CPU changes.

Is not true anymore since "KVM: x86: update pvclock area conditionally,
on cpu migration".

Add task migration notification back.

Problem noticed by Andy Lutomirski.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CC: stable@kernel.org # 3.11+
2015-03-23 20:22:48 -03:00
Greg Kroah-Hartman
caa445d808 Merge 4.0-rc5 into tty-next
We want the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-23 21:45:24 +01:00
Andy Lutomirski
7a2806741e x86/asm/entry: Remove user_mode_vm()
It has no callers anymore.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a594afd6a0bddb1311bd7c92a15201c87fbb8681.1426728647.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 11:14:33 +01:00
Andy Lutomirski
efa7045103 x86/asm/entry: Make user_mode() work correctly if regs came from VM86 mode
user_mode() is now identical to user_mode_vm().  Subsequent patches
will change all callers of user_mode_vm() to user_mode() and then
delete user_mode_vm().

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/0dd03eacb5f0a2b5ba0240de25347a31b493c289.1426728647.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 11:13:51 +01:00
Andy Lutomirski
a67e7277d0 x86/asm/entry: Add user_mode_ignore_vm86()
user_mode() is dangerous and user_mode_vm() has a confusing name.

Add user_mode_ignore_vm86() (equivalent to current user_mode()).
We'll change the small number of legitimate users of user_mode()
to user_mode_ignore_vm86().

Inspired by grsec, although this works rather differently.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/202c56ca63823c338af8e2e54948dbe222da6343.1426728647.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 11:13:36 +01:00
Ingo Molnar
e4518ab90f Linux 4.0-rc5
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Merge tag 'v4.0-rc5' into x86/asm, to resolve conflicts

Conflicts:
	arch/x86/kernel/entry_64.S

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 11:13:15 +01:00
Ingo Molnar
e1b63dec2d Merge branch 'sched/urgent' into sched/core, to pick up fixes before applying new patches
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:50:29 +01:00
Borislav Petkov
b85e67d148 x86/fpu: Rename drop_init_fpu() to fpu_reset_state()
Call it what it does and in accordance with the context where it is
used: we reset the FPU state either because we were unable to restore it
from the one saved in the task or because we simply want to reset it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:13:59 +01:00
Borislav Petkov
d2d0ac9a46 x86/fpu: Fold __drop_fpu() into its sole user
Fold it into drop_fpu(). Phew, one less FPU function to pay attention
to.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:13:59 +01:00
Oleg Nesterov
8f4d81863b x86/fpu: Introduce restore_init_xstate()
Extract the "use_eager_fpu()" code from drop_init_fpu() into a new,
simple helper restore_init_xstate(). The next patch adds another user.

- It is not clear why we do not check use_fxsr() like fpu_restore_checking()
  does. eager_fpu_init_bp() calls setup_init_fpu_buf() too, and we have the
  "eagerfpu=on" kernel option.

- Ignoring the fact that init_xstate_buf is "struct xsave_struct *", not
  "union thread_xstate *", it is not clear why we can not simply use
  fpu_restore_checking() and avoid the code duplication.

- It is not clear why we can't call setup_init_fpu_buf() unconditionally
  to always create init_xstate_buf(). Then do_device_not_available() path
  (at least) could use restore_init_xstate() too. It doesn't need to init
  fpu->state, its content doesn't matter until unlazy_fpu()/__switch_to()/etc
  which overwrites this memory anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150311173429.GD5032@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:13:58 +01:00
Oleg Nesterov
fb14b4eadf x86/fpu: Document user_fpu_begin()
Currently, user_fpu_begin() has a single caller and it is not clear why
do we actually need it and why we should not worry about preemption
right after preempt_enable().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150311173409.GC5032@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:13:58 +01:00
Ingo Molnar
eda2360ad1 Linux 4.0-rc5
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Merge tag 'v4.0-rc5' into x86/fpu, to prevent conflicts

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 10:13:36 +01:00
Brian Gerst
1daeaa3151 x86/asm/entry: Fix execve() and sigreturn() syscalls to always return via IRET
Both the execve() and sigreturn() family of syscalls have the
ability to change registers in ways that may not be compatabile
with the syscall path they were called from.

In particular, SYSRET and SYSEXIT can't handle non-default %cs and %ss,
and some bits in eflags.

These syscalls have stubs that are hardcoded to jump to the IRET path,
and not return to the original syscall path.

The following commit:

   76f5df43ca ("Always allocate a complete "struct pt_regs" on the kernel stack")

recently changed this for some 32-bit compat syscalls, but introduced a bug where
execve from a 32-bit program to a 64-bit program would fail because it still returned
via SYSRETL. This caused Wine to fail when built for both 32-bit and 64-bit.

This patch sets TIF_NOTIFY_RESUME for execve() and sigreturn() so
that the IRET path is always taken on exit to userspace.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1426978461-32089-1-git-send-email-brgerst@gmail.com
[ Improved the changelog and comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23 08:52:46 +01:00
Linus Torvalds
3d7a6db537 Power management and ACPI fixes for v4.0-rc5
- Revert a recent PCI commit related to IRQ resources management
    that introduced a regression for drivers attempting to bind to
    devices whose previous drivers did not balance pci_enable_device()
    and pci_disable_device() as expected (Rafael J Wysocki).
 
  - Fix a deadlock in at91_rtc_interrupt() introduced by a typo in a
    recent commit related to wakeup interrupt handling (Dan Carpenter).
 
  - Allow the power capping RAPL (Running-Average Power Limit) driver
    to use different energy units for domains within one CPU package
    which is necessary to handle Intel Haswell EP processors correctly
    (Jacob Pan).
 
  - Improve the cpuidle mvebu driver's handling of Armada XP SoCs by
    updating the target residency and exit latency numbers for those
    chips (Sebastien Rannou).
 
  - Prevent the cpuidle mvebu driver from calling cpu_pm_enter() twice
    in a row before cpu_pm_exit() is called on the same CPU which
    breaks the core's assumptions regarding the usage of those
    functions (Gregory Clement).
 
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Merge tag 'pm+acpi-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI fixes from Rafael Wysocki:
 "These are fixes for recent regressions (PCI/ACPI resources and at91
  RTC locking), a stable-candidate powercap RAPL driver fix and two ARM
  cpuidle fixes (one stable-candidate too).

  Specifics:

   - Revert a recent PCI commit related to IRQ resources management that
     introduced a regression for drivers attempting to bind to devices
     whose previous drivers did not balance pci_enable_device() and
     pci_disable_device() as expected (Rafael J Wysocki).

   - Fix a deadlock in at91_rtc_interrupt() introduced by a typo in a
     recent commit related to wakeup interrupt handling (Dan Carpenter).

   - Allow the power capping RAPL (Running-Average Power Limit) driver
     to use different energy units for domains within one CPU package
     which is necessary to handle Intel Haswell EP processors correctly
     (Jacob Pan).

   - Improve the cpuidle mvebu driver's handling of Armada XP SoCs by
     updating the target residency and exit latency numbers for those
     chips (Sebastien Rannou).

   - Prevent the cpuidle mvebu driver from calling cpu_pm_enter() twice
     in a row before cpu_pm_exit() is called on the same CPU which
     breaks the core's assumptions regarding the usage of those
     functions (Gregory Clement)"

* tag 'pm+acpi-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "x86/PCI: Refine the way to release PCI IRQ resources"
  rtc: at91rm9200: double locking bug in at91_rtc_interrupt()
  powercap / RAPL: handle domains with different energy units
  cpuidle: mvebu: Update cpuidle thresholds for Armada XP SOCs
  cpuidle: mvebu: Fix the CPU PM notifier usage
2015-03-21 12:51:36 -07:00
Rafael J. Wysocki
9e8ce4b96b Revert "x86/PCI: Refine the way to release PCI IRQ resources"
Commit b4b55cda58 (Refine the way to release PCI IRQ resources)
introduced a regression in the PCI IRQ resource management by causing
the IRQ resource of a device, established when pci_enabled_device()
is called on a fully disabled device, to be released when the driver
is unbound from the device, regardless of the enable_cnt.

This leads to the situation that an ill-behaved driver can now make a
device unusable to subsequent drivers by an imbalance in their use of
pci_enable/disable_device().  That is a serious problem for secondary
drivers like vfio-pci, which are innocent of the transgressions of
the previous driver.

Since the solution of this problem is not immediate and requires
further discussion, revert commit b4b55cda58 and the issue it was
supposed to address (a bug related to xen-pciback) will be taken
care of in a different way going forward.

Reported-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-03-20 14:56:19 +01:00
Zhonghui Fu
431d452af1 PM / sleep: add pm-trace support for suspending phase
Occasionally, the system can't come back up after suspend/resume
due to problems of device suspending phase. This patch make
PM_TRACE infrastructure cover device suspending phase of
suspend/resume process, and the information in RTC can tell
developers which device suspending function make system hang.

Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-03-18 15:54:27 +01:00
Ingo Molnar
ac9af4983e x86/asm/entry/64: Remove thread_struct::usersp
Nothing uses thread_struct::usersp anymore, so remove it.

Originally-from: Denys Vlasenko <dvlasenk@redhat.com>
Tested-by: Borislav Petkov <bp@alien8.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 16:01:41 +01:00
Ingo Molnar
9854dd74c3 x86/asm/entry/64: Simplify 'old_rsp' usage
Remove all manipulations of PER_CPU(old_rsp) in C code:

 - it is not used on SYSRET return anymore, and system entries
   are atomic, so updating it from the fork and context switch
   paths is pointless.

 - Tweak a few related comments as well: we no longer have a
   "partial stack frame" on entry, ever.

Based on (split out of) patch from Denys Vlasenko.

Originally-from: Denys Vlasenko <dvlasenk@redhat.com>
Tested-by: Borislav Petkov <bp@alien8.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426599779-8010-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 16:01:41 +01:00
Denys Vlasenko
d828c71fba x86/asm/entry/32: Document the 32-bit SYSENTER "emergency stack" better
Before the patch, the 'tss_struct::stack' field was not referenced anywhere.

It was used only to set SYSENTER's stack to point after the last byte
of tss_struct, thus the trailing field, stack[64], was used.

But grep would not know it. You can comment it out, compile,
and kernel will even run until an unlucky NMI corrupts
io_bitmap[] (which is also not easily detectable).

This patch changes code so that the purpose and usage of this
field is not mysterious anymore, and can be easily grepped for.

This does change generated code, for a subtle reason:
since tss_struct is ____cacheline_aligned, there happens to be
5 longs of padding at the end. Old code was using the padding
too; new code will strictly use it only for SYSENTER_stack[].

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1425912738-559-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:29 +01:00
Denys Vlasenko
5c39403e00 x86/asm/entry: Simplify task_pt_regs() macro definition
Before this change, task_pt_regs() was using KSTK_TOP(),
and it was the only use of that macro. In turn, KSTK_TOP used
THREAD_SIZE_LONGS, and it was the only use of that macro too.

Fold these macros into task_pt_regs(). Tweak comment
about "- 8" - we now use a symbolic constant, not literal 8.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426255743-5394-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:28 +01:00
Andy Lutomirski
76e4c4908a x86/asm/entry/32: Document our abuse of x86_hw_tss::ss1 and x86_hw_tss::sp1
This has confused me for a while.  Now that I figured it out, document it.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b7efc1b7364039824776f68e9ddee9ec1500e894.1426009661.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:27 +01:00
Andy Lutomirski
d9e05cc5a5 x86/asm/entry: Unify and fix initial thread_struct::sp0 values
x86_32 and x86_64 need slightly different thread_struct::sp0 values, and
x86_32's was incorrect for init.

This never mattered -- the init thread never runs user code, so we never
used thread_struct::sp0 for anything.

Fix it and mostly unify them.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1b810c1d2e797e27bb4a7708c426101161edd1f6.1426009661.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:27 +01:00
Andy Lutomirski
3ee4298f44 x86/asm/entry: Create and use a 'TOP_OF_KERNEL_STACK_PADDING' macro
x86_32, unlike x86_64, pads the top of the kernel stack, because the
hardware stack frame formats are variable in size.

Document this padding and give it a name.

This should make no change whatsoever to the compiled kernel
image. It also doesn't fix any of the current bugs in this area.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/02bf2f54b8dcb76a62a142b6dfe07d4ef7fc582e.1426009661.git.luto@amacapital.net
[ Fixed small details, such as a missed magic constant in entry_32.S pointed out by Denys Vlasenko. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:26 +01:00
Andy Lutomirski
9a036b93a3 x86/signal/64: Remove 'fs' and 'gs' from sigcontext
As far as I can tell, these fields have been set to zero on save
and ignored on restore since Linux was imported into git.
Rename them '__pad1' and '__pad2' to avoid confusion.  This may
also allow us to recycle them some day.

This also adds a comment clarifying the history of those fields.

I'm intentionally avoiding calling either of them '__pad0': the
field formerly known as '__pad0' is now 'ss'.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/844f8490e938780c03355be4c9b69eb4c494bf4e.1426193719.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:26 +01:00
Andy Lutomirski
c6f2062935 x86/signal/64: Fix SS handling for signals delivered to 64-bit programs
The comment in the signal code says that apps can save/restore
other segments on their own.  It's true that apps can *save* SS
on their own, but there's no way for apps to restore it: SYSCALL
effectively resets SS to __USER_DS, so any value that user code
tries to load into SS gets lost on entry to sigreturn.

This recycles two padding bytes in the segment selector area for SS.

While we're at it, we need a second change to make this useful.

If the signal we're delivering is caused by a bad SS value,
saving that value isn't enough.  We need to remove that bad
value from the regs before we try to deliver the signal.  Oddly,
the i386 code already got this right.

I suspect that 64-bit programs that try to run 16-bit code and
use signals will have a lot of trouble without this.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/405594361340a2ec32f8e2b115c142df0e180d8e.1426193719.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-17 09:25:25 +01:00
Borislav Petkov
69797dafe3 Revert "x86/mm/ASLR: Propagate base load address calculation"
This reverts commit:

  f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")

The main reason for the revert is that the new boot flag does not work
at all currently, and in order to make this work, we need non-trivial
changes to the x86 boot code which we didn't manage to get done in
time for merging.

And even if we did, they would've been too risky so instead of
rushing things and break booting 4.1 on boxes left and right, we
will be very strict and conservative and will take our time with
this to fix and test it properly.

Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: H. Peter Anvin <hpa@linux.intel.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150316100628.GD22995@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-16 11:18:21 +01:00
Len Brown
b253149b84 sched/idle/x86: Restore mwait_idle() to fix boot hangs, to improve power savings and to improve performance
In Linux-3.9 we removed the mwait_idle() loop:

  69fb3676df ("x86 idle: remove mwait_idle() and "idle=mwait" cmdline param")

The reasoning was that modern machines should be sufficiently
happy during the boot process using the default_idle() HALT
loop, until cpuidle loads and either acpi_idle or intel_idle
invoke the newer MWAIT-with-hints idle loop.

But two machines reported problems:

 1. Certain Core2-era machines support MWAIT-C1 and HALT only.
    MWAIT-C1 is preferred for optimal power and performance.
    But if they support just C1, cpuidle never loads and
    so they use the boot-time default idle loop forever.

 2. Some laptops will boot-hang if HALT is used,
    but will boot successfully if MWAIT is used.
    This appears to be a hidden assumption in BIOS SMI,
    that is presumably valid on the proprietary OS
    where the BIOS was validated.

       https://bugzilla.kernel.org/show_bug.cgi?id=60770

So here we effectively revert the patch above, restoring
the mwait_idle() loop.  However, we don't bother restoring
the idle=mwait cmdline parameter, since it appears to add
no value.

Maintainer notes:

  For 3.9, simply revert 69fb3676df
  for 3.10, patch -F3 applies, fuzz needed due to __cpuinit use in
  context For 3.11, 3.12, 3.13, this patch applies cleanly

Tested-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Mike Galbraith <bitbucket@online.de>
Cc: <stable@vger.kernel.org> # 3.9+
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ian Malone <ibmalone@gmail.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/345254a551eb5a6a866e048d7ab570fd2193aca4.1389763084.git.len.brown@intel.com
[ Ported to recent kernels. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-16 11:14:21 +01:00
Oleg Nesterov
f4c3686386 x86/fpu: Drop_fpu() should not assume that tsk equals current
drop_fpu() does clear_used_math() and usually this is correct
because tsk == current.

However switch_fpu_finish()->restore_fpu_checking() is called before
__switch_to() updates the "current_task" variable. If it fails,
we will wrongly clear the PF_USED_MATH flag of the previous task.

So use clear_stopped_child_used_math() instead.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150309171041.GB11388@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13 12:44:29 +01:00
Paul E. McKenney
2a442c9c64 x86: Use common outgoing-CPU-notification code
This commit removes the open-coded CPU-offline notification with new
common code.  Among other things, this change avoids calling scheduler
code using RCU from an offline CPU that RCU is ignoring.  It also allows
Xen to notice at online time that the CPU did not go offline correctly.
Note that Xen has the surviving CPU carry out some cleanup operations,
so if the surviving CPU times out, these cleanup operations might have
been carried out while the outgoing CPU was still running.  It might
therefore be unwise to bring this CPU back online, and this commit
avoids doing so.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <x86@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: <xen-devel@lists.xenproject.org>
2015-03-11 13:22:35 -07:00
Andy Shevchenko
079119a2c7 serial, x86: use UPF_* constants for flags
This patch fixes the following sparse warnings:

drivers/tty/serial/8250/8250_core.c:3231:32: warning: incorrect type in assignment (different base types)
drivers/tty/serial/8250/8250_core.c:3231:32:    expected restricted upf_t [usertype] flags
drivers/tty/serial/8250/8250_core.c:3231:32:    got unsigned int const [unsigned] flags

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-11 14:01:17 +01:00
Joel Schopp
5cb56059c9 kvm: x86: make kvm_emulate_* consistant
Currently kvm_emulate() skips the instruction but kvm_emulate_* sometimes
don't.  The end reult is the caller ends up doing the skip themselves.
Let's make them consistant.

Signed-off-by: Joel Schopp <joel.schopp@amd.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-10 20:29:15 -03:00
Denys Vlasenko
263042e463 x86/asm/entry/64: Save user RSP in pt_regs->sp on SYSCALL64 fastpath
Prepare for the removal of 'usersp', by simplifying PER_CPU(old_rsp) usage:

  - use it only as temp storage

  - store the userspace stack pointer immediately in pt_regs->sp
    on syscall entry, instead of using it later, on syscall exit.

  - change C code to use pt_regs->sp only, instead of PER_CPU(old_rsp)
    and task->thread.usersp.

FIXUP/RESTORE_TOP_OF_STACK are simplified as well.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1425926364-9526-4-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-10 13:56:10 +01:00
Denys Vlasenko
29722cd4ef x86/asm/entry/64: Save R11 into pt_regs->flags on SYSCALL64 fastpath
Before this patch, R11 was saved in pt_regs->r11.

Which looks natural, but requires messy shuffling to/from iret
frame whenever ptrace or e.g. sys_iopl() wants to modify flags -
because that's how this register is used by SYSCALL/SYSRET.

This patch saves R11 in pt_regs->flags, and uses that value for
the SYSRET64 instruction. Shuffling is eliminated.

FIXUP/RESTORE_TOP_OF_STACK are simplified.

stub_iopl is no longer needed: pt_regs->flags needs no fixing up.

Testing shows that syscall fast path is ~54.3 ns before
and after the patch (on 2.7 GHz Sandy Bridge CPU).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1425926364-9526-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-10 13:56:10 +01:00
Oleg Nesterov
1d23c4518b x86/fpu: Factor out memset(xstate, 0) in fpu_finit() paths
fx_finit() has two users but only fpu_finit() needs to clear
xstate, alloc_bootmem_align() in setup_init_fpu_buf() returns
zero-filled memory.

And note that both memset()'s look confusing. Yes, offsetof() is
0 for ->fxsave or ->fsave, but it would be cleaner to turn
them into a single memset() which zeroes fpu->state.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425967585-4725-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/20150302183257.GC23085@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-10 07:14:31 +01:00
Greg Kroah-Hartman
e94f16a4fd Merge 4.0-rc3 into char-misc-next
We want the mei fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-09 08:44:23 +01:00
Greg Kroah-Hartman
becba85f0e Merge 4.0-rc3 into tty-testing
This resolves a merge issue in drivers/tty/serial/8250/8250_pci.c

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-09 07:08:37 +01:00
Andy Lutomirski
a7fcf28d43 x86/asm/entry: Replace this_cpu_sp0() with current_top_of_stack() and fix it on x86_32
I broke 32-bit kernels.  The implementation of sp0 was correct
as far as I can tell, but sp0 was much weirder on x86_32 than I
realized.  It has the following issues:

 - Init's sp0 is inconsistent with everything else's: non-init tasks
   are offset by 8 bytes.  (I have no idea why, and the comment is unhelpful.)

 - vm86 does crazy things to sp0.

Fix it up by replacing this_cpu_sp0() with
current_top_of_stack() and using a new percpu variable to track
the top of the stack on x86_32.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 75182b1632 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()")
Link: http://lkml.kernel.org/r/d09dbe270883433776e0cbee3c7079433349e96d.1425692936.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-07 09:34:03 +01:00
Andy Shevchenko
1bd187de53 x86, intel-mid: remove Intel MID specific serial support
Since we have a native 8250 driver carrying the Intel MID serial devices the
specific support is not needed anymore. This patch removes it for Intel MID.

Note that the console device name is changed from ttyMFDx to ttySx.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:25:18 +01:00
Andy Lutomirski
d0a0de21f8 x86/asm/entry: Remove INIT_TSS and fold the definitions into 'cpu_tss'
The INIT_TSS is unnecessary.  Just define the initial TSS where
'cpu_tss' is defined.

While we're at it, merge the 32-bit and 64-bit definitions.  The
only syntactic change is that 32-bit kernels were computing sp0
as long, but now they compute it as unsigned long.

Verified by objdump: the contents and relocations of
.data..percpu..shared_aligned are unchanged on 32-bit and 64-bit
kernels.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8fc39fa3f6c5d635e93afbdd1a0fe0678a6d7913.1425611534.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-06 08:32:58 +01:00
Andy Lutomirski
24933b82c0 x86/asm/entry: Rename 'init_tss' to 'cpu_tss'
It has nothing to do with init -- there's only one TSS per cpu.

Other names considered include:

 - current_tss: Confusing because we never switch the tss.
 - singleton_tss: Too long.

This patch was generated with 's/init_tss/cpu_tss/g'.  Followup
patches will fix INIT_TSS and INIT_TSS_IST by hand.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/da29fb2a793e4f649d93ce2d1ed320ebe8516262.1425611534.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-06 08:32:58 +01:00
Andy Lutomirski
75182b1632 x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()
This will make modifying the semantics of kernel_stack easier.

The change to ist_begin_non_atomic() is necessary because sp0 no
longer points to the same THREAD_SIZE-aligned region as RSP;
it's one byte too high for that.  At Denys' suggestion, rather
than offsetting it, just check explicitly that we're in the
correct range ending at sp0.  This has the added benefit that we
no longer assume that the thread stack is aligned to
THREAD_SIZE.

Suggested-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ef8254ad414cbb8034c9a56396eeb24f5dd5b0de.1425611534.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-06 08:32:57 +01:00
Andy Lutomirski
8ef46a672a x86/asm/entry: Add this_cpu_sp0() to read sp0 for the current cpu
We currently store references to the top of the kernel stack in
multiple places: kernel_stack (with an offset) and
init_tss.x86_tss.sp0 (no offset).  The latter is defined by
hardware and is a clean canonical way to find the top of the
stack.  Add an accessor so we can start using it.

This needs minor paravirt tweaks.  On native, sp0 defines the
top of the kernel stack and is therefore always correct.  On Xen
and lguest, the hypervisor tracks the top of the stack, but we
want to start reading sp0 in the kernel.  Fixing this is simple:
just update our local copy of sp0 as well as the hypervisor's
copy on task switches.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8d675581859712bee09a055ed8f785d80dac1eca.1425611534.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-06 08:32:57 +01:00
Quentin Casasnovas
06c8173eb9 x86/fpu/xsaves: Fix improper uses of __ex_table
Commit:

  f31a9f7c71 ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area")

introduced alternative instructions for XSAVES/XRSTORS and commit:

  adb9d526e9 ("x86/xsaves: Add xsaves and xrstors support for booting time")

added support for the XSAVES/XRSTORS instructions at boot time.

Unfortunately both failed to properly protect them against faulting:

The 'xstate_fault' macro will use the closest label named '1'
backward and that ends up in the .altinstr_replacement section
rather than in .text. This means that the kernel will never find
in the __ex_table the .text address where this instruction might
fault, leading to serious problems if userspace manages to
trigger the fault.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Jamie Iles <jamie.iles@oracle.com>
[ Improved the changelog, fixed some whitespace noise. ]
Acked-by: Borislav Petkov <bp@alien8.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Cc: Allan Xavier <mr.a.xavier@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: adb9d526e9 ("x86/xsaves: Add xsaves and xrstors support for booting time")
Fixes: f31a9f7c71 ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-05 18:20:36 +01:00
Wang Nan
5eca7453d6 x86/traps: Separate set_intr_gate() and clean up early_trap_init()
As early_trap_init() doesn't use IST, replace
set_intr_gate_ist() and set_system_intr_gate_ist() with their
standard counterparts.

set_intr_gate() requires a trace_debug symbol which we don't
have and won't use. This patch separates set_intr_gate() into two
parts, and uses base version in early_trap_init().

Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: <dave.hansen@linux.intel.com>
Cc: <lizefan@huawei.com>
Cc: <masami.hiramatsu.pt@hitachi.com>
Cc: <oleg@redhat.com>
Cc: <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425010789-13714-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-05 00:47:29 +01:00
Denys Vlasenko
d441c1f2b7 x86/asm/entry/64: Simplify optimistic SYSRET
Avoid redundant load of %r11 (it is already loaded a few
instructions before).

Also simplify %rsp restoration, instead of two steps:

         add $0x80, %rsp
         mov 0x18(%rsp), %rsp

we can do a simplified single step to restore user-space RSP:

         mov 0x98(%rsp), %rsp

and get the same result.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
[ Clarified the changelog. ]
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1aef69b346a6db0d99cdfb0f5ba83e8c985e27d7.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:52 +01:00
Denys Vlasenko
911d2bb5cc x86/asm/entry/64: Use more readable constants
Constants such as SS+8 or SS+8-RIP are mysterious.
In most cases, SS+8 is just meant to be SIZEOF_PTREGS,
SS+8-RIP is RIP's offset in the iret frame.

This patch changes some of these constants to be less
mysterious.

No code changes (verified with objdump).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1d20491384773bd606e23a382fac23ddb49b5178.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:52 +01:00
Denys Vlasenko
f2db9382c1 x86/asm/entry: Do mass removal of 'ARGOFFSET'
ARGOFFSET is zero now, removing it changes no code.

A few macros lost "offset" parameter, since it is always zero
now too.

No code changes - verified with objdump.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/8689f937622d9d2db0ab8be82331fa15e4ed4713.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:50 +01:00
Denys Vlasenko
e90e147cbc x86/asm/entry/64: Fix comments
- Misleading and slightly incorrect comments in "struct pt_regs" are
   fixed (four instances).

 - Fix incorrect comment atop EMPTY_FRAME macro.

 - Explain in more detail what we do with stack layout during hw interrupt.

 - Correct comments about "partial stack frame" which are no longer
   true.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1423778052-21038-3-git-send-email-dvlasenk@redhat.com
Link: http://lkml.kernel.org/r/e1f4429c491fe6ceeddb879dea2786e0f8920f9c.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:49 +01:00
Denys Vlasenko
76f5df43ca x86/asm/entry/64: Always allocate a complete "struct pt_regs" on the kernel stack
The 64-bit entry code was using six stack slots less by not
saving/restoring registers which are callee-preserved according
to the C ABI, and was not allocating space for them.

Only when syscalls needed a complete "struct pt_regs" was
the complete area allocated and filled in.

As an additional twist, on interrupt entry a "slightly less
truncated pt_regs" trick is used, to make nested interrupt
stacks easier to unwind.

This proved to be a source of significant obfuscation and subtle
bugs. For example, 'stub_fork' had to pop the return address,
extend the struct, save registers, and push return address back.
Ugly. 'ia32_ptregs_common' pops return address and "returns" via
jmp insn, throwing a wrench into CPU return stack cache.

This patch changes the code to always allocate a complete
"struct pt_regs" on the kernel stack. The saving of registers
is still done lazily.

"Partial pt_regs" trick on interrupt stack is retained.

Macros which manipulate "struct pt_regs" on stack are reworked:

 - ALLOC_PT_GPREGS_ON_STACK allocates the structure.

 - SAVE_C_REGS saves to it those registers which are clobbered
   by C code.

 - SAVE_EXTRA_REGS saves to it all other registers.

 - Corresponding RESTORE_* and REMOVE_PT_GPREGS_FROM_STACK macros
   reverse it.

'ia32_ptregs_common', 'stub_fork' and friends lost their ugly dance
with the return pointer.

LOAD_ARGS32 in ia32entry.S now uses symbolic stack offsets
instead of magic numbers.

'error_entry' and 'save_paranoid' now use SAVE_C_REGS +
SAVE_EXTRA_REGS instead of having it open-coded yet again.

Patch was run-tested: 64-bit executables, 32-bit executables,
strace works.

Timing tests did not show measurable difference in 32-bit
and 64-bit syscalls.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1423778052-21038-2-git-send-email-dvlasenk@redhat.com
Link: http://lkml.kernel.org/r/b89763d354aa23e670b9bdf3a40ae320320a7c2e.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:49 +01:00
Denys Vlasenko
49db46a67b x86/asm: Introduce push/pop macros which generate CFI_REL_OFFSET and CFI_RESTORE
Sequences:

        pushl_cfi %reg
        CFI_REL_OFFSET reg, 0

and:

        popl_cfi %reg
        CFI_RESTORE reg

happen quite often. This patch adds macros which generate them.

No assembly changes (verified with objdump -dr vmlinux.o).

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1421017655-25561-1-git-send-email-dvlasenk@redhat.com
Link: http://lkml.kernel.org/r/2202eb90f175cf45d1b2d1c64dbb5676a8ad07ad.1424989793.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 22:50:49 +01:00
Ingo Molnar
f8e92fb4b0 A more involved rework of the alternatives framework to be able to
pad instructions and thus make using the alternatives macros more
 straightforward and without having to figure out old and new instruction
 sizes but have the toolchain figure that out for us.
 
 Furthermore, it optimizes JMPs used so that fetch and decode can be
 relieved with smaller versions of the JMPs, where possible.
 
 Some stats:
 
 x86_64 defconfig:
 
 Alternatives sites total:               2478
 Total padding added (in Bytes):         6051
 
 The padding is currently done for:
 
 X86_FEATURE_ALWAYS
 X86_FEATURE_ERMS
 X86_FEATURE_LFENCE_RDTSC
 X86_FEATURE_MFENCE_RDTSC
 X86_FEATURE_SMAP
 
 This is with the latest version of the patchset. Of course, on each
 machine the alternatives sites actually being patched are a proper
 subset of the total number.
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Merge tag 'alternatives_padding' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/asm

Pull alternative instructions framework improvements from Borislav Petkov:

 "A more involved rework of the alternatives framework to be able to
  pad instructions and thus make using the alternatives macros more
  straightforward and without having to figure out old and new instruction
  sizes but have the toolchain figure that out for us.

  Furthermore, it optimizes JMPs used so that fetch and decode can be
  relieved with smaller versions of the JMPs, where possible.

  Some stats:

    x86_64 defconfig:

    Alternatives sites total:               2478
    Total padding added (in Bytes):         6051

  The padding is currently done for:

    X86_FEATURE_ALWAYS
    X86_FEATURE_ERMS
    X86_FEATURE_LFENCE_RDTSC
    X86_FEATURE_MFENCE_RDTSC
    X86_FEATURE_SMAP

  This is with the latest version of the patchset. Of course, on each
  machine the alternatives sites actually being patched are a proper
  subset of the total number."

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 06:36:15 +01:00
Ingo Molnar
d2c032e3dc Linux 4.0-rc2
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Merge tag 'v4.0-rc2' into x86/asm, to refresh the tree

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-04 06:35:43 +01:00
Borislav Petkov
e3d8f67476 x86/microcode/intel: Move mc arg last in get_matching_{microcode|sig}
... arguments list so that it comes more natural for those functions to
have the signature, processor flags and revision together, before the
rest of the args.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
2015-03-02 20:32:13 +01:00
Borislav Petkov
58ce8d6d3a x86/microcode: Consolidate family,model, ... code
... to the header. Split the family acquiring function into a
main one, doing CPUID and a helper which computes the extended
family and is used in multiple places. Get rid of the locally-grown
get_x86_{family,model}().

While at it, rename local variables to something more descriptive and
vertically align assignments for better readability.

There should be no functionality change resulting from this patch.

Signed-off-by: Borislav Petkov <bp@suse.de>
2015-03-02 20:32:07 +01:00
Borislav Petkov
4f5e5f2b57 x86/microcode/intel: Rename update_match_revision()
... to revision_is_newer() and push it up into the header and make it an
inline function.

Signed-off-by: Borislav Petkov <bp@suse.de>
2015-03-02 20:32:03 +01:00
Dexuan Cui
89f9f6796d hv: vmbus_post_msg: retry the hypercall on some transient errors
I got HV_STATUS_INVALID_CONNECTION_ID on Hyper-V 2008 R2 when keeping running
"rmmod hv_netvsc; modprobe hv_netvsc; rmmod hv_utils; modprobe hv_utils"
in a Linux guest. Looks the host has some kind of throttling mechanism if
some kinds of hypercalls are sent too frequently.
Without the patch, the driver can occasionally fail to load.

Also let's retry HV_STATUS_INSUFFICIENT_MEMORY, though we didn't get it
before.

Removed 'case -ENOMEM', since the hypervisor doesn't return this.

CC: "K. Y. Srinivasan" <kys@microsoft.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-01 19:30:07 -08:00
Peter P Waskiewicz Jr
cbc82b1726 x86: Add support for Intel Cache QoS Monitoring (CQM) detection
This patch adds support for the new Cache QoS Monitoring (CQM)
feature found in future Intel Xeon processors.  It includes the
new values to track CQM resources to the cpuinfo_x86 structure,
plus the CPUID detection routines for CQM.

CQM allows a process, or set of processes, to be tracked by the CPU
to determine the cache usage of that task group.  Using this data
from the CPU, software can be written to extract this data and
report cache usage and occupancy for a particular process, or
group of processes.

More information about Cache QoS Monitoring can be found in the
Intel (R) x86 Architecture Software Developer Manual, section 17.14.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Chris Webb <chris@arachsys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jacob Shin <jacob.w.shin@gmail.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Honeyman <stevenhoneyman@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-25 13:53:31 +01:00
Borislav Petkov
a930dc4543 x86/asm: Cleanup prefetch primitives
This is based on a patch originally by hpa.

With the current improvements to the alternatives, we can simply use %P1
as a mem8 operand constraint and rely on the toolchain to generate the
proper instruction sizes. For example, on 32-bit, where we use an empty
old instruction we get:

  apply_alternatives: feat: 6*32+8, old: (c104648b, len: 4), repl: (c195566c, len: 4)
  c104648b: alt_insn: 90 90 90 90
  c195566c: rpl_insn: 0f 0d 4b 5c

  ...

  apply_alternatives: feat: 6*32+8, old: (c18e09b4, len: 3), repl: (c1955948, len: 3)
  c18e09b4: alt_insn: 90 90 90
  c1955948: rpl_insn: 0f 0d 08

  ...

  apply_alternatives: feat: 6*32+8, old: (c1190cf9, len: 7), repl: (c1955a79, len: 7)
  c1190cf9: alt_insn: 90 90 90 90 90 90 90
  c1955a79: rpl_insn: 0f 0d 0d a0 d4 85 c1

all with the proper padding done depending on the size of the
replacement instruction the compiler generates.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
2015-02-23 13:44:17 +01:00
Borislav Petkov
c70e1b475f x86/asm: Use alternative_2() in rdtsc_barrier()
... now that we have it.

Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Borislav Petkov <bp@suse.de>
2015-02-23 13:44:17 +01:00
Borislav Petkov
669f8a9001 x86/smap: Use ALTERNATIVE macro
... and drop unfolded version. No need for ASM_NOP3 anymore either as
the alternatives do the proper padding at build time and insert proper
NOPs at boot time.

There should be no apparent operational change from this patch.

Signed-off-by: Borislav Petkov <bp@suse.de>
2015-02-23 13:44:14 +01:00