Commit Graph

7296 Commits

Author SHA1 Message Date
Rodrigo Vivi
176d5325d1 Merge airlied/drm-next into drm-intel-next-queued
Catchup with upstream.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
2017-11-14 07:43:00 -08:00
Hans de Goede
af0ab55ffe x86/platform/intel/iosf_mbi: Add unlocked PMIC bus access notifier unregister
For race free unregistration drivers may need to acquire PMIC bus access
through iosf_mbi_punit_acquire() and then (un)register the notifier without
dropping the lock.

This commit adds an unlocked variant of
iosf_mbi_unregister_pmic_bus_access_notifier for this use case.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171019111620.26761-2-hdegoede@redhat.com
2017-11-10 13:14:02 +01:00
Ingo Molnar
90edaac627 Revert "x86/mm: Limit mmap() of /dev/mem to valid physical addresses"
This reverts commit ce56a86e2a.

There's unanticipated interaction with some boot parameters like 'mem=',
which now cause the new checks via valid_mmap_phys_addr_range() to be too
restrictive, crashing a Qemu bootup in fact, as reported by Fengguang Wu.

So while the motivation of the change is still entirely valid, we
need a few more rounds of testing to get it right - it's way too late
after -rc6, so revert it for now.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Craig Bergstrom <craigb@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dsafonov@virtuozzo.com
Cc: kirill.shutemov@linux.intel.com
Cc: mhocko@suse.com
Cc: oleg@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 10:06:49 +02:00
Craig Bergstrom
ce56a86e2a x86/mm: Limit mmap() of /dev/mem to valid physical addresses
Currently, it is possible to mmap() any offset from /dev/mem.  If a
program mmaps() /dev/mem offsets outside of the addressable limits
of a system, the page table can be corrupted by setting reserved bits.

For example if you mmap() offset 0x0001000000000000 of /dev/mem on an
x86_64 system with a 48-bit bus, the page fault handler will be called
with error_code set to RSVD.  The kernel then crashes with a page table
corruption error.

This change prevents this page table corruption on x86 by refusing
to mmap offsets higher than the highest valid address in the system.

Signed-off-by: Craig Bergstrom <craigb@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: dsafonov@virtuozzo.com
Cc: kirill.shutemov@linux.intel.com
Cc: mhocko@suse.com
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/20171019192856.39672-1-craigb@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20 09:48:00 +02:00
Andy Lutomirski
7ac7f2c315 x86/mm: Remove debug/x86/tlb_defer_switch_to_init_mm
Borislav thinks that we don't need this knob in a released kernel.
Get rid of it.

Requested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: b956575bed ("x86/mm: Flush more aggressively in lazy TLB mode")
Link: http://lkml.kernel.org/r/1fa72431924e81e86c164ff7881bf9240d1f1a6c.1508000261.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-18 15:25:02 +02:00
Andy Lutomirski
4e57b94664 x86/mm: Tidy up "x86/mm: Flush more aggressively in lazy TLB mode"
Due to timezones, commit:

  b956575bed ("x86/mm: Flush more aggressively in lazy TLB mode")

was an outdated patch that well tested and fixed the bug but didn't
address Borislav's review comments.

Tidy it up:

 - The name "tlb_use_lazy_mode()" was highly confusing.  Change it to
   "tlb_defer_switch_to_init_mm()", which describes what it actually
   means.

 - Move the static_branch crap into a helper.

 - Improve comments.

Actually removing the debugfs option is in the next patch.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: b956575bed ("x86/mm: Flush more aggressively in lazy TLB mode")
Link: http://lkml.kernel.org/r/154ef95428d4592596b6e98b0af1d2747d6cfbf8.1508000261.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-18 15:25:02 +02:00
Linus Torvalds
e7a36a6ec9 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "A landry list of fixes:

   - fix reboot breakage on some PCID-enabled system

   - fix crashes/hangs on some PCID-enabled systems

   - fix microcode loading on certain older CPUs

   - various unwinder fixes

   - extend an APIC quirk to more hardware systems and disable APIC
     related warning on virtualized systems

   - various Hyper-V fixes

   - a macro definition robustness fix

   - remove jprobes IRQ disabling

   - various mem-encryption fixes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode: Do the family check first
  x86/mm: Flush more aggressively in lazy TLB mode
  x86/apic: Update TSC_DEADLINE quirk with additional SKX stepping
  x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors
  x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
  x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing
  x86/hyperv: Don't use percpu areas for pcpu_flush/pcpu_flush_ex structures
  x86/hyperv: Clear vCPU banks between calls to avoid flushing unneeded vCPUs
  x86/unwind: Disable unwinder warnings on 32-bit
  x86/unwind: Align stack pointer in unwinder dump
  x86/unwind: Use MSB for frame pointer encoding on 32-bit
  x86/unwind: Fix dereference of untrusted pointer
  x86/alternatives: Fix alt_max_short macro to really be a max()
  x86/mm/64: Fix reboot interaction with CR4.PCIDE
  kprobes/x86: Remove IRQ disabling from jprobe handlers
  kprobes/x86: Set up frame pointer in kprobe trampoline
2017-10-14 15:26:38 -04:00
Linus Torvalds
7b764cedcb Merge branch 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS fixes from Ingo Molnar:
 "A boot parameter fix, plus a header export fix"

* 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Hide mca_cfg
  RAS/CEC: Use the right length for "cec_disable"
2017-10-14 15:19:11 -04:00
Andy Lutomirski
b956575bed x86/mm: Flush more aggressively in lazy TLB mode
Since commit:

  94b1b03b51 ("x86/mm: Rework lazy TLB mode and TLB freshness tracking")

x86's lazy TLB mode has been all the way lazy: when running a kernel thread
(including the idle thread), the kernel keeps using the last user mm's
page tables without attempting to maintain user TLB coherence at all.

From a pure semantic perspective, this is fine -- kernel threads won't
attempt to access user pages, so having stale TLB entries doesn't matter.

Unfortunately, I forgot about a subtlety.  By skipping TLB flushes,
we also allow any paging-structure caches that may exist on the CPU
to become incoherent.  This means that we can have a
paging-structure cache entry that references a freed page table, and
the CPU is within its rights to do a speculative page walk starting
at the freed page table.

I can imagine this causing two different problems:

 - A speculative page walk starting from a bogus page table could read
   IO addresses.  I haven't seen any reports of this causing problems.

 - A speculative page walk that involves a bogus page table can install
   garbage in the TLB.  Such garbage would always be at a user VA, but
   some AMD CPUs have logic that triggers a machine check when it notices
   these bogus entries.  I've seen a couple reports of this.

Boris further explains the failure mode:

> It is actually more of an optimization which assumes that paging-structure
> entries are in WB DRAM:
>
> "TlbCacheDis: cacheable memory disable. Read-write. 0=Enables
> performance optimization that assumes PML4, PDP, PDE, and PTE entries
> are in cacheable WB-DRAM; memory type checks may be bypassed, and
> addresses outside of WB-DRAM may result in undefined behavior or NB
> protocol errors. 1=Disables performance optimization and allows PML4,
> PDP, PDE and PTE entries to be in any memory type. Operating systems
> that maintain page tables in memory types other than WB- DRAM must set
> TlbCacheDis to insure proper operation."
>
> The MCE generated is an NB protocol error to signal that
>
> "Link: A specific coherent-only packet from a CPU was issued to an
> IO link. This may be caused by software which addresses page table
> structures in a memory type other than cacheable WB-DRAM without
> properly configuring MSRC001_0015[TlbCacheDis]. This may occur, for
> example, when page table structure addresses are above top of memory. In
> such cases, the NB will generate an MCE if it sees a mismatch between
> the memory operation generated by the core and the link type."
>
> I'm assuming coherent-only packets don't go out on IO links, thus the
> error.

To fix this, reinstate TLB coherence in lazy mode.  With this patch
applied, we do it in one of two ways:

 - If we have PCID, we simply switch back to init_mm's page tables
   when we enter a kernel thread -- this seems to be quite cheap
   except for the cost of serializing the CPU.

 - If we don't have PCID, then we set a flag and switch to init_mm
   the first time we would otherwise need to flush the TLB.

The /sys/kernel/debug/x86/tlb_use_lazy_mode debug switch can be changed
to override the default mode for benchmarking.

In theory, we could optimize this better by only flushing the TLB in
lazy CPUs when a page table is freed.  Doing that would require
auditing the mm code to make sure that all page table freeing goes
through tlb_remove_page() as well as reworking some data structures
to implement the improved flush logic.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Reported-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Johannes Hirte <johannes.hirte@datenkhaos.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 94b1b03b51 ("x86/mm: Rework lazy TLB mode and TLB freshness tracking")
Link: http://lkml.kernel.org/r/20171009170231.fkpraqokz6e4zeco@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-14 09:21:24 +02:00
Vitaly Kuznetsov
a3b7424392 x86/hyperv: Clear vCPU banks between calls to avoid flushing unneeded vCPUs
hv_flush_pcpu_ex structures are not cleared between calls for performance
reasons (they're variable size up to PAGE_SIZE each) but we must clear
hv_vp_set.bank_contents part of it to avoid flushing unneeded vCPUs. The
rest of the structure is formed correctly.

To do the clearing in an efficient way stash the maximum possible vCPU
number (this may differ from Linux CPU id).

Reported-by: Jork Loeser <Jork.Loeser@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20171006154854.18092-1-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-10 12:53:00 +02:00
Mathias Krause
6b32c126d3 x86/alternatives: Fix alt_max_short macro to really be a max()
The alt_max_short() macro in asm/alternative.h does not work as
intended, leading to nasty bugs. E.g. alt_max_short("1", "3")
evaluates to 3, but alt_max_short("3", "1") evaluates to 1 -- not
exactly the maximum of 1 and 3.

In fact, I had to learn it the hard way by crashing my kernel in not
so funny ways by attempting to make use of the ALTENATIVE_2 macro
with alternatives where the first one was larger than the second
one.

According to [1] and commit dbe4058a6a ("x86/alternatives: Fix
ALTERNATIVE_2 padding generation properly") the right handed side
should read "-(-(a < b))" not "-(-(a - b))". Fix that, to make the
macro work as intended.

While at it, fix up the comments regarding the additional "-", too.
It's not about gas' usage of s32 but brain dead logic of having a
"true" value of -1 for the < operator ... *sigh*

Btw., the one in asm/alternative-asm.h is correct. And, apparently,
all current users of ALTERNATIVE_2() pass same sized alternatives,
avoiding to hit the bug.

[1] http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax

Reviewed-and-tested-by: Borislav Petkov <bp@suse.de>
Fixes: dbe4058a6a ("x86/alternatives: Fix ALTERNATIVE_2 padding generation properly")
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1507228213-13095-1-git-send-email-minipli@googlemail.com
2017-10-09 13:35:17 +02:00
Borislav Petkov
262e681183 x86/mce: Hide mca_cfg
Now that lguest is gone, put it in the internal header which should be
used only by MCA/RAS code.

Add missing header guards while at it.

No functional change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20171002092836.22971-3-bp@alien8.de
2017-10-05 14:23:06 +02:00
Boqun Feng
a2b7861bb3 kvm/x86: Avoid async PF preempting the kernel incorrectly
Currently, in PREEMPT_COUNT=n kernel, kvm_async_pf_task_wait() could call
schedule() to reschedule in some cases.  This could result in
accidentally ending the current RCU read-side critical section early,
causing random memory corruption in the guest, or otherwise preempting
the currently running task inside between preempt_disable and
preempt_enable.

The difficulty to handle this well is because we don't know whether an
async PF delivered in a preemptible section or RCU read-side critical section
for PREEMPT_COUNT=n, since preempt_disable()/enable() and rcu_read_lock/unlock()
are both no-ops in that case.

To cure this, we treat any async PF interrupting a kernel context as one
that cannot be preempted, preventing kvm_async_pf_task_wait() from choosing
the schedule() path in that case.

To do so, a second parameter for kvm_async_pf_task_wait() is introduced,
so that we know whether it's called from a context interrupting the
kernel, and the parameter is set properly in all the callsites.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-10-04 18:28:53 +02:00
Linus Torvalds
368f89984b Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
 "This contains the following fixes and improvements:

   - Avoid dereferencing an unprotected VMA pointer in the fault signal
     generation code

   - Fix inline asm call constraints for GCC 4.4

   - Use existing register variable to retrieve the stack pointer
     instead of forcing the compiler to create another indirect access
     which results in excessive extra 'mov %rsp, %<dst>' instructions

   - Disable branch profiling for the memory encryption code to prevent
     an early boot crash

   - Fix a sparse warning caused by casting the __user annotation in
     __get_user_asm_u64() away

   - Fix an off by one error in the loop termination of the error patch
     in the x86 sysfs init code

   - Add missing CPU IDs to various Intel specific drivers to enable the
     functionality on recent hardware

   - More (init) constification in the numachip code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/asm: Use register variable to get stack pointer value
  x86/mm: Disable branch profiling in mem_encrypt.c
  x86/asm: Fix inline asm call constraints for GCC 4.4
  perf/x86/intel/uncore: Correct num_boxes for IIO and IRP
  perf/x86/intel/rapl: Add missing CPU IDs
  perf/x86/msr: Add missing CPU IDs
  perf/x86/intel/cstate: Add missing CPU IDs
  x86: Don't cast away the __user in __get_user_asm_u64()
  x86/sysfs: Fix off-by-one error in loop termination
  x86/mm: Fix fault error path using unsafe vma pointer
  x86/numachip: Add const and __initconst to numachip2_clockevent
2017-10-01 13:55:32 -07:00
Linus Torvalds
9f2a5128b9 xen: fixes for 4.14-rc3
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Merge tag 'for-linus-4.14c-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - avoid a warning when compiling with clang

 - consider read-only bits in xen-pciback when writing to a BAR

 - fix a boot crash of pv-domains

* tag 'for-linus-4.14c-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/mmu: Call xen_cleanhighmap() with 4MB aligned for page tables mapping
  xen-pciback: relax BAR sizing write value check
  x86/xen: clean up clang build warning
2017-09-29 12:24:28 -07:00
Andrey Ryabinin
196bd485ee x86/asm: Use register variable to get stack pointer value
Currently we use current_stack_pointer() function to get the value
of the stack pointer register. Since commit:

  f5caf621ee ("x86/asm: Fix inline asm call constraints for Clang")

... we have a stack register variable declared. It can be used instead of
current_stack_pointer() function which allows to optimize away some
excessive "mov %rsp, %<dst>" instructions:

 -mov    %rsp,%rdx
 -sub    %rdx,%rax
 -cmp    $0x3fff,%rax
 -ja     ffffffff810722fd <ist_begin_non_atomic+0x2d>

 +sub    %rsp,%rax
 +cmp    $0x3fff,%rax
 +ja     ffffffff810722fa <ist_begin_non_atomic+0x2a>

Remove current_stack_pointer(), rename __asm_call_sp to current_stack_pointer
and use it instead of the removed function.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170929141537.29167-1-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-29 19:39:44 +02:00
Josh Poimboeuf
520a13c530 x86/asm: Fix inline asm call constraints for GCC 4.4
The kernel test bot (run by Xiaolong Ye) reported that the following commit:

  f5caf621ee ("x86/asm: Fix inline asm call constraints for Clang")

is causing double faults in a kernel compiled with GCC 4.4.

Linus subsequently diagnosed the crash pattern and the buggy commit and found that
the issue is with this code:

  register unsigned int __asm_call_sp asm("esp");
  #define ASM_CALL_CONSTRAINT "+r" (__asm_call_sp)

Even on a 64-bit kernel, it's using ESP instead of RSP.  That causes GCC
to produce the following bogus code:

  ffffffff8147461d:       89 e0                   mov    %esp,%eax
  ffffffff8147461f:       4c 89 f7                mov    %r14,%rdi
  ffffffff81474622:       4c 89 fe                mov    %r15,%rsi
  ffffffff81474625:       ba 20 00 00 00          mov    $0x20,%edx
  ffffffff8147462a:       89 c4                   mov    %eax,%esp
  ffffffff8147462c:       e8 bf 52 05 00          callq  ffffffff814c98f0 <copy_user_generic_unrolled>

Despite the absurdity of it backing up and restoring the stack pointer
for no reason, the bug is actually the fact that it's only backing up
and restoring the lower 32 bits of the stack pointer.  The upper 32 bits
are getting cleared out, corrupting the stack pointer.

So change the '__asm_call_sp' register variable to be associated with
the actual full-size stack pointer.

This also requires changing the __ASM_SEL() macro to be based on the
actual compiled arch size, rather than the CONFIG value, because
CONFIG_X86_64 compiles some files with '-m32' (e.g., realmode and vdso).
Otherwise Clang fails to build the kernel because it complains about the
use of a 64-bit register (RSP) in a 32-bit file.

Reported-and-Bisected-and-Tested-by: kernel test robot <xiaolong.ye@intel.com>
Diagnosed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: LKP <lkp@01.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f5caf621ee ("x86/asm: Fix inline asm call constraints for Clang")
Link: http://lkml.kernel.org/r/20170928215826.6sdpmwtkiydiytim@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-29 13:15:44 +02:00
Ingo Molnar
8474c532b5 Merge branch 'WIP.x86/fpu' into x86/fpu, because it's ready
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 10:17:43 +02:00
Eric Biggers
e63e5d5c15 x86/fpu: Introduce validate_xstate_header()
Move validation of user-supplied xstate_header into a helper function,
in preparation of calling it from both the ptrace and sigreturn syscall
paths.

The new function also considers it to be an error if *any* reserved bits
are set, whereas before we were just clearing most of them silently.

This should reduce the chance of bugs that fail to correctly validate
user-supplied XSAVE areas.  It also will expose any broken userspace
programs that set the other reserved bits; this is desirable because
such programs will lose compatibility with future CPUs and kernels if
those bits are ever used for anything.  (There shouldn't be any such
programs, and in fact in the case where the compacted format is in use
we were already validating xfeatures.  But you never know...)

Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20170924105913.9157-2-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 09:43:45 +02:00
Ingo Molnar
369a036de2 x86/fpu: Rename fpu__activate_fpstate_read/write() to fpu__prepare_[read|write]()
As per the new nomenclature we don't 'activate' the FPU state
anymore, we initialize it. So drop the _activate_fpstate name
from these functions, which were a bit of a mouthful anyway,
and name them:

	fpu__prepare_read()
	fpu__prepare_write()

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 09:43:44 +02:00
Ingo Molnar
2ce03d850b x86/fpu: Rename fpu__activate_curr() to fpu__initialize()
Rename this function to better express that it's all about
initializing the FPU state of a task which goes hand in hand
with the fpu::initialized field.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-33-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 09:43:44 +02:00
Ingo Molnar
e4a81bfcaa x86/fpu: Rename fpu::fpstate_active to fpu::initialized
The x86 FPU code used to have a complex state machine where both the FPU
registers and the FPU state context could be 'active' (or inactive)
independently of each other - which enabled features like lazy FPU restore.

Much of this complexity is gone in the current code: now we basically can
have FPU-less tasks (kernel threads) that don't use (and save/restore) FPU
state at all, plus full FPU users that save/restore directly with no laziness
whatsoever.

But the fpu::fpstate_active still carries bits of the old complexity - meanwhile
this flag has become a simple flag that shows whether the FPU context saving
area in the thread struct is initialized and used, or not.

Rename it to fpu::initialized to express this simplicity in the name as well.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-30-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 09:43:36 +02:00
Ingo Molnar
685c930d6e x86/fpu: Remove fpu__current_fpstate_write_begin/end()
These functions are not used anymore, so remove them.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-29-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-26 09:42:20 +02:00
Ville Syrjälä
5ac751d9e6 x86: Don't cast away the __user in __get_user_asm_u64()
Don't cast away the __user in __get_user_asm_u64() on x86-32.
Prevents sparse getting upset.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170912164000.13745-1-ville.syrjala@linux.intel.com
2017-09-25 09:36:16 +02:00
Eric Biggers
d5c8028b47 x86/fpu: Reinitialize FPU registers if restoring FPU state fails
Userspace can change the FPU state of a task using the ptrace() or
rt_sigreturn() system calls.  Because reserved bits in the FPU state can
cause the XRSTOR instruction to fail, the kernel has to carefully
validate that no reserved bits or other invalid values are being set.

Unfortunately, there have been bugs in this validation code.  For
example, we were not checking that the 'xcomp_bv' field in the
xstate_header was 0.  As-is, such bugs are exploitable to read the FPU
registers of other processes on the system.  To do so, an attacker can
create a task, assign to it an invalid FPU state, then spin in a loop
and monitor the values of the FPU registers.  Because the task's FPU
registers are not being restored, sometimes the FPU registers will have
the values from another process.

This is likely to continue to be a problem in the future because the
validation done by the CPU instructions like XRSTOR is not immediately
visible to kernel developers.  Nor will invalid FPU states ever be
encountered during ordinary use --- they will only be seen during
fuzzing or exploits.  There can even be reserved bits outside the
xstate_header which are easy to forget about.  For example, the MXCSR
register contains reserved bits, which were not validated by the
KVM_SET_XSAVE ioctl until commit a575813bfe ("KVM: x86: Fix load
damaged SSEx MXCSR register").

Therefore, mitigate this class of vulnerability by restoring the FPU
registers from init_fpstate if restoring from the task's state fails.

We actually used to do this, but it was (perhaps unwisely) removed by
commit 9ccc27a5d2 ("x86/fpu: Remove error return values from
copy_kernel_to_*regs() functions").  This new patch is also a bit
different.  First, it only clears the registers, not also the bad
in-memory state; this is simpler and makes it easier to make the
mitigation cover all callers of __copy_kernel_to_fpregs().  Second, it
does the register clearing in an exception handler so that no extra
instructions are added to context switches.  In fact, we *remove*
instructions, since previously we were always zeroing the register
containing 'err' even if CONFIG_X86_DEBUG_FPU was disabled.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20170922174156.16780-4-ebiggers3@gmail.com
Link: http://lkml.kernel.org/r/20170923130016.21448-27-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-25 09:26:38 +02:00
Andi Kleen
03eaec81ac x86/fpu: Turn WARN_ON() in context switch into WARN_ON_FPU()
copy_xregs_to_kernel checks if the alternatives have been already
patched.

This WARN_ON() is always executed in every context switch.

All the other checks in fpu internal.h are WARN_ON_FPU(), but
this one is plain WARN_ON(). I assume it was forgotten to switch it.

So switch it to WARN_ON_FPU() too to avoid some unnecessary code
in the context switch, and a potentially expensive cache line miss for the
global variable.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170329062605.4970-1-andi@firstfloor.org
Link: http://lkml.kernel.org/r/20170923130016.21448-24-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:35 +02:00
Rik van Riel
0852b37417 x86/fpu: Add FPU state copying quirk to handle XRSTOR failure on Intel Skylake CPUs
On Skylake CPUs I noticed that XRSTOR is unable to deal with states
created by copyout_from_xsaves() if the xstate has only SSE/YMM state, and
no FP state. That is, xfeatures had XFEATURE_MASK_SSE set, but not
XFEATURE_MASK_FP.

The reason is that part of the SSE/YMM state lives in the MXCSR and
MXCSR_FLAGS fields of the FP state.

Ensure that whenever we copy SSE or YMM state around, the MXCSR and
MXCSR_FLAGS fields are also copied around.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170210085445.0f1cc708@annuminas.surriel.com
Link: http://lkml.kernel.org/r/20170923130016.21448-22-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:34 +02:00
Ingo Molnar
99dc26bda2 x86/fpu: Remove struct fpu::fpregs_active
The previous changes paved the way for the removal of the
fpu::fpregs_active state flag - we now only have the
fpu::fpstate_active and fpu::last_cpu fields left.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-21-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:34 +02:00
Ingo Molnar
6cf4edbe05 x86/fpu: Decouple fpregs_activate()/fpregs_deactivate() from fpu->fpregs_active
The fpregs_activate()/fpregs_deactivate() are currently called in such a pattern:

	if (!fpu->fpregs_active)
		fpregs_activate(fpu);

	...

	if (fpu->fpregs_active)
		fpregs_deactivate(fpu);

But note that it's actually safe to call them without checking the flag first.

This further decouples the fpu->fpregs_active flag from actual FPU logic.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-20-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:34 +02:00
Ingo Molnar
f1c8cd0176 x86/fpu: Change fpu->fpregs_active users to fpu->fpstate_active
We want to simplify the FPU state machine by eliminating fpu->fpregs_active,
and we can do that because the two state flags (::fpregs_active and
::fpstate_active) are set essentially together.

The old lazy FPU switching code used to make a distinction - but there's
no lazy switching code anymore, we always switch in an 'eager' fashion.

Do this by first changing all substantial uses of fpu->fpregs_active
to fpu->fpstate_active and adding a few debug checks to double check
our assumption is correct.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-19-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:34 +02:00
Ingo Molnar
b3a163081c x86/fpu: Simplify fpu->fpregs_active use
The fpregs_active() inline function is pretty pointless - in almost
all the callsites it can be replaced with a direct fpu->fpregs_active
access.

Do so and eliminate the extra layer of obfuscation.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-16-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:33 +02:00
Ingo Molnar
6d7f7da553 x86/fpu: Flip the parameter order in copy_*_to_xstate()
Make it more consistent with regular memcpy() semantics, where the destination
argument comes first.

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-15-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:33 +02:00
Ingo Molnar
7b9094c688 x86/fpu: Remove 'kbuf' parameter from the copy_user_to_xstate() API
No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-14-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:33 +02:00
Ingo Molnar
59dffa4edb x86/fpu: Remove 'ubuf' parameter from the copy_kernel_to_xstate() API
No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-13-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:33 +02:00
Ingo Molnar
79fecc2b75 x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate()
Similar to:

  x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user()

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-12-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:32 +02:00
Ingo Molnar
56583c9a14 x86/fpu: Clarify parameter names in the copy_xstate_to_*() methods
Right now there's a confusing mixture of 'offset' and 'size' parameters:

 - __copy_xstate_to_*() input parameter 'end_pos' not not really an offset,
   but the full size of the copy to be performed.

 - input parameter 'count' to copy_xstate_to_*() shadows that of
   __copy_xstate_to_*()'s 'count' parameter name - but the roles
   are different: the first one is the total number of bytes to
   be copied, while the second one is a partial copy size.

To unconfuse all this, use a consistent set of parameter names:

 - 'size' is the partial copy size within a single xstate component
 - 'size_total' is the total copy requested
 - 'offset_start' is the requested starting offset.
 - 'offset' is the offset within an xstate component.

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-9-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:32 +02:00
Ingo Molnar
d7eda6c99c x86/fpu: Clean up parameter order in the copy_xstate_to_*() APIs
Parameter ordering is weird:

  int copy_xstate_to_kernel(unsigned int pos, unsigned int count, void *kbuf, struct xregs_state *xsave);
  int copy_xstate_to_user(unsigned int pos, unsigned int count, void __user *ubuf, struct xregs_state *xsave);

'pos' and 'count', which are attributes of the destination buffer, are listed before the destination
buffer itself ...

List them after the primary arguments instead.

This makes the code more similar to regular memcpy() variant APIs.

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-6-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:31 +02:00
Ingo Molnar
a69c158fb3 x86/fpu: Remove 'kbuf' parameter from the copy_xstate_to_user() APIs
The 'kbuf' parameter is unused in the _user() side of the API, remove it.

This simplifies the code and makes it easier to think about.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-5-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:31 +02:00
Ingo Molnar
4d981cf2d9 x86/fpu: Remove 'ubuf' parameter from the copy_xstate_to_kernel() APIs
The 'ubuf' parameter is unused in the _kernel() side of the API, remove it.

This simplifies the code and makes it easier to think about.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-4-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:31 +02:00
Ingo Molnar
f0d4f30a7f x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user()
copy_xstate_to_user() is a weird API - in part due to a bad API inherited
from the regset APIs.

But don't propagate that bad API choice into the FPU code - so as a first
step split the API into kernel and user buffer handling routines.

(Also split the xstate_copyout() internal helper.)

The split API is a dumb duplication that should be obviously correct, the
real splitting will be done in the next patch.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-3-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:30 +02:00
Ingo Molnar
656f083116 x86/fpu: Rename copyin_to_xsaves()/copyout_from_xsaves() to copy_user_to_xstate()/copy_xstate_to_user()
The 'copyin/copyout' nomenclature needlessly departs from what the modern FPU code
uses, which is:

 copy_fpregs_to_fpstate()
 copy_fpstate_to_sigframe()
 copy_fregs_to_user()
 copy_fxregs_to_kernel()
 copy_fxregs_to_user()
 copy_kernel_to_fpregs()
 copy_kernel_to_fregs()
 copy_kernel_to_fxregs()
 copy_kernel_to_xregs()
 copy_user_to_fregs()
 copy_user_to_fxregs()
 copy_user_to_xregs()
 copy_xregs_to_kernel()
 copy_xregs_to_user()

I.e. according to this pattern, the following rename should be done:

  copyin_to_xsaves()    -> copy_user_to_xstate()
  copyout_from_xsaves() -> copy_xstate_to_user()

or, if we want to be pedantic, denote that that the user-space format is ptrace:

  copyin_to_xsaves()    -> copy_user_ptrace_to_xstate()
  copyout_from_xsaves() -> copy_xstate_to_user_ptrace()

But I'd suggest the shorter, non-pedantic name.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-2-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-24 13:04:30 +02:00
Josh Poimboeuf
f5caf621ee x86/asm: Fix inline asm call constraints for Clang
For inline asm statements which have a CALL instruction, we list the
stack pointer as a constraint to convince GCC to ensure the frame
pointer is set up first:

  static inline void foo()
  {
	register void *__sp asm(_ASM_SP);
	asm("call bar" : "+r" (__sp))
  }

Unfortunately, that pattern causes Clang to corrupt the stack pointer.

The fix is easy: convert the stack pointer register variable to a global
variable.

It should be noted that the end result is different based on the GCC
version.  With GCC 6.4, this patch has exactly the same result as
before:

	defconfig	defconfig-nofp	distro		distro-nofp
 before	9820389		9491555		8816046		8516940
 after	9820389		9491555		8816046		8516940

With GCC 7.2, however, GCC's behavior has changed.  It now changes its
behavior based on the conversion of the register variable to a global.
That somehow convinces it to *always* set up the frame pointer before
inserting *any* inline asm.  (Therefore, listing the variable as an
output constraint is a no-op and is no longer necessary.)  It's a bit
overkill, but the performance impact should be negligible.  And in fact,
there's a nice improvement with frame pointers disabled:

	defconfig	defconfig-nofp	distro		distro-nofp
 before	9796316		9468236		9076191		8790305
 after	9796957		9464267		9076381		8785949

So in summary, while listing the stack pointer as an output constraint
is no longer necessary for newer versions of GCC, it's still needed for
older versions.

Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3db862e970c432ae823cf515c52b54fec8270e0e.1505942196.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-23 15:06:20 +02:00
Colin Ian King
51a9a8284e x86/xen: clean up clang build warning
In the case where sizeof(maddr) != sizeof(long) p is initialized and
never read and clang throws a warning on this.  Move declaration of
p to clean up the clang build warning:

warning: Value stored to 'p' during its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-09-21 12:34:03 -04:00
Andy Lutomirski
52a2af400c x86/mm/64: Stop using CR3.PCID == 0 in ASID-aware code
Putting the logical ASID into CR3's PCID bits directly means that we
have two cases to consider separately: ASID == 0 and ASID != 0.
This means that bugs that only hit in one of these cases trigger
nondeterministically.

There were some bugs like this in the past, and I think there's
still one in current kernels.  In particular, we have a number of
ASID-unware code paths that save CR3, write some special value, and
then restore CR3.  This includes suspend/resume, hibernate, kexec,
EFI, and maybe other things I've missed.  This is currently
dangerous: if ASID != 0, then this code sequence will leave garbage
in the TLB tagged for ASID 0.  We could potentially see corruption
when switching back to ASID 0.  In principle, an
initialize_tlbstate_and_flush() call after these sequences would
solve the problem, but EFI, at least, does not call this.  (And it
probably shouldn't -- initialize_tlbstate_and_flush() is rather
expensive.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/cdc14bbe5d3c3ef2a562be09a6368ffe9bd947a6.1505663533.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-17 18:59:08 +02:00
Andy Lutomirski
47061a24e2 x86/mm: Factor out CR3-building code
Current, the code that assembles a value to load into CR3 is
open-coded everywhere.  Factor it out into helpers build_cr3() and
build_cr3_noflush().

This makes one semantic change: __get_current_cr3_fast() was wrong
on SME systems.  No one noticed because the only caller is in the
VMX code, and there are no CPUs with both SME and VMX.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <Thomas.Lendacky@amd.com>
Link: http://lkml.kernel.org/r/ce350cf11e93e2842d14d0b95b0199c7d881f527.1505663533.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-17 18:59:08 +02:00
Linus Torvalds
9db59599ae * PPC bugfixes
* RCU splat fix
 * swait races fix
 * pointless userspace-triggerable BUG() fix
 * misc fixes for KVM_RUN corner cases
 * nested virt correctness fixes + one host DoS
 * some cleanups
 * clang build fix
 * fix AMD AVIC with default QEMU command line options
 * x86 bugfixes
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more KVM updates from Paolo Bonzini:
 - PPC bugfixes
 - RCU splat fix
 - swait races fix
 - pointless userspace-triggerable BUG() fix
 - misc fixes for KVM_RUN corner cases
 - nested virt correctness fixes + one host DoS
 - some cleanups
 - clang build fix
 - fix AMD AVIC with default QEMU command line options
 - x86 bugfixes

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly
  kvm: vmx: Handle VMLAUNCH/VMRESUME failure properly
  kvm: nVMX: Remove nested_vmx_succeed after successful VM-entry
  kvm,mips: Fix potential swait_active() races
  kvm,powerpc: Serialize wq active checks in ops->vcpu_kick
  kvm: Serialize wq active checks in kvm_vcpu_wake_up()
  kvm,x86: Fix apf_task_wake_one() wq serialization
  kvm,lapic: Justify use of swait_active()
  kvm,async_pf: Use swq_has_sleeper()
  sched/wait: Add swq_has_sleeper()
  KVM: VMX: Do not BUG() on out-of-bounds guest IRQ
  KVM: Don't accept obviously wrong gsi values via KVM_IRQFD
  kvm: nVMX: Don't allow L2 to access the hardware CR8
  KVM: trace events: update list of exit reasons
  KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" exceptions simultaneously
  KVM: X86: Don't block vCPU if there is pending exception
  KVM: SVM: Add irqchip_split() checks before enabling AVIC
  KVM: Add struct kvm_vcpu pointer parameter to get_enable_apicv()
  KVM: SVM: Refactor AVIC vcpu initialization into avic_init_vcpu()
  KVM: x86: fix clang build
  ...
2017-09-15 15:43:55 -07:00
Suravee Suthikulpanit
b2a05feff2 KVM: Add struct kvm_vcpu pointer parameter to get_enable_apicv()
Modify struct kvm_x86_ops.arch.apicv_active() to take struct kvm_vcpu
pointer as parameter in preparation to subsequent changes.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-13 18:29:06 +02:00
Joerg Roedel
98152b83e0 KVM: x86: Remove .get_pkru() from kvm_x86_ops
The commit

	9dd21e104bc ('KVM: x86: simplify handling of PKRU')

removed all users and providers of that call-back, but
didn't remove it. Remove it now.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-09-13 15:33:04 +02:00
Juergen Gross
87930019c7 x86/paravirt: Remove no longer used paravirt functions
With removal of lguest some of the paravirt functions are no longer
needed:

	->read_cr4()
	->store_idt()
	->set_pmd_at()
	->set_pud_at()
	->pte_update()

Remove them.

Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: chrisw@sous-sol.org
Cc: jeremy@goop.org
Cc: rusty@rustcorp.com.au
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170904102527.25409-1-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-13 10:55:15 +02:00
Linus Torvalds
680352bda5 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 "Two fixes: dead code removal, plus a SME memory encryption fix on
  32-bit kernels that crashed Xen guests"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Remove unused and undefined __generic_processor_info() declaration
  x86/mm: Make the SME mask a u64
2017-09-12 11:34:39 -07:00