Currently, when we have a process using the transactional memory
facilities on POWER8 (that is, the processor is in transactional
or suspended state), and the process enters the kernel and the
kernel then uses the floating-point or vector (VMX/Altivec) facility,
we end up corrupting the user-visible FP/VMX/VSX state. This
happens, for example, if a page fault causes a copy-on-write
operation, because the copy_page function will use VMX to do the
copy on POWER8. The test program below demonstrates the bug.
The bug happens because when FP/VMX state for a transactional process
is stored in the thread_struct, we store the checkpointed state in
.fp_state/.vr_state and the transactional (current) state in
.transact_fp/.transact_vr. However, when the kernel wants to use
FP/VMX, it calls enable_kernel_fp() or enable_kernel_altivec(),
which saves the current state in .fp_state/.vr_state. Furthermore,
when we return to the user process we return with FP/VMX/VSX
disabled. The next time the process uses FP/VMX/VSX, we don't know
which set of state (the current register values, .fp_state/.vr_state,
or .transact_fp/.transact_vr) we should be using, since we have no
way to tell if we are still in the same transaction, and if not,
whether the previous transaction succeeded or failed.
Thus it is necessary to strictly adhere to the rule that if FP has
been enabled at any point in a transaction, we must keep FP enabled
for the user process with the current transactional state in the
FP registers, until we detect that it is no longer in a transaction.
Similarly for VMX; once enabled it must stay enabled until the
process is no longer transactional.
In order to keep this rule, we add a new thread_info flag which we
test when returning from the kernel to userspace, called TIF_RESTORE_TM.
This flag indicates that there is FP/VMX/VSX state to be restored
before entering userspace, and when it is set the .tm_orig_msr field
in the thread_struct indicates what state needs to be restored.
The restoration is done by restore_tm_state(). The TIF_RESTORE_TM
bit is set by new giveup_fpu/altivec_maybe_transactional helpers,
which are called from enable_kernel_fp/altivec, giveup_vsx, and
flush_fp/altivec_to_thread instead of giveup_fpu/altivec.
The other thing to be done is to get the transactional FP/VMX/VSX
state from .fp_state/.vr_state when doing reclaim, if that state
has been saved there by giveup_fpu/altivec_maybe_transactional.
Having done this, we set the FP/VMX bit in the thread's MSR after
reclaim to indicate that that part of the state is now valid
(having been reclaimed from the processor's checkpointed state).
Finally, in the signal handling code, we move the clearing of the
transactional state bits in the thread's MSR a bit earlier, before
calling flush_fp_to_thread(), so that we don't unnecessarily set
the TIF_RESTORE_TM bit.
This is the test program:
/* Michael Neuling 4/12/2013
*
* See if the altivec state is leaked out of an aborted transaction due to
* kernel vmx copy loops.
*
* gcc -m64 htm_vmxcopy.c -o htm_vmxcopy
*
*/
/* We don't use all of these, but for reference: */
int main(int argc, char *argv[])
{
long double vecin = 1.3;
long double vecout;
unsigned long pgsize = getpagesize();
int i;
int fd;
int size = pgsize*16;
char tmpfile[] = "/tmp/page_faultXXXXXX";
char buf[pgsize];
char *a;
uint64_t aborted = 0;
fd = mkstemp(tmpfile);
assert(fd >= 0);
memset(buf, 0, pgsize);
for (i = 0; i < size; i += pgsize)
assert(write(fd, buf, pgsize) == pgsize);
unlink(tmpfile);
a = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
assert(a != MAP_FAILED);
asm __volatile__(
"lxvd2x 40,0,%[vecinptr] ; " // set 40 to initial value
TBEGIN
"beq 3f ;"
TSUSPEND
"xxlxor 40,40,40 ; " // set 40 to 0
"std 5, 0(%[map]) ;" // cause kernel vmx copy page
TABORT
TRESUME
TEND
"li %[res], 0 ;"
"b 5f ;"
"3: ;" // Abort handler
"li %[res], 1 ;"
"5: ;"
"stxvd2x 40,0,%[vecoutptr] ; "
: [res]"=r"(aborted)
: [vecinptr]"r"(&vecin),
[vecoutptr]"r"(&vecout),
[map]"r"(a)
: "memory", "r0", "r3", "r4", "r5", "r6", "r7");
if (aborted && (vecin != vecout)){
printf("FAILED: vector state leaked on abort %f != %f\n",
(double)vecin, (double)vecout);
exit(1);
}
munmap(a, size);
close(fd);
printf("PASSED!\n");
return 0;
}
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
TIF_PERFMON_WORK and TIF_PERFMON_CTXSW are completely unused. They
appear to be related to the old perfmon2 code, which has been
superseded by the perf_event infrastructure. This removes their
definitions so that the bits can be used for other purposes.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull powerpc LE updates from Ben Herrenschmidt:
"With my previous pull request I mentioned some remaining Little Endian
patches, notably support for our new ABI, which I was sitting on
making sure it was all finalized.
The toolchain folks confirmed it now, the new ABI is stable and merged
with gcc, so we are all good. Oh and we actually missed the actual
Kconfig switch for LE so here it is, along with a couple more bug
fixes.
I have more fixes but not related to LE so I'll send them as a
separate pull request tomorrow, let's get this one out of the way.
Note that this supports running user space binaries using the new ABI,
but the kernel itself still needs to be built with the old one. We'll
bring fixes for that after -rc1.
Here's Anton log that goes with this series:
This patch series adds support for the new ABI, LPAR support for
H_SET_MODE and finally adds a kconfig option and defconfig.
ABIv2 support was recently committed to binutils and gcc, and should
be merged into glibc soon. There are a number of very nice
improvements including the removal of function descriptors. Rusty's
kernel patches allow binaries of either ABI to work, easing the
transition"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Wrong DWARF CFI in the kernel vdso for little-endian / ELFv2
powerpc: Add pseries_le_defconfig
powerpc: Add CONFIG_CPU_LITTLE_ENDIAN kernel config option.
powerpc: Don't use ELFv2 ABI to build the kernel
powerpc: ELF2 binaries signal handling
powerpc: ELF2 binaries launched directly.
powerpc: Set eflags correctly for ELF ABIv2 core dumps.
powerpc: Add TIF_ELF2ABI flag.
pseries: Add H_SET_MODE to change exception endianness
powerpc/pseries: Fix endian issues in pseries EEH code
Little endian ppc64 is getting an exciting new ABI. This is reflected
by the bottom two bits of e_flags in the ELF header:
0 == legacy binaries (v1 ABI)
1 == binaries using the old ABI (compiled with a new toolchain)
2 == binaries using the new ABI.
We store this in a thread flag, because we need to set it in core
dumps and for signal delivery. Our chief concern is that it doesn't
use function descriptors.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is the syscall slow path hooks for context tracking subsystem,
corresponding to
[PATCH] x86: Syscall hooks for userspace RCU extended QS
commit bf5a3c13b9
TIF_MEMDIE is moved to the second 16-bits (with value 17), as it seems there
is no asm code using it. TIF_NOHZ is added to _TIF_SYCALL_T_OR_A, so it is
better for it to be in the same 16 bits with others in the group, so in the
asm code, andi. with this group could work.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Move it to a common place. Preparatory patch for implementing
set/clear for the idle need_resched poll implementation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.446034505@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull pile 2 of execve and kernel_thread unification work from Al Viro:
"Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for
several more architectures plus assorted signal fixes and cleanups.
There'll be more (in particular, real fixes for the alpha
do_notify_resume() irq mess)..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits)
alpha: don't open-code trace_report_syscall_{enter,exit}
Uninclude linux/freezer.h
m32r: trim masks
avr32: trim masks
tile: don't bother with SIGTRAP in setup_frame
microblaze: don't bother with SIGTRAP in setup_rt_frame()
mn10300: don't bother with SIGTRAP in setup_frame()
frv: no need to raise SIGTRAP in setup_frame()
x86: get rid of duplicate code in case of CONFIG_VM86
unicore32: remove pointless test
h8300: trim _TIF_WORK_MASK
parisc: decide whether to go to slow path (tracesys) based on thread flags
parisc: don't bother looping in do_signal()
parisc: fix double restarts
bury the rest of TIF_IRET
sanitize tsk_is_polling()
bury _TIF_RESTORE_SIGMASK
unicore32: unobfuscate _TIF_WORK_MASK
mips: NOTIFY_RESUME is not needed in TIF masks
mips: merge the identical "return from syscall" per-ABI code
...
Conflicts:
arch/arm/include/asm/thread_info.h
Make default just return 0. The current default (checking
TIF_POLLING_NRFLAG) is taken to architectures that need it;
ones that don't do polling in their idle threads don't need
to defined TIF_POLLING_NRFLAG at all.
ia64 defined both TS_POLLING (used by its tsk_is_polling())
and TIF_POLLING_NRFLAG (not used at all). Killed the latter...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We need to add a new thread flag, TIF_EMULATE_STACK_STORE,
for emulating stack store operation while exiting exception.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is the port of uprobes to powerpc. Usage is similar to x86.
[root@xxxx ~]# ./bin/perf probe -x /lib64/libc.so.6 malloc
Added new event:
probe_libc:malloc (on 0xb4860)
You can now use it in all perf tools, such as:
perf record -e probe_libc:malloc -aR sleep 1
[root@xxxx ~]# ./bin/perf record -e probe_libc:malloc -aR sleep 20
[ perf record: Woken up 22 times to write data ]
[ perf record: Captured and wrote 5.843 MB perf.data (~255302 samples) ]
[root@xxxx ~]# ./bin/perf report --stdio
...
69.05% tar libc-2.12.so [.] malloc
28.57% rm libc-2.12.so [.] malloc
1.32% avahi-daemon libc-2.12.so [.] malloc
0.58% bash libc-2.12.so [.] malloc
0.28% sshd libc-2.12.so [.] malloc
0.08% irqbalance libc-2.12.so [.] malloc
0.05% bzip2 libc-2.12.so [.] malloc
0.04% sleep libc-2.12.so [.] malloc
0.03% multipathd libc-2.12.so [.] malloc
0.01% sendmail libc-2.12.so [.] malloc
0.01% automount libc-2.12.so [.] malloc
The trap_nr addition patch is a prereq.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull powerpc updates from Benjamin Herrenschmidt:
"Here are the powerpc goodies for 3.5. Main highlights are:
- Support for the NX crypto engine in Power7+
- A bunch of Anton goodness, including some micro optimization of our
syscall entry on Power7
- I converted a pile of our thermal control drivers to the new i2c
APIs (essentially turning the old therm_pm72 into a proper set of
windfarm drivers). That's one more step toward removing the
deprecated i2c APIs, there's still a few drivers to fix, but we are
getting close
- kexec/kdump support for 47x embedded cores
The big missing thing here is no updates from Freescale. Not sure
what's up here, but with Kumar not working for them anymore things are
a bit in a state of flux in that area."
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (71 commits)
powerpc: Fix irq distribution
Revert "powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags"
powerpc: Fixing a cputhread code documentation
powerpc/crypto: Enable the PFO-based encryption device
powerpc/crypto: Build files for the nx device driver
powerpc/crypto: debugfs routines and docs for the nx device driver
powerpc/crypto: SHA512 hash routines for nx encryption
powerpc/crypto: SHA256 hash routines for nx encryption
powerpc/crypto: AES-XCBC mode routines for nx encryption
powerpc/crypto: AES-GCM mode routines for nx encryption
powerpc/crypto: AES-ECB mode routines for nx encryption
powerpc/crypto: AES-CTR mode routines for nx encryption
powerpc/crypto: AES-CCM mode routines for nx encryption
powerpc/crypto: AES-CBC mode routines for nx encryption
powerpc/crypto: nx driver code supporting nx encryption
powerpc/pseries: Enable the PFO-based RNG accelerator
powerpc/pseries/hwrng: PFO-based hwrng driver
powerpc/pseries: Add PFO support to the VIO bus
powerpc/pseries: Add pseries update notifier for OFDT prop changes
powerpc/pseries: Add new hvcall constants to support PFO
...
'TIF_RUNLATCH' is already dropped from
commit fe1952fc0a
powerpc: Rework runlatch code
So '_TIF_RUNLATCH' should be removed as well.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The core now has a threadinfo allocator which uses a kmemcache when
THREAD_SIZE < PAGE_SIZE.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Link: http://lkml.kernel.org/r/20120505150142.059161130@linutronix.de
This moves the inlines into system.h and changes the runlatch
code to use the thread local flags (non-atomic) rather than
the TIF flags (atomic) to keep track of the latch state.
The code to turn it back on in an asynchronous interrupt is
now simplified and partially inlined.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch implements the raw syscall tracepoints on PowerPC and exports
them for ftrace syscalls to use.
To minimise reworking existing code, I slightly re-ordered the thread
info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit
within the 16 bits of the andi. instruction's UI field. The instructions
in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the
_TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing
is enabled.
In the case of 64bit PowerPC, arch_syscall_addr and
arch_syscall_match_sym_name are overridden to allow ftrace syscalls to
work given the unusual system call table structure and symbol names that
start with a period.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Fix up powerpc to the new mmu_gather stuff.
PPC has an extra batching queue to RCU free the actual pagetable
allocations, use the ARCH extentions for that for now.
For the ppc64_tlb_batch, which tracks the vaddrs to unhash from the
hardware hash-table, keep using per-cpu arrays but flush on context switch
and use a TLF bit to track the lazy_mmu state.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a node parameter to alloc_thread_info(), and change its name to
alloc_thread_info_node()
This change is needed to allow NUMA aware kthread_create_on_cpu()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here are the powerpc bits to remove TIF_ABI_PENDING now that
set_personality() is called at the appropriate place in exec.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull the initial preempt_count value into a single
definition site.
Maintainers for: alpha, ia64 and m68k, please have a look,
your arch code is funny.
The header magic is a bit odd, but similar to the KERNEL_DS
one, CPP waits with expanding these macros until the
INIT_THREAD_INFO macro itself is expanded, which is in
arch/*/kernel/init_task.c where we've already included
sched.h so we're good.
Cc: tony.luck@intel.com
Cc: rth@twiddle.net
Cc: geert@linux-m68k.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move is_32bit_task into asm/thread_info.h, that allows us to test for
32/64bit tasks without an ugly CONFIG_PPC64 ifdef.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch adds support for 256KB pages on ppc44x-based boards.
For simplification of implementation with 256KB pages we still assume
2-level paging. As a side effect this leads to wasting extra memory space
reserved for PTE tables: only 1/4 of pages allocated for PTEs are
actually used. But this may be an acceptable trade-off to achieve the
high performance we have with big PAGE_SIZEs in some applications (e.g.
RAID).
Also with 256KB PAGE_SIZE we increase THREAD_SIZE up to 32KB to minimize
the risk of stack overflows in the cases of on-stack arrays, which size
depends on the page size (e.g. multipage BIOs, NTFS, etc.).
With 256KB PAGE_SIZE we need to decrease the PKMAP_ORDER at least down
to 9, otherwise all high memory (2 ^ 10 * PAGE_SIZE == 256MB) we'll be
occupied by PKMAP addresses leaving no place for vmalloc. We do not
separate PKMAP_ORDER for 256K from 16K/64K PAGE_SIZE here; actually that
value of 10 in support for 16K/64K had been selected rather intuitively.
Thus now for all cases of PAGE_SIZE on ppc44x (including the default, 4KB,
one) we have 512 pages for PKMAP.
Because ELF standard supports only page sizes up to 64K, then you should
use binutils later than 2.17.50.0.3 with '-zmax-page-size' set to 256K
for building applications, which are to be run with the 256KB-page sized
kernel. If using the older binutils, then you should patch them like follows:
--- binutils/bfd/elf32-ppc.c.orig
+++ binutils/bfd/elf32-ppc.c
-#define ELF_MAXPAGESIZE 0x10000
+#define ELF_MAXPAGESIZE 0x40000
One more restriction we currently have with 256KB page sizes is inability
to use shmem safely, so, for now, the 256KB is available only if you turn
the CONFIG_SHMEM option off (another variant is to use BROKEN).
Though, if you need shmem with 256KB pages, you can always remove the !SHMEM
dependency in 'config PPC_256K_PAGES', and use the workaround available here:
http://lkml.org/lkml/2008/12/19/20
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
