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| author | Kevin Hao <haokexin@gmail.com> | 2017-01-22 09:50:23 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-01-23 10:40:18 +0100 |
| commit | 4c833368f0bf748d4147bf301b1f95bc8eccb3c0 (patch) | |
| tree | 35d8afb3af6a869b3b40257bf6a2883527ea8c1c /arch/x86 | |
| parent | x86/microcode/intel: Drop stashed AP patch pointer optimization (diff) | |
| download | linux-4c833368f0bf748d4147bf301b1f95bc8eccb3c0.tar.xz linux-4c833368f0bf748d4147bf301b1f95bc8eccb3c0.zip | |
x86/fpu: Set the xcomp_bv when we fake up a XSAVES area
I got the following calltrace on a Apollo Lake SoC with 32-bit kernel:
WARNING: CPU: 2 PID: 261 at arch/x86/include/asm/fpu/internal.h:363 fpu__restore+0x1f5/0x260
[...]
Hardware name: Intel Corp. Broxton P/NOTEBOOK, BIOS APLIRVPA.X64.0138.B35.1608091058 08/09/2016
Call Trace:
dump_stack()
__warn()
? fpu__restore()
warn_slowpath_null()
fpu__restore()
__fpu__restore_sig()
fpu__restore_sig()
restore_sigcontext.isra.9()
sys_sigreturn()
do_int80_syscall_32()
entry_INT80_32()
The reason is that a #GP occurs when executing XRSTORS. The root cause
is that we forget to set the xcomp_bv when we fake up the XSAVES area
in the copyin_to_xsaves() function.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
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/1485075023-30161-1-git-send-email-haokexin@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 1d7770447b3e..e287b9075527 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1070,6 +1070,7 @@ int copyin_to_xsaves(const void *kbuf, const void __user *ubuf, * Add back in the features that came in from userspace: */ xsave->header.xfeatures |= xfeatures; + xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xsave->header.xfeatures; return 0; } |