diff options
| author | Andy Lutomirski | 2015-10-06 02:47:53 +0200 |
|---|---|---|
| committer | Ingo Molnar | 2015-10-07 11:34:07 +0200 |
| commit | dd27f998f0ed3c797032a82033fa191be7c61e4c (patch) | |
| tree | 6832032ef0f59fa865526b13f0b32489ce8b2287 | |
| parent | selftests/x86: Add a test for ptrace syscall restart and arg modification (diff) | |
| download | kernel-qcow2-linux-dd27f998f0ed3c797032a82033fa191be7c61e4c.tar.gz kernel-qcow2-linux-dd27f998f0ed3c797032a82033fa191be7c61e4c.tar.xz kernel-qcow2-linux-dd27f998f0ed3c797032a82033fa191be7c61e4c.zip | |
x86/entry/64/compat: Fix SYSENTER's NT flag before user memory access
Clearing NT is part of the prologue, whereas loading up arg6
makes more sense to think about as part of syscall processing.
Reorder them.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/19eb235828b2d2a52c53459e09f2974e15e65a35.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index a9360d40fb7f..e2cca89c1ed3 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -89,15 +89,6 @@ ENTRY(entry_SYSENTER_compat) sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */ /* - * no need to do an access_ok check here because rbp has been - * 32-bit zero extended - */ - ASM_STAC -1: movl (%rbp), %ebp - _ASM_EXTABLE(1b, ia32_badarg) - ASM_CLAC - - /* * Sysenter doesn't filter flags, so we need to clear NT * ourselves. To save a few cycles, we can check whether * NT was set instead of doing an unconditional popfq. @@ -106,6 +97,15 @@ ENTRY(entry_SYSENTER_compat) jnz sysenter_fix_flags sysenter_flags_fixed: + /* + * No need to do an access_ok() check here because RBP has been + * 32-bit zero extended: + */ + ASM_STAC +1: movl (%rbp), %ebp + _ASM_EXTABLE(1b, ia32_badarg) + ASM_CLAC + orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jnz sysenter_tracesys |