diff options
| author | Andy Lutomirski <luto@kernel.org> | 2015-12-16 23:18:48 -0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-12-21 16:05:01 +0100 |
| commit | 30bfa7b3488bfb1bb75c9f50a5fcac1832970c60 (patch) | |
| tree | af1e7d3bb55f826b936c7a292b8f0f389b641222 /arch/x86/entry/entry_64_compat.S | |
| parent | 6a613ac6bc015f8ef75806d397d69dbac4a8d8c4 (diff) | |
| download | linux-30bfa7b3488bfb1bb75c9f50a5fcac1832970c60.tar.bz2 | |
x86/entry: Restore traditional SYSENTER calling convention
It turns out that some Android versions hardcode the SYSENTER
calling convention. This is buggy and will cause problems no
matter what the kernel does. Nonetheless, we should try to
support it.
Credit goes to Linus for pointing out a clean way to handle
the SYSENTER/SYSCALL clobber differences while preserving
straightforward DWARF annotations.
I believe that the original offending Android commit was:
https://android.googlesource.com/platform%2Fbionic/+/7dc3684d7a2587e43e6d2a8e0e3f39bf759bd535
Reported-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-and-tested-by: Borislav Petkov <bp@alien8.de>
Cc: <mark.gross@intel.com>
Cc: Su Tao <tao.su@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: <frank.wang@intel.com>
Cc: <borun.fu@intel.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Mingwei Shi <mingwei.shi@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/entry/entry_64_compat.S')
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 402e34a21559..6a1ae3751e82 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -63,7 +63,7 @@ ENTRY(entry_SYSENTER_compat) /* Construct struct pt_regs on stack */ pushq $__USER32_DS /* pt_regs->ss */ - pushq %rcx /* pt_regs->sp */ + pushq %rbp /* pt_regs->sp (stashed in bp) */ /* * Push flags. This is nasty. First, interrupts are currently @@ -82,14 +82,14 @@ ENTRY(entry_SYSENTER_compat) pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ pushq %rdx /* pt_regs->dx */ - pushq %rcx /* pt_regs->cx (will be overwritten) */ + pushq %rcx /* pt_regs->cx */ pushq $-ENOSYS /* pt_regs->ax */ pushq %r8 /* pt_regs->r8 = 0 */ pushq %r8 /* pt_regs->r9 = 0 */ pushq %r8 /* pt_regs->r10 = 0 */ pushq %r8 /* pt_regs->r11 = 0 */ pushq %rbx /* pt_regs->rbx */ - pushq %rbp /* pt_regs->rbp */ + pushq %rbp /* pt_regs->rbp (will be overwritten) */ pushq %r8 /* pt_regs->r12 = 0 */ pushq %r8 /* pt_regs->r13 = 0 */ pushq %r8 /* pt_regs->r14 = 0 */ @@ -179,7 +179,7 @@ ENTRY(entry_SYSCALL_compat) pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ pushq %rdx /* pt_regs->dx */ - pushq %rcx /* pt_regs->cx (will be overwritten) */ + pushq %rbp /* pt_regs->cx (stashed in bp) */ pushq $-ENOSYS /* pt_regs->ax */ xorq %r8,%r8 pushq %r8 /* pt_regs->r8 = 0 */ @@ -187,7 +187,7 @@ ENTRY(entry_SYSCALL_compat) pushq %r8 /* pt_regs->r10 = 0 */ pushq %r8 /* pt_regs->r11 = 0 */ pushq %rbx /* pt_regs->rbx */ - pushq %rbp /* pt_regs->rbp */ + pushq %rbp /* pt_regs->rbp (will be overwritten) */ pushq %r8 /* pt_regs->r12 = 0 */ pushq %r8 /* pt_regs->r13 = 0 */ pushq %r8 /* pt_regs->r14 = 0 */ |