diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-07-24 14:16:43 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-07-24 16:36:00 +0200 |
| commit | c0c3322e98029e752526d906d9e3a680ed213c03 (patch) | |
| tree | 27c75dca77c0aa214449eb37d72deeb8d3825555 | |
| parent | 8a0a5da6d9cbf1b142115ff6e6b253a82633c3d9 (diff) | |
x86/asm/entry/32: Revert 'Do not use R9 in SYSCALL32' commit
This change reverts most of commit 53e9accf0f 'Do not use R9 in
SYSCALL32'. I don't yet understand how, but code in that commit
sometimes fails to preserve EBP.
See https://bugzilla.kernel.org/show_bug.cgi?id=101061
"Problems while executing 32-bit code on AMD64"
Reported-and-tested-by: Krzysztof A. Sobiecki <sobkas@gmail.com>
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Will Drewry <wad@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
Link: http://lkml.kernel.org/r/1437740203-11552-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index bb187a6a877c..5a1844765a7a 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -205,7 +205,6 @@ sysexit_from_sys_call: movl RDX(%rsp), %edx /* arg3 */ movl RSI(%rsp), %ecx /* arg4 */ movl RDI(%rsp), %r8d /* arg5 */ - movl %ebp, %r9d /* arg6 */ .endm .macro auditsys_exit exit @@ -236,6 +235,7 @@ sysexit_from_sys_call: sysenter_auditsys: auditsys_entry_common + movl %ebp, %r9d /* reload 6th syscall arg */ jmp sysenter_dispatch sysexit_audit: @@ -336,7 +336,7 @@ ENTRY(entry_SYSCALL_compat) * 32-bit zero extended: */ ASM_STAC -1: movl (%r8), %ebp +1: movl (%r8), %r9d _ASM_EXTABLE(1b, ia32_badarg) ASM_CLAC orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) @@ -346,7 +346,7 @@ ENTRY(entry_SYSCALL_compat) cstar_do_call: /* 32-bit syscall -> 64-bit C ABI argument conversion */ movl %edi, %r8d /* arg5 */ - movl %ebp, %r9d /* arg6 */ + /* r9 already loaded */ /* arg6 */ xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */ movl %ebx, %edi /* arg1 */ movl %edx, %edx /* arg3 (zero extension) */ @@ -358,7 +358,6 @@ cstar_dispatch: call *ia32_sys_call_table(, %rax, 8) movq %rax, RAX(%rsp) 1: - movl RCX(%rsp), %ebp DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) @@ -392,7 +391,9 @@ sysretl_from_sys_call: #ifdef CONFIG_AUDITSYSCALL cstar_auditsys: + movl %r9d, R9(%rsp) /* register to be clobbered by call */ auditsys_entry_common + movl R9(%rsp), %r9d /* reload 6th syscall arg */ jmp cstar_dispatch sysretl_audit: @@ -404,14 +405,16 @@ cstar_tracesys: testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jz cstar_auditsys #endif + xchgl %r9d, %ebp SAVE_EXTRA_REGS xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) movq %rax, R10(%rsp) - movq %rax, R9(%rsp) + movq %r9, R9(%rsp) movq %rax, R8(%rsp) movq %rsp, %rdi /* &pt_regs -> arg1 */ call syscall_trace_enter + movl R9(%rsp), %r9d /* Reload arg registers from stack. (see sysenter_tracesys) */ movl RCX(%rsp), %ecx @@ -421,6 +424,7 @@ cstar_tracesys: movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS + xchgl %ebp, %r9d jmp cstar_do_call END(entry_SYSCALL_compat) |