diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-06-07 20:24:30 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-06-08 23:43:37 +0200 |
| commit | eb47854415825a69b1c578e7487da571227ba25a (patch) | |
| tree | 0510b51cec06a715b67db35a5d993a72b16f2d2e /arch/x86/entry | |
| parent | 4d7321381e5c7102a3d3faf0a0a0035a09619612 (diff) | |
| download | lwn-eb47854415825a69b1c578e7487da571227ba25a.tar.gz lwn-eb47854415825a69b1c578e7487da571227ba25a.zip | |
x86/asm/entry/32: Reinstate clearing of pt_regs->r8..r11 on EFAULT path
I broke this recently when I changed pt_regs->r8..r11 clearing
logic in INT 80 code path.
There is a branch from SYSENTER/SYSCALL code to INT 80 code:
if we fail to retrieve arg6, we return EFAULT. Before this
patch, in this case we don't clear pt_regs->r8..r11.
This patch fixes this. The resulting code is smaller and
simpler.
While at it, remove incorrect comment about syscall dispatching
CALL insn: it does not use RIP-relative addressing form (the
comment was meant to be "TODO: make this rip-relative", and
morphed since then, dropping "TODO").
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1433701470-28800-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 59840e33d203..5757ddec35d6 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -413,9 +413,7 @@ END(entry_SYSCALL_compat) ia32_badarg: ASM_CLAC - movq $-EFAULT, %rax - jmp ia32_sysret - + movq $-EFAULT, RAX(%rsp) ia32_ret_from_sys_call: xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) @@ -486,9 +484,7 @@ ia32_do_call: cmpq $(IA32_NR_syscalls-1), %rax ja 1f - call *ia32_sys_call_table(, %rax, 8) /* RIP relative */ - -ia32_sysret: + call *ia32_sys_call_table(, %rax, 8) movq %rax, RAX(%rsp) 1: jmp int_ret_from_sys_call |