diff options
| author | Denys Vlasenko <[email protected]> | 2015-06-02 21:04:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2015-06-05 13:22:22 +0200 |
| commit | ef0cd5dc25404594f832dad9133abae52e3b2fa3 (patch) | |
| tree | 4a0e07001da4018a61c813033598219e20625715 | |
| parent | 61b1e3e782d6784b714c0d80de529e0737d0e79c (diff) | |
x86/asm/entry/32: Open-code CLEAR_RREGS
This macro is small, has only four callsites, and one of them is
slightly different using a conditional parameter.
A few saved lines aren't worth the resulting obfuscation.
Generated machine code is identical.
Signed-off-by: Denys Vlasenko <[email protected]>
[ Added comments. ]
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | arch/x86/entry/ia32entry.S | 33 |
1 files changed, 20 insertions, 13 deletions
diff --git a/arch/x86/entry/ia32entry.S b/arch/x86/entry/ia32entry.S index f00a409dc403..8a45d2cd2bef 100644 --- a/arch/x86/entry/ia32entry.S +++ b/arch/x86/entry/ia32entry.S @@ -29,15 +29,6 @@ .section .entry.text, "ax" - /* clobbers %rax */ - .macro CLEAR_RREGS _r9=rax - xorl %eax,%eax - movq %rax,R11(%rsp) - movq %rax,R10(%rsp) - movq %\_r9,R9(%rsp) - movq %rax,R8(%rsp) - .endm - /* * Reload arg registers from stack in case ptrace changed them. * We don't reload %eax because syscall_trace_enter() returned @@ -243,7 +234,11 @@ sysexit_from_sys_call: TRACE_IRQS_OFF testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jz \exit - CLEAR_RREGS + xorl %eax, %eax /* do not leak kernel information */ + movq %rax, R11(%rsp) + movq %rax, R10(%rsp) + movq %rax, R9(%rsp) + movq %rax, R8(%rsp) jmp int_with_check .endm @@ -267,7 +262,11 @@ sysenter_tracesys: jz sysenter_auditsys #endif SAVE_EXTRA_REGS - CLEAR_RREGS + xorl %eax, %eax /* do not leak kernel information */ + movq %rax, R11(%rsp) + movq %rax, R10(%rsp) + movq %rax, R9(%rsp) + movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ @@ -407,7 +406,11 @@ cstar_tracesys: #endif xchgl %r9d,%ebp SAVE_EXTRA_REGS - CLEAR_RREGS r9 + xorl %eax, %eax /* do not leak kernel information */ + movq %rax, R11(%rsp) + movq %rax, R10(%rsp) + movq %r9, R9(%rsp) + movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */ @@ -422,7 +425,11 @@ ia32_badarg: jmp ia32_sysret ia32_ret_from_sys_call: - CLEAR_RREGS + xorl %eax, %eax /* do not leak kernel information */ + movq %rax, R11(%rsp) + movq %rax, R10(%rsp) + movq %rax, R9(%rsp) + movq %rax, R8(%rsp) jmp int_ret_from_sys_call /* |