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Message-Id: <1433271842-9139-1-git-send-email-dvlasenk@redhat.com> Date: Tue, 2 Jun 2015 21:04:01 +0200 From: Denys Vlasenko <dvlasenk@...hat.com> To: Ingo Molnar <mingo@...nel.org> Cc: Denys Vlasenko <dvlasenk@...hat.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Steven Rostedt <rostedt@...dmis.org>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...capital.net>, Oleg Nesterov <oleg@...hat.com>, Frederic Weisbecker <fweisbec@...il.com>, Alexei Starovoitov <ast@...mgrid.com>, Will Drewry <wad@...omium.org>, Kees Cook <keescook@...omium.org>, x86@...nel.org, linux-kernel@...r.kernel.org Subject: [PATCH 1/2] x86/asm/entry/32: Open-code CLEAR_RREGS. No code changes. 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 <dvlasenk@...hat.com> CC: Linus Torvalds <torvalds@...ux-foundation.org> CC: Steven Rostedt <rostedt@...dmis.org> CC: Ingo Molnar <mingo@...nel.org> CC: Borislav Petkov <bp@...en8.de> CC: "H. Peter Anvin" <hpa@...or.com> CC: Andy Lutomirski <luto@...capital.net> CC: Oleg Nesterov <oleg@...hat.com> CC: Frederic Weisbecker <fweisbec@...il.com> CC: Alexei Starovoitov <ast@...mgrid.com> CC: Will Drewry <wad@...omium.org> CC: Kees Cook <keescook@...omium.org> CC: x86@...nel.org CC: linux-kernel@...r.kernel.org --- These two patches are on top of "Simplify zeroing of pt_regs->r8..r11" patch. arch/x86/ia32/ia32entry.S | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 2801cbe..86cbfe6 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/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 + 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 + 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 + 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 + movq %rax, R11(%rsp) + movq %rax, R10(%rsp) + movq %rax, R9(%rsp) + movq %rax, R8(%rsp) jmp int_ret_from_sys_call /* -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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