Commit-ID: 73cbf687914fd5f4ef88a42a55784fd28b7450cf Gitweb: http://git.kernel.org/tip/73cbf687914fd5f4ef88a42a55784fd28b7450cf Author: Denys Vlasenko <dvlasenk@xxxxxxxxxx> AuthorDate: Tue, 2 Jun 2015 21:04:02 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Fri, 5 Jun 2015 13:22:22 +0200 x86/asm/entry/32: Open-code LOAD_ARGS32 This macro is small, has only three 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@xxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Will Drewry <wad@xxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1433271842-9139-2-git-send-email-dvlasenk@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/entry/ia32entry.S | 54 +++++++++++++++++++++++++--------------------- 1 file changed, 29 insertions(+), 25 deletions(-) diff --git a/arch/x86/entry/ia32entry.S b/arch/x86/entry/ia32entry.S index 8a45d2c..56f819e 100644 --- a/arch/x86/entry/ia32entry.S +++ b/arch/x86/entry/ia32entry.S @@ -29,28 +29,6 @@ .section .entry.text, "ax" - /* - * Reload arg registers from stack in case ptrace changed them. - * We don't reload %eax because syscall_trace_enter() returned - * the %rax value we should see. Instead, we just truncate that - * value to 32 bits again as we did on entry from user mode. - * If it's a new value set by user_regset during entry tracing, - * this matches the normal truncation of the user-mode value. - * If it's -1 to make us punt the syscall, then (u32)-1 is still - * an appropriately invalid value. - */ - .macro LOAD_ARGS32 _r9=0 - .if \_r9 - movl R9(%rsp),%r9d - .endif - movl RCX(%rsp),%ecx - movl RDX(%rsp),%edx - movl RSI(%rsp),%esi - movl RDI(%rsp),%edi - movl %eax,%eax /* zero extension */ - .endm - - #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret32) swapgs @@ -269,7 +247,14 @@ sysenter_tracesys: 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 */ + + /* Reload arg registers from stack. (see sysenter_tracesys) */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ + RESTORE_EXTRA_REGS jmp sysenter_do_call ENDPROC(ia32_sysenter_target) @@ -413,7 +398,15 @@ cstar_tracesys: 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 */ + movl R9(%rsp),%r9d + + /* Reload arg registers from stack. (see sysenter_tracesys) */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ + RESTORE_EXTRA_REGS xchgl %ebp,%r9d jmp cstar_do_call @@ -502,7 +495,18 @@ ia32_tracesys: SAVE_EXTRA_REGS movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ + /* + * Reload arg registers from stack in case ptrace changed them. + * Don't reload %eax because syscall_trace_enter() returned + * the %rax value we should see. But do truncate it to 32 bits. + * If it's -1 to make us punt the syscall, then (u32)-1 is still + * an appropriately invalid value. + */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp ia32_do_call END(ia32_syscall) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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