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@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: Brian Gerst <brgerst@gmail.com>
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/1433271842-9139-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/entry/ia32entry.S b/arch/x86/entry/ia32entry.S
index 8a45d2cd2beffe57ae7b0617a7a2d32a052ca4a8..56f819e99258cf6b5544ea97b8070b951e5fa314 100644 (file)
--- 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)