x86-64: Cleanup some assembly entry points

system_call_after_swapgs doesn't really benefit from forcing
alignment from it - quite the opposite, native code needlessly
so far got a big NOP instruction inserted in front of it. Xen
being the only user of the separate entry point can well live
with the branch going to three bytes into a cache line.

The compatibility mode ptregs entry points for one can make use
of the GLOBAL() macro, and should be suitably aligned. Their
shared continuation point (ia32_ptregs_common) otoh doesn't need
to be global at all, but should continue to be properly aligned.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/4ED4CEEA020000780006407D@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 0d5c279f3732d6f295f38485103a76791db14da8..3e274564f6bf0d89f06b489484eb7d86faa049d6 100644 (file)
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -453,8 +453,8 @@ quiet_ni_syscall:
        CFI_ENDPROC
        
        .macro PTREGSCALL label, func, arg
-       .globl \label
-\label:
+       ALIGN
+GLOBAL(\label)
        leaq \func(%rip),%rax
        leaq -ARGOFFSET+8(%rsp),\arg    /* 8 for return address */
        jmp  ia32_ptregs_common 
@@ -471,7 +471,8 @@ quiet_ni_syscall:
        PTREGSCALL stub32_vfork, sys_vfork, %rdi
        PTREGSCALL stub32_iopl, sys_iopl, %rsi
 
-ENTRY(ia32_ptregs_common)
+       ALIGN
+ia32_ptregs_common:
        popq %r11
        CFI_ENDPROC
        CFI_STARTPROC32 simple

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 75f72a50cf269c72e4a57472a91e639ac29f86cd..cfad7fce6163f81990002db7610f0423781e212b 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -465,7 +465,7 @@ ENTRY(system_call)
         * after the swapgs, so that it can do the swapgs
         * for the guest and jump here on syscall.
         */
-ENTRY(system_call_after_swapgs)
+GLOBAL(system_call_after_swapgs)
 
        movq    %rsp,PER_CPU_VAR(old_rsp)
        movq    PER_CPU_VAR(kernel_stack),%rsp