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authorJan Beulich <JBeulich@suse.com>2011-11-29 12:24:10 +0100
committerIngo Molnar <mingo@elte.hu>2011-12-05 17:24:43 +0100
commitf6b2bc847641ea38e2655c8424fef5d2d19f35f9 (patch)
tree47f7d2ebb9cd1434b5fd8ef0113a4b0cbb0741a2
parentx86-64: Slightly shorten line system call entry and exit paths (diff)
downloadlinux-f6b2bc847641ea38e2655c8424fef5d2d19f35f9.tar.xz
linux-f6b2bc847641ea38e2655c8424fef5d2d19f35f9.zip
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>
-rw-r--r--arch/x86/ia32/ia32entry.S7
-rw-r--r--arch/x86/kernel/entry_64.S2
2 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 0d5c279f3732..3e274564f6bf 100644
--- 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 75f72a50cf26..cfad7fce6163 100644
--- 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