[tip:x86/asm] x86/asm: Remove thread_info.sysenter_return
From: tip-bot for Andy Lutomirski
Date: Fri Oct 09 2015 - 09:14:23 EST
Commit-ID: 487e3bf4f77699160aa81a414200060a78a67c3d
Gitweb: http://git.kernel.org/tip/487e3bf4f77699160aa81a414200060a78a67c3d
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Mon, 5 Oct 2015 17:48:16 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 9 Oct 2015 09:41:11 +0200
x86/asm: Remove thread_info.sysenter_return
It's no longer needed.
We could reinstate something like it as an optimization, which
would remove two cachelines from the fast syscall entry working
set. I benchmarked it, and it makes no difference whatsoever to
the performance of cache-hot compat syscalls on Sandy Bridge.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/f08cc0cff30201afe9bb565c47134c0a6c1a96a2.1444091585.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/thread_info.h | 1 -
arch/x86/kernel/asm-offsets.c | 3 ---
2 files changed, 4 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 8afdc3e..a1ecd21 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -59,7 +59,6 @@ struct thread_info {
__u32 cpu; /* current CPU */
int saved_preempt_count;
mm_segment_t addr_limit;
- void __user *sysenter_return;
unsigned int sig_on_uaccess_error:1;
unsigned int uaccess_err:1; /* uaccess failed */
};
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 8e3d22a1..95a18e2 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -54,9 +54,6 @@ void common(void) {
OFFSET(IA32_SIGCONTEXT_ip, sigcontext_ia32, ip);
BLANK();
- OFFSET(TI_sysenter_return, thread_info, sysenter_return);
-
- BLANK();
OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe_ia32, uc.uc_mcontext);
#endif
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