From c12a229bc5971534537a7d0e49e44f9f1f5d0336 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 5 Nov 2009 11:03:59 -0500 Subject: x86: Remove unused thread_return label from switch_to() Remove unused thread_return label from switch_to() macro on x86-64. Since this symbol cuts into schedule(), backtrace at the latter half of schedule() was always shown as thread_return(). Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE LKML-Reference: <20091105160359.5181.26225.stgit@harusame> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/system.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/x86/include/asm/system.h') diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index f08f97374892..1a953e26401c 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -128,8 +128,6 @@ do { \ "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \ "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */ \ "call __switch_to\n\t" \ - ".globl thread_return\n" \ - "thread_return:\n\t" \ "movq "__percpu_arg([current_task])",%%rsi\n\t" \ __switch_canary \ "movq %P[thread_info](%%rsi),%%r8\n\t" \ -- cgit v1.2.3 From 79b0379cee09b00ef309384aff652e328e438c79 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Wed, 25 Nov 2009 14:18:26 -0500 Subject: x86: Optimize loadsegment() Zero the input register in the exception handler instead of using an extra register to pass in a zero value. Signed-off-by: Brian Gerst LKML-Reference: <1259176706-5908-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/system.h | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'arch/x86/include/asm/system.h') diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 1a953e26401c..537395a2877a 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -156,18 +156,19 @@ extern void native_load_gs_index(unsigned); * segment if something goes wrong.. */ #define loadsegment(seg, value) \ +do { \ + unsigned short __val = value; \ asm volatile("\n" \ "1:\t" \ "movl %k0,%%" #seg "\n" \ - "2:\n" \ ".section .fixup,\"ax\"\n" \ - "3:\t" \ - "movl %k1, %%" #seg "\n\t" \ - "jmp 2b\n" \ + "2:\t" \ + "xorl %k0,%k0\n\t" \ + "jmp 1b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b,3b) \ - : :"r" (value), "r" (0) : "memory") - + _ASM_EXTABLE(1b, 2b) \ + : "+r" (__val) : : "memory"); \ +} while (0) /* * Save a segment register away -- cgit v1.2.3 From 64b028b22616946a05bf9580f7f7f7ee2ac070b4 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 26 Nov 2009 10:37:55 +0100 Subject: x86: Clean up the loadsegment() macro Make it readable in the source too, not just in the assembly output. No change in functionality. Cc: Brian Gerst LKML-Reference: <1259176706-5908-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/system.h | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) (limited to 'arch/x86/include/asm/system.h') diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 537395a2877a..022a84386de8 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -155,19 +155,21 @@ extern void native_load_gs_index(unsigned); * Load a segment. Fall back on loading the zero * segment if something goes wrong.. */ -#define loadsegment(seg, value) \ -do { \ - unsigned short __val = value; \ - asm volatile("\n" \ - "1:\t" \ - "movl %k0,%%" #seg "\n" \ - ".section .fixup,\"ax\"\n" \ - "2:\t" \ - "xorl %k0,%k0\n\t" \ - "jmp 1b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 2b) \ - : "+r" (__val) : : "memory"); \ +#define loadsegment(seg, value) \ +do { \ + unsigned short __val = (value); \ + \ + asm volatile(" \n" \ + "1: movl %k0,%%" #seg " \n" \ + \ + ".section .fixup,\"ax\" \n" \ + "2: xorl %k0,%k0 \n" \ + " jmp 1b \n" \ + ".previous \n" \ + \ + _ASM_EXTABLE(1b, 2b) \ + \ + : "+r" (__val) : : "memory"); \ } while (0) /* -- cgit v1.2.3