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x86: move switch_to macro to system.h
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This patch moves the switch_to() macro to system.h

As those macros are fundamentally different between i386 and x86_64,
they are enclosed around an ifdef.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Glauber de Oliveira Costa authored and Ingo Molnar committed Jan 30, 2008
1 parent 833d846 commit 0a3b4d1
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Showing 3 changed files with 61 additions and 74 deletions.
61 changes: 61 additions & 0 deletions include/asm-x86/system.h
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Expand Up @@ -6,8 +6,69 @@
#include <linux/kernel.h>

#ifdef CONFIG_X86_32
#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */

struct task_struct; /* one of the stranger aspects of C forward declarations */
extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,
struct task_struct *next));

/*
* Saving eflags is important. It switches not only IOPL between tasks,
* it also protects other tasks from NT leaking through sysenter etc.
*/
#define switch_to(prev, next, last) do { \
unsigned long esi, edi; \
asm volatile("pushfl\n\t" /* Save flags */ \
"pushl %%ebp\n\t" \
"movl %%esp,%0\n\t" /* save ESP */ \
"movl %5,%%esp\n\t" /* restore ESP */ \
"movl $1f,%1\n\t" /* save EIP */ \
"pushl %6\n\t" /* restore EIP */ \
"jmp __switch_to\n" \
"1:\t" \
"popl %%ebp\n\t" \
"popfl" \
:"=m" (prev->thread.sp), "=m" (prev->thread.ip), \
"=a" (last), "=S" (esi), "=D" (edi) \
:"m" (next->thread.sp), "m" (next->thread.ip), \
"2" (prev), "d" (next)); \
} while (0)

# include "system_32.h"
#else
#define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
#define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"

/* frame pointer must be last for get_wchan */
#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"

#define __EXTRA_CLOBBER \
, "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
"r12", "r13", "r14", "r15"

/* Save restore flags to clear handle leaking NT */
#define switch_to(prev, next, last) \
asm volatile(SAVE_CONTEXT \
"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 %%gs:%P[pda_pcurrent],%%rsi\n\t" \
"movq %P[thread_info](%%rsi),%%r8\n\t" \
LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \
"movq %%rax,%%rdi\n\t" \
"jc ret_from_fork\n\t" \
RESTORE_CONTEXT \
: "=a" (last) \
: [next] "S" (next), [prev] "D" (prev), \
[threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \
[ti_flags] "i" (offsetof(struct thread_info, flags)), \
[tif_fork] "i" (TIF_FORK), \
[thread_info] "i" (offsetof(struct task_struct, stack)), \
[pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
: "memory", "cc" __EXTRA_CLOBBER)
# include "system_64.h"
#endif

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31 changes: 0 additions & 31 deletions include/asm-x86/system_32.h
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Expand Up @@ -5,37 +5,6 @@
#include <asm/cpufeature.h>
#include <asm/cmpxchg.h>

#ifdef __KERNEL__
#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */

struct task_struct; /* one of the stranger aspects of C forward declarations.. */
extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));

/*
* Saving eflags is important. It switches not only IOPL between tasks,
* it also protects other tasks from NT leaking through sysenter etc.
*/
#define switch_to(prev,next,last) do { \
unsigned long esi,edi; \
asm volatile("pushfl\n\t" /* Save flags */ \
"pushl %%ebp\n\t" \
"movl %%esp,%0\n\t" /* save ESP */ \
"movl %5,%%esp\n\t" /* restore ESP */ \
"movl $1f,%1\n\t" /* save EIP */ \
"pushl %6\n\t" /* restore EIP */ \
"jmp __switch_to\n" \
"1:\t" \
"popl %%ebp\n\t" \
"popfl" \
:"=m" (prev->thread.sp),"=m" (prev->thread.ip), \
"=a" (last),"=S" (esi),"=D" (edi) \
:"m" (next->thread.sp),"m" (next->thread.ip), \
"2" (prev), "d" (next)); \
} while (0)

#endif /* __KERNEL__ */


#include <linux/irqflags.h>

/*
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43 changes: 0 additions & 43 deletions include/asm-x86/system_64.h
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Expand Up @@ -4,49 +4,6 @@
#include <asm/segment.h>
#include <asm/cmpxchg.h>

#ifdef __KERNEL__

/* entries in ARCH_DLINFO: */
#ifdef CONFIG_IA32_EMULATION
# define AT_VECTOR_SIZE_ARCH 2
#else
# define AT_VECTOR_SIZE_ARCH 1
#endif

#define __SAVE(reg,offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
#define __RESTORE(reg,offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"

/* frame pointer must be last for get_wchan */
#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"

#define __EXTRA_CLOBBER \
,"rcx","rbx","rdx","r8","r9","r10","r11","r12","r13","r14","r15"

/* Save restore flags to clear handle leaking NT */
#define switch_to(prev,next,last) \
asm volatile(SAVE_CONTEXT \
"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 %%gs:%P[pda_pcurrent],%%rsi\n\t" \
"movq %P[thread_info](%%rsi),%%r8\n\t" \
LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \
"movq %%rax,%%rdi\n\t" \
"jc ret_from_fork\n\t" \
RESTORE_CONTEXT \
: "=a" (last) \
: [next] "S" (next), [prev] "D" (prev), \
[threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \
[ti_flags] "i" (offsetof(struct thread_info, flags)),\
[tif_fork] "i" (TIF_FORK), \
[thread_info] "i" (offsetof(struct task_struct, stack)), \
[pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
: "memory", "cc" __EXTRA_CLOBBER)

#endif /* __KERNEL__ */

static inline unsigned long read_cr8(void)
{
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