diff options
| author | Glauber de Oliveira Costa <gcosta@redhat.com> | 2008-01-30 13:31:08 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 13:31:08 +0100 |
| commit | 0a3b4d151a8e57f50ce5a12c7ea5ec9965cf0b5a (patch) | |
| tree | d052ba5e4b35484a78d613d3af42e4026b2fc192 /include/asm-x86/system.h | |
| parent | 833d8469b102365f427f7791e79ec1843ff5f164 (diff) | |
x86: move switch_to macro to system.h
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>
Diffstat (limited to 'include/asm-x86/system.h')
| -rw-r--r-- | include/asm-x86/system.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h index 4c15eb11a91..ba3403f1d02 100644 --- a/include/asm-x86/system.h +++ b/include/asm-x86/system.h @@ -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 |