diff options
Diffstat (limited to 'include/asm-x86/system.h')
| -rw-r--r-- | include/asm-x86/system.h | 115 |
1 files changed, 64 insertions, 51 deletions
diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h index 9cff02ffe6c..a2f04cd79b2 100644 --- a/include/asm-x86/system.h +++ b/include/asm-x86/system.h @@ -27,22 +27,44 @@ struct task_struct *__switch_to(struct task_struct *prev, * 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" \ +#define switch_to(prev, next, last) \ +do { \ + /* \ + * Context-switching clobbers all registers, so we clobber \ + * them explicitly, via unused output variables. \ + * (EAX and EBP is not listed because EBP is saved/restored \ + * explicitly for wchan access and EAX is the return value of \ + * __switch_to()) \ + */ \ + unsigned long ebx, ecx, edx, esi, edi; \ + \ + asm volatile("pushfl\n\t" /* save flags */ \ + "pushl %%ebp\n\t" /* save EBP */ \ + "movl %%esp,%[prev_sp]\n\t" /* save ESP */ \ + "movl %[next_sp],%%esp\n\t" /* restore ESP */ \ + "movl $1f,%[prev_ip]\n\t" /* save EIP */ \ + "pushl %[next_ip]\n\t" /* restore EIP */ \ + "jmp __switch_to\n" /* regparm call */ \ "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)); \ + "popl %%ebp\n\t" /* restore EBP */ \ + "popfl\n" /* restore flags */ \ + \ + /* output parameters */ \ + : [prev_sp] "=m" (prev->thread.sp), \ + [prev_ip] "=m" (prev->thread.ip), \ + "=a" (last), \ + \ + /* clobbered output registers: */ \ + "=b" (ebx), "=c" (ecx), "=d" (edx), \ + "=S" (esi), "=D" (edi) \ + \ + /* input parameters: */ \ + : [next_sp] "m" (next->thread.sp), \ + [next_ip] "m" (next->thread.ip), \ + \ + /* regparm parameters for __switch_to(): */ \ + [prev] "a" (prev), \ + [next] "d" (next)); \ } while (0) /* @@ -122,35 +144,34 @@ extern void load_gs_index(unsigned); */ #define loadsegment(seg, 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" \ - ".previous\n" \ - _ASM_EXTABLE(1b,3b) \ - : :"r" (value), "r" (0)) + "1:\t" \ + "movl %k0,%%" #seg "\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3:\t" \ + "movl %k1, %%" #seg "\n\t" \ + "jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE(1b,3b) \ + : :"r" (value), "r" (0)) /* * Save a segment register away */ -#define savesegment(seg, value) \ +#define savesegment(seg, value) \ asm volatile("mov %%" #seg ",%0":"=rm" (value)) static inline unsigned long get_limit(unsigned long segment) { unsigned long __limit; - __asm__("lsll %1,%0" - :"=r" (__limit):"r" (segment)); - return __limit+1; + asm("lsll %1,%0" : "=r" (__limit) : "r" (segment)); + return __limit + 1; } static inline void native_clts(void) { - asm volatile ("clts"); + asm volatile("clts"); } /* @@ -165,43 +186,43 @@ static unsigned long __force_order; static inline unsigned long native_read_cr0(void) { unsigned long val; - asm volatile("mov %%cr0,%0\n\t" :"=r" (val), "=m" (__force_order)); + asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr0(unsigned long val) { - asm volatile("mov %0,%%cr0": :"r" (val), "m" (__force_order)); + asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr2(void) { unsigned long val; - asm volatile("mov %%cr2,%0\n\t" :"=r" (val), "=m" (__force_order)); + asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr2(unsigned long val) { - asm volatile("mov %0,%%cr2": :"r" (val), "m" (__force_order)); + asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr3(void) { unsigned long val; - asm volatile("mov %%cr3,%0\n\t" :"=r" (val), "=m" (__force_order)); + asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr3(unsigned long val) { - asm volatile("mov %0,%%cr3": :"r" (val), "m" (__force_order)); + asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr4(void) { unsigned long val; - asm volatile("mov %%cr4,%0\n\t" :"=r" (val), "=m" (__force_order)); + asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } @@ -213,7 +234,7 @@ static inline unsigned long native_read_cr4_safe(void) #ifdef CONFIG_X86_32 asm volatile("1: mov %%cr4, %0\n" "2:\n" - _ASM_EXTABLE(1b,2b) + _ASM_EXTABLE(1b, 2b) : "=r" (val), "=m" (__force_order) : "0" (0)); #else val = native_read_cr4(); @@ -223,7 +244,7 @@ static inline unsigned long native_read_cr4_safe(void) static inline void native_write_cr4(unsigned long val) { - asm volatile("mov %0,%%cr4": :"r" (val), "m" (__force_order)); + asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order)); } #ifdef CONFIG_X86_64 @@ -244,6 +265,7 @@ static inline void native_wbinvd(void) { asm volatile("wbinvd": : :"memory"); } + #ifdef CONFIG_PARAVIRT #include <asm/paravirt.h> #else @@ -276,7 +298,7 @@ static inline void clflush(volatile void *__p) asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p)); } -#define nop() __asm__ __volatile__ ("nop") +#define nop() asm volatile ("nop") void disable_hlt(void); void enable_hlt(void); @@ -296,16 +318,7 @@ void default_idle(void); */ #ifdef CONFIG_X86_32 /* - * For now, "wmb()" doesn't actually do anything, as all - * Intel CPU's follow what Intel calls a *Processor Order*, - * in which all writes are seen in the program order even - * outside the CPU. - * - * I expect future Intel CPU's to have a weaker ordering, - * but I'd also expect them to finally get their act together - * and add some real memory barriers if so. - * - * Some non intel clones support out of order store. wmb() ceases to be a + * Some non-Intel clones support out of order store. wmb() ceases to be a * nop for these. */ #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) @@ -384,7 +397,7 @@ void default_idle(void); # define smp_wmb() barrier() #endif #define smp_read_barrier_depends() read_barrier_depends() -#define set_mb(var, value) do { (void) xchg(&var, value); } while (0) +#define set_mb(var, value) do { (void)xchg(&var, value); } while (0) #else #define smp_mb() barrier() #define smp_rmb() barrier() |