diff options
| -rw-r--r-- | arch/x86_64/kernel/setup64.c | 3 | ||||
| -rw-r--r-- | include/asm-x86_64/pda.h | 41 |
2 files changed, 25 insertions, 19 deletions
diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c index e85cfbb49b6..491361752c7 100644 --- a/arch/x86_64/kernel/setup64.c +++ b/arch/x86_64/kernel/setup64.c @@ -121,7 +121,10 @@ void pda_init(int cpu) /* Setup up data that may be needed in __get_free_pages early */ asm volatile("movl %0,%%fs ; movl %0,%%gs" :: "r" (0)); + /* Memory clobbers used to order PDA accessed */ + mb(); wrmsrl(MSR_GS_BASE, pda); + mb(); pda->cpunumber = cpu; pda->irqcount = -1; diff --git a/include/asm-x86_64/pda.h b/include/asm-x86_64/pda.h index b47c3df9ed1..55e21da96e7 100644 --- a/include/asm-x86_64/pda.h +++ b/include/asm-x86_64/pda.h @@ -36,40 +36,43 @@ extern struct x8664_pda boot_cpu_pda[]; * There is no fast way to get the base address of the PDA, all the accesses * have to mention %fs/%gs. So it needs to be done this Torvaldian way. */ -#define sizeof_field(type,field) (sizeof(((type *)0)->field)) -#define typeof_field(type,field) typeof(((type *)0)->field) - extern void __bad_pda_field(void); +/* proxy_pda doesn't actually exist, but tell gcc it is accessed + for all PDA accesses so it gets read/write dependencies right. */ +extern struct x8664_pda _proxy_pda; + #define pda_offset(field) offsetof(struct x8664_pda, field) #define pda_to_op(op,field,val) do { \ - typedef typeof_field(struct x8664_pda, field) T__; \ - switch (sizeof_field(struct x8664_pda, field)) { \ + typedef typeof(_proxy_pda.field) T__; \ + switch (sizeof(_proxy_pda.field)) { \ case 2: \ -asm volatile(op "w %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \ +asm(op "w %1,%%gs:%P2" : "+m" (_proxy_pda.field) : \ + "ri" ((T__)val),"i"(pda_offset(field))); break; \ case 4: \ -asm volatile(op "l %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \ +asm(op "l %1,%%gs:%P2" : "+m" (_proxy_pda.field) : \ + "ri" ((T__)val),"i"(pda_offset(field))); break; \ case 8: \ -asm volatile(op "q %0,%%gs:%P1"::"ri" ((T__)val),"i"(pda_offset(field)):"memory"); break; \ - default: __bad_pda_field(); \ +asm(op "q %1,%%gs:%P2": "+m" (_proxy_pda.field) : \ + "ri" ((T__)val),"i"(pda_offset(field))); break; \ +default: __bad_pda_field(); \ } \ } while (0) -/* - * AK: PDA read accesses should be neither volatile nor have an memory clobber. - * Unfortunately removing them causes all hell to break lose currently. - */ #define pda_from_op(op,field) ({ \ - typeof_field(struct x8664_pda, field) ret__; \ - switch (sizeof_field(struct x8664_pda, field)) { \ + typeof(_proxy_pda.field) ret__; \ + switch (sizeof(_proxy_pda.field)) { \ case 2: \ -asm volatile(op "w %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\ +asm(op "w %%gs:%P1,%0":"=r" (ret__):\ + "i" (pda_offset(field)), "m" (_proxy_pda.field)); break;\ case 4: \ -asm volatile(op "l %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\ +asm(op "l %%gs:%P1,%0":"=r" (ret__):\ + "i" (pda_offset(field)), "m" (_proxy_pda.field)); break;\ case 8: \ -asm volatile(op "q %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\ - default: __bad_pda_field(); \ +asm(op "q %%gs:%P1,%0":"=r" (ret__):\ + "i" (pda_offset(field)), "m" (_proxy_pda.field)); break;\ +default: __bad_pda_field(); \ } \ ret__; }) |