diff options
| -rw-r--r-- | arch/sparc64/kernel/sparc64_ksyms.c | 9 | ||||
| -rw-r--r-- | arch/sparc64/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/sparc64/lib/mb.S | 73 | ||||
| -rw-r--r-- | include/asm-sparc64/system.h | 49 |
4 files changed, 43 insertions, 90 deletions
diff --git a/arch/sparc64/kernel/sparc64_ksyms.c b/arch/sparc64/kernel/sparc64_ksyms.c index d89fc24808d3..7d9a0f6c437d 100644 --- a/arch/sparc64/kernel/sparc64_ksyms.c +++ b/arch/sparc64/kernel/sparc64_ksyms.c @@ -403,12 +403,3 @@ EXPORT_SYMBOL(xor_vis_4); EXPORT_SYMBOL(xor_vis_5); EXPORT_SYMBOL(prom_palette); - -/* memory barriers */ -EXPORT_SYMBOL(mb); -EXPORT_SYMBOL(rmb); -EXPORT_SYMBOL(wmb); -EXPORT_SYMBOL(membar_storeload); -EXPORT_SYMBOL(membar_storeload_storestore); -EXPORT_SYMBOL(membar_storeload_loadload); -EXPORT_SYMBOL(membar_storestore_loadstore); diff --git a/arch/sparc64/lib/Makefile b/arch/sparc64/lib/Makefile index 6201f1040982..40dbeec7e5d6 100644 --- a/arch/sparc64/lib/Makefile +++ b/arch/sparc64/lib/Makefile @@ -12,7 +12,7 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \ U1memcpy.o U1copy_from_user.o U1copy_to_user.o \ U3memcpy.o U3copy_from_user.o U3copy_to_user.o U3patch.o \ copy_in_user.o user_fixup.o memmove.o \ - mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o mb.o + mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o diff --git a/arch/sparc64/lib/mb.S b/arch/sparc64/lib/mb.S deleted file mode 100644 index 4004f748619f..000000000000 --- a/arch/sparc64/lib/mb.S +++ /dev/null @@ -1,73 +0,0 @@ -/* mb.S: Out of line memory barriers. - * - * Copyright (C) 2005 David S. Miller (davem@davemloft.net) - */ - - /* These are here in an effort to more fully work around - * Spitfire Errata #51. Essentially, if a memory barrier - * occurs soon after a mispredicted branch, the chip can stop - * executing instructions until a trap occurs. Therefore, if - * interrupts are disabled, the chip can hang forever. - * - * It used to be believed that the memory barrier had to be - * right in the delay slot, but a case has been traced - * recently wherein the memory barrier was one instruction - * after the branch delay slot and the chip still hung. The - * offending sequence was the following in sym_wakeup_done() - * of the sym53c8xx_2 driver: - * - * call sym_ccb_from_dsa, 0 - * movge %icc, 0, %l0 - * brz,pn %o0, .LL1303 - * mov %o0, %l2 - * membar #LoadLoad - * - * The branch has to be mispredicted for the bug to occur. - * Therefore, we put the memory barrier explicitly into a - * "branch always, predicted taken" delay slot to avoid the - * problem case. - */ - - .text - -99: retl - nop - - .globl mb -mb: ba,pt %xcc, 99b - membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad - .size mb, .-mb - - .globl rmb -rmb: ba,pt %xcc, 99b - membar #LoadLoad - .size rmb, .-rmb - - .globl wmb -wmb: ba,pt %xcc, 99b - membar #StoreStore - .size wmb, .-wmb - - .globl membar_storeload -membar_storeload: - ba,pt %xcc, 99b - membar #StoreLoad - .size membar_storeload, .-membar_storeload - - .globl membar_storeload_storestore -membar_storeload_storestore: - ba,pt %xcc, 99b - membar #StoreLoad | #StoreStore - .size membar_storeload_storestore, .-membar_storeload_storestore - - .globl membar_storeload_loadload -membar_storeload_loadload: - ba,pt %xcc, 99b - membar #StoreLoad | #LoadLoad - .size membar_storeload_loadload, .-membar_storeload_loadload - - .globl membar_storestore_loadstore -membar_storestore_loadstore: - ba,pt %xcc, 99b - membar #StoreStore | #LoadStore - .size membar_storestore_loadstore, .-membar_storestore_loadstore diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h index 5e94c05dc2fc..b5417529f6f1 100644 --- a/include/asm-sparc64/system.h +++ b/include/asm-sparc64/system.h @@ -28,13 +28,48 @@ enum sparc_cpu { #define ARCH_SUN4C_SUN4 0 #define ARCH_SUN4 0 -extern void mb(void); -extern void rmb(void); -extern void wmb(void); -extern void membar_storeload(void); -extern void membar_storeload_storestore(void); -extern void membar_storeload_loadload(void); -extern void membar_storestore_loadstore(void); +/* These are here in an effort to more fully work around Spitfire Errata + * #51. Essentially, if a memory barrier occurs soon after a mispredicted + * branch, the chip can stop executing instructions until a trap occurs. + * Therefore, if interrupts are disabled, the chip can hang forever. + * + * It used to be believed that the memory barrier had to be right in the + * delay slot, but a case has been traced recently wherein the memory barrier + * was one instruction after the branch delay slot and the chip still hung. + * The offending sequence was the following in sym_wakeup_done() of the + * sym53c8xx_2 driver: + * + * call sym_ccb_from_dsa, 0 + * movge %icc, 0, %l0 + * brz,pn %o0, .LL1303 + * mov %o0, %l2 + * membar #LoadLoad + * + * The branch has to be mispredicted for the bug to occur. Therefore, we put + * the memory barrier explicitly into a "branch always, predicted taken" + * delay slot to avoid the problem case. + */ +#define membar_safe(type) \ +do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \ + " membar " type "\n" \ + "1:\n" \ + : : : "memory"); \ +} while (0) + +#define mb() \ + membar_safe("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad") +#define rmb() \ + membar_safe("#LoadLoad") +#define wmb() \ + membar_safe("#StoreStore") +#define membar_storeload() \ + membar_safe("#StoreLoad") +#define membar_storeload_storestore() \ + membar_safe("#StoreLoad | #StoreStore") +#define membar_storeload_loadload() \ + membar_safe("#StoreLoad | #LoadLoad") +#define membar_storestore_loadstore() \ + membar_safe("#StoreStore | #LoadStore") #endif |