diff options
| -rw-r--r-- | arch/powerpc/include/asm/cputable.h | 14 | ||||
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 22 |
2 files changed, 31 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h index 3a40a992e594..f3a1fdd9cf08 100644 --- a/arch/powerpc/include/asm/cputable.h +++ b/arch/powerpc/include/asm/cputable.h @@ -198,6 +198,7 @@ extern const char *powerpc_base_platform; #define CPU_FTR_CP_USE_DCBTZ LONG_ASM_CONST(0x0040000000000000) #define CPU_FTR_UNALIGNED_LD_STD LONG_ASM_CONST(0x0080000000000000) #define CPU_FTR_ASYM_SMT LONG_ASM_CONST(0x0100000000000000) +#define CPU_FTR_STCX_CHECKS_ADDRESS LONG_ASM_CONST(0x0200000000000000) #ifndef __ASSEMBLY__ @@ -392,28 +393,31 @@ extern const char *powerpc_base_platform; CPU_FTR_MMCRA | CPU_FTR_CTRL) #define CPU_FTRS_POWER4 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ - CPU_FTR_MMCRA | CPU_FTR_CP_USE_DCBTZ) + CPU_FTR_MMCRA | CPU_FTR_CP_USE_DCBTZ | \ + CPU_FTR_STCX_CHECKS_ADDRESS) #define CPU_FTRS_PPC970 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_ALTIVEC_COMP | CPU_FTR_CAN_NAP | CPU_FTR_MMCRA | \ - CPU_FTR_CP_USE_DCBTZ) + CPU_FTR_CP_USE_DCBTZ | CPU_FTR_STCX_CHECKS_ADDRESS) #define CPU_FTRS_POWER5 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_MMCRA | CPU_FTR_SMT | \ CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \ - CPU_FTR_PURR) + CPU_FTR_PURR | CPU_FTR_STCX_CHECKS_ADDRESS) #define CPU_FTRS_POWER6 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_MMCRA | CPU_FTR_SMT | \ CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \ CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \ - CPU_FTR_DSCR | CPU_FTR_UNALIGNED_LD_STD) + CPU_FTR_DSCR | CPU_FTR_UNALIGNED_LD_STD | \ + CPU_FTR_STCX_CHECKS_ADDRESS) #define CPU_FTRS_POWER7 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_MMCRA | CPU_FTR_SMT | \ CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \ CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \ - CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT) + CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \ + CPU_FTR_STCX_CHECKS_ADDRESS) #define CPU_FTRS_CELL (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \ diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 42e9d908914a..4d5fa12ca6e8 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -202,7 +202,9 @@ syscall_exit: bge- syscall_error syscall_error_cont: ld r7,_NIP(r1) +BEGIN_FTR_SECTION stdcx. r0,0,r1 /* to clear the reservation */ +END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) andi. r6,r8,MSR_PR ld r4,_LINK(r1) /* @@ -419,6 +421,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) sync #endif /* CONFIG_SMP */ + /* + * If we optimise away the clear of the reservation in system + * calls because we know the CPU tracks the address of the + * reservation, then we need to clear it here to cover the + * case that the kernel context switch path has no larx + * instructions. + */ +BEGIN_FTR_SECTION + ldarx r6,0,r1 +END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS) + addi r6,r4,-THREAD /* Convert THREAD to 'current' */ std r6,PACACURRENT(r13) /* Set new 'current' */ @@ -576,7 +589,16 @@ ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ISERIES) andi. r0,r3,MSR_RI beq- unrecov_restore + /* + * Clear the reservation. If we know the CPU tracks the address of + * the reservation then we can potentially save some cycles and use + * a larx. On POWER6 and POWER7 this is significantly faster. + */ +BEGIN_FTR_SECTION stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r4,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) /* * Clear RI before restoring r13. If we are returning to |
