From 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad Mon Sep 17 00:00:00 2001 From: Mihai Caraman Date: Mon, 6 Aug 2012 03:27:07 +0000 Subject: [PATCH] powerpc/booke64: Use SPRG0/3 scratch for bolted TLB miss & crit int Embedded.Hypervisor category defines GSPRG0..3 physical registers for guests. Avoid SPRG4-7 usage as scratch in host exception handlers, otherwise guest SPRG4-7 registers will be clobbered. For bolted TLB miss exception handlers, which is the version currently supported by KVM, use SPRN_SPRG_GEN_SCRATCH aka SPRG0 instead of SPRN_SPRG_TLB_SCRATCH aka SPRG6. Keep using TLB PACA slots to fit in one 64-byte cache line. For critical exception handlers use SPRG3 instead of SPRG7. Provide a routine to store and restore user-visible SPRGs. This will be subsequently used to restore VDSO information in SPRG3. Add EX_R13 to paca slots to free up SPRG3 and change the critical exception epilog to use it. Signed-off-by: Mihai Caraman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/exception-64e.h | 5 +++-- arch/powerpc/include/asm/reg.h | 5 +++-- arch/powerpc/kernel/exceptions-64e.S | 17 +++++++++++++++-- arch/powerpc/mm/tlb_low_64e.S | 4 ++-- 4 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h index e73452f09019..51fa43e536b9 100644 --- a/arch/powerpc/include/asm/exception-64e.h +++ b/arch/powerpc/include/asm/exception-64e.h @@ -46,8 +46,9 @@ #define EX_CR (1 * 8) #define EX_R10 (2 * 8) #define EX_R11 (3 * 8) -#define EX_R14 (4 * 8) -#define EX_R15 (5 * 8) +#define EX_R13 (4 * 8) +#define EX_R14 (5 * 8) +#define EX_R15 (6 * 8) /* * The TLB miss exception uses different slots. diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index c195bf0e6241..a391244c18e1 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -761,7 +761,8 @@ * 64-bit embedded * - SPRG0 generic exception scratch * - SPRG2 TLB exception stack - * - SPRG3 CPU and NUMA node for VDSO getcpu (user visible) + * - SPRG3 critical exception scratch and + * CPU and NUMA node for VDSO getcpu (user visible) * - SPRG4 unused (user visible) * - SPRG6 TLB miss scratch (user visible, sorry !) * - SPRG7 critical exception scratch @@ -858,7 +859,7 @@ #ifdef CONFIG_PPC_BOOK3E_64 #define SPRN_SPRG_MC_SCRATCH SPRN_SPRG8 -#define SPRN_SPRG_CRIT_SCRATCH SPRN_SPRG7 +#define SPRN_SPRG_CRIT_SCRATCH SPRN_SPRG3 #define SPRN_SPRG_DBG_SCRATCH SPRN_SPRG9 #define SPRN_SPRG_TLB_EXFRAME SPRN_SPRG2 #define SPRN_SPRG_TLB_SCRATCH SPRN_SPRG6 diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index 83c20e84a4fb..7476b0ae09fb 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -42,6 +42,7 @@ mfspr r13,SPRN_SPRG_PACA; /* get PACA */ \ std r10,PACA_EX##type+EX_R10(r13); \ std r11,PACA_EX##type+EX_R11(r13); \ + PROLOG_STORE_RESTORE_SCRATCH_##type; \ mfcr r10; /* save CR */ \ mfspr r11,SPRN_##type##_SRR1;/* what are we coming from */ \ DO_KVM intnum,SPRN_##type##_SRR1; /* KVM hook */ \ @@ -99,6 +100,18 @@ #define GDBELL_EXCEPTION_PROLOG(n, intnum, addition) \ EXCEPTION_PROLOG(n, intnum, GDBELL, addition##_GDBELL(n)) +/* + * Store user-visible scratch in PACA exception slots and restore proper value + */ +#define PROLOG_STORE_RESTORE_SCRATCH_GEN +#define PROLOG_STORE_RESTORE_SCRATCH_GDBELL +#define PROLOG_STORE_RESTORE_SCRATCH_DBG +#define PROLOG_STORE_RESTORE_SCRATCH_MC + +#define PROLOG_STORE_RESTORE_SCRATCH_CRIT \ + mfspr r10,SPRN_SPRG_CRIT_SCRATCH; /* get r13 */ \ + std r10,PACA_EXCRIT+EX_R13(r13) + /* Variants of the "addition" argument for the prolog */ #define PROLOG_ADDITION_NONE_GEN(n) @@ -454,7 +467,7 @@ interrupt_end_book3e: mtcr r10 ld r10,PACA_EXCRIT+EX_R10(r13) /* restore registers */ ld r11,PACA_EXCRIT+EX_R11(r13) - mfspr r13,SPRN_SPRG_CRIT_SCRATCH + ld r13,PACA_EXCRIT+EX_R13(r13) rfci /* Normal debug exception */ @@ -467,7 +480,7 @@ interrupt_end_book3e: /* Now we mash up things to make it look like we are coming on a * normal exception */ - mfspr r15,SPRN_SPRG_CRIT_SCRATCH + ld r15,PACA_EXCRIT+EX_R13(r13) mtspr SPRN_SPRG_GEN_SCRATCH,r15 mfspr r14,SPRN_DBSR EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE) diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index d884fa44d34f..b4113bf86353 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -40,7 +40,7 @@ **********************************************************************/ .macro tlb_prolog_bolted intnum addr - mtspr SPRN_SPRG_TLB_SCRATCH,r13 + mtspr SPRN_SPRG_GEN_SCRATCH,r13 mfspr r13,SPRN_SPRG_PACA std r10,PACA_EXTLB+EX_TLB_R10(r13) mfcr r10 @@ -69,7 +69,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) ld r15,PACA_EXTLB+EX_TLB_R15(r13) TLB_MISS_RESTORE_STATS_BOLTED ld r16,PACA_EXTLB+EX_TLB_R16(r13) - mfspr r13,SPRN_SPRG_TLB_SCRATCH + mfspr r13,SPRN_SPRG_GEN_SCRATCH .endm /* Data TLB miss */ -- 2.20.1