From a314ea5abf6dbaf35f14c9bd1d93105260fb9336 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 24 Nov 2020 15:24:57 +0000 Subject: [PATCH] powerpc/8xx: Use SPRN_SPRG_SCRATCH2 in ITLB miss exception In order to re-enable MMU earlier, ensure ITLB miss exception cannot clobber SPRN_SPRG_SCRATCH0 and SPRN_SPRG_SCRATCH1. Do so by using SPRN_SPRG_SCRATCH2 and SPRN_M_TW instead, like the DTLB miss exception. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/abc78e8e9577d473691ebb9996c6413b37bfd9ca.1606231483.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/head_8xx.S | 12 ++++++------ arch/powerpc/perf/8xx-pmu.c | 4 ++-- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 4d792a8fdc1b..ef451fb08d68 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -190,8 +190,8 @@ SystemCall: #endif InstructionTLBMiss: - mtspr SPRN_SPRG_SCRATCH0, r10 - mtspr SPRN_SPRG_SCRATCH1, r11 + mtspr SPRN_SPRG_SCRATCH2, r10 + mtspr SPRN_M_TW, r11 /* If we are faulting a kernel address, we have to use the * kernel page tables. @@ -230,8 +230,8 @@ InstructionTLBMiss: mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ /* Restore registers */ -0: mfspr r10, SPRN_SPRG_SCRATCH0 - mfspr r11, SPRN_SPRG_SCRATCH1 +0: mfspr r10, SPRN_SPRG_SCRATCH2 + mfspr r11, SPRN_M_TW rfi patch_site 0b, patch__itlbmiss_exit_1 @@ -240,8 +240,8 @@ InstructionTLBMiss: 0: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) addi r10, r10, 1 stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) - mfspr r10, SPRN_SPRG_SCRATCH0 - mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r10, SPRN_SPRG_SCRATCH2 + mfspr r11, SPRN_M_TW rfi #endif diff --git a/arch/powerpc/perf/8xx-pmu.c b/arch/powerpc/perf/8xx-pmu.c index e53c3c161257..02db58c7427a 100644 --- a/arch/powerpc/perf/8xx-pmu.c +++ b/arch/powerpc/perf/8xx-pmu.c @@ -165,9 +165,9 @@ static void mpc8xx_pmu_del(struct perf_event *event, int flags) break; case PERF_8xx_ID_ITLB_LOAD_MISS: if (atomic_dec_return(&itlb_miss_ref) == 0) { - /* mfspr r10, SPRN_SPRG_SCRATCH0 */ + /* mfspr r10, SPRN_SPRG_SCRATCH2 */ struct ppc_inst insn = ppc_inst(PPC_INST_MFSPR | __PPC_RS(R10) | - __PPC_SPR(SPRN_SPRG_SCRATCH0)); + __PPC_SPR(SPRN_SPRG_SCRATCH2)); patch_instruction_site(&patch__itlbmiss_exit_1, insn); }