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authorChristophe Leroy <christophe.leroy@csgroup.eu>2020-11-24 15:24:57 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2020-12-09 23:48:12 +1100
commita314ea5abf6dbaf35f14c9bd1d93105260fb9336 (patch)
tree923c8dce3f3deb28a56f4f7627ef34e5de51b4db
parent576e02bbf1062b9118d5bbb96a40ed3b6b359f22 (diff)
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 <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/abc78e8e9577d473691ebb9996c6413b37bfd9ca.1606231483.git.christophe.leroy@csgroup.eu
-rw-r--r--arch/powerpc/kernel/head_8xx.S12
-rw-r--r--arch/powerpc/perf/8xx-pmu.c4
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);
}