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-rw-r--r--arch/powerpc/kernel/head_64.S35
1 files changed, 33 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index e16eb2a33173..6ff3cf506088 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -191,6 +191,37 @@ exception_marker:
ori reg,reg,(label)@l; /* virt addr of handler ... */
#endif
+/*
+ * Equal to EXCEPTION_PROLOG_PSERIES, except that it forces 64bit mode.
+ * The firmware calls the registered system_reset_fwnmi and
+ * machine_check_fwnmi handlers in 32bit mode if the cpu happens to run
+ * a 32bit application at the time of the event.
+ * This firmware bug is present on POWER4 and JS20.
+ */
+#define EXCEPTION_PROLOG_PSERIES_FORCE_64BIT(area, label) \
+ mfspr r13,SPRN_SPRG3; /* get paca address into r13 */ \
+ std r9,area+EX_R9(r13); /* save r9 - r12 */ \
+ std r10,area+EX_R10(r13); \
+ std r11,area+EX_R11(r13); \
+ std r12,area+EX_R12(r13); \
+ mfspr r9,SPRN_SPRG1; \
+ std r9,area+EX_R13(r13); \
+ mfcr r9; \
+ clrrdi r12,r13,32; /* get high part of &label */ \
+ mfmsr r10; \
+ /* force 64bit mode */ \
+ li r11,5; /* MSR_SF_LG|MSR_ISF_LG */ \
+ rldimi r10,r11,61,0; /* insert into top 3 bits */ \
+ /* done 64bit mode */ \
+ mfspr r11,SPRN_SRR0; /* save SRR0 */ \
+ LOAD_HANDLER(r12,label) \
+ ori r10,r10,MSR_IR|MSR_DR|MSR_RI; \
+ mtspr SPRN_SRR0,r12; \
+ mfspr r12,SPRN_SRR1; /* and SRR1 */ \
+ mtspr SPRN_SRR1,r10; \
+ rfid; \
+ b . /* prevent speculative execution */
+
#define EXCEPTION_PROLOG_PSERIES(area, label) \
mfspr r13,SPRN_SPRG3; /* get paca address into r13 */ \
std r9,area+EX_R9(r13); /* save r9 - r12 */ \
@@ -604,14 +635,14 @@ slb_miss_user_pseries:
system_reset_fwnmi:
HMT_MEDIUM
mtspr SPRN_SPRG1,r13 /* save r13 */
- EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common)
+ EXCEPTION_PROLOG_PSERIES_FORCE_64BIT(PACA_EXGEN, system_reset_common)
.globl machine_check_fwnmi
.align 7
machine_check_fwnmi:
HMT_MEDIUM
mtspr SPRN_SPRG1,r13 /* save r13 */
- EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
+ EXCEPTION_PROLOG_PSERIES_FORCE_64BIT(PACA_EXMC, machine_check_common)
#ifdef CONFIG_PPC_ISERIES
/*** ISeries-LPAR interrupt handlers ***/

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