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-rw-r--r--arch/powerpc/kernel/asm-offsets.c4
-rw-r--r--arch/powerpc/kernel/exceptions-64s.S111
-rw-r--r--arch/powerpc/kernel/traps.c12
3 files changed, 127 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 2ea5cc0..41a2839 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -232,6 +232,10 @@ int main(void)
DEFINE(PACA_DTL_RIDX, offsetof(struct paca_struct, dtl_ridx));
#endif /* CONFIG_PPC_STD_MMU_64 */
DEFINE(PACAEMERGSP, offsetof(struct paca_struct, emergency_sp));
+#ifdef CONFIG_PPC_BOOK3S_64
+ DEFINE(PACAMCEMERGSP, offsetof(struct paca_struct, mc_emergency_sp));
+ DEFINE(PACA_IN_MCE, offsetof(struct paca_struct, in_mce));
+#endif
DEFINE(PACAHWCPUID, offsetof(struct paca_struct, hw_cpu_id));
DEFINE(PACAKEXECSTATE, offsetof(struct paca_struct, kexec_state));
DEFINE(PACA_STARTTIME, offsetof(struct paca_struct, starttime));
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 9f905e4..4034dfb 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -156,7 +156,11 @@ machine_check_pSeries_1:
HMT_MEDIUM_PPR_DISCARD
SET_SCRATCH0(r13) /* save r13 */
EXCEPTION_PROLOG_0(PACA_EXMC)
+BEGIN_FTR_SECTION
+ b machine_check_pSeries_early
+FTR_SECTION_ELSE
b machine_check_pSeries_0
+ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
. = 0x300
.globl data_access_pSeries
@@ -405,6 +409,64 @@ denorm_exception_hv:
.align 7
/* moved from 0x200 */
+machine_check_pSeries_early:
+BEGIN_FTR_SECTION
+ EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200)
+ /*
+ * Register contents:
+ * R13 = PACA
+ * R9 = CR
+ * Original R9 to R13 is saved on PACA_EXMC
+ *
+ * Switch to mc_emergency stack and handle re-entrancy (though we
+ * currently don't test for overflow). Save MCE registers srr1,
+ * srr0, dar and dsisr and then set ME=1
+ *
+ * We use paca->in_mce to check whether this is the first entry or
+ * nested machine check. We increment paca->in_mce to track nested
+ * machine checks.
+ *
+ * If this is the first entry then set stack pointer to
+ * paca->mc_emergency_sp, otherwise r1 is already pointing to
+ * stack frame on mc_emergency stack.
+ *
+ * NOTE: We are here with MSR_ME=0 (off), which means we risk a
+ * checkstop if we get another machine check exception before we do
+ * rfid with MSR_ME=1.
+ */
+ mr r11,r1 /* Save r1 */
+ lhz r10,PACA_IN_MCE(r13)
+ cmpwi r10,0 /* Are we in nested machine check */
+ bne 0f /* Yes, we are. */
+ /* First machine check entry */
+ ld r1,PACAMCEMERGSP(r13) /* Use MC emergency stack */
+0: subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */
+ addi r10,r10,1 /* increment paca->in_mce */
+ sth r10,PACA_IN_MCE(r13)
+ std r11,GPR1(r1) /* Save r1 on the stack. */
+ std r11,0(r1) /* make stack chain pointer */
+ mfspr r11,SPRN_SRR0 /* Save SRR0 */
+ std r11,_NIP(r1)
+ mfspr r11,SPRN_SRR1 /* Save SRR1 */
+ std r11,_MSR(r1)
+ mfspr r11,SPRN_DAR /* Save DAR */
+ std r11,_DAR(r1)
+ mfspr r11,SPRN_DSISR /* Save DSISR */
+ std r11,_DSISR(r1)
+ std r9,_CCR(r1) /* Save CR in stackframe */
+ /* Save r9 through r13 from EXMC save area to stack frame. */
+ EXCEPTION_PROLOG_COMMON_2(PACA_EXMC)
+ mfmsr r11 /* get MSR value */
+ ori r11,r11,MSR_ME /* turn on ME bit */
+ ori r11,r11,MSR_RI /* turn on RI bit */
+ ld r12,PACAKBASE(r13) /* get high part of &label */
+ LOAD_HANDLER(r12, machine_check_handle_early)
+ mtspr SPRN_SRR0,r12
+ mtspr SPRN_SRR1,r11
+ rfid
+ b . /* prevent speculative execution */
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
+
machine_check_pSeries:
.globl machine_check_fwnmi
machine_check_fwnmi:
@@ -712,6 +774,55 @@ machine_check_common:
bl .machine_check_exception
b .ret_from_except
+#define MACHINE_CHECK_HANDLER_WINDUP \
+ /* Clear MSR_RI before setting SRR0 and SRR1. */\
+ li r0,MSR_RI; \
+ mfmsr r9; /* get MSR value */ \
+ andc r9,r9,r0; \
+ mtmsrd r9,1; /* Clear MSR_RI */ \
+ /* Move original SRR0 and SRR1 into the respective regs */ \
+ ld r9,_MSR(r1); \
+ mtspr SPRN_SRR1,r9; \
+ ld r3,_NIP(r1); \
+ mtspr SPRN_SRR0,r3; \
+ ld r9,_CTR(r1); \
+ mtctr r9; \
+ ld r9,_XER(r1); \
+ mtxer r9; \
+ ld r9,_LINK(r1); \
+ mtlr r9; \
+ REST_GPR(0, r1); \
+ REST_8GPRS(2, r1); \
+ REST_GPR(10, r1); \
+ ld r11,_CCR(r1); \
+ mtcr r11; \
+ /* Decrement paca->in_mce. */ \
+ lhz r12,PACA_IN_MCE(r13); \
+ subi r12,r12,1; \
+ sth r12,PACA_IN_MCE(r13); \
+ REST_GPR(11, r1); \
+ REST_2GPRS(12, r1); \
+ /* restore original r1. */ \
+ ld r1,GPR1(r1)
+
+ /*
+ * Handle machine check early in real mode. We come here with
+ * ME=1, MMU (IR=0 and DR=0) off and using MC emergency stack.
+ */
+ .align 7
+ .globl machine_check_handle_early
+machine_check_handle_early:
+BEGIN_FTR_SECTION
+ std r0,GPR0(r1) /* Save r0 */
+ EXCEPTION_PROLOG_COMMON_3(0x200)
+ bl .save_nvgprs
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl .machine_check_early
+ /* Deliver the machine check to host kernel in V mode. */
+ MACHINE_CHECK_HANDLER_WINDUP
+ b machine_check_pSeries
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
+
STD_EXCEPTION_COMMON_ASYNC(0x500, hardware_interrupt, do_IRQ)
STD_EXCEPTION_COMMON_ASYNC(0x900, decrementer, .timer_interrupt)
STD_EXCEPTION_COMMON(0x980, hdecrementer, .hdec_interrupt)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 907a472..97a1ce7 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -285,6 +285,18 @@ void system_reset_exception(struct pt_regs *regs)
/* What should we do here? We could issue a shutdown or hard reset. */
}
+
+/*
+ * This function is called in real mode. Strictly no printk's please.
+ *
+ * regs->nip and regs->msr contains srr0 and ssr1.
+ */
+long machine_check_early(struct pt_regs *regs)
+{
+ /* TODO: handle/decode machine check reason */
+ return 0;
+}
+
#endif
/*
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