diff options
| -rw-r--r-- | arch/powerpc/include/asm/exception-64s.h | 6 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 5 | ||||
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 37 | ||||
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 8 | ||||
| -rw-r--r-- | arch/powerpc/xmon/xmon.c | 1 |
6 files changed, 51 insertions, 7 deletions
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 63a309a432ad..59134ebd7d49 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -275,6 +275,12 @@ END_FTR_SECTION_NESTED(ftr,ftr,943) #endif +/* Do not enable RI */ +#define EXCEPTION_PROLOG_PSERIES_NORI(area, label, h, extra, vec) \ + EXCEPTION_PROLOG_0(area); \ + EXCEPTION_PROLOG_1(area, extra, vec); \ + EXCEPTION_PROLOG_PSERIES_1_NORI(label, h); + #define __KVM_HANDLER(area, h, n) \ BEGIN_FTR_SECTION_NESTED(947) \ diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 601e2327dd8c..b1197c1affac 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -187,12 +187,15 @@ struct paca_struct { #ifdef CONFIG_PPC_BOOK3S_64 /* Exclusive emergency stack pointer for machine check exception. */ void *mc_emergency_sp; + + u16 in_nmi; /* In nmi handler */ + /* * Flag to check whether we are in machine check early handler * and already using emergency stack. */ u16 in_mce; - u8 hmi_event_available; /* HMI event is available */ + u8 hmi_event_available; /* HMI event is available */ #endif /* Stuff for accurate time accounting */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 46732ee70b43..1466e96d36cf 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -235,6 +235,7 @@ int main(void) #ifdef CONFIG_PPC_BOOK3S_64 OFFSET(PACAMCEMERGSP, paca_struct, mc_emergency_sp); OFFSET(PACA_IN_MCE, paca_struct, in_mce); + OFFSET(PACA_IN_NMI, paca_struct, in_nmi); #endif OFFSET(PACAHWCPUID, paca_struct, hw_cpu_id); OFFSET(PACAKEXECSTATE, paca_struct, kexec_state); diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 3a654b1f24e9..4be62568fbc2 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -116,7 +116,11 @@ EXC_VIRT_NONE(0x4000, 0x100) EXC_REAL_BEGIN(system_reset, 0x100, 0x100) SET_SCRATCH0(r13) - EXCEPTION_PROLOG_PSERIES(PACA_EXNMI, system_reset_common, EXC_STD, + /* + * MSR_RI is not enabled, because PACA_EXNMI and nmi stack is + * being used, so a nested NMI exception would corrupt it. + */ + EXCEPTION_PROLOG_PSERIES_NORI(PACA_EXNMI, system_reset_common, EXC_STD, IDLETEST, 0x100) EXC_REAL_END(system_reset, 0x100, 0x100) @@ -128,9 +132,31 @@ EXC_COMMON_BEGIN(system_reset_idle_common) #endif EXC_COMMON_BEGIN(system_reset_common) + /* + * Increment paca->in_nmi then enable MSR_RI. SLB or MCE will be able + * to recover, but nested NMI will notice in_nmi and not recover + * because of the use of the NMI stack. in_nmi reentrancy is tested in + * system_reset_exception. + */ + lhz r10,PACA_IN_NMI(r13) + addi r10,r10,1 + sth r10,PACA_IN_NMI(r13) + li r10,MSR_RI + mtmsrd r10,1 + EXCEPTION_COMMON(PACA_EXNMI, 0x100, - system_reset, system_reset_exception, - ret_from_except, ADD_NVGPRS;ADD_RECONCILE) + system_reset, system_reset_exception, 1f, + ADD_NVGPRS;ADD_RECONCILE) +1: /* EXCEPTION_COMMON continues here */ + + /* + * The stack is no longer in use, decrement in_nmi. + */ + lhz r10,PACA_IN_NMI(r13) + subi r10,r10,1 + sth r10,PACA_IN_NMI(r13) + + b ret_from_except #ifdef CONFIG_PPC_PSERIES /* @@ -138,8 +164,9 @@ EXC_COMMON_BEGIN(system_reset_common) */ TRAMP_REAL_BEGIN(system_reset_fwnmi) SET_SCRATCH0(r13) /* save r13 */ - EXCEPTION_PROLOG_PSERIES(PACA_EXNMI, system_reset_common, EXC_STD, - NOTEST, 0x100) + /* See comment at system_reset exception */ + EXCEPTION_PROLOG_PSERIES_NORI(PACA_EXNMI, system_reset_common, + EXC_STD, NOTEST, 0x100) #endif /* CONFIG_PPC_PSERIES */ diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 76f6045b021b..2393d3c46236 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -282,11 +282,17 @@ void system_reset_exception(struct pt_regs *regs) /* See if any machine dependent calls */ if (ppc_md.system_reset_exception) { if (ppc_md.system_reset_exception(regs)) - return; + goto out; } die("System Reset", regs, SIGABRT); +out: +#ifdef CONFIG_PPC_BOOK3S_64 + BUG_ON(get_paca()->in_nmi == 0); + if (get_paca()->in_nmi > 1) + panic("Unrecoverable nested System Reset"); +#endif /* Must die if the interrupt is not recoverable */ if (!(regs->msr & MSR_RI)) panic("Unrecoverable System Reset"); diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 2b21e90fff8d..99348a2961b8 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -2236,6 +2236,7 @@ static void dump_one_paca(int cpu) DUMP(p, emergency_sp, "p"); #ifdef CONFIG_PPC_BOOK3S_64 DUMP(p, mc_emergency_sp, "p"); + DUMP(p, in_nmi, "x"); DUMP(p, in_mce, "x"); DUMP(p, hmi_event_available, "x"); #endif |