diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index eee8f843f3d67f7d8d9888e7c1c47c51e324a0e6..a5757bef03cd28d36ae29df1af288a82a83a8aee 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -435,14 +435,32 @@ void hv_nmi_check_nonrecoverable(struct pt_regs *regs) void system_reset_exception(struct pt_regs *regs) { + unsigned long hsrr0, hsrr1; + bool nested = in_nmi(); + bool saved_hsrrs = false; + /* * Avoid crashes in case of nested NMI exceptions. Recoverability * is determined by RI and in_nmi */ - bool nested = in_nmi(); if (!nested) nmi_enter(); + /* + * System reset can interrupt code where HSRRs are live and MSR[RI]=1. + * The system reset interrupt itself may clobber HSRRs (e.g., to call + * OPAL), so save them here and restore them before returning. + * + * Machine checks don't need to save HSRRs, as the real mode handler + * is careful to avoid them, and the regular handler is not delivered + * as an NMI. + */ + if (cpu_has_feature(CPU_FTR_HVMODE)) { + hsrr0 = mfspr(SPRN_HSRR0); + hsrr1 = mfspr(SPRN_HSRR1); + saved_hsrrs = true; + } + hv_nmi_check_nonrecoverable(regs); __this_cpu_inc(irq_stat.sreset_irqs); @@ -492,6 +510,11 @@ void system_reset_exception(struct pt_regs *regs) if (!(regs->msr & MSR_RI)) nmi_panic(regs, "Unrecoverable System Reset"); + if (saved_hsrrs) { + mtspr(SPRN_HSRR0, hsrr0); + mtspr(SPRN_HSRR1, hsrr1); + } + if (!nested) nmi_exit();