From ada68a66b72687e6b74e35c42efd1783e84b01fd Mon Sep 17 00:00:00 2001 From: Mahesh Salgaonkar Date: Tue, 23 Jun 2020 15:57:50 +0530 Subject: [PATCH] powerpc/64s: Move HMI IRQ stat from percpu variable to paca. With the proposed change in percpu bootmem allocator to use page mapping [1], the percpu first chunk memory area can come from vmalloc ranges. This makes the HMI (Hypervisor Maintenance Interrupt) handler crash the kernel whenever percpu variable is accessed in real mode. This patch fixes this issue by moving the HMI IRQ stat inside paca for safe access in realmode. [1] https://lore.kernel.org/linuxppc-dev/20200608070904.387440-1-aneesh.kumar@linux.ibm.com/ Suggested-by: Aneesh Kumar K.V Signed-off-by: Mahesh Salgaonkar Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/159290806973.3642154.5244613424529764050.stgit@jupiter --- arch/powerpc/include/asm/hardirq.h | 1 - arch/powerpc/include/asm/paca.h | 1 + arch/powerpc/kernel/irq.c | 9 ++++++--- arch/powerpc/kernel/mce.c | 2 +- arch/powerpc/kvm/book3s_hv_ras.c | 2 +- 5 files changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h index f1e9067bd5ac1..f133b5930ae15 100644 --- a/arch/powerpc/include/asm/hardirq.h +++ b/arch/powerpc/include/asm/hardirq.h @@ -13,7 +13,6 @@ typedef struct { unsigned int pmu_irqs; unsigned int mce_exceptions; unsigned int spurious_irqs; - unsigned int hmi_exceptions; unsigned int sreset_irqs; #ifdef CONFIG_PPC_WATCHDOG unsigned int soft_nmi_irqs; diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 45a839a7c6cfa..cc07c399306e5 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -225,6 +225,7 @@ struct paca_struct { u16 in_mce; u8 hmi_event_available; /* HMI event is available */ u8 hmi_p9_special_emu; /* HMI P9 special emulation */ + u32 hmi_irqs; /* HMI irq stat */ #endif u8 ftrace_enabled; /* Hard disable ftrace */ diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 05b1cc0e009e4..bf21ebd361900 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -621,13 +621,14 @@ int arch_show_interrupts(struct seq_file *p, int prec) seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions); seq_printf(p, " Machine check exceptions\n"); +#ifdef CONFIG_PPC_BOOK3S_64 if (cpu_has_feature(CPU_FTR_HVMODE)) { seq_printf(p, "%*s: ", prec, "HMI"); for_each_online_cpu(j) - seq_printf(p, "%10u ", - per_cpu(irq_stat, j).hmi_exceptions); + seq_printf(p, "%10u ", paca_ptrs[j]->hmi_irqs); seq_printf(p, " Hypervisor Maintenance Interrupts\n"); } +#endif seq_printf(p, "%*s: ", prec, "NMI"); for_each_online_cpu(j) @@ -665,7 +666,9 @@ u64 arch_irq_stat_cpu(unsigned int cpu) sum += per_cpu(irq_stat, cpu).mce_exceptions; sum += per_cpu(irq_stat, cpu).spurious_irqs; sum += per_cpu(irq_stat, cpu).timer_irqs_others; - sum += per_cpu(irq_stat, cpu).hmi_exceptions; +#ifdef CONFIG_PPC_BOOK3S_64 + sum += paca_ptrs[cpu]->hmi_irqs; +#endif sum += per_cpu(irq_stat, cpu).sreset_irqs; #ifdef CONFIG_PPC_WATCHDOG sum += per_cpu(irq_stat, cpu).soft_nmi_irqs; diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index c2fa8ee63720e..ada59f6c4298f 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -727,7 +727,7 @@ long hmi_exception_realmode(struct pt_regs *regs) { int ret; - __this_cpu_inc(irq_stat.hmi_exceptions); + local_paca->hmi_irqs++; ret = hmi_handle_debugtrig(regs); if (ret >= 0) diff --git a/arch/powerpc/kvm/book3s_hv_ras.c b/arch/powerpc/kvm/book3s_hv_ras.c index 79f7d07ef674c..6028628ea3acf 100644 --- a/arch/powerpc/kvm/book3s_hv_ras.c +++ b/arch/powerpc/kvm/book3s_hv_ras.c @@ -244,7 +244,7 @@ long kvmppc_realmode_hmi_handler(void) { bool resync_req; - __this_cpu_inc(irq_stat.hmi_exceptions); + local_paca->hmi_irqs++; if (hmi_handle_debugtrig(NULL) >= 0) return 1; -- 2.30.2