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powerpc/64s: Move HMI IRQ stat from percpu variable to paca.

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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 <aneesh.kumar@linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159290806973.3642154.5244613424529764050.stgit@jupiter
This commit is contained in:
Mahesh Salgaonkar
2020-06-23 15:57:50 +05:30
committed by Michael Ellerman
parent d3c61954fc
commit ada68a66b7
5 changed files with 9 additions and 6 deletions
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9
arch/powerpc/kernel/irq.c
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@@ -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;