diff options
| -rw-r--r-- | arch/x86/include/asm/reboot.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 16 | ||||
| -rw-r--r-- | arch/x86/kernel/reboot.c | 24 |
3 files changed, 32 insertions, 9 deletions
diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h index a82c4f1b4d83..2cb1cc253d51 100644 --- a/arch/x86/include/asm/reboot.h +++ b/arch/x86/include/asm/reboot.h @@ -25,5 +25,6 @@ void __noreturn machine_real_restart(unsigned int type); typedef void (*nmi_shootdown_cb)(int, struct pt_regs*); void nmi_shootdown_cpus(nmi_shootdown_cb callback); +void run_crash_ipi_callback(struct pt_regs *regs); #endif /* _ASM_X86_REBOOT_H */ diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 424aec4a4c71..8a2cdd736fa4 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -29,6 +29,7 @@ #include <asm/mach_traps.h> #include <asm/nmi.h> #include <asm/x86_init.h> +#include <asm/reboot.h> #define CREATE_TRACE_POINTS #include <trace/events/nmi.h> @@ -356,8 +357,19 @@ static void default_do_nmi(struct pt_regs *regs) return; } - /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */ - raw_spin_lock(&nmi_reason_lock); + /* + * Non-CPU-specific NMI: NMI sources can be processed on any CPU. + * + * Another CPU may be processing panic routines while holding + * nmi_reason_lock. Check if the CPU issued the IPI for crash dumping, + * and if so, call its callback directly. If there is no CPU preparing + * crash dump, we simply loop here. + */ + while (!raw_spin_trylock(&nmi_reason_lock)) { + run_crash_ipi_callback(regs); + cpu_relax(); + } + reason = x86_platform.get_nmi_reason(); if (reason & NMI_REASON_MASK) { diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 1da13022d544..d64889aa2d46 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -793,17 +793,23 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback) /* Leave the nmi callback set */ } +/* + * Check if the crash dumping IPI got issued and if so, call its callback + * directly. This function is used when we have already been in NMI handler. + * It doesn't return. + */ +void run_crash_ipi_callback(struct pt_regs *regs) +{ + if (crash_ipi_issued) + crash_nmi_callback(0, regs); +} + /* Override the weak function in kernel/panic.c */ void nmi_panic_self_stop(struct pt_regs *regs) { while (1) { - /* - * Wait for the crash dumping IPI to be issued, and then - * call its callback directly. - */ - if (READ_ONCE(crash_ipi_issued)) - crash_nmi_callback(0, regs); /* Don't return */ - + /* If no CPU is preparing crash dump, we simply loop here. */ + run_crash_ipi_callback(regs); cpu_relax(); } } @@ -813,4 +819,8 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback) { /* No other CPUs to shoot down */ } + +void run_crash_ipi_callback(struct pt_regs *regs) +{ +} #endif |