| Message ID | 20161228043605.27470-3-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Dec 28, 2016 at 01:36:01PM +0900, AKASHI Takahiro wrote: > Primary kernel calls machine_crash_shutdown() to shut down non-boot cpus > and save registers' status in per-cpu ELF notes before starting crash > dump kernel. See kernel_kexec(). > Even if not all secondary cpus have shut down, we do kdump anyway. > > As we don't have to make non-boot(crashed) cpus offline (to preserve > correct status of cpus at crash dump) before shutting down, this patch > also adds a variant of smp_send_stop(). > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > Reviewed-by: James Morse <james.morse@arm.com> > Acked-by: Catalin Marinas <catalin.marinas@arm.com> > --- > arch/arm64/include/asm/hardirq.h | 2 +- > arch/arm64/include/asm/kexec.h | 42 +++++++++++++++++++++++++- > arch/arm64/include/asm/smp.h | 2 ++ > arch/arm64/kernel/machine_kexec.c | 56 ++++++++++++++++++++++++++++++++-- > arch/arm64/kernel/smp.c | 63 +++++++++++++++++++++++++++++++++++++++ > 5 files changed, 160 insertions(+), 5 deletions(-) [...] > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > index d050d720a1b4..cea009f2657d 100644 > --- a/arch/arm64/include/asm/smp.h > +++ b/arch/arm64/include/asm/smp.h > @@ -148,6 +148,8 @@ static inline void cpu_panic_kernel(void) > */ > bool cpus_are_stuck_in_kernel(void); > > +extern void smp_send_crash_stop(void); > + > #endif /* ifndef __ASSEMBLY__ */ > > #endif /* ifndef __ASM_SMP_H */ > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > index bc96c8a7fc79..c60346d33bb1 100644 > --- a/arch/arm64/kernel/machine_kexec.c > +++ b/arch/arm64/kernel/machine_kexec.c > @@ -9,6 +9,9 @@ > * published by the Free Software Foundation. > */ > > +#include <linux/interrupt.h> > +#include <linux/irq.h> > +#include <linux/kernel.h> > #include <linux/kexec.h> > #include <linux/smp.h> > > @@ -22,6 +25,7 @@ > extern const unsigned char arm64_relocate_new_kernel[]; > extern const unsigned long arm64_relocate_new_kernel_size; > > +static bool in_crash_kexec; Do you actually need this bool? Why not call kexec_crash_loaded() instead? Will
Hi Will, On Tue, Jan 10, 2017 at 11:32:48AM +0000, Will Deacon wrote: > On Wed, Dec 28, 2016 at 01:36:01PM +0900, AKASHI Takahiro wrote: > > Primary kernel calls machine_crash_shutdown() to shut down non-boot cpus > > and save registers' status in per-cpu ELF notes before starting crash > > dump kernel. See kernel_kexec(). > > Even if not all secondary cpus have shut down, we do kdump anyway. > > > > As we don't have to make non-boot(crashed) cpus offline (to preserve > > correct status of cpus at crash dump) before shutting down, this patch > > also adds a variant of smp_send_stop(). > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > > Reviewed-by: James Morse <james.morse@arm.com> > > Acked-by: Catalin Marinas <catalin.marinas@arm.com> > > --- > > arch/arm64/include/asm/hardirq.h | 2 +- > > arch/arm64/include/asm/kexec.h | 42 +++++++++++++++++++++++++- > > arch/arm64/include/asm/smp.h | 2 ++ > > arch/arm64/kernel/machine_kexec.c | 56 ++++++++++++++++++++++++++++++++-- > > arch/arm64/kernel/smp.c | 63 +++++++++++++++++++++++++++++++++++++++ > > 5 files changed, 160 insertions(+), 5 deletions(-) > > [...] > > > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > > index d050d720a1b4..cea009f2657d 100644 > > --- a/arch/arm64/include/asm/smp.h > > +++ b/arch/arm64/include/asm/smp.h > > @@ -148,6 +148,8 @@ static inline void cpu_panic_kernel(void) > > */ > > bool cpus_are_stuck_in_kernel(void); > > > > +extern void smp_send_crash_stop(void); > > + > > #endif /* ifndef __ASSEMBLY__ */ > > > > #endif /* ifndef __ASM_SMP_H */ > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index bc96c8a7fc79..c60346d33bb1 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -9,6 +9,9 @@ > > * published by the Free Software Foundation. > > */ > > > > +#include <linux/interrupt.h> > > +#include <linux/irq.h> > > +#include <linux/kernel.h> > > #include <linux/kexec.h> > > #include <linux/smp.h> > > > > @@ -22,6 +25,7 @@ > > extern const unsigned char arm64_relocate_new_kernel[]; > > extern const unsigned long arm64_relocate_new_kernel_size; > > > > +static bool in_crash_kexec; > > Do you actually need this bool? Why not call kexec_crash_loaded() instead? The two have different meanings: "in_crash_kexec" indicates that kdump is taking place, while kexec_crash_loaded() tells us only whether crash dump kernel has been loaded or not. It is crucial to distinguish them especially for machine_kexec() which can be called on normal kexec even if kdump has been set up. Thanks, -Takahiro AKASHI > Will
On Wed, Jan 11, 2017 at 03:36:28PM +0900, AKASHI Takahiro wrote: > On Tue, Jan 10, 2017 at 11:32:48AM +0000, Will Deacon wrote: > > On Wed, Dec 28, 2016 at 01:36:01PM +0900, AKASHI Takahiro wrote: > > > @@ -22,6 +25,7 @@ > > > extern const unsigned char arm64_relocate_new_kernel[]; > > > extern const unsigned long arm64_relocate_new_kernel_size; > > > > > > +static bool in_crash_kexec; > > > > Do you actually need this bool? Why not call kexec_crash_loaded() instead? > > The two have different meanings: > "in_crash_kexec" indicates that kdump is taking place, while > kexec_crash_loaded() tells us only whether crash dump kernel has been > loaded or not. > > It is crucial to distinguish them especially for machine_kexec() > which can be called on normal kexec even if kdump has been set up. Ah, I see. So how about just doing: if (kimage == kexec_crash_image) in machine_kexec? Will
diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h index 8740297dac77..1473fc2f7ab7 100644 --- a/arch/arm64/include/asm/hardirq.h +++ b/arch/arm64/include/asm/hardirq.h @@ -20,7 +20,7 @@ #include <linux/threads.h> #include <asm/irq.h> -#define NR_IPI 6 +#define NR_IPI 7 typedef struct { unsigned int __softirq_pending; diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index 04744dc5fb61..f40ace1fa21a 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -40,7 +40,47 @@ static inline void crash_setup_regs(struct pt_regs *newregs, struct pt_regs *oldregs) { - /* Empty routine needed to avoid build errors. */ + if (oldregs) { + memcpy(newregs, oldregs, sizeof(*newregs)); + } else { + u64 tmp1, tmp2; + + __asm__ __volatile__ ( + "stp x0, x1, [%2, #16 * 0]\n" + "stp x2, x3, [%2, #16 * 1]\n" + "stp x4, x5, [%2, #16 * 2]\n" + "stp x6, x7, [%2, #16 * 3]\n" + "stp x8, x9, [%2, #16 * 4]\n" + "stp x10, x11, [%2, #16 * 5]\n" + "stp x12, x13, [%2, #16 * 6]\n" + "stp x14, x15, [%2, #16 * 7]\n" + "stp x16, x17, [%2, #16 * 8]\n" + "stp x18, x19, [%2, #16 * 9]\n" + "stp x20, x21, [%2, #16 * 10]\n" + "stp x22, x23, [%2, #16 * 11]\n" + "stp x24, x25, [%2, #16 * 12]\n" + "stp x26, x27, [%2, #16 * 13]\n" + "stp x28, x29, [%2, #16 * 14]\n" + "mov %0, sp\n" + "stp x30, %0, [%2, #16 * 15]\n" + + "/* faked current PSTATE */\n" + "mrs %0, CurrentEL\n" + "mrs %1, SPSEL\n" + "orr %0, %0, %1\n" + "mrs %1, DAIF\n" + "orr %0, %0, %1\n" + "mrs %1, NZCV\n" + "orr %0, %0, %1\n" + /* pc */ + "adr %1, 1f\n" + "1:\n" + "stp %1, %0, [%2, #16 * 16]\n" + : "=&r" (tmp1), "=&r" (tmp2) + : "r" (newregs) + : "memory" + ); + } } #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index d050d720a1b4..cea009f2657d 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -148,6 +148,8 @@ static inline void cpu_panic_kernel(void) */ bool cpus_are_stuck_in_kernel(void); +extern void smp_send_crash_stop(void); + #endif /* ifndef __ASSEMBLY__ */ #endif /* ifndef __ASM_SMP_H */ diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index bc96c8a7fc79..c60346d33bb1 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -9,6 +9,9 @@ * published by the Free Software Foundation. */ +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> #include <linux/kexec.h> #include <linux/smp.h> @@ -22,6 +25,7 @@ extern const unsigned char arm64_relocate_new_kernel[]; extern const unsigned long arm64_relocate_new_kernel_size; +static bool in_crash_kexec; static unsigned long kimage_start; /** @@ -148,7 +152,8 @@ void machine_kexec(struct kimage *kimage) /* * New cpus may have become stuck_in_kernel after we loaded the image. */ - BUG_ON(cpus_are_stuck_in_kernel() || (num_online_cpus() > 1)); + BUG_ON((cpus_are_stuck_in_kernel() || (num_online_cpus() > 1)) && + !WARN_ON(in_crash_kexec)); reboot_code_buffer_phys = page_to_phys(kimage->control_code_page); reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys); @@ -200,13 +205,58 @@ void machine_kexec(struct kimage *kimage) * relocation is complete. */ - cpu_soft_restart(1, reboot_code_buffer_phys, kimage->head, + cpu_soft_restart(!in_crash_kexec, reboot_code_buffer_phys, kimage->head, kimage_start, 0); BUG(); /* Should never get here. */ } +static void machine_kexec_mask_interrupts(void) +{ + unsigned int i; + struct irq_desc *desc; + + for_each_irq_desc(i, desc) { + struct irq_chip *chip; + int ret; + + chip = irq_desc_get_chip(desc); + if (!chip) + continue; + + /* + * First try to remove the active state. If this + * fails, try to EOI the interrupt. + */ + ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false); + + if (ret && irqd_irq_inprogress(&desc->irq_data) && + chip->irq_eoi) + chip->irq_eoi(&desc->irq_data); + + if (chip->irq_mask) + chip->irq_mask(&desc->irq_data); + + if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) + chip->irq_disable(&desc->irq_data); + } +} + +/** + * machine_crash_shutdown - shutdown non-crashing cpus and save registers + */ void machine_crash_shutdown(struct pt_regs *regs) { - /* Empty routine needed to avoid build errors. */ + local_irq_disable(); + + in_crash_kexec = true; + + /* shutdown non-crashing cpus */ + smp_send_crash_stop(); + + /* for crashing cpu */ + crash_save_cpu(regs, smp_processor_id()); + machine_kexec_mask_interrupts(); + + pr_info("Starting crashdump kernel...\n"); } diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index cb87234cfcf2..446c6d48f8ec 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -37,6 +37,7 @@ #include <linux/completion.h> #include <linux/of.h> #include <linux/irq_work.h> +#include <linux/kexec.h> #include <asm/alternative.h> #include <asm/atomic.h> @@ -74,6 +75,7 @@ enum ipi_msg_type { IPI_RESCHEDULE, IPI_CALL_FUNC, IPI_CPU_STOP, + IPI_CPU_CRASH_STOP, IPI_TIMER, IPI_IRQ_WORK, IPI_WAKEUP @@ -753,6 +755,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = { S(IPI_RESCHEDULE, "Rescheduling interrupts"), S(IPI_CALL_FUNC, "Function call interrupts"), S(IPI_CPU_STOP, "CPU stop interrupts"), + S(IPI_CPU_CRASH_STOP, "CPU stop (for crash dump) interrupts"), S(IPI_TIMER, "Timer broadcast interrupts"), S(IPI_IRQ_WORK, "IRQ work interrupts"), S(IPI_WAKEUP, "CPU wake-up interrupts"), @@ -827,6 +830,29 @@ static void ipi_cpu_stop(unsigned int cpu) cpu_relax(); } +#ifdef CONFIG_KEXEC_CORE +static atomic_t waiting_for_crash_ipi; +#endif + +static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) +{ +#ifdef CONFIG_KEXEC_CORE + crash_save_cpu(regs, cpu); + + atomic_dec(&waiting_for_crash_ipi); + + local_irq_disable(); + +#ifdef CONFIG_HOTPLUG_CPU + if (cpu_ops[cpu]->cpu_die) + cpu_ops[cpu]->cpu_die(cpu); +#endif + + /* just in case */ + cpu_park_loop(); +#endif +} + /* * Main handler for inter-processor interrupts */ @@ -857,6 +883,15 @@ void handle_IPI(int ipinr, struct pt_regs *regs) irq_exit(); break; + case IPI_CPU_CRASH_STOP: + if (IS_ENABLED(CONFIG_KEXEC_CORE)) { + irq_enter(); + ipi_cpu_crash_stop(cpu, regs); + + unreachable(); + } + break; + #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST case IPI_TIMER: irq_enter(); @@ -929,6 +964,34 @@ void smp_send_stop(void) cpumask_pr_args(cpu_online_mask)); } +#ifdef CONFIG_KEXEC_CORE +void smp_send_crash_stop(void) +{ + cpumask_t mask; + unsigned long timeout; + + if (num_online_cpus() == 1) + return; + + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + + atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); + + pr_crit("SMP: stopping secondary CPUs\n"); + smp_cross_call(&mask, IPI_CPU_CRASH_STOP); + + /* Wait up to one second for other CPUs to stop */ + timeout = USEC_PER_SEC; + while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--) + udelay(1); + + if (atomic_read(&waiting_for_crash_ipi) > 0) + pr_warning("SMP: failed to stop secondary CPUs %*pbl\n", + cpumask_pr_args(cpu_online_mask)); +} +#endif + /* * not supported here */