diff options
Diffstat (limited to 'arch/powerpc/kexec/crash.c')
| -rw-r--r-- | arch/powerpc/kexec/crash.c | 277 |
1 files changed, 246 insertions, 31 deletions
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index 80f54723cf6d..a325c1c02f96 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -16,6 +16,8 @@ #include <linux/delay.h> #include <linux/irq.h> #include <linux/types.h> +#include <linux/libfdt.h> +#include <linux/memory.h> #include <asm/processor.h> #include <asm/machdep.h> @@ -24,6 +26,7 @@ #include <asm/setjmp.h> #include <asm/debug.h> #include <asm/interrupt.h> +#include <asm/kexec_ranges.h> /* * The primary CPU waits a while for all secondary CPUs to enter. This is to @@ -40,6 +43,14 @@ #define REAL_MODE_TIMEOUT 10000 static int time_to_dump; + +/* + * In case of system reset, secondary CPUs enter crash_kexec_secondary with out + * having to send an IPI explicitly. So, indicate if the crash is via + * system reset to avoid sending another IPI. + */ +static int is_via_system_reset; + /* * crash_wake_offline should be set to 1 by platforms that intend to wake * up offline cpus prior to jumping to a kdump kernel. Currently powernv @@ -101,7 +112,7 @@ void crash_ipi_callback(struct pt_regs *regs) /* NOTREACHED */ } -static void crash_kexec_prepare_cpus(int cpu) +static void crash_kexec_prepare_cpus(void) { unsigned int msecs; volatile unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ @@ -113,7 +124,15 @@ static void crash_kexec_prepare_cpus(int cpu) if (crash_wake_offline) ncpus = num_present_cpus() - 1; - crash_send_ipi(crash_ipi_callback); + /* + * If we came in via system reset, secondaries enter via crash_kexec_secondary(). + * So, wait a while for the secondary CPUs to enter for that case. + * Else, send IPI to all other CPUs. + */ + if (is_via_system_reset) + mdelay(PRIMARY_TIMEOUT); + else + crash_send_ipi(crash_ipi_callback); smp_wmb(); again: @@ -202,7 +221,7 @@ void crash_kexec_secondary(struct pt_regs *regs) #else /* ! CONFIG_SMP */ -static void crash_kexec_prepare_cpus(int cpu) +static void crash_kexec_prepare_cpus(void) { /* * move the secondaries to us so that we can copy @@ -248,6 +267,32 @@ noinstr static void __maybe_unused crash_kexec_wait_realmode(int cpu) static inline void crash_kexec_wait_realmode(int cpu) {} #endif /* CONFIG_SMP && CONFIG_PPC64 */ +void crash_kexec_prepare(void) +{ + /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */ + printk_deferred_enter(); + + /* + * This function is only called after the system + * has panicked or is otherwise in a critical state. + * The minimum amount of code to allow a kexec'd kernel + * to run successfully needs to happen here. + * + * In practice this means stopping other cpus in + * an SMP system. + * The kernel is broken so disable interrupts. + */ + hard_irq_disable(); + + /* + * Make a note of crashing cpu. Will be used in machine_kexec + * such that another IPI will not be sent. + */ + crashing_cpu = smp_processor_id(); + + crash_kexec_prepare_cpus(); +} + /* * Register a function to be called on shutdown. Only use this if you * can't reset your device in the second kernel. @@ -308,38 +353,16 @@ EXPORT_SYMBOL(crash_shutdown_unregister); void default_machine_crash_shutdown(struct pt_regs *regs) { - unsigned int i; + volatile unsigned int i; int (*old_handler)(struct pt_regs *regs); - /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */ - printk_deferred_enter(); - - /* - * This function is only called after the system - * has panicked or is otherwise in a critical state. - * The minimum amount of code to allow a kexec'd kernel - * to run successfully needs to happen here. - * - * In practice this means stopping other cpus in - * an SMP system. - * The kernel is broken so disable interrupts. - */ - hard_irq_disable(); - - /* - * Make a note of crashing cpu. Will be used in machine_kexec - * such that another IPI will not be sent. - */ - crashing_cpu = smp_processor_id(); - - /* - * If we came in via system reset, wait a while for the secondary - * CPUs to enter. - */ if (TRAP(regs) == INTERRUPT_SYSTEM_RESET) - mdelay(PRIMARY_TIMEOUT); + is_via_system_reset = 1; - crash_kexec_prepare_cpus(crashing_cpu); + if (IS_ENABLED(CONFIG_SMP)) + crash_smp_send_stop(); + else + crash_kexec_prepare(); crash_save_cpu(regs, crashing_cpu); @@ -375,3 +398,195 @@ void default_machine_crash_shutdown(struct pt_regs *regs) if (ppc_md.kexec_cpu_down) ppc_md.kexec_cpu_down(1, 0); } + +#ifdef CONFIG_CRASH_HOTPLUG +#undef pr_fmt +#define pr_fmt(fmt) "crash hp: " fmt + +/* + * Advertise preferred elfcorehdr size to userspace via + * /sys/kernel/crash_elfcorehdr_size sysfs interface. + */ +unsigned int arch_crash_get_elfcorehdr_size(void) +{ + unsigned long phdr_cnt; + + /* A program header for possible CPUs + vmcoreinfo */ + phdr_cnt = num_possible_cpus() + 1; + if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) + phdr_cnt += CONFIG_CRASH_MAX_MEMORY_RANGES; + + return sizeof(struct elfhdr) + (phdr_cnt * sizeof(Elf64_Phdr)); +} + +/** + * update_crash_elfcorehdr() - Recreate the elfcorehdr and replace it with old + * elfcorehdr in the kexec segment array. + * @image: the active struct kimage + * @mn: struct memory_notify data handler + */ +static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *mn) +{ + int ret; + struct crash_mem *cmem = NULL; + struct kexec_segment *ksegment; + void *ptr, *mem, *elfbuf = NULL; + unsigned long elfsz, memsz, base_addr, size; + + ksegment = &image->segment[image->elfcorehdr_index]; + mem = (void *) ksegment->mem; + memsz = ksegment->memsz; + + ret = get_crash_memory_ranges(&cmem); + if (ret) { + pr_err("Failed to get crash mem range\n"); + return; + } + + /* + * The hot unplugged memory is part of crash memory ranges, + * remove it here. + */ + if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) { + base_addr = PFN_PHYS(mn->start_pfn); + size = mn->nr_pages * PAGE_SIZE; + ret = remove_mem_range(&cmem, base_addr, size); + if (ret) { + pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n"); + goto out; + } + } + + ret = crash_prepare_elf64_headers(cmem, false, &elfbuf, &elfsz); + if (ret) { + pr_err("Failed to prepare elf header\n"); + goto out; + } + + /* + * It is unlikely that kernel hit this because elfcorehdr kexec + * segment (memsz) is built with addition space to accommodate growing + * number of crash memory ranges while loading the kdump kernel. It is + * Just to avoid any unforeseen case. + */ + if (elfsz > memsz) { + pr_err("Updated crash elfcorehdr elfsz %lu > memsz %lu", elfsz, memsz); + goto out; + } + + ptr = __va(mem); + if (ptr) { + /* Temporarily invalidate the crash image while it is replaced */ + xchg(&kexec_crash_image, NULL); + + /* Replace the old elfcorehdr with newly prepared elfcorehdr */ + memcpy((void *)ptr, elfbuf, elfsz); + + /* The crash image is now valid once again */ + xchg(&kexec_crash_image, image); + } +out: + kvfree(cmem); + kvfree(elfbuf); +} + +/** + * get_fdt_index - Loop through the kexec segment array and find + * the index of the FDT segment. + * @image: a pointer to kexec_crash_image + * + * Returns the index of FDT segment in the kexec segment array + * if found; otherwise -1. + */ +static int get_fdt_index(struct kimage *image) +{ + void *ptr; + unsigned long mem; + int i, fdt_index = -1; + + /* Find the FDT segment index in kexec segment array. */ + for (i = 0; i < image->nr_segments; i++) { + mem = image->segment[i].mem; + ptr = __va(mem); + + if (ptr && fdt_magic(ptr) == FDT_MAGIC) { + fdt_index = i; + break; + } + } + + return fdt_index; +} + +/** + * update_crash_fdt - updates the cpus node of the crash FDT. + * + * @image: a pointer to kexec_crash_image + */ +static void update_crash_fdt(struct kimage *image) +{ + void *fdt; + int fdt_index; + + fdt_index = get_fdt_index(image); + if (fdt_index < 0) { + pr_err("Unable to locate FDT segment.\n"); + return; + } + + fdt = __va((void *)image->segment[fdt_index].mem); + + /* Temporarily invalidate the crash image while it is replaced */ + xchg(&kexec_crash_image, NULL); + + /* update FDT to reflect changes in CPU resources */ + if (update_cpus_node(fdt)) + pr_err("Failed to update crash FDT"); + + /* The crash image is now valid once again */ + xchg(&kexec_crash_image, image); +} + +int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags) +{ +#ifdef CONFIG_KEXEC_FILE + if (image->file_mode) + return 1; +#endif + return kexec_flags & KEXEC_CRASH_HOTPLUG_SUPPORT; +} + +/** + * arch_crash_handle_hotplug_event - Handle crash CPU/Memory hotplug events to update the + * necessary kexec segments based on the hotplug event. + * @image: a pointer to kexec_crash_image + * @arg: struct memory_notify handler for memory hotplug case and NULL for CPU hotplug case. + * + * Update the kdump image based on the type of hotplug event, represented by image->hp_action. + * CPU add: Update the FDT segment to include the newly added CPU. + * CPU remove: No action is needed, with the assumption that it's okay to have offline CPUs + * part of the FDT. + * Memory add/remove: No action is taken as this is not yet supported. + */ +void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) +{ + struct memory_notify *mn; + + switch (image->hp_action) { + case KEXEC_CRASH_HP_REMOVE_CPU: + return; + + case KEXEC_CRASH_HP_ADD_CPU: + update_crash_fdt(image); + break; + + case KEXEC_CRASH_HP_REMOVE_MEMORY: + case KEXEC_CRASH_HP_ADD_MEMORY: + mn = (struct memory_notify *)arg; + update_crash_elfcorehdr(image, mn); + return; + default: + pr_warn_once("Unknown hotplug action\n"); + } +} +#endif /* CONFIG_CRASH_HOTPLUG */ |