diff options
Diffstat (limited to 'kernel/crash_core.c')
| -rw-r--r-- | kernel/crash_core.c | 84 |
1 files changed, 57 insertions, 27 deletions
diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 63cf89393c6e..99dac1aa972a 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -21,6 +21,8 @@ #include <linux/reboot.h> #include <linux/btf.h> #include <linux/objtool.h> +#include <linux/delay.h> +#include <linux/panic.h> #include <asm/page.h> #include <asm/sections.h> @@ -33,6 +35,11 @@ /* Per cpu memory for storing cpu states in case of system crash. */ note_buf_t __percpu *crash_notes; +/* time to wait for possible DMA to finish before starting the kdump kernel + * when a CMA reservation is used + */ +#define CMA_DMA_TIMEOUT_SEC 10 + #ifdef CONFIG_CRASH_DUMP int kimage_crash_copy_vmcoreinfo(struct kimage *image) @@ -97,6 +104,14 @@ int kexec_crash_loaded(void) } EXPORT_SYMBOL_GPL(kexec_crash_loaded); +static void crash_cma_clear_pending_dma(void) +{ + if (!crashk_cma_cnt) + return; + + mdelay(CMA_DMA_TIMEOUT_SEC * 1000); +} + /* * No panic_cpu check version of crash_kexec(). This function is called * only when panic_cpu holds the current CPU number; this is the only CPU @@ -119,6 +134,7 @@ void __noclone __crash_kexec(struct pt_regs *regs) crash_setup_regs(&fixed_regs, regs); crash_save_vmcoreinfo(); machine_crash_shutdown(&fixed_regs); + crash_cma_clear_pending_dma(); machine_kexec(kexec_crash_image); } kexec_unlock(); @@ -128,17 +144,7 @@ STACK_FRAME_NON_STANDARD(__crash_kexec); __bpf_kfunc void crash_kexec(struct pt_regs *regs) { - int old_cpu, this_cpu; - - /* - * Only one CPU is allowed to execute the crash_kexec() code as with - * panic(). Otherwise parallel calls of panic() and crash_kexec() - * may stop each other. To exclude them, we use panic_cpu here too. - */ - old_cpu = PANIC_CPU_INVALID; - this_cpu = raw_smp_processor_id(); - - if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) { + if (panic_try_start()) { /* This is the 1st CPU which comes here, so go ahead. */ __crash_kexec(regs); @@ -146,7 +152,7 @@ __bpf_kfunc void crash_kexec(struct pt_regs *regs) * Reset panic_cpu to allow another panic()/crash_kexec() * call. */ - atomic_set(&panic_cpu, PANIC_CPU_INVALID); + panic_reset(); } } @@ -259,6 +265,20 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, return 0; } +/** + * crash_exclude_mem_range - exclude a mem range for existing ranges + * @mem: mem->range contains an array of ranges sorted in ascending order + * @mstart: the start of to-be-excluded range + * @mend: the start of to-be-excluded range + * + * If you are unsure if a range split will happen, to avoid function call + * failure because of -ENOMEM, always make sure + * mem->max_nr_ranges == mem->nr_ranges + 1 + * before calling the function each time. + * + * returns 0 if a memory range is excluded successfully + * return -ENOMEM if mem->ranges doesn't have space to hold split ranges + */ int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { @@ -318,6 +338,7 @@ int crash_exclude_mem_range(struct crash_mem *mem, return 0; } +EXPORT_SYMBOL_GPL(crash_exclude_mem_range); ssize_t crash_get_memory_size(void) { @@ -352,7 +373,7 @@ static int __crash_shrink_memory(struct resource *old_res, old_res->start = 0; old_res->end = 0; } else { - crashk_res.end = ram_res->start - 1; + old_res->end = ram_res->start - 1; } crash_free_reserved_phys_range(ram_res->start, ram_res->end); @@ -436,7 +457,7 @@ void crash_save_cpu(struct pt_regs *regs, int cpu) memset(&prstatus, 0, sizeof(prstatus)); prstatus.common.pr_pid = current->pid; elf_core_copy_regs(&prstatus.pr_reg, regs); - buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, + buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS, &prstatus, sizeof(prstatus)); final_note(buf); } @@ -505,7 +526,8 @@ int crash_check_hotplug_support(void) crash_hotplug_lock(); /* Obtain lock while reading crash information */ if (!kexec_trylock()) { - pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n"); + if (!kexec_in_progress) + pr_info("kexec_trylock() failed, kdump image may be inaccurate\n"); crash_hotplug_unlock(); return 0; } @@ -520,18 +542,25 @@ int crash_check_hotplug_support(void) } /* - * To accurately reflect hot un/plug changes of cpu and memory resources - * (including onling and offlining of those resources), the elfcorehdr - * (which is passed to the crash kernel via the elfcorehdr= parameter) - * must be updated with the new list of CPUs and memories. + * To accurately reflect hot un/plug changes of CPU and Memory resources + * (including onling and offlining of those resources), the relevant + * kexec segments must be updated with latest CPU and Memory resources. + * + * Architectures must ensure two things for all segments that need + * updating during hotplug events: + * + * 1. Segments must be large enough to accommodate a growing number of + * resources. + * 2. Exclude the segments from SHA verification. * - * In order to make changes to elfcorehdr, two conditions are needed: - * First, the segment containing the elfcorehdr must be large enough - * to permit a growing number of resources; the elfcorehdr memory size - * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. - * Second, purgatory must explicitly exclude the elfcorehdr from the - * list of segments it checks (since the elfcorehdr changes and thus - * would require an update to purgatory itself to update the digest). + * For example, on most architectures, the elfcorehdr (which is passed + * to the crash kernel via the elfcorehdr= parameter) must include the + * new list of CPUs and memory. To make changes to the elfcorehdr, it + * should be large enough to permit a growing number of CPU and Memory + * resources. One can estimate the elfcorehdr memory size based on + * NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. The elfcorehdr is + * excluded from SHA verification by default if the architecture + * supports crash hotplug. */ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg) { @@ -540,7 +569,8 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, crash_hotplug_lock(); /* Obtain lock while changing crash information */ if (!kexec_trylock()) { - pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n"); + if (!kexec_in_progress) + pr_info("kexec_trylock() failed, kdump image may be inaccurate\n"); crash_hotplug_unlock(); return; } |