diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h index e75970351bcd..95a98b390d62 100644 --- a/arch/powerpc/include/asm/kexec.h +++ b/arch/powerpc/include/asm/kexec.h @@ -141,6 +141,9 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg); int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags); #define arch_crash_hotplug_support arch_crash_hotplug_support + +unsigned int arch_crash_get_elfcorehdr_size(void); +#define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size #endif /* CONFIG_CRASH_HOTPLUG */ extern int crashing_cpu; diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h index 8489e844b447..14055896cbcb 100644 --- a/arch/powerpc/include/asm/kexec_ranges.h +++ b/arch/powerpc/include/asm/kexec_ranges.h @@ -7,6 +7,7 @@ void sort_memory_ranges(struct crash_mem *mrngs, bool merge); struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges); int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size); +int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size); int get_exclude_memory_ranges(struct crash_mem **mem_ranges); int get_reserved_memory_ranges(struct crash_mem **mem_ranges); int get_crash_memory_ranges(struct crash_mem **mem_ranges); diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index 8938a19af12f..21b193e938a3 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -25,6 +26,7 @@ #include #include #include +#include /* * The primary CPU waits a while for all secondary CPUs to enter. This is to @@ -398,6 +400,94 @@ void default_machine_crash_shutdown(struct pt_regs *regs) #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); + if (elfbuf) + kvfree(elfbuf); +} + /** * get_fdt_index - Loop through the kexec segment array and find * the index of the FDT segment. @@ -478,6 +568,8 @@ int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags) */ 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; @@ -488,7 +580,8 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) case KEXEC_CRASH_HP_REMOVE_MEMORY: case KEXEC_CRASH_HP_ADD_MEMORY: - pr_info_once("Crash update is not supported for memory hotplug\n"); + mn = (struct memory_notify *)arg; + update_crash_elfcorehdr(image, mn); return; default: pr_warn_once("Unknown hotplug action\n"); diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c index 2640a804fcdf..925a69ad2468 100644 --- a/arch/powerpc/kexec/file_load_64.c +++ b/arch/powerpc/kexec/file_load_64.c @@ -595,6 +595,23 @@ static void update_backup_region_phdr(struct kimage *image, Elf64_Ehdr *ehdr) } } +static unsigned int kdump_extra_elfcorehdr_size(struct crash_mem *cmem) +{ +#if defined(CONFIG_CRASH_HOTPLUG) && defined(CONFIG_MEMORY_HOTPLUG) + unsigned int extra_sz = 0; + + if (CONFIG_CRASH_MAX_MEMORY_RANGES > (unsigned int)PN_XNUM) + pr_warn("Number of Phdrs %u exceeds max\n", CONFIG_CRASH_MAX_MEMORY_RANGES); + else if (cmem->nr_ranges >= CONFIG_CRASH_MAX_MEMORY_RANGES) + pr_warn("Configured crash mem ranges may not be enough\n"); + else + extra_sz = (CONFIG_CRASH_MAX_MEMORY_RANGES - cmem->nr_ranges) * sizeof(Elf64_Phdr); + + return extra_sz; +#endif + return 0; +} + /** * load_elfcorehdr_segment - Setup crash memory ranges and initialize elfcorehdr * segment needed to load kdump kernel. @@ -626,7 +643,8 @@ static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf) kbuf->buffer = headers; kbuf->mem = KEXEC_BUF_MEM_UNKNOWN; - kbuf->bufsz = kbuf->memsz = headers_sz; + kbuf->bufsz = headers_sz; + kbuf->memsz = headers_sz + kdump_extra_elfcorehdr_size(cmem); kbuf->top_down = false; ret = kexec_add_buffer(kbuf); diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c index b1f4267d9b17..3702b0bdab14 100644 --- a/arch/powerpc/kexec/ranges.c +++ b/arch/powerpc/kexec/ranges.c @@ -620,4 +620,89 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges) pr_err("Failed to setup crash memory ranges\n"); return ret; } + +/** + * remove_mem_range - Removes the given memory range from the range list. + * @mem_ranges: Range list to remove the memory range to. + * @base: Base address of the range to remove. + * @size: Size of the memory range to remove. + * + * (Re)allocates memory, if needed. + * + * Returns 0 on success, negative errno on error. + */ +int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size) +{ + u64 end; + int ret = 0; + unsigned int i; + u64 mstart, mend; + struct crash_mem *mem_rngs = *mem_ranges; + + if (!size) + return 0; + + /* + * Memory range are stored as start and end address, use + * the same format to do remove operation. + */ + end = base + size - 1; + + for (i = 0; i < mem_rngs->nr_ranges; i++) { + mstart = mem_rngs->ranges[i].start; + mend = mem_rngs->ranges[i].end; + + /* + * Memory range to remove is not part of this range entry + * in the memory range list + */ + if (!(base >= mstart && end <= mend)) + continue; + + /* + * Memory range to remove is equivalent to this entry in the + * memory range list. Remove the range entry from the list. + */ + if (base == mstart && end == mend) { + for (; i < mem_rngs->nr_ranges - 1; i++) { + mem_rngs->ranges[i].start = mem_rngs->ranges[i+1].start; + mem_rngs->ranges[i].end = mem_rngs->ranges[i+1].end; + } + mem_rngs->nr_ranges--; + goto out; + } + /* + * Start address of the memory range to remove and the + * current memory range entry in the list is same. Just + * move the start address of the current memory range + * entry in the list to end + 1. + */ + else if (base == mstart) { + mem_rngs->ranges[i].start = end + 1; + goto out; + } + /* + * End address of the memory range to remove and the + * current memory range entry in the list is same. + * Just move the end address of the current memory + * range entry in the list to base - 1. + */ + else if (end == mend) { + mem_rngs->ranges[i].end = base - 1; + goto out; + } + /* + * Memory range to remove is not at the edge of current + * memory range entry. Split the current memory entry into + * two half. + */ + else { + mem_rngs->ranges[i].end = base - 1; + size = mem_rngs->ranges[i].end - end; + ret = add_mem_range(mem_ranges, end + 1, size); + } + } +out: + return ret; +} #endif /* CONFIG_CRASH_DUMP */