// SPDX-License-Identifier: GPL-2.0-only/* * crash.c - kernel crash support code. * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/buildid.h>#include <linux/init.h>#include <linux/utsname.h>#include <linux/vmalloc.h>#include <linux/sizes.h>#include <linux/kexec.h>#include <linux/memory.h>#include <linux/mm.h>#include <linux/cpuhotplug.h>#include <linux/memblock.h>#include <linux/kmemleak.h>#include <linux/crash_core.h>#include <linux/reboot.h>#include <linux/btf.h>#include <linux/objtool.h> #include <asm/page.h>#include <asm/sections.h> #include <crypto/sha1.h> #include "kallsyms_internal.h"#include "kexec_internal.h" /* Per cpu memory for storing cpu states in case of system crash. */note_buf_t __percpu *crash_notes; #ifdef CONFIG_CRASH_DUMP int kimage_crash_copy_vmcoreinfo(struct kimage *image){ struct page *vmcoreinfo_page; void *safecopy; if (!IS_ENABLED(CONFIG_CRASH_DUMP)) return 0; if (image->type != KEXEC_TYPE_CRASH) return 0; /* * For kdump, allocate one vmcoreinfo safe copy from the * crash memory. as we have arch_kexec_protect_crashkres() * after kexec syscall, we naturally protect it from write * (even read) access under kernel direct mapping. But on * the other hand, we still need to operate it when crash * happens to generate vmcoreinfo note, hereby we rely on * vmap for this purpose. */ vmcoreinfo_page = kimage_alloc_control_pages(image, 0); if (!vmcoreinfo_page) { pr_warn("Could not allocate vmcoreinfo buffer\n"); return -ENOMEM; } safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL); if (!safecopy) { pr_warn("Could not vmap vmcoreinfo buffer\n"); return -ENOMEM; } image->vmcoreinfo_data_copy = safecopy; crash_update_vmcoreinfo_safecopy(safecopy); return 0;} int kexec_should_crash(struct task_struct *p){ /* * If crash_kexec_post_notifiers is enabled, don't run * crash_kexec() here yet, which must be run after panic * notifiers in panic(). */ if (crash_kexec_post_notifiers) return 0; /* * There are 4 panic() calls in make_task_dead() path, each of which * corresponds to each of these 4 conditions. */ if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) return 1; return 0;} int kexec_crash_loaded(void){ return !!kexec_crash_image;}EXPORT_SYMBOL_GPL(kexec_crash_loaded); /* * 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 * which processes crash_kexec routines. */void __noclone __crash_kexec(struct pt_regs *regs){ /* Take the kexec_lock here to prevent sys_kexec_load * running on one cpu from replacing the crash kernel * we are using after a panic on a different cpu. * * If the crash kernel was not located in a fixed area * of memory the xchg(&kexec_crash_image) would be * sufficient. But since I reuse the memory... */ if (kexec_trylock()) { if (kexec_crash_image) { struct pt_regs fixed_regs; crash_setup_regs(&fixed_regs, regs); crash_save_vmcoreinfo(); machine_crash_shutdown(&fixed_regs); machine_kexec(kexec_crash_image); } kexec_unlock(); }}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)) { /* This is the 1st CPU which comes here, so go ahead. */ __crash_kexec(regs); /* * Reset panic_cpu to allow another panic()/crash_kexec() * call. */ atomic_set(&panic_cpu, PANIC_CPU_INVALID); }} static inline resource_size_t crash_resource_size(const struct resource *res){ return !res->end ? 0 : resource_size(res);} int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz){ Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; unsigned char *buf; unsigned int cpu, i; unsigned long long notes_addr; unsigned long mstart, mend; /* extra phdr for vmcoreinfo ELF note */ nr_phdr = nr_cpus + 1; nr_phdr += mem->nr_ranges; /* * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). * I think this is required by tools like gdb. So same physical * memory will be mapped in two ELF headers. One will contain kernel * text virtual addresses and other will have __va(physical) addresses. */ nr_phdr++; elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); buf = vzalloc(elf_sz); if (!buf) return -ENOMEM; ehdr = (Elf64_Ehdr *)buf; phdr = (Elf64_Phdr *)(ehdr + 1); memcpy(ehdr->e_ident, ELFMAG, SELFMAG); ehdr->e_ident[EI_CLASS] = ELFCLASS64; ehdr->e_ident[EI_DATA] = ELFDATA2LSB; ehdr->e_ident[EI_VERSION] = EV_CURRENT; ehdr->e_ident[EI_OSABI] = ELF_OSABI; memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); ehdr->e_type = ET_CORE; ehdr->e_machine = ELF_ARCH; ehdr->e_version = EV_CURRENT; ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); /* Prepare one phdr of type PT_NOTE for each possible CPU */ for_each_possible_cpu(cpu) { phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); phdr->p_offset = phdr->p_paddr = notes_addr; phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); (ehdr->e_phnum)++; phdr++; } /* Prepare one PT_NOTE header for vmcoreinfo */ phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; (ehdr->e_phnum)++; phdr++; /* Prepare PT_LOAD type program header for kernel text region */ if (need_kernel_map) { phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_vaddr = (unsigned long) _text; phdr->p_filesz = phdr->p_memsz = _end - _text; phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); ehdr->e_phnum++; phdr++; } /* Go through all the ranges in mem->ranges[] and prepare phdr */ for (i = 0; i < mem->nr_ranges; i++) { mstart = mem->ranges[i].start; mend = mem->ranges[i].end; phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = mstart; phdr->p_paddr = mstart; phdr->p_vaddr = (unsigned long) __va(mstart); phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; phdr->p_align = 0; ehdr->e_phnum++;#ifdef CONFIG_KEXEC_FILE kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, ehdr->e_phnum, phdr->p_offset);#endif phdr++; } *addr = buf; *sz = elf_sz; return 0;} int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend){ int i; unsigned long long start, end, p_start, p_end; for (i = 0; i < mem->nr_ranges; i++) { start = mem->ranges[i].start; end = mem->ranges[i].end; p_start = mstart; p_end = mend; if (p_start > end) continue; /* * Because the memory ranges in mem->ranges are stored in * ascending order, when we detect `p_end < start`, we can * immediately exit the for loop, as the subsequent memory * ranges will definitely be outside the range we are looking * for. */ if (p_end < start) break; /* Truncate any area outside of range */ if (p_start < start) p_start = start; if (p_end > end) p_end = end; /* Found completely overlapping range */ if (p_start == start && p_end == end) { memmove(&mem->ranges[i], &mem->ranges[i + 1], (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i])); i--; mem->nr_ranges--; } else if (p_start > start && p_end < end) { /* Split original range */ if (mem->nr_ranges >= mem->max_nr_ranges) return -ENOMEM; memmove(&mem->ranges[i + 2], &mem->ranges[i + 1], (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i])); mem->ranges[i].end = p_start - 1; mem->ranges[i + 1].start = p_end + 1; mem->ranges[i + 1].end = end; i++; mem->nr_ranges++; } else if (p_start != start) mem->ranges[i].end = p_start - 1; else mem->ranges[i].start = p_end + 1; } return 0;} ssize_t crash_get_memory_size(void){ ssize_t size = 0; if (!kexec_trylock()) return -EBUSY; size += crash_resource_size(&crashk_res); size += crash_resource_size(&crashk_low_res); kexec_unlock(); return size;} static int __crash_shrink_memory(struct resource *old_res, unsigned long new_size){ struct resource *ram_res; ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL); if (!ram_res) return -ENOMEM; ram_res->start = old_res->start + new_size; ram_res->end = old_res->end; ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM; ram_res->name = "System RAM"; if (!new_size) { release_resource(old_res); old_res->start = 0; old_res->end = 0; } else { crashk_res.end = ram_res->start - 1; } crash_free_reserved_phys_range(ram_res->start, ram_res->end); insert_resource(&iomem_resource, ram_res); return 0;} int crash_shrink_memory(unsigned long new_size){ int ret = 0; unsigned long old_size, low_size; if (!kexec_trylock()) return -EBUSY; if (kexec_crash_image) { ret = -ENOENT; goto unlock; } low_size = crash_resource_size(&crashk_low_res); old_size = crash_resource_size(&crashk_res) + low_size; new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN); if (new_size >= old_size) { ret = (new_size == old_size) ? 0 : -EINVAL; goto unlock; } /* * (low_size > new_size) implies that low_size is greater than zero. * This also means that if low_size is zero, the else branch is taken. * * If low_size is greater than 0, (low_size > new_size) indicates that * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res * needs to be shrunken. */ if (low_size > new_size) { ret = __crash_shrink_memory(&crashk_res, 0); if (ret) goto unlock; ret = __crash_shrink_memory(&crashk_low_res, new_size); } else { ret = __crash_shrink_memory(&crashk_res, new_size - low_size); } /* Swap crashk_res and crashk_low_res if needed */ if (!crashk_res.end && crashk_low_res.end) { crashk_res.start = crashk_low_res.start; crashk_res.end = crashk_low_res.end; release_resource(&crashk_low_res); crashk_low_res.start = 0; crashk_low_res.end = 0; insert_resource(&iomem_resource, &crashk_res); } unlock: kexec_unlock(); return ret;} void crash_save_cpu(struct pt_regs *regs, int cpu){ struct elf_prstatus prstatus; u32 *buf; if ((cpu < 0) || (cpu >= nr_cpu_ids)) return; /* Using ELF notes here is opportunistic. * I need a well defined structure format * for the data I pass, and I need tags * on the data to indicate what information I have * squirrelled away. ELF notes happen to provide * all of that, so there is no need to invent something new. */ buf = (u32 *)per_cpu_ptr(crash_notes, cpu); if (!buf) return; 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, &prstatus, sizeof(prstatus)); final_note(buf);} static int __init crash_notes_memory_init(void){ /* Allocate memory for saving cpu registers. */ size_t size, align; /* * crash_notes could be allocated across 2 vmalloc pages when percpu * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc * pages are also on 2 continuous physical pages. In this case the * 2nd part of crash_notes in 2nd page could be lost since only the * starting address and size of crash_notes are exported through sysfs. * Here round up the size of crash_notes to the nearest power of two * and pass it to __alloc_percpu as align value. This can make sure * crash_notes is allocated inside one physical page. */ size = sizeof(note_buf_t); align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE); /* * Break compile if size is bigger than PAGE_SIZE since crash_notes * definitely will be in 2 pages with that. */ BUILD_BUG_ON(size > PAGE_SIZE); crash_notes = __alloc_percpu(size, align); if (!crash_notes) { pr_warn("Memory allocation for saving cpu register states failed\n"); return -ENOMEM; } return 0;}subsys_initcall(crash_notes_memory_init); #endif /*CONFIG_CRASH_DUMP*/ #ifdef CONFIG_CRASH_HOTPLUG#undef pr_fmt#define pr_fmt(fmt) "crash hp: " fmt /* * Different than kexec/kdump loading/unloading/jumping/shrinking which * usually rarely happen, there will be many crash hotplug events notified * during one short period, e.g one memory board is hot added and memory * regions are online. So mutex lock __crash_hotplug_lock is used to * serialize the crash hotplug handling specifically. */static DEFINE_MUTEX(__crash_hotplug_lock);#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock) /* * This routine utilized when the crash_hotplug sysfs node is read. * It reflects the kernel's ability/permission to update the kdump * image directly. */Lines 1–500 of 672. Load more
// SPDX-License-Identifier: GPL-2.0-only /* * crash.c - kernel crash support code. * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/buildid.h> #include <linux/init.h> #include <linux/utsname.h> #include <linux/vmalloc.h> #include <linux/sizes.h> #include <linux/kexec.h> #include <linux/memory.h> #include <linux/mm.h> #include <linux/cpuhotplug.h> #include <linux/memblock.h> #include <linux/kmemleak.h> #include <linux/crash_core.h> #include <linux/reboot.h> #include <linux/btf.h> #include <linux/objtool.h> #include <asm/page.h> #include <asm/sections.h> #include <crypto/sha1.h> #include "kallsyms_internal.h" #include "kexec_internal.h" /* Per cpu memory for storing cpu states in case of system crash. */ note_buf_t __percpu *crash_notes; #ifdef CONFIG_CRASH_DUMP int kimage_crash_copy_vmcoreinfo(struct kimage *image) { struct page *vmcoreinfo_page; void *safecopy; if (!IS_ENABLED(CONFIG_CRASH_DUMP)) return 0; if (image->type != KEXEC_TYPE_CRASH) return 0; /* * For kdump, allocate one vmcoreinfo safe copy from the * crash memory. as we have arch_kexec_protect_crashkres() * after kexec syscall, we naturally protect it from write * (even read) access under kernel direct mapping. But on * the other hand, we still need to operate it when crash * happens to generate vmcoreinfo note, hereby we rely on * vmap for this purpose. */ vmcoreinfo_page = kimage_alloc_control_pages(image, 0); if (!vmcoreinfo_page) { pr_warn("Could not allocate vmcoreinfo buffer\n"); return -ENOMEM; } safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL); if (!safecopy) { pr_warn("Could not vmap vmcoreinfo buffer\n"); return -ENOMEM; } image->vmcoreinfo_data_copy = safecopy; crash_update_vmcoreinfo_safecopy(safecopy); return 0; } int kexec_should_crash(struct task_struct *p) { /* * If crash_kexec_post_notifiers is enabled, don't run * crash_kexec() here yet, which must be run after panic * notifiers in panic(). */ if (crash_kexec_post_notifiers) return 0; /* * There are 4 panic() calls in make_task_dead() path, each of which * corresponds to each of these 4 conditions. */ if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) return 1; return 0; } int kexec_crash_loaded(void) { return !!kexec_crash_image; } EXPORT_SYMBOL_GPL(kexec_crash_loaded); /* * 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 * which processes crash_kexec routines. */ void __noclone __crash_kexec(struct pt_regs *regs) { /* Take the kexec_lock here to prevent sys_kexec_load * running on one cpu from replacing the crash kernel * we are using after a panic on a different cpu. * * If the crash kernel was not located in a fixed area * of memory the xchg(&kexec_crash_image) would be * sufficient. But since I reuse the memory... */ if (kexec_trylock()) { if (kexec_crash_image) { struct pt_regs fixed_regs; crash_setup_regs(&fixed_regs, regs); crash_save_vmcoreinfo(); machine_crash_shutdown(&fixed_regs); machine_kexec(kexec_crash_image); } kexec_unlock(); } } 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)) { /* This is the 1st CPU which comes here, so go ahead. */ __crash_kexec(regs); /* * Reset panic_cpu to allow another panic()/crash_kexec() * call. */ atomic_set(&panic_cpu, PANIC_CPU_INVALID); } } static inline resource_size_t crash_resource_size(const struct resource *res) { return !res->end ? 0 : resource_size(res); } int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz) { Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; unsigned char *buf; unsigned int cpu, i; unsigned long long notes_addr; unsigned long mstart, mend; /* extra phdr for vmcoreinfo ELF note */ nr_phdr = nr_cpus + 1; nr_phdr += mem->nr_ranges; /* * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). * I think this is required by tools like gdb. So same physical * memory will be mapped in two ELF headers. One will contain kernel * text virtual addresses and other will have __va(physical) addresses. */ nr_phdr++; elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); buf = vzalloc(elf_sz); if (!buf) return -ENOMEM; ehdr = (Elf64_Ehdr *)buf; phdr = (Elf64_Phdr *)(ehdr + 1); memcpy(ehdr->e_ident, ELFMAG, SELFMAG); ehdr->e_ident[EI_CLASS] = ELFCLASS64; ehdr->e_ident[EI_DATA] = ELFDATA2LSB; ehdr->e_ident[EI_VERSION] = EV_CURRENT; ehdr->e_ident[EI_OSABI] = ELF_OSABI; memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); ehdr->e_type = ET_CORE; ehdr->e_machine = ELF_ARCH; ehdr->e_version = EV_CURRENT; ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); /* Prepare one phdr of type PT_NOTE for each possible CPU */ for_each_possible_cpu(cpu) { phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); phdr->p_offset = phdr->p_paddr = notes_addr; phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); (ehdr->e_phnum)++; phdr++; } /* Prepare one PT_NOTE header for vmcoreinfo */ phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; (ehdr->e_phnum)++; phdr++; /* Prepare PT_LOAD type program header for kernel text region */ if (need_kernel_map) { phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_vaddr = (unsigned long) _text; phdr->p_filesz = phdr->p_memsz = _end - _text; phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); ehdr->e_phnum++; phdr++; } /* Go through all the ranges in mem->ranges[] and prepare phdr */ for (i = 0; i < mem->nr_ranges; i++) { mstart = mem->ranges[i].start; mend = mem->ranges[i].end; phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = mstart; phdr->p_paddr = mstart; phdr->p_vaddr = (unsigned long) __va(mstart); phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; phdr->p_align = 0; ehdr->e_phnum++; #ifdef CONFIG_KEXEC_FILE kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, ehdr->e_phnum, phdr->p_offset); #endif phdr++; } *addr = buf; *sz = elf_sz; return 0; } int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { int i; unsigned long long start, end, p_start, p_end; for (i = 0; i < mem->nr_ranges; i++) { start = mem->ranges[i].start; end = mem->ranges[i].end; p_start = mstart; p_end = mend; if (p_start > end) continue; /* * Because the memory ranges in mem->ranges are stored in * ascending order, when we detect `p_end < start`, we can * immediately exit the for loop, as the subsequent memory * ranges will definitely be outside the range we are looking * for. */ if (p_end < start) break; /* Truncate any area outside of range */ if (p_start < start) p_start = start; if (p_end > end) p_end = end; /* Found completely overlapping range */ if (p_start == start && p_end == end) { memmove(&mem->ranges[i], &mem->ranges[i + 1], (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i])); i--; mem->nr_ranges--; } else if (p_start > start && p_end < end) { /* Split original range */ if (mem->nr_ranges >= mem->max_nr_ranges) return -ENOMEM; memmove(&mem->ranges[i + 2], &mem->ranges[i + 1], (mem->nr_ranges - (i + 1)) * sizeof(mem->ranges[i])); mem->ranges[i].end = p_start - 1; mem->ranges[i + 1].start = p_end + 1; mem->ranges[i + 1].end = end; i++; mem->nr_ranges++; } else if (p_start != start) mem->ranges[i].end = p_start - 1; else mem->ranges[i].start = p_end + 1; } return 0; } ssize_t crash_get_memory_size(void) { ssize_t size = 0; if (!kexec_trylock()) return -EBUSY; size += crash_resource_size(&crashk_res); size += crash_resource_size(&crashk_low_res); kexec_unlock(); return size; } static int __crash_shrink_memory(struct resource *old_res, unsigned long new_size) { struct resource *ram_res; ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL); if (!ram_res) return -ENOMEM; ram_res->start = old_res->start + new_size; ram_res->end = old_res->end; ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM; ram_res->name = "System RAM"; if (!new_size) { release_resource(old_res); old_res->start = 0; old_res->end = 0; } else { crashk_res.end = ram_res->start - 1; } crash_free_reserved_phys_range(ram_res->start, ram_res->end); insert_resource(&iomem_resource, ram_res); return 0; } int crash_shrink_memory(unsigned long new_size) { int ret = 0; unsigned long old_size, low_size; if (!kexec_trylock()) return -EBUSY; if (kexec_crash_image) { ret = -ENOENT; goto unlock; } low_size = crash_resource_size(&crashk_low_res); old_size = crash_resource_size(&crashk_res) + low_size; new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN); if (new_size >= old_size) { ret = (new_size == old_size) ? 0 : -EINVAL; goto unlock; } /* * (low_size > new_size) implies that low_size is greater than zero. * This also means that if low_size is zero, the else branch is taken. * * If low_size is greater than 0, (low_size > new_size) indicates that * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res * needs to be shrunken. */ if (low_size > new_size) { ret = __crash_shrink_memory(&crashk_res, 0); if (ret) goto unlock; ret = __crash_shrink_memory(&crashk_low_res, new_size); } else { ret = __crash_shrink_memory(&crashk_res, new_size - low_size); } /* Swap crashk_res and crashk_low_res if needed */ if (!crashk_res.end && crashk_low_res.end) { crashk_res.start = crashk_low_res.start; crashk_res.end = crashk_low_res.end; release_resource(&crashk_low_res); crashk_low_res.start = 0; crashk_low_res.end = 0; insert_resource(&iomem_resource, &crashk_res); } unlock: kexec_unlock(); return ret; } void crash_save_cpu(struct pt_regs *regs, int cpu) { struct elf_prstatus prstatus; u32 *buf; if ((cpu < 0) || (cpu >= nr_cpu_ids)) return; /* Using ELF notes here is opportunistic. * I need a well defined structure format * for the data I pass, and I need tags * on the data to indicate what information I have * squirrelled away. ELF notes happen to provide * all of that, so there is no need to invent something new. */ buf = (u32 *)per_cpu_ptr(crash_notes, cpu); if (!buf) return; 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, &prstatus, sizeof(prstatus)); final_note(buf); } static int __init crash_notes_memory_init(void) { /* Allocate memory for saving cpu registers. */ size_t size, align; /* * crash_notes could be allocated across 2 vmalloc pages when percpu * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc * pages are also on 2 continuous physical pages. In this case the * 2nd part of crash_notes in 2nd page could be lost since only the * starting address and size of crash_notes are exported through sysfs. * Here round up the size of crash_notes to the nearest power of two * and pass it to __alloc_percpu as align value. This can make sure * crash_notes is allocated inside one physical page. */ size = sizeof(note_buf_t); align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE); /* * Break compile if size is bigger than PAGE_SIZE since crash_notes * definitely will be in 2 pages with that. */ BUILD_BUG_ON(size > PAGE_SIZE); crash_notes = __alloc_percpu(size, align); if (!crash_notes) { pr_warn("Memory allocation for saving cpu register states failed\n"); return -ENOMEM; } return 0; } subsys_initcall(crash_notes_memory_init); #endif /*CONFIG_CRASH_DUMP*/ #ifdef CONFIG_CRASH_HOTPLUG #undef pr_fmt #define pr_fmt(fmt) "crash hp: " fmt /* * Different than kexec/kdump loading/unloading/jumping/shrinking which * usually rarely happen, there will be many crash hotplug events notified * during one short period, e.g one memory board is hot added and memory * regions are online. So mutex lock __crash_hotplug_lock is used to * serialize the crash hotplug handling specifically. */ static DEFINE_MUTEX(__crash_hotplug_lock); #define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock) #define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock) /* * This routine utilized when the crash_hotplug sysfs node is read. * It reflects the kernel's ability/permission to update the kdump * image directly. */