diff options
Diffstat (limited to 'kernel/crash_core.c')
| -rw-r--r-- | kernel/crash_core.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 90ce1dfd591c..336083fba623 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -10,6 +10,7 @@ #include <linux/utsname.h> #include <linux/vmalloc.h> #include <linux/sizes.h> +#include <linux/kexec.h> #include <asm/page.h> #include <asm/sections.h> @@ -18,6 +19,9 @@ #include "kallsyms_internal.h" +/* Per cpu memory for storing cpu states in case of system crash. */ +note_buf_t __percpu *crash_notes; + /* vmcoreinfo stuff */ unsigned char *vmcoreinfo_data; size_t vmcoreinfo_size; @@ -314,6 +318,187 @@ static int __init parse_crashkernel_dummy(char *arg) } early_param("crashkernel", parse_crashkernel_dummy); +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 present CPU */ + for_each_present_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++; + pr_debug("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); + 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, j; + unsigned long long start, end, p_start, p_end; + struct range temp_range = {0, 0}; + + 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 (mstart > end || mend < start) + continue; + + /* Truncate any area outside of range */ + if (mstart < start) + p_start = start; + if (mend > end) + p_end = end; + + /* Found completely overlapping range */ + if (p_start == start && p_end == end) { + mem->ranges[i].start = 0; + mem->ranges[i].end = 0; + if (i < mem->nr_ranges - 1) { + /* Shift rest of the ranges to left */ + for (j = i; j < mem->nr_ranges - 1; j++) { + mem->ranges[j].start = + mem->ranges[j+1].start; + mem->ranges[j].end = + mem->ranges[j+1].end; + } + + /* + * Continue to check if there are another overlapping ranges + * from the current position because of shifting the above + * mem ranges. + */ + i--; + mem->nr_ranges--; + continue; + } + mem->nr_ranges--; + return 0; + } + + if (p_start > start && p_end < end) { + /* Split original range */ + mem->ranges[i].end = p_start - 1; + temp_range.start = p_end + 1; + temp_range.end = end; + } else if (p_start != start) + mem->ranges[i].end = p_start - 1; + else + mem->ranges[i].start = p_end + 1; + break; + } + + /* If a split happened, add the split to array */ + if (!temp_range.end) + return 0; + + /* Split happened */ + if (i == mem->max_nr_ranges - 1) + return -ENOMEM; + + /* Location where new range should go */ + j = i + 1; + if (j < mem->nr_ranges) { + /* Move over all ranges one slot towards the end */ + for (i = mem->nr_ranges - 1; i >= j; i--) + mem->ranges[i + 1] = mem->ranges[i]; + } + + mem->ranges[j].start = temp_range.start; + mem->ranges[j].end = temp_range.end; + mem->nr_ranges++; + return 0; +} + Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type, void *data, size_t data_len) { @@ -515,3 +700,36 @@ static int __init crash_save_vmcoreinfo_init(void) } subsys_initcall(crash_save_vmcoreinfo_init); + +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); |