diff options
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/Makefile | 1 | ||||
| -rw-r--r-- | fs/proc/proc_misc.c | 6 | ||||
| -rw-r--r-- | fs/proc/vmcore.c | 451 |
3 files changed, 458 insertions, 0 deletions
diff --git a/fs/proc/Makefile b/fs/proc/Makefile index 738b9b6..7431d7b 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -11,4 +11,5 @@ proc-y += inode.o root.o base.o generic.o array.o \ kmsg.o proc_tty.o proc_misc.o proc-$(CONFIG_PROC_KCORE) += kcore.o +proc-$(CONFIG_PROC_VMCORE) += vmcore.o proc-$(CONFIG_PROC_DEVICETREE) += proc_devtree.o diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index 94b570a..a345355 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -44,6 +44,7 @@ #include <linux/jiffies.h> #include <linux/sysrq.h> #include <linux/vmalloc.h> +#include <linux/crash_dump.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -618,6 +619,11 @@ void __init proc_misc_init(void) (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE; } #endif +#ifdef CONFIG_PROC_VMCORE + proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL); + if (proc_vmcore) + proc_vmcore->proc_fops = &proc_vmcore_operations; +#endif #ifdef CONFIG_MAGIC_SYSRQ entry = create_proc_entry("sysrq-trigger", S_IWUSR, NULL); if (entry) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c new file mode 100644 index 0000000..8ad4678 --- /dev/null +++ b/fs/proc/vmcore.c @@ -0,0 +1,451 @@ +/* + * fs/proc/vmcore.c Interface for accessing the crash + * dump from the system's previous life. + * Heavily borrowed from fs/proc/kcore.c + * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) + * Copyright (C) IBM Corporation, 2004. All rights reserved + * + */ + +#include <linux/config.h> +#include <linux/mm.h> +#include <linux/proc_fs.h> +#include <linux/user.h> +#include <linux/a.out.h> +#include <linux/elf.h> +#include <linux/elfcore.h> +#include <linux/proc_fs.h> +#include <linux/highmem.h> +#include <linux/bootmem.h> +#include <linux/init.h> +#include <linux/crash_dump.h> +#include <linux/list.h> +#include <asm/uaccess.h> +#include <asm/io.h> + +/* List representing chunks of contiguous memory areas and their offsets in + * vmcore file. + */ +static LIST_HEAD(vmcore_list); + +/* Stores the pointer to the buffer containing kernel elf core headers. */ +static char *elfcorebuf; +static size_t elfcorebuf_sz; + +/* Total size of vmcore file. */ +static u64 vmcore_size; + +struct proc_dir_entry *proc_vmcore = NULL; + +/* Reads a page from the oldmem device from given offset. */ +static ssize_t read_from_oldmem(char *buf, size_t count, + loff_t *ppos, int userbuf) +{ + unsigned long pfn, offset; + size_t nr_bytes; + ssize_t read = 0, tmp; + + if (!count) + return 0; + + offset = (unsigned long)(*ppos % PAGE_SIZE); + pfn = (unsigned long)(*ppos / PAGE_SIZE); + if (pfn > saved_max_pfn) + return -EINVAL; + + do { + if (count > (PAGE_SIZE - offset)) + nr_bytes = PAGE_SIZE - offset; + else + nr_bytes = count; + + tmp = copy_oldmem_page(pfn, buf, nr_bytes, offset, userbuf); + if (tmp < 0) + return tmp; + *ppos += nr_bytes; + count -= nr_bytes; + buf += nr_bytes; + read += nr_bytes; + ++pfn; + offset = 0; + } while (count); + + return read; +} + +/* Maps vmcore file offset to respective physical address in memroy. */ +static u64 map_offset_to_paddr(loff_t offset, struct list_head *vc_list, + struct vmcore **m_ptr) +{ + struct vmcore *m; + u64 paddr; + + list_for_each_entry(m, vc_list, list) { + u64 start, end; + start = m->offset; + end = m->offset + m->size - 1; + if (offset >= start && offset <= end) { + paddr = m->paddr + offset - start; + *m_ptr = m; + return paddr; + } + } + *m_ptr = NULL; + return 0; +} + +/* Read from the ELF header and then the crash dump. On error, negative value is + * returned otherwise number of bytes read are returned. + */ +static ssize_t read_vmcore(struct file *file, char __user *buffer, + size_t buflen, loff_t *fpos) +{ + ssize_t acc = 0, tmp; + size_t tsz, nr_bytes; + u64 start; + struct vmcore *curr_m = NULL; + + if (buflen == 0 || *fpos >= vmcore_size) + return 0; + + /* trim buflen to not go beyond EOF */ + if (buflen > vmcore_size - *fpos) + buflen = vmcore_size - *fpos; + + /* Read ELF core header */ + if (*fpos < elfcorebuf_sz) { + tsz = elfcorebuf_sz - *fpos; + if (buflen < tsz) + tsz = buflen; + if (copy_to_user(buffer, elfcorebuf + *fpos, tsz)) + return -EFAULT; + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + + /* leave now if filled buffer already */ + if (buflen == 0) + return acc; + } + + start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m); + if (!curr_m) + return -EINVAL; + if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) + tsz = buflen; + + /* Calculate left bytes in current memory segment. */ + nr_bytes = (curr_m->size - (start - curr_m->paddr)); + if (tsz > nr_bytes) + tsz = nr_bytes; + + while (buflen) { + tmp = read_from_oldmem(buffer, tsz, &start, 1); + if (tmp < 0) + return tmp; + buflen -= tsz; + *fpos += tsz; + buffer += tsz; + acc += tsz; + if (start >= (curr_m->paddr + curr_m->size)) { + if (curr_m->list.next == &vmcore_list) + return acc; /*EOF*/ + curr_m = list_entry(curr_m->list.next, + struct vmcore, list); + start = curr_m->paddr; + } + if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) + tsz = buflen; + /* Calculate left bytes in current memory segment. */ + nr_bytes = (curr_m->size - (start - curr_m->paddr)); + if (tsz > nr_bytes) + tsz = nr_bytes; + } + return acc; +} + +static int open_vmcore(struct inode *inode, struct file *filp) +{ + return 0; +} + +struct file_operations proc_vmcore_operations = { + .read = read_vmcore, + .open = open_vmcore, +}; + +static struct vmcore* __init get_new_element(void) +{ + struct vmcore *p; + + p = kmalloc(sizeof(*p), GFP_KERNEL); + if (p) + memset(p, 0, sizeof(*p)); + return p; +} + +static u64 __init get_vmcore_size_elf64(char *elfptr) +{ + int i; + u64 size; + Elf64_Ehdr *ehdr_ptr; + Elf64_Phdr *phdr_ptr; + + ehdr_ptr = (Elf64_Ehdr *)elfptr; + phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); + size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr)); + for (i = 0; i < ehdr_ptr->e_phnum; i++) { + size += phdr_ptr->p_memsz; + phdr_ptr++; + } + return size; +} + +/* Merges all the PT_NOTE headers into one. */ +static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, + struct list_head *vc_list) +{ + int i, nr_ptnote=0, rc=0; + char *tmp; + Elf64_Ehdr *ehdr_ptr; + Elf64_Phdr phdr, *phdr_ptr; + Elf64_Nhdr *nhdr_ptr; + u64 phdr_sz = 0, note_off; + + ehdr_ptr = (Elf64_Ehdr *)elfptr; + phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); + for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { + int j; + void *notes_section; + struct vmcore *new; + u64 offset, max_sz, sz, real_sz = 0; + if (phdr_ptr->p_type != PT_NOTE) + continue; + nr_ptnote++; + max_sz = phdr_ptr->p_memsz; + offset = phdr_ptr->p_offset; + notes_section = kmalloc(max_sz, GFP_KERNEL); + if (!notes_section) + return -ENOMEM; + rc = read_from_oldmem(notes_section, max_sz, &offset, 0); + if (rc < 0) { + kfree(notes_section); + return rc; + } + nhdr_ptr = notes_section; + for (j = 0; j < max_sz; j += sz) { + if (nhdr_ptr->n_namesz == 0) + break; + sz = sizeof(Elf64_Nhdr) + + ((nhdr_ptr->n_namesz + 3) & ~3) + + ((nhdr_ptr->n_descsz + 3) & ~3); + real_sz += sz; + nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz); + } + + /* Add this contiguous chunk of notes section to vmcore list.*/ + new = get_new_element(); + if (!new) { + kfree(notes_section); + return -ENOMEM; + } + new->paddr = phdr_ptr->p_offset; + new->size = real_sz; + list_add_tail(&new->list, vc_list); + phdr_sz += real_sz; + kfree(notes_section); + } + + /* Prepare merged PT_NOTE program header. */ + phdr.p_type = PT_NOTE; + phdr.p_flags = 0; + note_off = sizeof(Elf64_Ehdr) + + (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr); + phdr.p_offset = note_off; + phdr.p_vaddr = phdr.p_paddr = 0; + phdr.p_filesz = phdr.p_memsz = phdr_sz; + phdr.p_align = 0; + + /* Add merged PT_NOTE program header*/ + tmp = elfptr + sizeof(Elf64_Ehdr); + memcpy(tmp, &phdr, sizeof(phdr)); + tmp += sizeof(phdr); + + /* Remove unwanted PT_NOTE program headers. */ + i = (nr_ptnote - 1) * sizeof(Elf64_Phdr); + *elfsz = *elfsz - i; + memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr))); + + /* Modify e_phnum to reflect merged headers. */ + ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; + + return 0; +} + +/* Add memory chunks represented by program headers to vmcore list. Also update + * the new offset fields of exported program headers. */ +static int __init process_ptload_program_headers_elf64(char *elfptr, + size_t elfsz, + struct list_head *vc_list) +{ + int i; + Elf64_Ehdr *ehdr_ptr; + Elf64_Phdr *phdr_ptr; + loff_t vmcore_off; + struct vmcore *new; + + ehdr_ptr = (Elf64_Ehdr *)elfptr; + phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */ + + /* First program header is PT_NOTE header. */ + vmcore_off = sizeof(Elf64_Ehdr) + + (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) + + phdr_ptr->p_memsz; /* Note sections */ + + for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { + if (phdr_ptr->p_type != PT_LOAD) + continue; + + /* Add this contiguous chunk of memory to vmcore list.*/ + new = get_new_element(); + if (!new) + return -ENOMEM; + new->paddr = phdr_ptr->p_offset; + new->size = phdr_ptr->p_memsz; + list_add_tail(&new->list, vc_list); + + /* Update the program header offset. */ + phdr_ptr->p_offset = vmcore_off; + vmcore_off = vmcore_off + phdr_ptr->p_memsz; + } + return 0; +} + +/* Sets offset fields of vmcore elements. */ +static void __init set_vmcore_list_offsets_elf64(char *elfptr, + struct list_head *vc_list) +{ + loff_t vmcore_off; + Elf64_Ehdr *ehdr_ptr; + struct vmcore *m; + + ehdr_ptr = (Elf64_Ehdr *)elfptr; + + /* Skip Elf header and program headers. */ + vmcore_off = sizeof(Elf64_Ehdr) + + (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr); + + list_for_each_entry(m, vc_list, list) { + m->offset = vmcore_off; + vmcore_off += m->size; + } +} + +static int __init parse_crash_elf64_headers(void) +{ + int rc=0; + Elf64_Ehdr ehdr; + u64 addr; + + addr = elfcorehdr_addr; + + /* Read Elf header */ + rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0); + if (rc < 0) + return rc; + + /* Do some basic Verification. */ + if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 || + (ehdr.e_type != ET_CORE) || + !elf_check_arch(&ehdr) || + ehdr.e_ident[EI_CLASS] != ELFCLASS64 || + ehdr.e_ident[EI_VERSION] != EV_CURRENT || + ehdr.e_version != EV_CURRENT || + ehdr.e_ehsize != sizeof(Elf64_Ehdr) || + ehdr.e_phentsize != sizeof(Elf64_Phdr) || + ehdr.e_phnum == 0) { + printk(KERN_WARNING "Warning: Core image elf header is not" + "sane\n"); + return -EINVAL; + } + + /* Read in all elf headers. */ + elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); + elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL); + if (!elfcorebuf) + return -ENOMEM; + addr = elfcorehdr_addr; + rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0); + if (rc < 0) { + kfree(elfcorebuf); + return rc; + } + + /* Merge all PT_NOTE headers into one. */ + rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list); + if (rc) { + kfree(elfcorebuf); + return rc; + } + rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz, + &vmcore_list); + if (rc) { + kfree(elfcorebuf); + return rc; + } + set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list); + return 0; +} + +static int __init parse_crash_elf_headers(void) +{ + unsigned char e_ident[EI_NIDENT]; + u64 addr; + int rc=0; + + addr = elfcorehdr_addr; + rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0); + if (rc < 0) + return rc; + if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) { + printk(KERN_WARNING "Warning: Core image elf header" + " not found\n"); + return -EINVAL; + } + + if (e_ident[EI_CLASS] == ELFCLASS64) { + rc = parse_crash_elf64_headers(); + if (rc) + return rc; + + /* Determine vmcore size. */ + vmcore_size = get_vmcore_size_elf64(elfcorebuf); + } else { + printk(KERN_WARNING "Warning: Core image elf header is not" + " sane\n"); + return -EINVAL; + } + return 0; +} + +/* Init function for vmcore module. */ +static int __init vmcore_init(void) +{ + int rc = 0; + + /* If elfcorehdr= has been passed in cmdline, then capture the dump.*/ + if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX)) + return rc; + rc = parse_crash_elf_headers(); + if (rc) { + printk(KERN_WARNING "Kdump: vmcore not initialized\n"); + return rc; + } + + /* Initialize /proc/vmcore size if proc is already up. */ + if (proc_vmcore) + proc_vmcore->size = vmcore_size; + return 0; +} +module_init(vmcore_init) |
