[PATCH] kdump: Parse elf32 headers and export through /proc/vmcore
o Adds support for parsing core ELF32 headers.
o I am expecting ELF32 support to go away down the line. This patch has been
introduced for testing purposes as gdb can not parse ELF64 headers for
i386. When a decent user space solution is available, ELF32 support
can go away.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 8ad4678..3b2e7b69 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -202,6 +202,23 @@
return size;
}
+static u64 __init get_vmcore_size_elf32(char *elfptr)
+{
+ int i;
+ u64 size;
+ Elf32_Ehdr *ehdr_ptr;
+ Elf32_Phdr *phdr_ptr;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+ phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
+ size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_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)
@@ -283,6 +300,87 @@
return 0;
}
+/* Merges all the PT_NOTE headers into one. */
+static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
+ struct list_head *vc_list)
+{
+ int i, nr_ptnote=0, rc=0;
+ char *tmp;
+ Elf32_Ehdr *ehdr_ptr;
+ Elf32_Phdr phdr, *phdr_ptr;
+ Elf32_Nhdr *nhdr_ptr;
+ u64 phdr_sz = 0, note_off;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+ phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_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(Elf32_Nhdr) +
+ ((nhdr_ptr->n_namesz + 3) & ~3) +
+ ((nhdr_ptr->n_descsz + 3) & ~3);
+ real_sz += sz;
+ nhdr_ptr = (Elf32_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(Elf32_Ehdr) +
+ (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_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(Elf32_Ehdr);
+ memcpy(tmp, &phdr, sizeof(phdr));
+ tmp += sizeof(phdr);
+
+ /* Remove unwanted PT_NOTE program headers. */
+ i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
+ *elfsz = *elfsz - i;
+ memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_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,
@@ -322,6 +420,43 @@
return 0;
}
+static int __init process_ptload_program_headers_elf32(char *elfptr,
+ size_t elfsz,
+ struct list_head *vc_list)
+{
+ int i;
+ Elf32_Ehdr *ehdr_ptr;
+ Elf32_Phdr *phdr_ptr;
+ loff_t vmcore_off;
+ struct vmcore *new;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+ phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
+
+ /* First program header is PT_NOTE header. */
+ vmcore_off = sizeof(Elf32_Ehdr) +
+ (ehdr_ptr->e_phnum) * sizeof(Elf32_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)
@@ -342,6 +477,26 @@
}
}
+/* Sets offset fields of vmcore elements. */
+static void __init set_vmcore_list_offsets_elf32(char *elfptr,
+ struct list_head *vc_list)
+{
+ loff_t vmcore_off;
+ Elf32_Ehdr *ehdr_ptr;
+ struct vmcore *m;
+
+ ehdr_ptr = (Elf32_Ehdr *)elfptr;
+
+ /* Skip Elf header and program headers. */
+ vmcore_off = sizeof(Elf32_Ehdr) +
+ (ehdr_ptr->e_phnum) * sizeof(Elf32_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;
@@ -398,6 +553,62 @@
return 0;
}
+static int __init parse_crash_elf32_headers(void)
+{
+ int rc=0;
+ Elf32_Ehdr ehdr;
+ u64 addr;
+
+ addr = elfcorehdr_addr;
+
+ /* Read Elf header */
+ rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_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] != ELFCLASS32||
+ ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
+ ehdr.e_version != EV_CURRENT ||
+ ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
+ ehdr.e_phentsize != sizeof(Elf32_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(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_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_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
+ if (rc) {
+ kfree(elfcorebuf);
+ return rc;
+ }
+ rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
+ &vmcore_list);
+ if (rc) {
+ kfree(elfcorebuf);
+ return rc;
+ }
+ set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
+ return 0;
+}
+
static int __init parse_crash_elf_headers(void)
{
unsigned char e_ident[EI_NIDENT];
@@ -421,6 +632,13 @@
/* Determine vmcore size. */
vmcore_size = get_vmcore_size_elf64(elfcorebuf);
+ } else if (e_ident[EI_CLASS] == ELFCLASS32) {
+ rc = parse_crash_elf32_headers();
+ if (rc)
+ return rc;
+
+ /* Determine vmcore size. */
+ vmcore_size = get_vmcore_size_elf32(elfcorebuf);
} else {
printk(KERN_WARNING "Warning: Core image elf header is not"
" sane\n");