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kexec_elf: support 32 bit ELF files 

The powerpc version only supported 64 bit. Add some
code to switch decoding of fields during runtime so
we can kexec a 32 bit kernel from a 64 bit kernel and
vice versa.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Sven Schnelle 2019-08-23 21:49:19 +02:00 committed by Helge Deller
parent 571ceb7d96
commit ea46a13ebf
1 changed files with 42 additions and 15 deletions
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57
kernel/kexec_elf.c
View File

@ -21,8 +21,6 @@
#include <linux/slab.h>
#include <linux/types.h>
#define elf_addr_to_cpu elf64_to_cpu
static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
{
return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
@ -152,9 +150,6 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type);
ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version);
ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry);
ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff);
ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff);
ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
@ -162,6 +157,24 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
switch (ehdr->e_ident[EI_CLASS]) {
case ELFCLASS64:
ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry);
ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff);
ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff);
break;
case ELFCLASS32:
ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry);
ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff);
ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff);
break;
default:
pr_debug("Unknown ELF class.\n");
return -EINVAL;
}
return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
}
@ -192,6 +205,7 @@ static int elf_read_phdr(const char *buf, size_t len,
{
/* Override the const in proghdrs, we are the ones doing the loading. */
struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
const struct elfhdr *ehdr = elf_info->ehdr;
const char *pbuf;
struct elf_phdr *buf_phdr;
@ -199,18 +213,31 @@ static int elf_read_phdr(const char *buf, size_t len,
buf_phdr = (struct elf_phdr *) pbuf;
phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset);
phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr);
phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr);
phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
/*
* The following fields have a type equivalent to Elf_Addr
* both in 32 bit and 64 bit ELF.
*/
phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz);
phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz);
phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align);
switch (ehdr->e_ident[EI_CLASS]) {
case ELFCLASS64:
phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset);
phdr->p_paddr = elf64_to_cpu(ehdr, buf_phdr->p_paddr);
phdr->p_vaddr = elf64_to_cpu(ehdr, buf_phdr->p_vaddr);
phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz);
phdr->p_memsz = elf64_to_cpu(ehdr, buf_phdr->p_memsz);
phdr->p_align = elf64_to_cpu(ehdr, buf_phdr->p_align);
break;
case ELFCLASS32:
phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset);
phdr->p_paddr = elf32_to_cpu(ehdr, buf_phdr->p_paddr);
phdr->p_vaddr = elf32_to_cpu(ehdr, buf_phdr->p_vaddr);
phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz);
phdr->p_memsz = elf32_to_cpu(ehdr, buf_phdr->p_memsz);
phdr->p_align = elf32_to_cpu(ehdr, buf_phdr->p_align);
break;
default:
pr_debug("Unknown ELF class.\n");
return -EINVAL;
}
return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
}