kernel/kexec_file.c: make purgatory_info->ehdr const

The kexec_purgatory buffer is read-only.  Thus all pointers into
kexec_purgatory are read-only, too.  Point this out by explicitly
marking purgatory_info->ehdr as 'const' and update the comments in
purgatory_info.

Link: http://lkml.kernel.org/r/20180321112751.22196-4-prudo@linux.vnet.ibm.com
Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Philipp Rudo 2018-04-13 15:36:17 -07:00 committed by Linus Torvalds
parent d2b8178ca7
commit 65c225d328
2 changed files with 13 additions and 8 deletions

View File

@ -99,14 +99,19 @@ struct compat_kexec_segment {
#ifdef CONFIG_KEXEC_FILE
struct purgatory_info {
/* Pointer to elf header of read only purgatory */
Elf_Ehdr *ehdr;
/* Pointer to purgatory sechdrs which are modifiable */
/*
* Pointer to elf header at the beginning of kexec_purgatory.
* Note: kexec_purgatory is read only
*/
const Elf_Ehdr *ehdr;
/*
* Temporary, modifiable buffer for sechdrs used for relocation.
* This memory can be freed post image load.
*/
Elf_Shdr *sechdrs;
/*
* Temporary buffer location where purgatory is loaded and relocated
* This memory can be freed post image load
* Temporary, modifiable buffer for stripped purgatory used for
* relocation. This memory can be freed post image load.
*/
void *purgatory_buf;

View File

@ -941,7 +941,7 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min,
if (kexec_purgatory_size <= 0)
return -EINVAL;
pi->ehdr = (Elf_Ehdr *)kexec_purgatory;
pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
ret = __kexec_load_purgatory(image, min, max, top_down);
if (ret)
@ -965,9 +965,9 @@ out:
static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
const char *name)
{
const Elf_Ehdr *ehdr;
Elf_Sym *syms;
Elf_Shdr *sechdrs;
Elf_Ehdr *ehdr;
int i, k;
const char *strtab;