[PATCH 03/17] kexec_file: Make purgatory_info->ehdr const

2018-02-12 Thread Philipp Rudo
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.

Signed-off-by: Philipp Rudo 
---
 include/linux/kexec.h | 17 +++--
 kernel/kexec_file.c   |  4 ++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 7bae5e87bf0d..10842eece180 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -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;
 
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 0f044457b40c..06fc9fdd2474 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -880,7 +880,7 @@ 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)
@@ -904,9 +904,9 @@ int kexec_load_purgatory(struct kimage *image, unsigned 
long min,
 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;
 
-- 
2.13.5



[PATCH 03/17] kexec_file: Make purgatory_info->ehdr const

2018-02-02 Thread Philipp Rudo
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.

Signed-off-by: Philipp Rudo 
---
 include/linux/kexec.h | 17 +++--
 kernel/kexec_file.c   |  4 ++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 7bae5e87bf0d..10842eece180 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -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;
 
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 0f044457b40c..06fc9fdd2474 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -880,7 +880,7 @@ 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)
@@ -904,9 +904,9 @@ int kexec_load_purgatory(struct kimage *image, unsigned 
long min,
 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;
 
-- 
2.13.5