[PATCH] Modules 2/3: Use sh_addr instead of sh_offset

Rusty Russell (rusty@rustcorp.com.au)
Thu, 02 Jan 2003 13:54:57 +1100


Linus, please apply.

Trivial substitution. Richard points out that we should be using
sh_addr to hold the address, rather than overloading sh_offset to be a
pointer. Fixes archs appropriately.

Name: Use sh_addr instead of overloading sh_offset.
From: Richard Henderson <rth@twiddle.net>
Status: Tested on 2.5.53
Depends: Module/nocommon.patch.gz

D: The original patch used to overload sh_offset to a pointer to the
D: location of the section. This uses sh_addr, which is more correct
D: and less surprising.

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/arm/kernel/module.c .27574-linux-2.5-bk.updated/arch/arm/kernel/module.c
--- .27574-linux-2.5-bk/arch/arm/kernel/module.c 2002-11-25 08:43:47.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/arm/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -88,7 +88,7 @@ apply_relocate(Elf32_Shdr *sechdrs, cons
Elf32_Shdr *symsec = sechdrs + symindex;
Elf32_Shdr *relsec = sechdrs + relindex;
Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
- Elf32_Rel *rel = (void *)relsec->sh_offset;
+ Elf32_Rel *rel = (void *)relsec->sh_addr;
unsigned int i;

for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
@@ -103,7 +103,7 @@ apply_relocate(Elf32_Shdr *sechdrs, cons
return -ENOEXEC;
}

- sym = ((Elf32_Sym *)symsec->sh_offset) + offset;
+ sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
if (!sym->st_value) {
printk(KERN_WARNING "%s: unknown symbol %s\n",
module->name, strtab + sym->st_name);
@@ -118,7 +118,7 @@ apply_relocate(Elf32_Shdr *sechdrs, cons
return -ENOEXEC;
}

- loc = dstsec->sh_offset + rel->r_offset;
+ loc = dstsec->sh_addr + rel->r_offset;

switch (ELF32_R_TYPE(rel->r_info)) {
case R_ARM_ABS32:
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/i386/kernel/module.c .27574-linux-2.5-bk.updated/arch/i386/kernel/module.c
--- .27574-linux-2.5-bk/arch/i386/kernel/module.c 2002-12-23 11:17:07.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/i386/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -68,7 +68,7 @@ int apply_relocate(Elf32_Shdr *sechdrs,
struct module *me)
{
unsigned int i;
- Elf32_Rel *rel = (void *)sechdrs[relsec].sh_offset;
+ Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
uint32_t *location;

@@ -76,10 +76,10 @@ int apply_relocate(Elf32_Shdr *sechdrs,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
- location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* This is the symbol it is referring to */
- sym = (Elf32_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rel[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/ppc/kernel/module.c .27574-linux-2.5-bk.updated/arch/ppc/kernel/module.c
--- .27574-linux-2.5-bk/arch/ppc/kernel/module.c 2002-12-10 15:56:47.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/ppc/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -176,7 +176,7 @@ int apply_relocate_add(Elf32_Shdr *sechd
struct module *module)
{
unsigned int i;
- Elf32_Rela *rela = (void *)sechdrs[relsec].sh_offset;
+ Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
uint32_t *location;
uint32_t value;
@@ -185,10 +185,10 @@ int apply_relocate_add(Elf32_Shdr *sechd
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
/* This is where to make the change */
- location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rela[i].r_offset;
/* This is the symbol it is referring to */
- sym = (Elf32_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rela[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/s390/kernel/module.c .27574-linux-2.5-bk.updated/arch/s390/kernel/module.c
--- .27574-linux-2.5-bk/arch/s390/kernel/module.c 2002-11-25 08:43:48.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/s390/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -78,7 +78,7 @@ int apply_relocate(Elf_Shdr *sechdrs,
struct module *me)
{
unsigned int i;
- ElfW(Rel) *rel = (void *)sechdrs[relsec].sh_offset;
+ ElfW(Rel) *rel = (void *)sechdrs[relsec].sh_addr;
ElfW(Sym) *sym;
ElfW(Addr) *location;

@@ -86,10 +86,10 @@ int apply_relocate(Elf_Shdr *sechdrs,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
- location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* This is the symbol it is referring to */
- sym = (ElfW(Sym) *)sechdrs[symindex].sh_offset
+ sym = (ElfW(Sym) *)sechdrs[symindex].sh_addr
+ ELFW(R_SYM)(rel[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/s390x/kernel/module.c .27574-linux-2.5-bk.updated/arch/s390x/kernel/module.c
--- .27574-linux-2.5-bk/arch/s390x/kernel/module.c 2002-11-25 08:43:49.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/s390x/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -78,7 +78,7 @@ int apply_relocate(Elf_Shdr *sechdrs,
struct module *me)
{
unsigned int i;
- ElfW(Rel) *rel = (void *)sechdrs[relsec].sh_offset;
+ ElfW(Rel) *rel = (void *)sechdrs[relsec].sh_addr;
ElfW(Sym) *sym;
ElfW(Addr) *location;

@@ -86,10 +86,10 @@ int apply_relocate(Elf_Shdr *sechdrs,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
- location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* This is the symbol it is referring to */
- sym = (ElfW(Sym) *)sechdrs[symindex].sh_offset
+ sym = (ElfW(Sym) *)sechdrs[symindex].sh_addr
+ ELFW(R_SYM)(rel[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/sparc/kernel/module.c .27574-linux-2.5-bk.updated/arch/sparc/kernel/module.c
--- .27574-linux-2.5-bk/arch/sparc/kernel/module.c 2002-11-25 08:43:49.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/sparc/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -71,7 +71,7 @@ int apply_relocate_add(Elf32_Shdr *sechd
struct module *me)
{
unsigned int i;
- Elf32_Rela *rel = (void *)sechdrs[relsec].sh_offset;
+ Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
u8 *location;
u32 *loc32;
@@ -80,11 +80,11 @@ int apply_relocate_add(Elf32_Shdr *sechd
Elf32_Addr v;

/* This is where to make the change */
- location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
loc32 = (u32 *) location;
/* This is the symbol it is referring to */
- sym = (Elf32_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rel[i].r_info);
if (!(v = sym->st_value)) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/sparc64/kernel/module.c .27574-linux-2.5-bk.updated/arch/sparc64/kernel/module.c
--- .27574-linux-2.5-bk/arch/sparc64/kernel/module.c 2002-11-25 08:43:49.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/sparc64/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -178,7 +178,7 @@ int apply_relocate_add(Elf64_Shdr *sechd
struct module *me)
{
unsigned int i;
- Elf64_Rela *rel = (void *)sechdrs[relsec].sh_offset;
+ Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf64_Sym *sym;
u8 *location;
u32 *loc32;
@@ -187,14 +187,14 @@ int apply_relocate_add(Elf64_Shdr *sechd
Elf64_Addr v;

/* This is where to make the change */
- location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
loc32 = (u32 *) location;

BUG_ON(((u64)location >> (u64)32) != (u64)0);

/* This is the symbol it is referring to */
- sym = (Elf64_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+ ELF64_R_SYM(rel[i].r_info);
if (!(v = sym->st_value)) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/v850/kernel/module.c .27574-linux-2.5-bk.updated/arch/v850/kernel/module.c
--- .27574-linux-2.5-bk/arch/v850/kernel/module.c 2002-11-28 10:20:03.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/v850/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -160,7 +160,7 @@ int apply_relocate_add (Elf32_Shdr *sech
struct module *mod)
{
unsigned int i;
- Elf32_Rela *rela = (void *)sechdrs[relsec].sh_offset;
+ Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;

DEBUGP ("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
@@ -168,11 +168,11 @@ int apply_relocate_add (Elf32_Shdr *sech
for (i = 0; i < sechdrs[relsec].sh_size / sizeof (*rela); i++) {
/* This is where to make the change */
uint32_t *loc
- = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rela[i].r_offset);
/* This is the symbol it is referring to */
Elf32_Sym *sym
- = ((Elf32_Sym *)sechdrs[symindex].sh_offset
+ = ((Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM (rela[i].r_info));
uint32_t val = sym->st_value;

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/arch/x86_64/kernel/module.c .27574-linux-2.5-bk.updated/arch/x86_64/kernel/module.c
--- .27574-linux-2.5-bk/arch/x86_64/kernel/module.c 2002-12-26 15:41:04.000000000 +1100
+++ .27574-linux-2.5-bk.updated/arch/x86_64/kernel/module.c 2002-12-29 22:07:55.000000000 +1100
@@ -49,7 +49,7 @@ int apply_relocate_add(Elf64_Shdr *sechd
struct module *me)
{
unsigned int i;
- Elf64_Rela *rel = (void *)sechdrs[relsec].sh_offset;
+ Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf64_Sym *sym;
void *loc;
u64 val;
@@ -58,11 +58,11 @@ int apply_relocate_add(Elf64_Shdr *sechd
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
- loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;

/* This is the symbol it is referring to */
- sym = (Elf64_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+ ELF64_R_SYM(rel[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .27574-linux-2.5-bk/kernel/module.c .27574-linux-2.5-bk.updated/kernel/module.c
--- .27574-linux-2.5-bk/kernel/module.c 2002-12-29 22:07:29.000000000 +1100
+++ .27574-linux-2.5-bk.updated/kernel/module.c 2002-12-29 22:11:18.000000000 +1100
@@ -94,7 +94,7 @@ static unsigned long find_local_symbol(E
const char *name)
{
unsigned int i;
- Elf_Sym *sym = (void *)sechdrs[symindex].sh_offset;
+ Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;

/* Search (defined) internal symbols first. */
for (i = 1; i < sechdrs[symindex].sh_size/sizeof(*sym); i++) {
@@ -793,7 +793,7 @@ static int handle_section(const char *na
struct module *mod)
{
int ret;
- const char *strtab = (char *)sechdrs[strindex].sh_offset;
+ const char *strtab = (char *)sechdrs[strindex].sh_addr;

switch (sechdrs[i].sh_type) {
case SHT_REL:
@@ -835,7 +835,7 @@ static int simplify_symbols(Elf_Shdr *se
/* First simplify defined symbols, so if they become the
"answer" to undefined symbols, copying their st_value us
correct. */
- for (sym = (void *)sechdrs[symindex].sh_offset, i = 0;
+ for (sym = (void *)sechdrs[symindex].sh_addr, i = 0;
i < sechdrs[symindex].sh_size / sizeof(Elf_Sym);
i++) {
switch (sym[i].st_shndx) {
@@ -857,20 +857,20 @@ static int simplify_symbols(Elf_Shdr *se
default:
sym[i].st_value
= (unsigned long)
- (sechdrs[sym[i].st_shndx].sh_offset
+ (sechdrs[sym[i].st_shndx].sh_addr
+ sym[i].st_value);
}
}

/* Now try to resolve undefined symbols */
- for (sym = (void *)sechdrs[symindex].sh_offset, i = 0;
+ for (sym = (void *)sechdrs[symindex].sh_addr, i = 0;
i < sechdrs[symindex].sh_size / sizeof(Elf_Sym);
i++) {
if (sym[i].st_shndx == SHN_UNDEF) {
/* Look for symbol */
struct kernel_symbol_group *ksg = NULL;
const char *strtab
- = (char *)sechdrs[strindex].sh_offset;
+ = (char *)sechdrs[strindex].sh_addr;

sym[i].st_value
= find_symbol_internal(sechdrs,
@@ -967,6 +967,10 @@ static struct module *load_module(void *

/* Find where important sections are */
for (i = 1; i < hdr->e_shnum; i++) {
+ /* Mark all sections sh_addr with their address in the
+ temporary image. */
+ sechdrs[i].sh_addr = (size_t)hdr + sechdrs[i].sh_offset;
+
if (sechdrs[i].sh_type == SHT_SYMTAB) {
/* Internal symbols */
DEBUGP("Symbol table in section %u\n", i);
@@ -1019,7 +1023,7 @@ static struct module *load_module(void *
err = -ENOEXEC;
goto free_hdr;
}
- mod = (void *)hdr + sechdrs[modindex].sh_offset;
+ mod = (void *)sechdrs[modindex].sh_addr;

/* Now copy in args */
err = strlen_user(uargs);
@@ -1079,7 +1083,7 @@ static struct module *load_module(void *
memset(ptr, 0, mod->init_size);
mod->module_init = ptr;

- /* Transfer each section which requires ALLOC, and set sh_offset
+ /* Transfer each section which requires ALLOC, and set sh_addr
fields to absolute addresses. */
used.core_size = 0;
used.init_size = 0;
@@ -1089,12 +1093,10 @@ static struct module *load_module(void *
hdr, &sechdrs[i], mod, &used);
if (IS_ERR(ptr))
goto cleanup;
- sechdrs[i].sh_offset = (unsigned long)ptr;
+ sechdrs[i].sh_addr = (unsigned long)ptr;
/* Have we just copied __this_module across? */
if (i == modindex)
mod = ptr;
- } else {
- sechdrs[i].sh_offset += (unsigned long)hdr;
}
}
/* Don't use more than we allocated! */
@@ -1113,7 +1115,7 @@ static struct module *load_module(void *
if (exportindex) {
mod->symbols.num_syms = (sechdrs[exportindex].sh_size
/ sizeof(*mod->symbols.syms));
- mod->symbols.syms = (void *)sechdrs[exportindex].sh_offset;
+ mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr;
}

/* Set up exception table */
@@ -1122,7 +1124,7 @@ static struct module *load_module(void *
mod->extable.num_entries = (sechdrs[exindex].sh_size
/ sizeof(struct
exception_table_entry));
- mod->extable.entry = (void *)sechdrs[exindex].sh_offset;
+ mod->extable.entry = (void *)sechdrs[exindex].sh_addr;
}

/* Now handle each section. */
@@ -1134,9 +1136,9 @@ static struct module *load_module(void *
}

#ifdef CONFIG_KALLSYMS
- mod->symtab = (void *)sechdrs[symindex].sh_offset;
+ mod->symtab = (void *)sechdrs[symindex].sh_addr;
mod->num_syms = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
- mod->strtab = (void *)sechdrs[strindex].sh_offset;
+ mod->strtab = (void *)sechdrs[strindex].sh_addr;
#endif
err = module_finalize(hdr, sechdrs, mod);
if (err < 0)
@@ -1146,16 +1148,16 @@ static struct module *load_module(void *
if (obsparmindex) {
err = obsolete_params(mod->name, mod->args,
(struct obsolete_modparm *)
- sechdrs[obsparmindex].sh_offset,
+ sechdrs[obsparmindex].sh_addr,
sechdrs[obsparmindex].sh_size
/ sizeof(struct obsolete_modparm),
sechdrs, symindex,
- (char *)sechdrs[strindex].sh_offset);
+ (char *)sechdrs[strindex].sh_addr);
} else {
/* Size of section 0 is 0, so this works well if no params */
err = parse_args(mod->name, mod->args,
(struct kernel_param *)
- sechdrs[setupindex].sh_offset,
+ sechdrs[setupindex].sh_addr,
sechdrs[setupindex].sh_size
/ sizeof(struct kernel_param),
NULL);

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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