Re: [BUILD-FAILURE] linux-next: Tree for June 30

H. Peter Anvin
2008-06-30T21:56:04Z

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Here is a patch to replace the hard-coded limit with dynamic allocation.
I have only build-tested it, but it seems to work.

Please try it out; barring any screams to the contrary I'll add it to -tip.

-hpa

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>From 3ba7b5c55e7f62b56c4d355c0619c92c739f0d81 Mon Sep 17 00:00:00 2001
From: H. Peter Anvin <hpa@zytor.com>
Date: Mon, 30 Jun 2008 14:42:18 -0700
Subject: [PATCH] x86: remove arbitrary ELF section limit in 32-bit relocatable kernel

Impact: build failure in maximal configurations

The 32-bit x86 relocatable kernel requires an auxilliary host program
to process the relocations. This program had a hard-coded arbitrary
limit of a 100 ELF sections. Instead of a hard-coded limit, allocate
the structures dynamically.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/x86/boot/compressed/relocs.c | 198 ++++++++++++++++++++----------------
1 files changed, 110 insertions(+), 88 deletions(-)

diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c
index edaadea..a1310c5 100644
--- a/arch/x86/boot/compressed/relocs.c
+++ b/arch/x86/boot/compressed/relocs.c
@@ -10,16 +10,20 @@
#define USE_BSD
#include <endian.h>

-#define MAX_SHDRS 100
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
static Elf32_Ehdr ehdr;
-static Elf32_Shdr shdr[MAX_SHDRS];
-static Elf32_Sym *symtab[MAX_SHDRS];
-static Elf32_Rel *reltab[MAX_SHDRS];
-static char *strtab[MAX_SHDRS];
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;

+struct section {
+ Elf32_Shdr shdr;
+ struct section *link;
+ Elf32_Sym *symtab;
+ Elf32_Rel *reltab;
+ char *strtab;
+};
+static struct section *secs;
+
/*
* Following symbols have been audited. There values are constant and do
* not change if bzImage is loaded at a different physical address than
@@ -35,7 +39,7 @@ static int is_safe_abs_reloc(const char* sym_name)
{
int i;

- for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
+ for (i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
if (!strcmp(sym_name, safe_abs_relocs[i]))
/* Match found */
return 1;
@@ -137,10 +141,10 @@ static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
- sec_strtab = strtab[ehdr.e_shstrndx];
+ sec_strtab = secs[ehdr.e_shstrndx].strtab;
name = "<noname>";
if (shndx < ehdr.e_shnum) {
- name = sec_strtab + shdr[shndx].sh_name;
+ name = sec_strtab + secs[shndx].shdr.sh_name;
}
else if (shndx == SHN_ABS) {
name = "ABSOLUTE";
@@ -159,7 +163,7 @@ static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
name = sym_strtab + sym->st_name;
}
else {
- name = sec_name(shdr[sym->st_shndx].sh_name);
+ name = sec_name(secs[sym->st_shndx].shdr.sh_name);
}
return name;
}
@@ -244,29 +248,34 @@ static void read_ehdr(FILE *fp)
static void read_shdrs(FILE *fp)
{
int i;
- if (ehdr.e_shnum > MAX_SHDRS) {
- die("%d section headers supported: %d\n",
- ehdr.e_shnum, MAX_SHDRS);
+ Elf32_Shdr shdr;
+
+ secs = calloc(ehdr.e_shnum, sizeof(struct section));
+ if (!secs) {
+ die("Unable to allocate %d section headers\n",
+ ehdr.e_shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
- if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
- die("Cannot read ELF section headers: %s\n",
- strerror(errno));
- }
- for(i = 0; i < ehdr.e_shnum; i++) {
- shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
- shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
- shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
- shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
- shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
- shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
- shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
- shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
- shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
- shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ if (fread(&shdr, sizeof shdr, 1, fp) != 1)
+ die("Cannot read ELF section headers %d/%d: %s\n",
+ i, ehdr.e_shnum, strerror(errno));
+ sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
+ sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
+ sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
+ sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
+ sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
+ sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
+ sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
+ sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
+ sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
+ sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
+ if (sec->shdr.sh_link < ehdr.e_shnum)
+ sec->link = &secs[sec->shdr.sh_link];
}

}
@@ -274,20 +283,22 @@ static void read_shdrs(FILE *fp)
static void read_strtabs(FILE *fp)
{
int i;
- for(i = 0; i < ehdr.e_shnum; i++) {
- if (shdr[i].sh_type != SHT_STRTAB) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ if (sec->shdr.sh_type != SHT_STRTAB) {
continue;
}
- strtab[i] = malloc(shdr[i].sh_size);
- if (!strtab[i]) {
+ sec->strtab = malloc(sec->shdr.sh_size);
+ if (!sec->strtab) {
die("malloc of %d bytes for strtab failed\n",
- shdr[i].sh_size);
+ sec->shdr.sh_size);
}
- if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
+ if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
- shdr[i].sh_offset, strerror(errno));
+ sec->shdr.sh_offset, strerror(errno));
}
- if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
+ if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
+ != sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
@@ -297,28 +308,31 @@ static void read_strtabs(FILE *fp)
static void read_symtabs(FILE *fp)
{
int i,j;
- for(i = 0; i < ehdr.e_shnum; i++) {
- if (shdr[i].sh_type != SHT_SYMTAB) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
}
- symtab[i] = malloc(shdr[i].sh_size);
- if (!symtab[i]) {
+ sec->symtab = malloc(sec->shdr.sh_size);
+ if (!sec->symtab) {
die("malloc of %d bytes for symtab failed\n",
- shdr[i].sh_size);
+ sec->shdr.sh_size);
}
- if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
+ if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
- shdr[i].sh_offset, strerror(errno));
+ sec->shdr.sh_offset, strerror(errno));
}
- if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
+ if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
+ != sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
- for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
- symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
- symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
- symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
- symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
+ for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
+ Elf32_Sym *sym = &sec->symtab[j];
+ sym->st_name = elf32_to_cpu(sym->st_name);
+ sym->st_value = elf32_to_cpu(sym->st_value);
+ sym->st_size = elf32_to_cpu(sym->st_size);
+ sym->st_shndx = elf16_to_cpu(sym->st_shndx);
}
}
}
@@ -327,26 +341,29 @@ static void read_symtabs(FILE *fp)
static void read_relocs(FILE *fp)
{
int i,j;
- for(i = 0; i < ehdr.e_shnum; i++) {
- if (shdr[i].sh_type != SHT_REL) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ if (sec->shdr.sh_type != SHT_REL) {
continue;
}
- reltab[i] = malloc(shdr[i].sh_size);
- if (!reltab[i]) {
+ sec->reltab = malloc(sec->shdr.sh_size);
+ if (!sec->reltab) {
die("malloc of %d bytes for relocs failed\n",
- shdr[i].sh_size);
+ sec->shdr.sh_size);
}
- if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
+ if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
- shdr[i].sh_offset, strerror(errno));
+ sec->shdr.sh_offset, strerror(errno));
}
- if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
+ if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
+ != sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
- for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
- reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
- reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
+ for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
+ Elf32_Rel *rel = &sec->reltab[j];
+ rel->r_offset = elf32_to_cpu(rel->r_offset);
+ rel->r_info = elf32_to_cpu(rel->r_info);
}
}
}
@@ -357,19 +374,21 @@ static void print_absolute_symbols(void)
int i;
printf("Absolute symbols\n");
printf(" Num: Value Size Type Bind Visibility Name\n");
- for(i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
char *sym_strtab;
Elf32_Sym *sh_symtab;
int j;
- if (shdr[i].sh_type != SHT_SYMTAB) {
+
+ if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
}
- sh_symtab = symtab[i];
- sym_strtab = strtab[shdr[i].sh_link];
- for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
+ sh_symtab = sec->symtab;
+ sym_strtab = sec->link->strtab;
+ for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
Elf32_Sym *sym;
const char *name;
- sym = &symtab[i][j];
+ sym = &sec->symtab[j];
name = sym_name(sym_strtab, sym);
if (sym->st_shndx != SHN_ABS) {
continue;
@@ -389,26 +408,27 @@ static void print_absolute_relocs(void)
{
int i, printed = 0;

- for(i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ struct section *sec_applies, *sec_symtab;
char *sym_strtab;
Elf32_Sym *sh_symtab;
- unsigned sec_applies, sec_symtab;
int j;
- if (shdr[i].sh_type != SHT_REL) {
+ if (sec->shdr.sh_type != SHT_REL) {
continue;
}
- sec_symtab = shdr[i].sh_link;
- sec_applies = shdr[i].sh_info;
- if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
+ sec_symtab = sec->link;
+ sec_applies = &secs[sec->shdr.sh_info];
+ if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
continue;
}
- sh_symtab = symtab[sec_symtab];
- sym_strtab = strtab[shdr[sec_symtab].sh_link];
- for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
+ sh_symtab = sec_symtab->symtab;
+ sym_strtab = sec_symtab->link->strtab;
+ for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
Elf32_Rel *rel;
Elf32_Sym *sym;
const char *name;
- rel = &reltab[i][j];
+ rel = &sec->reltab[j];
sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
name = sym_name(sym_strtab, sym);
if (sym->st_shndx != SHN_ABS) {
@@ -456,26 +476,28 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
{
int i;
/* Walk through the relocations */
- for(i = 0; i < ehdr.e_shnum; i++) {
+ for (i = 0; i < ehdr.e_shnum; i++) {
char *sym_strtab;
Elf32_Sym *sh_symtab;
- unsigned sec_applies, sec_symtab;
+ struct section *sec_applies, *sec_symtab;
int j;
- if (shdr[i].sh_type != SHT_REL) {
+ struct section *sec = &secs[i];
+
+ if (sec->shdr.sh_type != SHT_REL) {
continue;
}
- sec_symtab = shdr[i].sh_link;
- sec_applies = shdr[i].sh_info;
- if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
+ sec_symtab = sec->link;
+ sec_applies = &secs[sec->shdr.sh_info];
+ if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
continue;
}
- sh_symtab = symtab[sec_symtab];
- sym_strtab = strtab[shdr[sec_symtab].sh_link];
- for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
+ sh_symtab = sec_symtab->symtab;
+ sym_strtab = sec->link->strtab;
+ for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
Elf32_Rel *rel;
Elf32_Sym *sym;
unsigned r_type;
- rel = &reltab[i][j];
+ rel = &sec->reltab[j];
sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
r_type = ELF32_R_TYPE(rel->r_info);
/* Don't visit relocations to absolute symbols */
@@ -539,7 +561,7 @@ static void emit_relocs(int as_text)
*/
printf(".section \".data.reloc\",\"a\"\n");
printf(".balign 4\n");
- for(i = 0; i < reloc_count; i++) {
+ for (i = 0; i < reloc_count; i++) {
printf("\t .long 0x%08lx\n", relocs[i]);
}
printf("\n");
@@ -550,7 +572,7 @@ static void emit_relocs(int as_text)
/* Print a stop */
printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
/* Now print each relocation */
- for(i = 0; i < reloc_count; i++) {
+ for (i = 0; i < reloc_count; i++) {
buf[0] = (relocs[i] >> 0) & 0xff;
buf[1] = (relocs[i] >> 8) & 0xff;
buf[2] = (relocs[i] >> 16) & 0xff;
@@ -577,7 +599,7 @@ int main(int argc, char **argv)
show_absolute_relocs = 0;
as_text = 0;
fname = NULL;
- for(i = 1; i < argc; i++) {
+ for (i = 1; i < argc; i++) {
char *arg = argv[i];
if (*arg == '-') {
if (strcmp(argv[1], "--abs-syms") == 0) {
--
1.5.4.1