>From 3ba7b5c55e7f62b56c4d355c0619c92c739f0d81 Mon Sep 17 00:00:00 2001 From: H. Peter Anvin 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 --- 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 -#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 = ""; 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