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scripts/sortextable: support objects with more than 64K sections.
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Building with a large config and -ffunction-sections results in a large
number of sections and sortextable needs to be able to handle that.
Implement support for > 64K sections as modpost does.

Signed-off-by: Jamie Iles <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Michal Marek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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jamieiles authored and torvalds committed Nov 13, 2013
1 parent a2529ad commit 59c3645
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Showing 2 changed files with 47 additions and 3 deletions.
24 changes: 24 additions & 0 deletions scripts/sortextable.c
Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,30 @@ static void (*w2)(uint16_t, uint16_t *);

typedef void (*table_sort_t)(char *, int);

/*
* Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
* the way to -256..-1, to avoid conflicting with real section
* indices.
*/
#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))

static inline int is_shndx_special(unsigned int i)
{
return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
}

/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
static inline unsigned int get_secindex(unsigned int shndx,
unsigned int sym_offs,
const Elf32_Word *symtab_shndx_start)
{
if (is_shndx_special(shndx))
return SPECIAL(shndx);
if (shndx != SHN_XINDEX)
return shndx;
return r(&symtab_shndx_start[sym_offs]);
}

/* 32 bit and 64 bit are very similar */
#include "sortextable.h"
#define SORTEXTABLE_64
Expand Down
26 changes: 23 additions & 3 deletions scripts/sortextable.h
Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,8 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
Elf_Shdr *symtab_sec = NULL;
Elf_Shdr *extab_sec = NULL;
Elf_Sym *sym;
const Elf_Sym *symtab;
Elf32_Word *symtab_shndx_start = NULL;
Elf_Sym *sort_needed_sym;
Elf_Shdr *sort_needed_sec;
Elf_Rel *relocs = NULL;
Expand All @@ -109,11 +111,22 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
int extab_index = 0;
int i;
int idx;
unsigned int num_sections;
unsigned int secindex_strings;

shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
shstrtab_sec = shdr + r2(&ehdr->e_shstrndx);

num_sections = r2(&ehdr->e_shnum);
if (num_sections == SHN_UNDEF)
num_sections = _r(&shdr[0].sh_size);

secindex_strings = r2(&ehdr->e_shstrndx);
if (secindex_strings == SHN_XINDEX)
secindex_strings = r(&shdr[0].sh_link);

shstrtab_sec = shdr + secindex_strings;
secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
for (i = 0; i < r2(&ehdr->e_shnum); i++) {
for (i = 0; i < num_sections; i++) {
idx = r(&shdr[i].sh_name);
if (strcmp(secstrtab + idx, "__ex_table") == 0) {
extab_sec = shdr + i;
Expand All @@ -129,6 +142,9 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
symtab_sec = shdr + i;
if (strcmp(secstrtab + idx, ".strtab") == 0)
strtab_sec = shdr + i;
if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
symtab_shndx_start = (Elf32_Word *)(
(const char *)ehdr + _r(&shdr[i].sh_offset));
}
if (strtab_sec == NULL) {
fprintf(stderr, "no .strtab in file: %s\n", fname);
Expand All @@ -138,6 +154,8 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
fprintf(stderr, "no .symtab in file: %s\n", fname);
fail_file();
}
symtab = (const Elf_Sym *)((const char *)ehdr +
_r(&symtab_sec->sh_offset));
if (extab_sec == NULL) {
fprintf(stderr, "no __ex_table in file: %s\n", fname);
fail_file();
Expand Down Expand Up @@ -176,7 +194,9 @@ do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
fname);
fail_file();
}
sort_needed_sec = &shdr[r2(&sort_needed_sym->st_shndx)];
sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
sort_needed_sym - symtab,
symtab_shndx_start)];
sort_done_location = (void *)ehdr +
_r(&sort_needed_sec->sh_offset) +
_r(&sort_needed_sym->st_value) -
Expand Down

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