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Do not look up any given symbol more than once. Does away with the vast

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majority of symbol table lookups.
This commit is contained in:
ad 2008-11-16 11:26:28 +00:00
parent 3c6470e287
commit d89eff7233
1 changed files with 34 additions and 28 deletions
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62
sys/kern/subr_kobj.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_kobj.c,v 1.27 2008/11/14 22:00:23 ad Exp $ */
/* $NetBSD: subr_kobj.c,v 1.28 2008/11/16 11:26:28 ad Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@ -63,7 +63,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_kobj.c,v 1.27 2008/11/14 22:00:23 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_kobj.c,v 1.28 2008/11/16 11:26:28 ad Exp $");
#define ELFSIZE ARCH_ELFSIZE
@ -143,7 +143,7 @@ struct kobj {
};
static int kobj_relocate(kobj_t, bool);
static int kobj_checkdup(kobj_t);
static int kobj_checksyms(kobj_t);
static void kobj_error(const char *, ...);
static int kobj_read(kobj_t, void **, size_t, off_t);
static int kobj_read_bits(kobj_t, void *, size_t, off_t);
@ -626,7 +626,7 @@ kobj_load(kobj_t ko)
* Perform local relocations only. Relocations relating to global
* symbols will be done by kobj_affix().
*/
error = kobj_checkdup(ko);
error = kobj_checksyms(ko);
if (error == 0) {
error = kobj_relocate(ko, true);
}
@ -836,8 +836,6 @@ kobj_sym_lookup(kobj_t ko, uintptr_t symidx)
{
const Elf_Sym *sym;
const char *symbol;
int error;
u_long addr;
/* Don't even try to lookup the symbol if the index is bogus. */
if (symidx >= ko->ko_symcnt)
@ -847,7 +845,7 @@ kobj_sym_lookup(kobj_t ko, uintptr_t symidx)
/* Quick answer if there is a definition included. */
if (sym->st_shndx != SHN_UNDEF) {
return sym->st_value;
return (uintptr_t)sym->st_value;
}
/* If we get here, then it is undefined and needs a lookup. */
@ -867,16 +865,7 @@ kobj_sym_lookup(kobj_t ko, uintptr_t symidx)
return 0;
}
/*
* Don't need to lock, as it is known that the symbol
* tables aren't going to change (we hold module_lock).
*/
error = ksyms_getval(NULL, symbol, &addr, KSYMS_ANY);
if (error != 0) {
kobj_error("symbol `%s' not found", symbol);
return (uintptr_t)0;
}
return (uintptr_t)addr;
return (uintptr_t)sym->st_value;
case STB_WEAK:
kobj_error("weak symbols not supported\n");
@ -906,33 +895,50 @@ kobj_findbase(kobj_t ko, int sec)
}
/*
* kobj_checkdup:
* kobj_checksyms:
*
* Scan symbol table for duplicates.
* Scan symbol table for duplicates and resolve references to
* exernal symbols.
*/
static int
kobj_checkdup(kobj_t ko)
kobj_checksyms(kobj_t ko)
{
unsigned long rval;
Elf_Sym *sym, *ms;
const char *name;
bool dup;
int error;
error = 0;
dup = false;
for (ms = (sym = ko->ko_symtab) + ko->ko_symcnt; sym < ms; sym++) {
/* Check validity of the symbol. */
if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL ||
sym->st_name == 0)
continue;
/* Check if the symbol already exists */
/*
* Look it up. Don't need to lock, as it is known that
* the symbol tables aren't going to change (we hold
* module_lock).
*/
name = ko->ko_strtab + sym->st_name;
if (ksyms_getval(NULL, name, &rval, KSYMS_EXTERN) != 0) {
if (ksyms_getval_unlocked(NULL, name, &rval,
KSYMS_EXTERN) != 0) {
if (sym->st_shndx == SHN_UNDEF) {
kobj_error("symbol `%s' not found", name);
error = ENOEXEC;
continue;
}
}
/* Save values of undefined globals. */
if (sym->st_shndx == SHN_UNDEF) {
sym->st_value = (Elf_Addr)rval;
continue;
}
/* Check (and complain) about differing values */
if (sym->st_value == rval || sym->st_shndx == SHN_UNDEF) {
/* Check (and complain) about differing values. */
if (sym->st_value == rval) {
continue;
}
if (strcmp(name, "_bss_start") == 0 ||
@ -948,10 +954,10 @@ kobj_checkdup(kobj_t ko)
continue;
}
kobj_error("global symbol `%s' redefined\n", name);
dup = true;
error = ENOEXEC;
}
return dup ? EEXIST : 0;
return error;
}
/*