Support really large LKMs. Find out how much space is needed for symbols
and then allocate it on demand. Rename some common symbols (__bss_start, _edata, _end, __start_link_set_*, __stop_link_set_*) so that ".<module>" is appended to them. This shrinks an amd64 kernel by 20KB of BSS.
This commit is contained in:
matt
parent
074a9e8fee
commit
f01501b2c6
@ -1,4 +1,4 @@
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/* $NetBSD: kern_ksyms.c,v 1.19 2004/02/18 20:41:09 matt Exp $ */
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/* $NetBSD: kern_ksyms.c,v 1.20 2004/02/18 23:44:49 matt Exp $ */
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/*
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* Copyright (c) 2001, 2003 Anders Magnusson (ragge@ludd.luth.se).
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* All rights reserved.
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@ -46,7 +46,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.19 2004/02/18 20:41:09 matt Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.20 2004/02/18 23:44:49 matt Exp $");
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#ifdef _KERNEL
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#include "opt_ddb.h"
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@ -604,43 +604,62 @@ ksyms_sizes_calc(void)
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#endif
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/*
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* Temporary work buffers for dynamic loaded symbol tables.
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* Temporary work structure for dynamic loaded symbol tables.
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* Will go away when in-kernel linker is in place.
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*/
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#define NSAVEDSYMS 512
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#define SZSYMNAMES NSAVEDSYMS*8 /* Just an approximation */
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static Elf_Sym savedsyms[NSAVEDSYMS];
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static int symnmoff[NSAVEDSYMS];
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static char symnames[SZSYMNAMES];
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static int cursyms, curnamep;
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struct syminfo {
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size_t cursyms;
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size_t curnamep;
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size_t maxsyms;
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size_t maxnamep;
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Elf_Sym *syms;
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int *symnmoff;
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char *symnames;
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};
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/*
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* Add a symbol to the temporary save area for symbols.
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* This routine will go away when the in-kernel linker is in place.
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*/
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static void
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addsym(Elf_Sym *sym, char *name)
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addsym(struct syminfo *info, const Elf_Sym *sym, const char *name,
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const char *mod)
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{
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int len;
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int len, mlen;
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#ifdef KSYMS_DEBUG
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if (ksyms_debug & FOLLOW_MORE_CALLS)
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printf("addsym: name %s val %lx\n", name, (long)sym->st_value);
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#endif
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if (cursyms == NSAVEDSYMS ||
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((len = strlen(name) + 1) + curnamep) > SZSYMNAMES) {
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len = strlen(name) + 1;
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if (mod)
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mlen = 1 + strlen(mod);
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else
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mlen = 0;
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if (info->cursyms == info->maxsyms ||
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(len + mlen + info->curnamep) > info->maxnamep) {
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printf("addsym: too many symbols, skipping '%s'\n", name);
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return;
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}
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strlcpy(&symnames[curnamep], name, sizeof(symnames) - curnamep);
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savedsyms[cursyms] = *sym;
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symnmoff[cursyms] = savedsyms[cursyms].st_name = curnamep;
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curnamep += len;
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strlcpy(&info->symnames[info->curnamep], name,
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info->maxnamep - info->curnamep);
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if (mlen) {
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info->symnames[info->curnamep + len - 1] = '.';
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strlcpy(&info->symnames[info->curnamep + len], mod,
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info->maxnamep - (info->curnamep + len));
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len += mlen;
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}
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info->syms[info->cursyms] = *sym;
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info->syms[info->cursyms].st_name = info->curnamep;
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info->symnmoff[info->cursyms] = info->curnamep;
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info->curnamep += len;
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#if NKSYMS
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if (len > ksyms_maxlen)
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ksyms_maxlen = len;
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#endif
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cursyms++;
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info->cursyms++;
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}
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/*
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* Adds a symbol table.
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@ -657,7 +676,8 @@ ksyms_addsymtab(const char *mod, void *symstart, vsize_t symsize,
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struct symtab *st;
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unsigned long rval;
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int i;
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char *str, *name;
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char *name;
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struct syminfo info;
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#ifdef KSYMS_DEBUG
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if (ksyms_debug & FOLLOW_CALLS)
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@ -683,10 +703,11 @@ ksyms_addsymtab(const char *mod, void *symstart, vsize_t symsize,
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/*
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* XXX - Only add a symbol if it do not exist already.
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* This is because of a flaw in the current LKM implementation,
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* the loop will be removed once the in-kernel linker is in place.
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* these loops will be removed once the in-kernel linker is in place.
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*/
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cursyms = curnamep = 0;
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memset(&info, 0, sizeof(info));
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for (i = 0; i < symsize/sizeof(Elf_Sym); i++) {
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char * const symname = strstart + sym[i].st_name;
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if (sym[i].st_name == 0)
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continue; /* Just ignore */
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@ -696,36 +717,80 @@ ksyms_addsymtab(const char *mod, void *symstart, vsize_t symsize,
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continue;
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/* Check if the symbol exists */
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if (ksyms_getval_from_kernel(NULL, strstart + sym[i].st_name,
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if (ksyms_getval_from_kernel(NULL, symname,
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&rval, KSYMS_EXTERN) == 0) {
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/* Check (and complain) about differing values */
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if (sym[i].st_value != rval) {
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printf("%s: symbol '%s' redeclared with "
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"different value (%lx != %lx)\n",
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mod, strstart + sym[i].st_name,
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rval, (long)sym[i].st_value);
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if (!strcmp(symname, "__bss_start") ||
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!strcmp(symname, "_edata") ||
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!strcmp(symname, "_end") ||
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!strncmp(symname, "__start_link_set_",17) ||
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!strncmp(symname, "__stop_link_set_",16)) {
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info.maxsyms++;
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info.maxnamep += strlen(symname) + 1 +
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strlen(mod) + 1;
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} else {
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printf("%s: symbol '%s' redeclared with"
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" different value (%lx != %lx)\n",
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mod, symname,
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rval, (long)sym[i].st_value);
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}
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}
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} else {
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/*
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* Count this symbol
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*/
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info.maxsyms++;
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info.maxnamep += strlen(symname) + 1;
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}
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}
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/*
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* Now that we know the sizes, malloc the structures.
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*/
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info.syms = malloc(sizeof(Elf_Sym)*info.maxsyms, M_DEVBUF, M_WAITOK);
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info.symnames = malloc(info.maxnamep, M_DEVBUF, M_WAITOK);
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info.symnmoff = malloc(sizeof(int)*info.maxsyms, M_DEVBUF, M_WAITOK);
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/*
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* Now that we have the symbols, actually fill in the structures.
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*/
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for (i = 0; i < symsize/sizeof(Elf_Sym); i++) {
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char * const symname = strstart + sym[i].st_name;
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if (sym[i].st_name == 0)
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continue; /* Just ignore */
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/* check validity of the symbol */
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/* XXX - save local symbols if DDB */
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if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
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continue;
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/* Check if the symbol exists */
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if (ksyms_getval_from_kernel(NULL, symname,
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&rval, KSYMS_EXTERN) == 0) {
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if ((sym[i].st_value != rval) &&
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(!strcmp(symname, "__bss_start") ||
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!strcmp(symname, "_edata") ||
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!strcmp(symname, "_end") ||
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!strncmp(symname, "__start_link_set_",17) ||
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!strncmp(symname, "__stop_link_set_",16))) {
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addsym(&info, &sym[i], symname, mod);
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}
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} else
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/* Ok, save this symbol */
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addsym(&sym[i], strstart + sym[i].st_name);
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addsym(&info, &sym[i], symname, NULL);
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}
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sym = malloc(sizeof(Elf_Sym)*cursyms, M_DEVBUF, M_WAITOK);
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str = malloc(curnamep, M_DEVBUF, M_WAITOK);
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memcpy(sym, savedsyms, sizeof(Elf_Sym)*cursyms);
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memcpy(str, symnames, curnamep);
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st = malloc(sizeof(struct symtab), M_DEVBUF, M_WAITOK);
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i = strlen(mod) + 1;
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name = malloc(i, M_DEVBUF, M_WAITOK);
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strlcpy(name, mod, i);
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st->sd_name = name;
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st->sd_symnmoff = malloc(sizeof(int)*cursyms, M_DEVBUF, M_WAITOK);
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memcpy(st->sd_symnmoff, symnmoff, sizeof(int)*cursyms);
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st->sd_symstart = sym;
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st->sd_symsize = sizeof(Elf_Sym)*cursyms;
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st->sd_strstart = str;
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st->sd_strsize = curnamep;
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st->sd_symnmoff = info.symnmoff;
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st->sd_symstart = info.syms;
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st->sd_symsize = sizeof(Elf_Sym)*info.maxsyms;
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st->sd_strstart = info.symnames;
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st->sd_strsize = info.maxnamep;
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/* Make them absolute references */
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sym = st->sd_symstart;
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@ -1,4 +1,4 @@
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/* $NetBSD: kern_lkm.c,v 1.70 2003/11/17 10:16:18 cube Exp $ */
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/* $NetBSD: kern_lkm.c,v 1.71 2004/02/18 23:44:49 matt Exp $ */
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/*
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* Copyright (c) 1994 Christopher G. Demetriou
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@ -41,7 +41,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_lkm.c,v 1.70 2003/11/17 10:16:18 cube Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_lkm.c,v 1.71 2004/02/18 23:44:49 matt Exp $");
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#include "opt_ddb.h"
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#include "opt_malloclog.h"
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@ -431,7 +431,13 @@ lkmioctl(dev, cmd, data, flag, p)
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/* call entry(load)... (assigns "private" portion) */
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error = (*(curp->entry))(curp, LKM_E_LOAD, LKM_VERSION);
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(void)ksyms_rensymtab("/lkmtemp/", curp->private.lkm_any->lkm_name);
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if (curp->syms && curp->sym_offset >= curp->sym_size) {
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ksyms_delsymtab("/lkmtemp/");
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error = ksyms_addsymtab(curp->private.lkm_any->lkm_name,
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(char *)curp->syms, curp->sym_symsize,
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(char *)curp->syms + curp->sym_symsize,
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curp->sym_size - curp->sym_symsize);
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}
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if (error) {
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/*
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* Module may refuse loading or may have a
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