Remove useless entries from the symbol table at load.
Add patricia-tree-style lookup code for symbols (for fast lookups).
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ragge
parent
38b24046a0
commit
4f432cf54f
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@ -1,4 +1,4 @@
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/* $NetBSD: kern_ksyms.c,v 1.7 2003/05/02 09:34:57 ragge Exp $ */
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/* $NetBSD: kern_ksyms.c,v 1.8 2003/05/07 21:28:16 ragge 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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@ -36,7 +36,6 @@
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/*
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* TODO:
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* Fix quick-search of symbols. (comes with linker)
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* Change the ugly way of adding new symbols (comes with linker)
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* Add kernel locking stuff.
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* (Ev) add support for poll.
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@ -129,9 +128,136 @@ static CIRCLEQ_HEAD(, symtab) symtab_queue =
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static struct symtab kernel_symtab;
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#define USE_PTREE
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#ifdef USE_PTREE
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/*
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* Patricia-tree-based lookup structure for the in-kernel global symbols.
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* Based on a design by Mikael Sundstrom, msm@sm.luth.se.
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*/
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struct ptree {
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int16_t bitno;
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int16_t lr[2];
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} *symb;
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static int16_t baseidx;
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static int treex = 1;
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#define P_BIT(key, bit) ((key[bit >> 3] >> (bit & 7)) & 1)
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#define STRING(idx) kernel_symtab.sd_symstart[idx].st_name + \
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kernel_symtab.sd_strstart
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/*
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* Walk down the tree until a terminal node is found.
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*/
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static int
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symbol_traverse(char *key)
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{
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int16_t nb, rbit = baseidx;
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while (rbit > 0) {
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nb = symb[rbit].bitno;
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rbit = symb[rbit].lr[P_BIT(key, nb)];
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}
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return -rbit;
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}
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static int
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ptree_add(char *key, int val)
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{
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int idx;
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int nix, cix, bit, rbit, sb, lastrbit, svbit, ix;
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char *m, *k;
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if (baseidx == 0) {
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baseidx = -val;
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return 0; /* First element */
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}
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/* Get string to match against */
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idx = symbol_traverse(key);
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/* Find first mismatching bit */
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m = STRING(idx);
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k = key;
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if (strcmp(m, k) == 0)
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return 1;
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for (cix = 0; *m && *k && *m == *k; m++, k++, cix += 8)
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;
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ix = ffs((int)*m ^ (int)*k) - 1;
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cix += ix;
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/* Create new node */
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nix = treex++;
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bit = P_BIT(key, cix);
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symb[nix].bitno = cix;
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symb[nix].lr[bit] = -val;
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/* Find where to insert node */
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rbit = baseidx;
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lastrbit = 0;
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for (;;) {
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if (rbit < 0)
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break;
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sb = symb[rbit].bitno;
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if (sb > cix)
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break;
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if (sb == cix)
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printf("symb[rbit].bitno == cix!!!\n");
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lastrbit = rbit;
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svbit = P_BIT(key, sb);
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rbit = symb[rbit].lr[svbit];
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}
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/* Do the actual insertion */
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if (lastrbit == 0) {
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/* first element */
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symb[nix].lr[!bit] = baseidx;
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baseidx = nix;
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} else {
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symb[nix].lr[!bit] = rbit;
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symb[lastrbit].lr[svbit] = nix;
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}
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return 0;
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}
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static int
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ptree_find(char *key)
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{
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int idx;
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if (baseidx == 0)
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return 0;
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idx = symbol_traverse(key);
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if (strcmp(key, STRING(idx)) == 0)
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return idx;
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return 0;
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}
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static void
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ptree_gen(char *off, struct symtab *tab)
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{
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Elf_Sym *sym;
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int i;
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if (off != NULL)
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symb = (struct ptree *)ALIGN(off);
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else
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symb = malloc((tab->sd_symsize/sizeof(Elf_Sym)) *
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sizeof(struct ptree), M_DEVBUF, M_WAITOK);
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symb--; /* sym index won't be 0 */
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sym = tab->sd_symstart;
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for (i = 1; i < tab->sd_symsize/sizeof(Elf_Sym); i++) {
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if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
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continue;
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ptree_add(tab->sd_strstart+sym[i].st_name, i);
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}
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}
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#endif
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/*
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* Finds a certain symbol name in a certain symbol table.
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* XXX - symbol hashing must be rewritten (missing)
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*/
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static Elf_Sym *
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findsym(char *name, struct symtab *table)
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@ -140,6 +266,11 @@ findsym(char *name, struct symtab *table)
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int i, sz = table->sd_symsize/sizeof(Elf_Sym);
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char *np;
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#ifdef USE_PTREE
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if (table == &kernel_symtab && (i = ptree_find(name)) != 0)
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return &start[i];
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#endif
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for (i = 0; i < sz; i++) {
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np = table->sd_strstart + start[i].st_name;
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if (name[0] == np[0] && name[1] == np[1] &&
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@ -156,6 +287,12 @@ void ksymsattach(int);
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void
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ksymsattach(int arg)
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{
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#ifdef USE_PTREE
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if (baseidx == 0)
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ptree_gen(0, &kernel_symtab);
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#endif
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}
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/*
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@ -166,9 +303,11 @@ static void
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addsymtab(char *name, Elf_Ehdr *ehdr, struct symtab *tab)
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{
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caddr_t start = (caddr_t)ehdr;
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caddr_t send;
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Elf_Shdr *shdr;
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Elf_Sym *sym;
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int i, j;
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Elf_Sym *sym, *nsym;
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int i, j, n, g;
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char *str;
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/* Find the symbol table and the corresponding string table. */
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shdr = (Elf_Shdr *)(start + ehdr->e_shoff);
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@ -187,21 +326,94 @@ addsymtab(char *name, Elf_Ehdr *ehdr, struct symtab *tab)
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break;
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}
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tab->sd_name = name;
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send = tab->sd_strstart + tab->sd_strsize;
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/* Change all symbols to be absolute references */
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sym = (Elf_Sym *)tab->sd_symstart;
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for (i = 0; i < tab->sd_symsize/sizeof(Elf_Sym); i++) {
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sym[i].st_shndx = SHN_ABS;
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if (sym[i].st_name == 0)
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#ifdef KSYMS_DEBUG
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printf("start %p sym %p symsz %d str %p strsz %d send %p\n",
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start, tab->sd_symstart, tab->sd_symsize,
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tab->sd_strstart, tab->sd_strsize, send);
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#endif
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/*
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* Pack symbol table by removing all file name references
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* and overwrite the elf header.
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*/
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sym = tab->sd_symstart;
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nsym = (Elf_Sym *)start;
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str = tab->sd_strstart;
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for (g = i = n = 0; i < tab->sd_symsize/sizeof(Elf_Sym); i++) {
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if (i == 0) {
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nsym[n++] = sym[i];
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continue;
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j = strlen(sym[i].st_name + tab->sd_strstart) + 1;
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}
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/*
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* Remove useless symbols.
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* Should actually remove all typeless symbols.
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*/
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if (sym[i].st_name == 0)
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continue; /* Skip nameless entries */
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if (ELF_ST_TYPE(sym[i].st_info) == STT_FILE)
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continue; /* Skip filenames */
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if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE &&
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sym[i].st_value == 0 &&
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strcmp(str + sym[i].st_name, "*ABS*") == 0)
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continue; /* XXX */
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if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE &&
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strcmp(str + sym[i].st_name, "gcc2_compiled.") == 0)
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continue; /* XXX */
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#ifndef DDB
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/* Only need global symbols */
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if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
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continue;
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#endif
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/* Save symbol. Set it as an absolute offset */
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nsym[n] = sym[i];
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nsym[n].st_shndx = SHN_ABS;
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if (ELF_ST_BIND(nsym[n].st_info) == STB_GLOBAL)
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g++;
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#if NKSYMS
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j = strlen(nsym[n].st_name + tab->sd_strstart) + 1;
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if (j > ksyms_maxlen)
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ksyms_maxlen = j;
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#endif
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n++;
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}
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tab->sd_symstart = nsym;
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tab->sd_symsize = n * sizeof(Elf_Sym);
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#ifdef notyet
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/*
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* Remove left-over strings.
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*/
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sym = tab->sd_symstart;
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str = (caddr_t)tab->sd_symstart + tab->sd_symsize;
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str[0] = 0;
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n = 1;
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for (i = 1; i < tab->sd_symsize/sizeof(Elf_Sym); i++) {
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strcpy(str+n, tab->sd_strstart + sym[i].st_name);
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sym[i].st_name = n;
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n += strlen(str+n) + 1;
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}
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tab->sd_strstart = str;
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tab->sd_strsize = n;
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#ifdef KSYMS_DEBUG
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printf("str %p strsz %d send %p\n", str, n, send);
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#endif
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#endif
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CIRCLEQ_INSERT_HEAD(&symtab_queue, tab, sd_queue);
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#ifdef notyet
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#ifdef USE_PTREE
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/* Try to use the freed space, if possible */
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if (send - str - n > g * sizeof(struct ptree))
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ptree_gen(str + n, tab);
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#endif
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#endif
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}
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/*
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@ -247,20 +459,24 @@ ksyms_init(int symsize, void *start, void *end)
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return; /* nothing to do */
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}
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#if NKSYMS
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/* Loaded header will be scratched in addsymtab */
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ksyms_hdr_init(start);
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#endif
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addsymtab("netbsd", ehdr, &kernel_symtab);
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#if NKSYMS
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ksyms_sizes_calc();
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#endif
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ksymsinited = 1;
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#ifdef DEBUG
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printf("Loaded initial symtab at %p, strtab at %p, # entries %ld\n",
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kernel_symtab.sd_symstart, kernel_symtab.sd_strstart,
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(long)kernel_symtab.sd_symsize/sizeof(Elf_Sym));
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#endif
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#if NKSYMS
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ksyms_hdr_init(start);
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#endif
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}
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/*
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@ -284,7 +500,6 @@ ksyms_getval(char *mod, char *sym, unsigned long *val, int type)
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printf("ksyms_getval: mod %s sym %s valp %p\n", mod, sym, val);
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#endif
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/* XXX search order XXX */
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CIRCLEQ_FOREACH(st, &symtab_queue, sd_queue) {
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if (mod && strcmp(st->sd_name, mod))
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continue;
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