1 files changed, 686 insertions, 0 deletions

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
new file mode 100644
index 000000000000..090ffda4adbc
--- /dev/null
+++ b/scripts/kallsyms.c
@@ -0,0 +1,686 @@
+/* Generate assembler source containing symbol information
+ *
+ * Copyright 2002       by Kai Germaschewski
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ *
+ * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
+ *
+ * ChangeLog:
+ *
+ * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
+ *      Changed the compression method from stem compression to "table lookup"
+ *      compression
+ *
+ *      Table compression uses all the unused char codes on the symbols and
+ *  maps these to the most used substrings (tokens). For instance, it might
+ *  map char code 0xF7 to represent "write_" and then in every symbol where
+ *  "write_" appears it can be replaced by 0xF7, saving 5 bytes.
+ *      The used codes themselves are also placed in the table so that the
+ *  decompresion can work without "special cases".
+ *      Applied to kernel symbols, this usually produces a compression ratio
+ *  of about 50%.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+/* maximum token length used. It doesn't pay to increase it a lot, because
+ * very long substrings probably don't repeat themselves too often. */
+#define MAX_TOK_SIZE            11
+#define KSYM_NAME_LEN           127
+
+/* we use only a subset of the complete symbol table to gather the token count,
+ * to speed up compression, at the expense of a little compression ratio */
+#define WORKING_SET             1024
+
+/* first find the best token only on the list of tokens that would profit more
+ * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
+ * Increasing this value will put less tokens on the "good" list, so the search
+ * is faster. However, if the good list runs out of tokens, we must painfully
+ * search the bad list. */
+#define GOOD_BAD_THRESHOLD      10
+
+/* token hash parameters */
+#define HASH_BITS               18
+#define HASH_TABLE_SIZE         (1 << HASH_BITS)
+#define HASH_MASK               (HASH_TABLE_SIZE - 1)
+#define HASH_BASE_OFFSET        2166136261U
+#define HASH_FOLD(a)            ((a)&(HASH_MASK))
+
+/* flags to mark symbols */
+#define SYM_FLAG_VALID          1
+#define SYM_FLAG_SAMPLED        2
+
+struct sym_entry {
+        unsigned long long addr;
+        char type;
+        unsigned char flags;
+        unsigned char len;
+        unsigned char *sym;
+};
+
+
+static struct sym_entry *table;
+static int size, cnt;
+static unsigned long long _stext, _etext, _sinittext, _einittext;
+static int all_symbols = 0;
+
+struct token {
+        unsigned char data[MAX_TOK_SIZE];
+        unsigned char len;
+        /* profit: the number of bytes that could be saved by inserting this
+         * token into the table */
+        int profit;
+        struct token *next;     /* next token on the hash list */
+        struct token *right;    /* next token on the good/bad list */
+        struct token *left;    /* previous token on the good/bad list */
+        struct token *smaller; /* token that is less one letter than this one */
+        };
+
+struct token bad_head, good_head;
+struct token *hash_table[HASH_TABLE_SIZE];
+
+/* the table that holds the result of the compression */
+unsigned char best_table[256][MAX_TOK_SIZE+1];
+unsigned char best_table_len[256];
+
+
+static void
+usage(void)
+{
+        fprintf(stderr, "Usage: kallsyms [--all-symbols] < in.map > out.S\n");
+        exit(1);
+}
+
+/*
+ * This ignores the intensely annoying "mapping symbols" found
+ * in ARM ELF files: $a, $t and $d.
+ */
+static inline int
+is_arm_mapping_symbol(const char *str)
+{
+        return str[0] == '$' && strchr("atd", str[1])
+               && (str[2] == '\0' || str[2] == '.');
+}
+
+static int
+read_symbol(FILE *in, struct sym_entry *s)
+{
+        char str[500];
+        int rc;
+
+        rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
+        if (rc != 3) {
+                if (rc != EOF) {
+                        /* skip line */
+                        fgets(str, 500, in);
+                }
+                return -1;
+        }
+
+        /* Ignore most absolute/undefined (?) symbols. */
+        if (strcmp(str, "_stext") == 0)
+                _stext = s->addr;
+        else if (strcmp(str, "_etext") == 0)
+                _etext = s->addr;
+        else if (strcmp(str, "_sinittext") == 0)
+                _sinittext = s->addr;
+        else if (strcmp(str, "_einittext") == 0)
+                _einittext = s->addr;
+        else if (toupper(s->type) == 'A')
+        {
+                /* Keep these useful absolute symbols */
+                if (strcmp(str, "__kernel_syscall_via_break") &&
+                    strcmp(str, "__kernel_syscall_via_epc") &&
+                    strcmp(str, "__kernel_sigtramp") &&
+                    strcmp(str, "__gp"))
+                        return -1;
+
+        }
+        else if (toupper(s->type) == 'U' ||
+                 is_arm_mapping_symbol(str))
+                return -1;
+
+        /* include the type field in the symbol name, so that it gets
+         * compressed together */
+        s->len = strlen(str) + 1;
+        s->sym = (char *) malloc(s->len + 1);
+        strcpy(s->sym + 1, str);
+        s->sym[0] = s->type;
+
+        return 0;
+}
+
+static int
+symbol_valid(struct sym_entry *s)
+{
+        /* Symbols which vary between passes.  Passes 1 and 2 must have
+         * identical symbol lists.  The kallsyms_* symbols below are only added
+         * after pass 1, they would be included in pass 2 when --all-symbols is
+         * specified so exclude them to get a stable symbol list.
+         */
+        static char *special_symbols[] = {
+                "kallsyms_addresses",
+                "kallsyms_num_syms",
+                "kallsyms_names",
+                "kallsyms_markers",
+                "kallsyms_token_table",
+                "kallsyms_token_index",
+
+        /* Exclude linker generated symbols which vary between passes */
+                "_SDA_BASE_",           /* ppc */
+                "_SDA2_BASE_",          /* ppc */
+                NULL };
+        int i;
+
+        /* if --all-symbols is not specified, then symbols outside the text
+         * and inittext sections are discarded */
+        if (!all_symbols) {
+                if ((s->addr < _stext || s->addr > _etext)
+                    && (s->addr < _sinittext || s->addr > _einittext))
+                        return 0;
+                /* Corner case.  Discard any symbols with the same value as
+                 * _etext or _einittext, they can move between pass 1 and 2
+                 * when the kallsyms data is added.  If these symbols move then
+                 * they may get dropped in pass 2, which breaks the kallsyms
+                 * rules.
+                 */
+                if ((s->addr == _etext && strcmp(s->sym + 1, "_etext")) ||
+                    (s->addr == _einittext && strcmp(s->sym + 1, "_einittext")))
+                        return 0;
+        }
+
+        /* Exclude symbols which vary between passes. */
+        if (strstr(s->sym + 1, "_compiled."))
+                return 0;
+
+        for (i = 0; special_symbols[i]; i++)
+                if( strcmp(s->sym + 1, special_symbols[i]) == 0 )
+                        return 0;
+
+        return 1;
+}
+
+static void
+read_map(FILE *in)
+{
+        while (!feof(in)) {
+                if (cnt >= size) {
+                        size += 10000;
+                        table = realloc(table, sizeof(*table) * size);
+                        if (!table) {
+                                fprintf(stderr, "out of memory\n");
+                                exit (1);
+                        }
+                }
+                if (read_symbol(in, &table[cnt]) == 0)
+                        cnt++;
+        }
+}
+
+static void output_label(char *label)
+{
+        printf(".globl %s\n",label);
+        printf("\tALGN\n");
+        printf("%s:\n",label);
+}
+
+/* uncompress a compressed symbol. When this function is called, the best table
+ * might still be compressed itself, so the function needs to be recursive */
+static int expand_symbol(unsigned char *data, int len, char *result)
+{
+        int c, rlen, total=0;
+
+        while (len) {
+                c = *data;
+                /* if the table holds a single char that is the same as the one
+                 * we are looking for, then end the search */
+                if (best_table[c][0]==c && best_table_len[c]==1) {
+                        *result++ = c;
+                        total++;
+                } else {
+                        /* if not, recurse and expand */
+                        rlen = expand_symbol(best_table[c], best_table_len[c], result);
+                        total += rlen;
+                        result += rlen;
+                }
+                data++;
+                len--;
+        }
+        *result=0;
+
+        return total;
+}
+
+static void
+write_src(void)
+{
+        int i, k, off, valid;
+        unsigned int best_idx[256];
+        unsigned int *markers;
+        char buf[KSYM_NAME_LEN+1];
+
+        printf("#include <asm/types.h>\n");
+        printf("#if BITS_PER_LONG == 64\n");
+        printf("#define PTR .quad\n");
+        printf("#define ALGN .align 8\n");
+        printf("#else\n");
+        printf("#define PTR .long\n");
+        printf("#define ALGN .align 4\n");
+        printf("#endif\n");
+
+        printf(".data\n");
+
+        output_label("kallsyms_addresses");
+        valid = 0;
+        for (i = 0; i < cnt; i++) {
+                if (table[i].flags & SYM_FLAG_VALID) {
+                        printf("\tPTR\t%#llx\n", table[i].addr);
+                        valid++;
+                }
+        }
+        printf("\n");
+
+        output_label("kallsyms_num_syms");
+        printf("\tPTR\t%d\n", valid);
+        printf("\n");
+
+        /* table of offset markers, that give the offset in the compressed stream
+         * every 256 symbols */
+        markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256));
+
+        output_label("kallsyms_names");
+        valid = 0;
+        off = 0;
+        for (i = 0; i < cnt; i++) {
+
+                if (!table[i].flags & SYM_FLAG_VALID)
+                        continue;
+
+                if ((valid & 0xFF) == 0)
+                        markers[valid >> 8] = off;
+
+                printf("\t.byte 0x%02x", table[i].len);
+                for (k = 0; k < table[i].len; k++)
+                        printf(", 0x%02x", table[i].sym[k]);
+                printf("\n");
+
+                off += table[i].len + 1;
+                valid++;
+        }
+        printf("\n");
+
+        output_label("kallsyms_markers");
+        for (i = 0; i < ((valid + 255) >> 8); i++)
+                printf("\tPTR\t%d\n", markers[i]);
+        printf("\n");
+
+        free(markers);
+
+        output_label("kallsyms_token_table");
+        off = 0;
+        for (i = 0; i < 256; i++) {
+                best_idx[i] = off;
+                expand_symbol(best_table[i],best_table_len[i],buf);
+                printf("\t.asciz\t\"%s\"\n", buf);
+                off += strlen(buf) + 1;
+        }
+        printf("\n");
+
+        output_label("kallsyms_token_index");
+        for (i = 0; i < 256; i++)
+                printf("\t.short\t%d\n", best_idx[i]);
+        printf("\n");
+}
+
+
+/* table lookup compression functions */
+
+static inline unsigned int rehash_token(unsigned int hash, unsigned char data)
+{
+        return ((hash * 16777619) ^ data);
+}
+
+static unsigned int hash_token(unsigned char *data, int len)
+{
+        unsigned int hash=HASH_BASE_OFFSET;
+        int i;
+
+        for (i = 0; i < len; i++)
+                hash = rehash_token(hash, data[i]);
+
+        return HASH_FOLD(hash);
+}
+
+/* find a token given its data and hash value */
+static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash)
+{
+        struct token *ptr;
+
+        ptr = hash_table[hash];
+
+        while (ptr) {
+                if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0))
+                        return ptr;
+                ptr=ptr->next;
+        }
+
+        return NULL;
+}
+
+static inline void insert_token_in_group(struct token *head, struct token *ptr)
+{
+        ptr->right = head->right;
+        ptr->right->left = ptr;
+        head->right = ptr;
+        ptr->left = head;
+}
+
+static inline void remove_token_from_group(struct token *ptr)
+{
+        ptr->left->right = ptr->right;
+        ptr->right->left = ptr->left;
+}
+
+
+/* build the counts for all the tokens that start with "data", and have lenghts
+ * from 2 to "len" */
+static void learn_token(unsigned char *data, int len)
+{
+        struct token *ptr,*last_ptr;
+        int i, newprofit;
+        unsigned int hash = HASH_BASE_OFFSET;
+        unsigned int hashes[MAX_TOK_SIZE + 1];
+
+        if (len > MAX_TOK_SIZE)
+                len = MAX_TOK_SIZE;
+
+        /* calculate and store the hash values for all the sub-tokens */
+        hash = rehash_token(hash, data[0]);
+        for (i = 2; i <= len; i++) {
+                hash = rehash_token(hash, data[i-1]);
+                hashes[i] = HASH_FOLD(hash);
+        }
+
+        last_ptr = NULL;
+        ptr = NULL;
+
+        for (i = len; i >= 2; i--) {
+                hash = hashes[i];
+
+                if (!ptr) ptr = find_token_hash(data, i, hash);
+
+                if (!ptr) {
+                        /* create a new token entry */
+                        ptr = (struct token *) malloc(sizeof(*ptr));
+
+                        memcpy(ptr->data, data, i);
+                        ptr->len = i;
+
+                        /* when we create an entry, it's profit is 0 because
+                         * we also take into account the size of the token on
+                         * the compressed table. We then subtract GOOD_BAD_THRESHOLD
+                         * so that the test to see if this token belongs to
+                         * the good or bad list, is a comparison to zero */
+                        ptr->profit = -GOOD_BAD_THRESHOLD;
+
+                        ptr->next = hash_table[hash];
+                        hash_table[hash] = ptr;
+
+                        insert_token_in_group(&bad_head, ptr);
+
+                        ptr->smaller = NULL;
+                } else {
+                        newprofit = ptr->profit + (ptr->len - 1);
+                        /* check to see if this token needs to be moved to a
+                         * different list */
+                        if((ptr->profit < 0) && (newprofit >= 0)) {
+                                remove_token_from_group(ptr);
+                                insert_token_in_group(&good_head,ptr);
+                        }
+                        ptr->profit = newprofit;
+                }
+
+                if (last_ptr) last_ptr->smaller = ptr;
+                last_ptr = ptr;
+
+                ptr = ptr->smaller;
+        }
+}
+
+/* decrease the counts for all the tokens that start with "data", and have lenghts
+ * from 2 to "len". This function is much simpler than learn_token because we have
+ * more guarantees (tho tokens exist, the ->smaller pointer is set, etc.)
+ * The two separate functions exist only because of compression performance */
+static void forget_token(unsigned char *data, int len)
+{
+        struct token *ptr;
+        int i, newprofit;
+        unsigned int hash=0;
+
+        if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE;
+
+        hash = hash_token(data, len);
+        ptr = find_token_hash(data, len, hash);
+
+        for (i = len; i >= 2; i--) {
+
+                newprofit = ptr->profit - (ptr->len - 1);
+                if ((ptr->profit >= 0) && (newprofit < 0)) {
+                        remove_token_from_group(ptr);
+                        insert_token_in_group(&bad_head, ptr);
+                }
+                ptr->profit=newprofit;
+
+                ptr=ptr->smaller;
+        }
+}
+
+/* count all the possible tokens in a symbol */
+static void learn_symbol(unsigned char *symbol, int len)
+{
+        int i;
+
+        for (i = 0; i < len - 1; i++)
+                learn_token(symbol + i, len - i);
+}
+
+/* decrease the count for all the possible tokens in a symbol */
+static void forget_symbol(unsigned char *symbol, int len)
+{
+        int i;
+
+        for (i = 0; i < len - 1; i++)
+                forget_token(symbol + i, len - i);
+}
+
+/* set all the symbol flags and do the initial token count */
+static void build_initial_tok_table(void)
+{
+        int i, use_it, valid;
+
+        valid = 0;
+        for (i = 0; i < cnt; i++) {
+                table[i].flags = 0;
+                if ( symbol_valid(&table[i]) ) {
+                        table[i].flags |= SYM_FLAG_VALID;
+                        valid++;
+                }
+        }
+
+        use_it = 0;
+        for (i = 0; i < cnt; i++) {
+
+                /* subsample the available symbols. This method is almost like
+                 * a Bresenham's algorithm to get uniformly distributed samples
+                 * across the symbol table */
+                if (table[i].flags & SYM_FLAG_VALID) {
+
+                        use_it += WORKING_SET;
+
+                        if (use_it >= valid) {
+                                table[i].flags |= SYM_FLAG_SAMPLED;
+                                use_it -= valid;
+                        }
+                }
+                if (table[i].flags & SYM_FLAG_SAMPLED)
+                        learn_symbol(table[i].sym, table[i].len);
+        }
+}
+
+/* replace a given token in all the valid symbols. Use the sampled symbols
+ * to update the counts */
+static void compress_symbols(unsigned char *str, int tlen, int idx)
+{
+        int i, len, learn, size;
+        unsigned char *p;
+
+        for (i = 0; i < cnt; i++) {
+
+                if (!(table[i].flags & SYM_FLAG_VALID)) continue;
+
+                len = table[i].len;
+                learn = 0;
+                p = table[i].sym;
+
+                do {
+                        /* find the token on the symbol */
+                        p = (unsigned char *) strstr((char *) p, (char *) str);
+                        if (!p) break;
+
+                        if (!learn) {
+                                /* if this symbol was used to count, decrease it */
+                                if (table[i].flags & SYM_FLAG_SAMPLED)
+                                        forget_symbol(table[i].sym, len);
+                                learn = 1;
+                        }
+
+                        *p = idx;
+                        size = (len - (p - table[i].sym)) - tlen + 1;
+                        memmove(p + 1, p + tlen, size);
+                        p++;
+                        len -= tlen - 1;
+
+                } while (size >= tlen);
+
+                if(learn) {
+                        table[i].len = len;
+                        /* if this symbol was used to count, learn it again */
+                        if(table[i].flags & SYM_FLAG_SAMPLED)
+                                learn_symbol(table[i].sym, len);
+                }
+        }
+}
+
+/* search the token with the maximum profit */
+static struct token *find_best_token(void)
+{
+        struct token *ptr,*best,*head;
+        int bestprofit;
+
+        bestprofit=-10000;
+
+        /* failsafe: if the "good" list is empty search from the "bad" list */
+        if(good_head.right == &good_head) head = &bad_head;
+        else head = &good_head;
+
+        ptr = head->right;
+        best = NULL;
+        while (ptr != head) {
+                if (ptr->profit > bestprofit) {
+                        bestprofit = ptr->profit;
+                        best = ptr;
+                }
+                ptr = ptr->right;
+        }
+
+        return best;
+}
+
+/* this is the core of the algorithm: calculate the "best" table */
+static void optimize_result(void)
+{
+        struct token *best;
+        int i;
+
+        /* using the '\0' symbol last allows compress_symbols to use standard
+         * fast string functions */
+        for (i = 255; i >= 0; i--) {
+
+                /* if this table slot is empty (it is not used by an actual
+                 * original char code */
+                if (!best_table_len[i]) {
+
+                        /* find the token with the breates profit value */
+                        best = find_best_token();
+
+                        /* place it in the "best" table */
+                        best_table_len[i] = best->len;
+                        memcpy(best_table[i], best->data, best_table_len[i]);
+                        /* zero terminate the token so that we can use strstr
+                           in compress_symbols */
+                        best_table[i][best_table_len[i]]='\0';
+
+                        /* replace this token in all the valid symbols */
+                        compress_symbols(best_table[i], best_table_len[i], i);
+                }
+        }
+}
+
+/* start by placing the symbols that are actually used on the table */
+static void insert_real_symbols_in_table(void)
+{
+        int i, j, c;
+
+        memset(best_table, 0, sizeof(best_table));
+        memset(best_table_len, 0, sizeof(best_table_len));
+
+        for (i = 0; i < cnt; i++) {
+                if (table[i].flags & SYM_FLAG_VALID) {
+                        for (j = 0; j < table[i].len; j++) {
+                                c = table[i].sym[j];
+                                best_table[c][0]=c;
+                                best_table_len[c]=1;
+                        }
+                }
+        }
+}
+
+static void optimize_token_table(void)
+{
+        memset(hash_table, 0, sizeof(hash_table));
+
+        good_head.left = &good_head;
+        good_head.right = &good_head;
+
+        bad_head.left = &bad_head;
+        bad_head.right = &bad_head;
+
+        build_initial_tok_table();
+
+        insert_real_symbols_in_table();
+
+        optimize_result();
+}
+
+
+int
+main(int argc, char **argv)
+{
+        if (argc == 2 && strcmp(argv[1], "--all-symbols") == 0)
+                all_symbols = 1;
+        else if (argc != 1)
+                usage();
+
+        read_map(stdin);
+        optimize_token_table();
+        write_src();
+
+        return 0;
+}
+