diff --git a/include/linux/module.h b/include/linux/module.h index c9f1200b23121a..b58f2de4895709 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -590,7 +590,8 @@ struct module *find_module(const char *name); /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if symnum out of range. */ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, - char *name, char *module_name, int *exported); + char *name, char *module_name, unsigned long *size, + int *exported); /* Look for this name: can be of form module:name. */ unsigned long module_kallsyms_lookup_name(const char *name); @@ -768,8 +769,8 @@ static inline int lookup_module_symbol_attrs(unsigned long addr, unsigned long * } static inline int module_get_kallsym(unsigned int symnum, unsigned long *value, - char *type, char *name, - char *module_name, int *exported) + char *type, char *name, char *module_name, + unsigned long *size, int *exported) { return -ERANGE; } diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index c81610ffc4ba82..e234c659dfe99b 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -36,6 +36,7 @@ */ extern const unsigned long kallsyms_addresses[] __weak; extern const int kallsyms_offsets[] __weak; +extern const unsigned long kallsyms_sizes[] __weak; extern const u8 kallsyms_names[] __weak; /* @@ -277,12 +278,24 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, } #endif /* CONFIG_LIVEPATCH */ +/* + * The caller passes in an address, and we return an index to the symbol -- + * potentially also size and offset information. + * But an address might map to multiple symbols because: + * - some symbols might have zero size + * - some symbols might be aliases of one another + * - some symbols might span (encompass) others + * The symbols should already be ordered so that, for a particular address, + * we first have the zero-size ones, then the biggest, then the smallest. + * So we find the index by: + * - finding the last symbol with the target address + * - backing the index up so long as both the address and size are unchanged + */ static unsigned long get_symbol_pos(unsigned long addr, unsigned long *symbolsize, unsigned long *offset) { - unsigned long symbol_start = 0, symbol_end = 0; - unsigned long i, low, high, mid; + unsigned long low, high, mid; /* This kernel should never had been booted. */ if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) @@ -303,36 +316,17 @@ static unsigned long get_symbol_pos(unsigned long addr, } /* - * Search for the first aliased symbol. Aliased - * symbols are symbols with the same address. + * Search for the first aliased symbol. */ - while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low)) + while (low + && kallsyms_sym_address(low-1) == kallsyms_sym_address(low) + && kallsyms_sizes[low-1] == kallsyms_sizes[low]) --low; - symbol_start = kallsyms_sym_address(low); - - /* Search for next non-aliased symbol. */ - for (i = low + 1; i < kallsyms_num_syms; i++) { - if (kallsyms_sym_address(i) > symbol_start) { - symbol_end = kallsyms_sym_address(i); - break; - } - } - - /* If we found no next symbol, we use the end of the section. */ - if (!symbol_end) { - if (is_kernel_inittext(addr)) - symbol_end = (unsigned long)_einittext; - else if (IS_ENABLED(CONFIG_KALLSYMS_ALL)) - symbol_end = (unsigned long)_end; - else - symbol_end = (unsigned long)_etext; - } - if (symbolsize) - *symbolsize = symbol_end - symbol_start; + *symbolsize = kallsyms_sizes[low]; if (offset) - *offset = addr - symbol_start; + *offset = addr - kallsyms_sym_address(low); return low; } @@ -653,6 +647,7 @@ struct kallsym_iter { loff_t pos_bpf_end; unsigned long value; unsigned int nameoff; /* If iterating in core kernel symbols. */ + unsigned long size; char type; char name[KSYM_NAME_LEN]; char module_name[MODULE_NAME_LEN]; @@ -687,7 +682,7 @@ static int get_ksymbol_mod(struct kallsym_iter *iter) int ret = module_get_kallsym(iter->pos - iter->pos_arch_end, &iter->value, &iter->type, iter->name, iter->module_name, - &iter->exported); + &iter->size, &iter->exported); iter->builtin_module_names = NULL; if (ret < 0) { @@ -760,6 +755,7 @@ static unsigned long get_ksymbol_core(struct kallsym_iter *iter, int kallmodsyms iter->exported = 0; iter->value = kallsyms_sym_address(iter->pos); + iter->size = kallsyms_sizes[iter->pos]; iter->type = kallsyms_get_symbol_type(off); iter->module_name[0] = '\0'; @@ -878,12 +874,14 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms) { void *value; struct kallsym_iter *iter = m->private; + unsigned long size; /* Some debugging symbols have no name. Ignore them. */ if (!iter->name[0]) return 0; value = iter->show_value ? (void *)iter->value : NULL; + size = iter->show_value ? iter->size : 0; /* * Real module, or built-in module and /proc/kallsyms being shown. @@ -903,15 +901,15 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms) * /proc/kallmodsyms, built as a module. */ if (iter->builtin_module_names == NULL) - seq_printf(m, "%px %c %s\t[%s]\n", value, - type, iter->name, + seq_printf(m, "%px %lx %c %s\t[%s]\n", value, + size, type, iter->name, iter->module_name); /* * /proc/kallmodsyms, single-module symbol. */ else if (*iter->builtin_module_names != '\0') - seq_printf(m, "%px %c %s\t[%s]\n", value, - type, iter->name, + seq_printf(m, "%px %lx %c %s\t[%s]\n", value, + size, type, iter->name, iter->builtin_module_names); /* * /proc/kallmodsyms, multimodule symbol. Formatted @@ -922,8 +920,8 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms) size_t i = *(char *)(iter->builtin_module_names + 1); const char *walk = iter->builtin_module_names + 2; - seq_printf(m, "%px %c %s\t[%s]", value, - type, iter->name, walk); + seq_printf(m, "%px %lx %c %s\t[%s]", value, + size, type, iter->name, walk); while (--i > 0) { walk += strlen(walk) + 1; @@ -935,7 +933,13 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms) #endif /* CONFIG_KALLMODSYMS */ seq_printf(m, "%px %c %s\t[%s]\n", value, type, iter->name, iter->module_name); - } else + /* + * Non-modular, /proc/kallmodsyms -> print size. + */ + } else if (kallmodsyms) + seq_printf(m, "%px %lx %c %s\n", value, size, + iter->type, iter->name); + else seq_printf(m, "%px %c %s\n", value, iter->type, iter->name); return 0; diff --git a/kernel/module.c b/kernel/module.c index 84a9141a5e159a..311eaa8fd21c99 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4405,7 +4405,8 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, } int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, - char *name, char *module_name, int *exported) + char *name, char *module_name, unsigned long *size, + int *exported) { struct module *mod; @@ -4424,6 +4425,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN); strlcpy(module_name, mod->name, MODULE_NAME_LEN); *exported = is_exported(name, *value, mod); + *size = kallsyms->symtab[symnum].st_size; preempt_enable(); return 0; } diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 93fdf0dcf587a3..fcb1d706809cac 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -5,7 +5,7 @@ * 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 + * Usage: nm -n -S vmlinux * | scripts/kallsyms [--all-symbols] [--absolute-percpu] * [--base-relative] [--builtin=modules_thick.builtin] * > symbols.S @@ -38,6 +38,7 @@ struct sym_entry { unsigned long long addr; + unsigned long long size; unsigned int len; unsigned int start_pos; unsigned int percpu_absolute; @@ -394,6 +395,7 @@ static bool is_ignored_symbol(const char *name, char type) "kallsyms_addresses", "kallsyms_offsets", "kallsyms_relative_base", + "kallsyms_sizes", "kallsyms_num_syms", "kallsyms_num_modules", "kallsyms_names", @@ -507,10 +509,11 @@ static struct sym_entry *read_symbol(FILE *in) unsigned long long addr; unsigned int len; struct sym_entry *sym; - int rc; + int rc = 0; + unsigned long long size; - rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name); - if (rc != 3) { + rc = fscanf(in, "%llx %llx %c %499s\n", &addr, &size, &type, name); + if (rc != 4) { if (rc != EOF && fgets(name, 500, in) == NULL) fprintf(stderr, "Read error or end of file.\n"); return NULL; @@ -548,6 +551,7 @@ static struct sym_entry *read_symbol(FILE *in) sym->sym[0] = type; strcpy(sym_name(sym), name); sym->percpu_absolute = 0; + sym->size = size; return sym; } @@ -932,6 +936,11 @@ static void write_src(void) printf("\n"); } + output_label("kallsyms_sizes"); + for (i = 0; i < table_cnt; i++) + printf("\tPTR\t%#llx\n", table[i]->size); + printf("\n"); + #ifdef CONFIG_KALLMODSYMS output_kallmodsyms_modules(); output_kallmodsyms_objfiles(); @@ -1189,6 +1198,18 @@ static int compare_symbols(const void *a, const void *b) if (sa->addr < sb->addr) return -1; + /* zero-size markers before nonzero-size symbols */ + if (sa->size > 0 && sb->size == 0) + return 1; + if (sa->size == 0 && sb->size > 0) + return -1; + + /* sort by size (large size preceding symbols it encompasses) */ + if (sa->size < sb->size) + return 1; + if (sa->size > sb->size) + return -1; + /* sort by "weakness" type */ wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W'); wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W'); diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 5301f3e77116d8..55815937399bb8 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -265,7 +265,12 @@ kallsyms() fi info KSYMS ${2} - ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2} + # "nm -S" does not print symbol size when size is 0 + # Therefore use awk to regularize the data: + # - when there are only three fields, add an explicit "0" + # - when there are already four fields, pass through as is + ${NM} -n -S ${1} | ${AWK} 'NF==3 {print $1, 0, $2, $3}; NF==4' | \ + scripts/kallsyms ${kallsymopt} > ${2} } # Perform one step in kallsyms generation, including temporary linking of