From 889dd20c6998c0cded684f5557748fc13a3b769e Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Thu, 23 Jan 2003 04:48:34 +0000 Subject: [PATCH] Patch from Joel Vallier to add modules symbols to the kernel symbol table in order to obtain better debug output from ksymoops. --- modutils/Config.in | 11 +++ modutils/insmod.c | 176 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 185 insertions(+), 2 deletions(-) diff --git a/modutils/Config.in b/modutils/Config.in index 9af0ad6dc..98aef0032 100644 --- a/modutils/Config.in +++ b/modutils/Config.in @@ -40,6 +40,17 @@ config CONFIG_FEATURE_INSMOD_VERSION_CHECKING help Please submit a patch to add help text for this item. +config CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS + bool " Add module symbols to kernel symbol table" + default n + depends on CONFIG_INSMOD + help + By adding module symbols to the kernel symbol table, Oops messages + occuring within kernel modules can be properly debugged. By enabling + this feature, module symbols will always be added to the kernel symbol + table for properly debugging support. If you are not interested in + Oops messages from kernel modules, say N. + config CONFIG_FEATURE_INSMOD_LOADINKMEM bool " In kernel memory optimization (uClinux only)" default n diff --git a/modutils/insmod.c b/modutils/insmod.c index eda4e1a48..db9e1997e 100644 --- a/modutils/insmod.c +++ b/modutils/insmod.c @@ -234,7 +234,7 @@ #ifndef MODUTILS_MODULE_H static const int MODUTILS_MODULE_H = 1; -#ident "$Id: insmod.c,v 1.92 2002/11/28 11:27:27 aaronl Exp $" +#ident "$Id: insmod.c,v 1.93 2003/01/23 04:48:34 andersen Exp $" /* This file contains the structures used by the 2.0 and 2.1 kernels. We do not use the kernel headers directly because we do not wish @@ -455,7 +455,7 @@ int delete_module(const char *); #ifndef MODUTILS_OBJ_H static const int MODUTILS_OBJ_H = 1; -#ident "$Id: insmod.c,v 1.92 2002/11/28 11:27:27 aaronl Exp $" +#ident "$Id: insmod.c,v 1.93 2003/01/23 04:48:34 andersen Exp $" /* The relocatable object is manipulated using elfin types. */ @@ -2654,6 +2654,37 @@ static int new_create_this_module(struct obj_file *f, const char *m_name) return 1; } +#ifdef CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS +/* add an entry to the __ksymtab section, creating it if necessary */ +static void new_add_ksymtab(struct obj_file *f, struct obj_symbol *sym) +{ + struct obj_section *sec; + ElfW(Addr) ofs; + + /* ensure __ksymtab is allocated, EXPORT_NOSYMBOLS creates a non-alloc section. + * If __ksymtab is defined but not marked alloc, x out the first character + * (no obj_delete routine) and create a new __ksymtab with the correct + * characteristics. + */ + sec = obj_find_section(f, "__ksymtab"); + if (sec && !(sec->header.sh_flags & SHF_ALLOC)) { + *((char *)(sec->name)) = 'x'; /* override const */ + sec = NULL; + } + if (!sec) + sec = obj_create_alloced_section(f, "__ksymtab", + tgt_sizeof_void_p, 0); + if (!sec) + return; + sec->header.sh_flags |= SHF_ALLOC; + sec->header.sh_addralign = tgt_sizeof_void_p; /* Empty section might + be byte-aligned */ + ofs = sec->header.sh_size; + obj_symbol_patch(f, sec->idx, ofs, sym); + obj_string_patch(f, sec->idx, ofs + tgt_sizeof_void_p, sym->name); + obj_extend_section(sec, 2 * tgt_sizeof_char_p); +} +#endif /* CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS */ static int new_create_module_ksymtab(struct obj_file *f) { @@ -2811,6 +2842,7 @@ new_init_module(const char *m_name, struct obj_file *f, #define new_init_module(x, y, z) TRUE #define new_create_this_module(x, y) 0 +#define new_add_ksymtab(x, y) -1 #define new_create_module_ksymtab(x) #define query_module(v, w, x, y, z) -1 @@ -3538,6 +3570,142 @@ static void check_tainted_module(struct obj_file *f, char *m_name) #define check_tainted_module(x, y) do { } while(0); #endif /* CONFIG_FEATURE_CHECK_TAINTED_MODULE */ +#ifdef CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS +/* add module source, timestamp, kernel version and a symbol for the + * start of some sections. this info is used by ksymoops to do better + * debugging. + */ +static int +get_module_version(struct obj_file *f, char str[STRVERSIONLEN]) +{ +#ifdef CONFIG_FEATURE_INSMOD_VERSION_CHECKING + if (get_modinfo_value(f, "kernel_version") == NULL) + return old_get_module_version(f, str); + else + return new_get_module_version(f, str); +#else /* CONFIG_FEATURE_INSMOD_VERSION_CHECKING */ + strncpy(str, "???", sizeof(str)); + return -1; +#endif /* CONFIG_FEATURE_INSMOD_VERSION_CHECKING */ +} + +/* add module source, timestamp, kernel version and a symbol for the + * start of some sections. this info is used by ksymoops to do better + * debugging. + */ +static void +add_ksymoops_symbols(struct obj_file *f, const char *filename, + const char *m_name) +{ + static const char symprefix[] = "__insmod_"; + struct obj_section *sec; + struct obj_symbol *sym; + char *name, *absolute_filename; + char str[STRVERSIONLEN], real[PATH_MAX]; + int i, l, lm_name, lfilename, use_ksymtab, version; + struct stat statbuf; + + static const char *section_names[] = { + ".text", + ".rodata", + ".data", + ".bss" + ".sbss" + }; + + if (realpath(filename, real)) { + absolute_filename = xstrdup(real); + } + else { + int save_errno = errno; + error_msg("cannot get realpath for %s", filename); + errno = save_errno; + perror(""); + absolute_filename = xstrdup(filename); + } + + lm_name = strlen(m_name); + lfilename = strlen(absolute_filename); + + /* add to ksymtab if it already exists or there is no ksymtab and other symbols + * are not to be exported. otherwise leave ksymtab alone for now, the + * "export all symbols" compatibility code will export these symbols later. + */ + use_ksymtab = obj_find_section(f, "__ksymtab") || !flag_export; + + if ((sec = obj_find_section(f, ".this"))) { + /* tag the module header with the object name, last modified + * timestamp and module version. worst case for module version + * is 0xffffff, decimal 16777215. putting all three fields in + * one symbol is less readable but saves kernel space. + */ + l = sizeof(symprefix)+ /* "__insmod_" */ + lm_name+ /* module name */ + 2+ /* "_O" */ + lfilename+ /* object filename */ + 2+ /* "_M" */ + 2*sizeof(statbuf.st_mtime)+ /* mtime in hex */ + 2+ /* "_V" */ + 8+ /* version in dec */ + 1; /* nul */ + name = xmalloc(l); + if (stat(absolute_filename, &statbuf) != 0) + statbuf.st_mtime = 0; + version = get_module_version(f, str); /* -1 if not found */ + snprintf(name, l, "%s%s_O%s_M%0*lX_V%d", + symprefix, m_name, absolute_filename, + (int)(2*sizeof(statbuf.st_mtime)), statbuf.st_mtime, + version); + sym = obj_add_symbol(f, name, -1, + ELFW(ST_INFO) (STB_GLOBAL, STT_NOTYPE), + sec->idx, sec->header.sh_addr, 0); + if (use_ksymtab) + new_add_ksymtab(f, sym); + } + free(absolute_filename); +#ifdef _NOT_SUPPORTED_ + /* record where the persistent data is going, same address as previous symbol */ + + if (f->persist) { + l = sizeof(symprefix)+ /* "__insmod_" */ + lm_name+ /* module name */ + 2+ /* "_P" */ + strlen(f->persist)+ /* data store */ + 1; /* nul */ + name = xmalloc(l); + snprintf(name, l, "%s%s_P%s", + symprefix, m_name, f->persist); + sym = obj_add_symbol(f, name, -1, ELFW(ST_INFO) (STB_GLOBAL, STT_NOTYPE), + sec->idx, sec->header.sh_addr, 0); + if (use_ksymtab) + new_add_ksymtab(f, sym); + } +#endif /* _NOT_SUPPORTED_ */ + /* tag the desired sections if size is non-zero */ + + for (i = 0; i < sizeof(section_names)/sizeof(section_names[0]); ++i) { + if ((sec = obj_find_section(f, section_names[i])) && + sec->header.sh_size) { + l = sizeof(symprefix)+ /* "__insmod_" */ + lm_name+ /* module name */ + 2+ /* "_S" */ + strlen(sec->name)+ /* section name */ + 2+ /* "_L" */ + 8+ /* length in dec */ + 1; /* nul */ + name = xmalloc(l); + snprintf(name, l, "%s%s_S%s_L%ld", + symprefix, m_name, sec->name, + (long)sec->header.sh_size); + sym = obj_add_symbol(f, name, -1, ELFW(ST_INFO) (STB_GLOBAL, STT_NOTYPE), + sec->idx, sec->header.sh_addr, 0); + if (use_ksymtab) + new_add_ksymtab(f, sym); + } + } +} +#endif /* CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS */ + extern int insmod_main( int argc, char **argv) { int opt; @@ -3788,6 +3956,10 @@ extern int insmod_main( int argc, char **argv) arch_create_got(f); hide_special_symbols(f); +#ifdef CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS + add_ksymoops_symbols(f, m_filename, m_name); +#endif /* CONFIG_FEATURE_INSMOD_KSYMOOPS_SYMBOLS */ + if (k_new_syscalls) new_create_module_ksymtab(f);