diff options
Diffstat (limited to 'kernel/kallsyms.c')
| -rw-r--r-- | kernel/kallsyms.c | 104 |
1 files changed, 84 insertions, 20 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index c851ca0ed357..0ba87982d017 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -25,7 +25,10 @@ #include <linux/filter.h> #include <linux/ftrace.h> #include <linux/kprobes.h> +#include <linux/build_bug.h> #include <linux/compiler.h> +#include <linux/module.h> +#include <linux/kernel.h> /* * These will be re-linked against their real values @@ -297,21 +300,14 @@ int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, get_symbol_pos(addr, symbolsize, offset); return 1; } - return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) || + return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) || !!__bpf_address_lookup(addr, symbolsize, offset, namebuf); } -/* - * Lookup an address - * - modname is set to NULL if it's in the kernel. - * - We guarantee that the returned name is valid until we reschedule even if. - * It resides in a module. - * - We also guarantee that modname will be valid until rescheduled. - */ -const char *kallsyms_lookup(unsigned long addr, - unsigned long *symbolsize, - unsigned long *offset, - char **modname, char *namebuf) +static const char *kallsyms_lookup_buildid(unsigned long addr, + unsigned long *symbolsize, + unsigned long *offset, char **modname, + const unsigned char **modbuildid, char *namebuf) { const char *ret; @@ -327,6 +323,8 @@ const char *kallsyms_lookup(unsigned long addr, namebuf, KSYM_NAME_LEN); if (modname) *modname = NULL; + if (modbuildid) + *modbuildid = NULL; ret = namebuf; goto found; @@ -334,7 +332,7 @@ const char *kallsyms_lookup(unsigned long addr, /* See if it's in a module or a BPF JITed image. */ ret = module_address_lookup(addr, symbolsize, offset, - modname, namebuf); + modname, modbuildid, namebuf); if (!ret) ret = bpf_address_lookup(addr, symbolsize, offset, modname, namebuf); @@ -348,6 +346,22 @@ found: return ret; } +/* + * Lookup an address + * - modname is set to NULL if it's in the kernel. + * - We guarantee that the returned name is valid until we reschedule even if. + * It resides in a module. + * - We also guarantee that modname will be valid until rescheduled. + */ +const char *kallsyms_lookup(unsigned long addr, + unsigned long *symbolsize, + unsigned long *offset, + char **modname, char *namebuf) +{ + return kallsyms_lookup_buildid(addr, symbolsize, offset, modname, + NULL, namebuf); +} + int lookup_symbol_name(unsigned long addr, char *symname) { int res; @@ -404,15 +418,17 @@ found: /* Look up a kernel symbol and return it in a text buffer. */ static int __sprint_symbol(char *buffer, unsigned long address, - int symbol_offset, int add_offset) + int symbol_offset, int add_offset, int add_buildid) { char *modname; + const unsigned char *buildid; const char *name; unsigned long offset, size; int len; address += symbol_offset; - name = kallsyms_lookup(address, &size, &offset, &modname, buffer); + name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid, + buffer); if (!name) return sprintf(buffer, "0x%lx", address - symbol_offset); @@ -424,8 +440,19 @@ static int __sprint_symbol(char *buffer, unsigned long address, if (add_offset) len += sprintf(buffer + len, "+%#lx/%#lx", offset, size); - if (modname) - len += sprintf(buffer + len, " [%s]", modname); + if (modname) { + len += sprintf(buffer + len, " [%s", modname); +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) + if (add_buildid && buildid) { + /* build ID should match length of sprintf */ +#if IS_ENABLED(CONFIG_MODULES) + static_assert(sizeof(typeof_member(struct module, build_id)) == 20); +#endif + len += sprintf(buffer + len, " %20phN", buildid); + } +#endif + len += sprintf(buffer + len, "]"); + } return len; } @@ -443,11 +470,28 @@ static int __sprint_symbol(char *buffer, unsigned long address, */ int sprint_symbol(char *buffer, unsigned long address) { - return __sprint_symbol(buffer, address, 0, 1); + return __sprint_symbol(buffer, address, 0, 1, 0); } EXPORT_SYMBOL_GPL(sprint_symbol); /** + * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer + * @buffer: buffer to be stored + * @address: address to lookup + * + * This function looks up a kernel symbol with @address and stores its name, + * offset, size, module name and module build ID to @buffer if possible. If no + * symbol was found, just saves its @address as is. + * + * This function returns the number of bytes stored in @buffer. + */ +int sprint_symbol_build_id(char *buffer, unsigned long address) +{ + return __sprint_symbol(buffer, address, 0, 1, 1); +} +EXPORT_SYMBOL_GPL(sprint_symbol_build_id); + +/** * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer * @buffer: buffer to be stored * @address: address to lookup @@ -460,7 +504,7 @@ EXPORT_SYMBOL_GPL(sprint_symbol); */ int sprint_symbol_no_offset(char *buffer, unsigned long address) { - return __sprint_symbol(buffer, address, 0, 0); + return __sprint_symbol(buffer, address, 0, 0, 0); } EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); @@ -480,7 +524,27 @@ EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); */ int sprint_backtrace(char *buffer, unsigned long address) { - return __sprint_symbol(buffer, address, -1, 1); + return __sprint_symbol(buffer, address, -1, 1, 0); +} + +/** + * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer + * @buffer: buffer to be stored + * @address: address to lookup + * + * This function is for stack backtrace and does the same thing as + * sprint_symbol() but with modified/decreased @address. If there is a + * tail-call to the function marked "noreturn", gcc optimized out code after + * the call so that the stack-saved return address could point outside of the + * caller. This function ensures that kallsyms will find the original caller + * by decreasing @address. This function also appends the module build ID to + * the @buffer if @address is within a kernel module. + * + * This function returns the number of bytes stored in @buffer. + */ +int sprint_backtrace_build_id(char *buffer, unsigned long address) +{ + return __sprint_symbol(buffer, address, -1, 1, 1); } /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ |