From 65b8a9b4d5525348e55cf63a43517610ee8e0970 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 5 Aug 2010 12:59:02 -0600 Subject: module: refactor load_module part 2 Here's a second one. It's slightly less trivial - since we now have error cases - and equally untested so it may well be totally broken. But it also cleans up a bit more, and avoids one of the goto targets, because the "move_module()" helper now does both allocations or none. Signed-off-by: Linus Torvalds Signed-off-by: Rusty Russell --- kernel/module.c | 129 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 72 insertions(+), 57 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 12905ed44393..19ddcb0dba36 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2082,7 +2082,8 @@ static void *module_alloc_update_bounds(unsigned long size) #ifdef CONFIG_DEBUG_KMEMLEAK static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, - Elf_Shdr *sechdrs, char *secstrings) + const Elf_Shdr *sechdrs, + const char *secstrings) { unsigned int i; @@ -2102,7 +2103,8 @@ static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, } #else static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, - Elf_Shdr *sechdrs, char *secstrings) + Elf_Shdr *sechdrs, + const char *secstrings) { } #endif @@ -2172,6 +2174,70 @@ static void find_module_sections(struct module *mod, Elf_Ehdr *hdr, #endif } +static struct module *move_module(struct module *mod, + Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + const char *secstrings, unsigned modindex) +{ + int i; + void *ptr; + + /* Do the allocs. */ + ptr = module_alloc_update_bounds(mod->core_size); + /* + * The pointer to this block is stored in the module structure + * which is inside the block. Just mark it as not being a + * leak. + */ + kmemleak_not_leak(ptr); + if (!ptr) + return ERR_PTR(-ENOMEM); + + memset(ptr, 0, mod->core_size); + mod->module_core = ptr; + + ptr = module_alloc_update_bounds(mod->init_size); + /* + * The pointer to this block is stored in the module structure + * which is inside the block. This block doesn't need to be + * scanned as it contains data and code that will be freed + * after the module is initialized. + */ + kmemleak_ignore(ptr); + if (!ptr && mod->init_size) { + module_free(mod, mod->module_core); + return ERR_PTR(-ENOMEM); + } + memset(ptr, 0, mod->init_size); + mod->module_init = ptr; + + /* Transfer each section which specifies SHF_ALLOC */ + DEBUGP("final section addresses:\n"); + for (i = 0; i < hdr->e_shnum; i++) { + void *dest; + + if (!(sechdrs[i].sh_flags & SHF_ALLOC)) + continue; + + if (sechdrs[i].sh_entsize & INIT_OFFSET_MASK) + dest = mod->module_init + + (sechdrs[i].sh_entsize & ~INIT_OFFSET_MASK); + else + dest = mod->module_core + sechdrs[i].sh_entsize; + + if (sechdrs[i].sh_type != SHT_NOBITS) + memcpy(dest, (void *)sechdrs[i].sh_addr, + sechdrs[i].sh_size); + /* Update sh_addr to point to copy in image. */ + sechdrs[i].sh_addr = (unsigned long)dest; + DEBUGP("\t0x%lx %s\n", + sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name); + } + /* Module has been moved. */ + mod = (void *)sechdrs[modindex].sh_addr; + kmemleak_load_module(mod, hdr, sechdrs, secstrings); + return mod; +} + /* Allocate and load the module: note that size of section 0 is always zero, and we rely on this for optional sections. */ static noinline struct module *load_module(void __user *umod, @@ -2188,7 +2254,6 @@ static noinline struct module *load_module(void __user *umod, unsigned int modindex, versindex, infoindex, pcpuindex; struct module *mod; long err = 0; - void *ptr = NULL; /* Stops spurious gcc warning */ unsigned long symoffs, stroffs, *strmap; void __percpu *percpu; struct _ddebug *debug = NULL; @@ -2342,61 +2407,12 @@ static noinline struct module *load_module(void __user *umod, symoffs = layout_symtab(mod, sechdrs, symindex, strindex, hdr, secstrings, &stroffs, strmap); - /* Do the allocs. */ - ptr = module_alloc_update_bounds(mod->core_size); - /* - * The pointer to this block is stored in the module structure - * which is inside the block. Just mark it as not being a - * leak. - */ - kmemleak_not_leak(ptr); - if (!ptr) { - err = -ENOMEM; + /* Allocate and move to the final place */ + mod = move_module(mod, hdr, sechdrs, secstrings, modindex); + if (IS_ERR(mod)) { + err = PTR_ERR(mod); goto free_percpu; } - memset(ptr, 0, mod->core_size); - mod->module_core = ptr; - - ptr = module_alloc_update_bounds(mod->init_size); - /* - * The pointer to this block is stored in the module structure - * which is inside the block. This block doesn't need to be - * scanned as it contains data and code that will be freed - * after the module is initialized. - */ - kmemleak_ignore(ptr); - if (!ptr && mod->init_size) { - err = -ENOMEM; - goto free_core; - } - memset(ptr, 0, mod->init_size); - mod->module_init = ptr; - - /* Transfer each section which specifies SHF_ALLOC */ - DEBUGP("final section addresses:\n"); - for (i = 0; i < hdr->e_shnum; i++) { - void *dest; - - if (!(sechdrs[i].sh_flags & SHF_ALLOC)) - continue; - - if (sechdrs[i].sh_entsize & INIT_OFFSET_MASK) - dest = mod->module_init - + (sechdrs[i].sh_entsize & ~INIT_OFFSET_MASK); - else - dest = mod->module_core + sechdrs[i].sh_entsize; - - if (sechdrs[i].sh_type != SHT_NOBITS) - memcpy(dest, (void *)sechdrs[i].sh_addr, - sechdrs[i].sh_size); - /* Update sh_addr to point to copy in image. */ - sechdrs[i].sh_addr = (unsigned long)dest; - DEBUGP("\t0x%lx %s\n", - sechdrs[i].sh_addr, secstrings + sechdrs[i].sh_name); - } - /* Module has been moved. */ - mod = (void *)sechdrs[modindex].sh_addr; - kmemleak_load_module(mod, hdr, sechdrs, secstrings); #if defined(CONFIG_MODULE_UNLOAD) mod->refptr = alloc_percpu(struct module_ref); @@ -2580,7 +2596,6 @@ static noinline struct module *load_module(void __user *umod, free_init: #endif module_free(mod, mod->module_init); - free_core: module_free(mod, mod->module_core); /* mod will be freed with core. Don't access it beyond this line! */ free_percpu: -- cgit v1.2.3