| Message ID | 20220331090909.113387-1-chenzhongjin@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ARM: module: Add all unwind tables when load module | expand |
On Thu, Mar 31, 2022 at 05:09:09PM +0800, Chen Zhongjin wrote: > for (s = sechdrs; s < sechdrs_end; s++) { > const char *secname = secstrs + s->sh_name; > + const Elf_Shdr *txt_sec = find_mod_section(hdr, sechdrs, > + strcmp(".ARM.exidx", secname) ? > + secname + strlen(".ARM.exidx") : ".text"); In addition to my comments on the above... > > - if (!(s->sh_flags & SHF_ALLOC)) > + if (!(s->sh_flags & SHF_ALLOC) || > + s->sh_type != ELF_SECTION_UNWIND) Please align "s->sh_type" with the ! on the line above (don't use a tab for this!) > continue; > > - if (strcmp(".ARM.exidx.init.text", secname) == 0) > - maps[ARM_SEC_INIT].unw_sec = s; > - else if (strcmp(".ARM.exidx", secname) == 0) > - maps[ARM_SEC_CORE].unw_sec = s; > - else if (strcmp(".ARM.exidx.exit.text", secname) == 0) > - maps[ARM_SEC_EXIT].unw_sec = s; > - else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) > - maps[ARM_SEC_UNLIKELY].unw_sec = s; > - else if (strcmp(".ARM.exidx.text.hot", secname) == 0) > - maps[ARM_SEC_HOT].unw_sec = s; > - else if (strcmp(".init.text", secname) == 0) > - maps[ARM_SEC_INIT].txt_sec = s; > - else if (strcmp(".text", secname) == 0) > - maps[ARM_SEC_CORE].txt_sec = s; > - else if (strcmp(".exit.text", secname) == 0) > - maps[ARM_SEC_EXIT].txt_sec = s; > - else if (strcmp(".text.unlikely", secname) == 0) > - maps[ARM_SEC_UNLIKELY].txt_sec = s; > - else if (strcmp(".text.hot", secname) == 0) > - maps[ARM_SEC_HOT].txt_sec = s; > + if (txt_sec) { > + struct unwind_table *table = > + unwind_table_add(s->sh_addr, > + s->sh_size, > + txt_sec->sh_addr, > + txt_sec->sh_size); blank line here please. > + list_add(&table->mod_list, &unwind_list->mod_list); and here. Otherwise, looks good. Thanks.
Very appreciate for your patient review! For my first patch it really helps a lot :D v3 update pushed now. Sorry forgot CC for last mail. On 2022/3/31 18:38, Russell King (Oracle) wrote: > On Thu, Mar 31, 2022 at 05:09:09PM +0800, Chen Zhongjin wrote: >> for (s = sechdrs; s < sechdrs_end; s++) { >> const char *secname = secstrs + s->sh_name; >> + const Elf_Shdr *txt_sec = find_mod_section(hdr, sechdrs, >> + strcmp(".ARM.exidx", secname) ? >> + secname + strlen(".ARM.exidx") : ".text"); > In addition to my comments on the above... > >> >> - if (!(s->sh_flags & SHF_ALLOC)) >> + if (!(s->sh_flags & SHF_ALLOC) || >> + s->sh_type != ELF_SECTION_UNWIND) > Please align "s->sh_type" with the ! on the line above (don't use a tab > for this!) > >> continue; >> >> - if (strcmp(".ARM.exidx.init.text", secname) == 0) >> - maps[ARM_SEC_INIT].unw_sec = s; >> - else if (strcmp(".ARM.exidx", secname) == 0) >> - maps[ARM_SEC_CORE].unw_sec = s; >> - else if (strcmp(".ARM.exidx.exit.text", secname) == 0) >> - maps[ARM_SEC_EXIT].unw_sec = s; >> - else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) >> - maps[ARM_SEC_UNLIKELY].unw_sec = s; >> - else if (strcmp(".ARM.exidx.text.hot", secname) == 0) >> - maps[ARM_SEC_HOT].unw_sec = s; >> - else if (strcmp(".init.text", secname) == 0) >> - maps[ARM_SEC_INIT].txt_sec = s; >> - else if (strcmp(".text", secname) == 0) >> - maps[ARM_SEC_CORE].txt_sec = s; >> - else if (strcmp(".exit.text", secname) == 0) >> - maps[ARM_SEC_EXIT].txt_sec = s; >> - else if (strcmp(".text.unlikely", secname) == 0) >> - maps[ARM_SEC_UNLIKELY].txt_sec = s; >> - else if (strcmp(".text.hot", secname) == 0) >> - maps[ARM_SEC_HOT].txt_sec = s; >> + if (txt_sec) { >> + struct unwind_table *table = >> + unwind_table_add(s->sh_addr, >> + s->sh_size, >> + txt_sec->sh_addr, >> + txt_sec->sh_size); > blank line here please. > >> + list_add(&table->mod_list, &unwind_list->mod_list); > and here. > > Otherwise, looks good. Thanks. >
diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h index cfffae67c04e..8139b6a33a22 100644 --- a/arch/arm/include/asm/module.h +++ b/arch/arm/include/asm/module.h @@ -3,20 +3,10 @@ #define _ASM_ARM_MODULE_H #include <asm-generic/module.h> - -struct unwind_table; +#include <asm/unwind.h> #ifdef CONFIG_ARM_UNWIND -enum { - ARM_SEC_INIT, - ARM_SEC_DEVINIT, - ARM_SEC_CORE, - ARM_SEC_EXIT, - ARM_SEC_DEVEXIT, - ARM_SEC_HOT, - ARM_SEC_UNLIKELY, - ARM_SEC_MAX, -}; +#define ELF_SECTION_UNWIND 0x70000001 #endif #define PLT_ENT_STRIDE L1_CACHE_BYTES @@ -36,7 +26,8 @@ struct mod_plt_sec { struct mod_arch_specific { #ifdef CONFIG_ARM_UNWIND - struct unwind_table *unwind[ARM_SEC_MAX]; + struct unwind_table unwind_list; + struct unwind_table *init_table; #endif #ifdef CONFIG_ARM_MODULE_PLTS struct mod_plt_sec core; diff --git a/arch/arm/include/asm/unwind.h b/arch/arm/include/asm/unwind.h index 0f8a3439902d..b51f85417f58 100644 --- a/arch/arm/include/asm/unwind.h +++ b/arch/arm/include/asm/unwind.h @@ -24,6 +24,7 @@ struct unwind_idx { struct unwind_table { struct list_head list; + struct list_head mod_list; const struct unwind_idx *start; const struct unwind_idx *origin; const struct unwind_idx *stop; diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c index 549abcedf795..0526c2a54825 100644 --- a/arch/arm/kernel/module.c +++ b/arch/arm/kernel/module.c @@ -459,46 +459,33 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, #ifdef CONFIG_ARM_UNWIND const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; - struct mod_unwind_map maps[ARM_SEC_MAX]; - int i; + struct unwind_table *unwind_list = &mod->arch.unwind_list; - memset(maps, 0, sizeof(maps)); + INIT_LIST_HEAD(&unwind_list->mod_list); + mod->arch.init_table = NULL; for (s = sechdrs; s < sechdrs_end; s++) { const char *secname = secstrs + s->sh_name; + const Elf_Shdr *txt_sec = find_mod_section(hdr, sechdrs, + strcmp(".ARM.exidx", secname) ? + secname + strlen(".ARM.exidx") : ".text"); - if (!(s->sh_flags & SHF_ALLOC)) + if (!(s->sh_flags & SHF_ALLOC) || + s->sh_type != ELF_SECTION_UNWIND) continue; - if (strcmp(".ARM.exidx.init.text", secname) == 0) - maps[ARM_SEC_INIT].unw_sec = s; - else if (strcmp(".ARM.exidx", secname) == 0) - maps[ARM_SEC_CORE].unw_sec = s; - else if (strcmp(".ARM.exidx.exit.text", secname) == 0) - maps[ARM_SEC_EXIT].unw_sec = s; - else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0) - maps[ARM_SEC_UNLIKELY].unw_sec = s; - else if (strcmp(".ARM.exidx.text.hot", secname) == 0) - maps[ARM_SEC_HOT].unw_sec = s; - else if (strcmp(".init.text", secname) == 0) - maps[ARM_SEC_INIT].txt_sec = s; - else if (strcmp(".text", secname) == 0) - maps[ARM_SEC_CORE].txt_sec = s; - else if (strcmp(".exit.text", secname) == 0) - maps[ARM_SEC_EXIT].txt_sec = s; - else if (strcmp(".text.unlikely", secname) == 0) - maps[ARM_SEC_UNLIKELY].txt_sec = s; - else if (strcmp(".text.hot", secname) == 0) - maps[ARM_SEC_HOT].txt_sec = s; + if (txt_sec) { + struct unwind_table *table = + unwind_table_add(s->sh_addr, + s->sh_size, + txt_sec->sh_addr, + txt_sec->sh_size); + list_add(&table->mod_list, &unwind_list->mod_list); + /* save init table for module_arch_freeing_init */ + if (strcmp(".ARM.exidx.init.text", secname) == 0) + mod->arch.init_table = table; + } } - - for (i = 0; i < ARM_SEC_MAX; i++) - if (maps[i].unw_sec && maps[i].txt_sec) - mod->arch.unwind[i] = - unwind_table_add(maps[i].unw_sec->sh_addr, - maps[i].unw_sec->sh_size, - maps[i].txt_sec->sh_addr, - maps[i].txt_sec->sh_size); #endif #ifdef CONFIG_ARM_PATCH_PHYS_VIRT s = find_mod_section(hdr, sechdrs, ".pv_table"); @@ -519,11 +506,13 @@ void module_arch_cleanup(struct module *mod) { #ifdef CONFIG_ARM_UNWIND - int i; + struct unwind_table *tmp; + struct unwind_table *n; - for (i = 0; i < ARM_SEC_MAX; i++) { - unwind_table_del(mod->arch.unwind[i]); - mod->arch.unwind[i] = NULL; + list_for_each_entry_safe(tmp, n, + &mod->arch.unwind_list.mod_list, mod_list) { + list_del(&tmp->mod_list); + unwind_table_del(tmp); } #endif } @@ -531,7 +520,12 @@ module_arch_cleanup(struct module *mod) void __weak module_arch_freeing_init(struct module *mod) { #ifdef CONFIG_ARM_UNWIND - unwind_table_del(mod->arch.unwind[ARM_SEC_INIT]); - mod->arch.unwind[ARM_SEC_INIT] = NULL; + struct unwind_table *init = mod->arch.init_table; + + if (init) { + mod->arch.init_table = NULL; + list_del(&init->mod_list); + unwind_table_del(init); + } #endif }
For EABI stack unwinding, when loading .ko module the EXIDX sections will be added to a unwind_table list. However not all EXIDX sections are added because EXIDX sections are searched by hardcoded section names. For functions in other sections such as .ref.text or .kprobes.text, gcc generates seprated EXIDX sections (such as .ARM.exidx.ref.text or .ARM.exidx.kprobes.text). These extra EXIDX sections are not loaded, so when unwinding functions in these sections, we will failed with: unwind: Index not found xxx To fix that, I refactor the code for searching and adding EXIDX sections: - Check section type to search EXIDX tables (0x70000001) instead of strcmp() the hardcoded names. Then find the corresponding text sections by their section names. - Add a unwind_table list in module->arch to save their own unwind_table instead of the fixed-lenth array. - Save .ARM.exidx.init.text section ptr, because it should be cleaned after module init. Now all EXIDX sections of .ko can be added correctly. Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> --- Changes v1 -> v2: - Rename "table_list" to "unwind_list" for consistency. - Drop unnecessary locals variable "txtname" and "sectype". - Merge condition checks for sh_flags and sh_type. --- arch/arm/include/asm/module.h | 17 ++------- arch/arm/include/asm/unwind.h | 1 + arch/arm/kernel/module.c | 70 ++++++++++++++++------------------- 3 files changed, 37 insertions(+), 51 deletions(-)