From ab4e0744e99b87e1a223e89fc3c9ae44f727c9a6 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 17 Dec 2020 15:02:42 -0600 Subject: objtool: Refactor ORC section generation Decouple ORC entries from instructions. This simplifies the control/data flow, and is going to make it easier to support alternative instructions which change the stack layout. Signed-off-by: Josh Poimboeuf --- tools/objtool/Makefile | 4 - tools/objtool/builtin-orc.c | 6 +- tools/objtool/include/objtool/arch.h | 4 - tools/objtool/include/objtool/check.h | 3 - tools/objtool/include/objtool/objtool.h | 3 +- tools/objtool/orc_gen.c | 272 ++++++++++++++++---------------- tools/objtool/weak.c | 7 +- 7 files changed, 140 insertions(+), 159 deletions(-) diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile index d179299980b9..92ce4fce7bc7 100644 --- a/tools/objtool/Makefile +++ b/tools/objtool/Makefile @@ -47,10 +47,6 @@ ifeq ($(SRCARCH),x86) SUBCMD_ORC := y endif -ifeq ($(SUBCMD_ORC),y) - CFLAGS += -DINSN_USE_ORC -endif - export SUBCMD_CHECK SUBCMD_ORC export srctree OUTPUT CFLAGS SRCARCH AWK include $(srctree)/tools/build/Makefile.include diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c index 6745f3328a0e..8273bbf7cebb 100644 --- a/tools/objtool/builtin-orc.c +++ b/tools/objtool/builtin-orc.c @@ -51,11 +51,7 @@ int cmd_orc(int argc, const char **argv) if (list_empty(&file->insn_list)) return 0; - ret = create_orc(file); - if (ret) - return ret; - - ret = create_orc_sections(file); + ret = orc_create(file); if (ret) return ret; diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h index dc4f503a3ae4..6ff0685f5cc5 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -11,10 +11,6 @@ #include #include -#ifdef INSN_USE_ORC -#include -#endif - enum insn_type { INSN_JUMP_CONDITIONAL, INSN_JUMP_UNCONDITIONAL, diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h index bba10968eac0..df1e3e8ed204 100644 --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -43,9 +43,6 @@ struct instruction { struct symbol *func; struct list_head stack_ops; struct cfi_state cfi; -#ifdef INSN_USE_ORC - struct orc_entry orc; -#endif }; static inline bool is_static_jump(struct instruction *insn) diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h index 32f4cd1da9fa..e114642efb65 100644 --- a/tools/objtool/include/objtool/objtool.h +++ b/tools/objtool/include/objtool/objtool.h @@ -26,7 +26,6 @@ struct objtool_file *objtool_open_read(const char *_objname); int check(struct objtool_file *file); int orc_dump(const char *objname); -int create_orc(struct objtool_file *file); -int create_orc_sections(struct objtool_file *file); +int orc_create(struct objtool_file *file); #endif /* _OBJTOOL_H */ diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c index 2e5fb787a382..38e1a8dbfff0 100644 --- a/tools/objtool/orc_gen.c +++ b/tools/objtool/orc_gen.c @@ -13,89 +13,84 @@ #include #include -int create_orc(struct objtool_file *file) +static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi) { - struct instruction *insn; + struct instruction *insn = container_of(cfi, struct instruction, cfi); + struct cfi_reg *bp = &cfi->regs[CFI_BP]; - for_each_insn(file, insn) { - struct orc_entry *orc = &insn->orc; - struct cfi_reg *cfa = &insn->cfi.cfa; - struct cfi_reg *bp = &insn->cfi.regs[CFI_BP]; + memset(orc, 0, sizeof(*orc)); - if (!insn->sec->text) - continue; - - orc->end = insn->cfi.end; + orc->end = cfi->end; - if (cfa->base == CFI_UNDEFINED) { - orc->sp_reg = ORC_REG_UNDEFINED; - continue; - } - - switch (cfa->base) { - case CFI_SP: - orc->sp_reg = ORC_REG_SP; - break; - case CFI_SP_INDIRECT: - orc->sp_reg = ORC_REG_SP_INDIRECT; - break; - case CFI_BP: - orc->sp_reg = ORC_REG_BP; - break; - case CFI_BP_INDIRECT: - orc->sp_reg = ORC_REG_BP_INDIRECT; - break; - case CFI_R10: - orc->sp_reg = ORC_REG_R10; - break; - case CFI_R13: - orc->sp_reg = ORC_REG_R13; - break; - case CFI_DI: - orc->sp_reg = ORC_REG_DI; - break; - case CFI_DX: - orc->sp_reg = ORC_REG_DX; - break; - default: - WARN_FUNC("unknown CFA base reg %d", - insn->sec, insn->offset, cfa->base); - return -1; - } + if (cfi->cfa.base == CFI_UNDEFINED) { + orc->sp_reg = ORC_REG_UNDEFINED; + return 0; + } - switch(bp->base) { - case CFI_UNDEFINED: - orc->bp_reg = ORC_REG_UNDEFINED; - break; - case CFI_CFA: - orc->bp_reg = ORC_REG_PREV_SP; - break; - case CFI_BP: - orc->bp_reg = ORC_REG_BP; - break; - default: - WARN_FUNC("unknown BP base reg %d", - insn->sec, insn->offset, bp->base); - return -1; - } + switch (cfi->cfa.base) { + case CFI_SP: + orc->sp_reg = ORC_REG_SP; + break; + case CFI_SP_INDIRECT: + orc->sp_reg = ORC_REG_SP_INDIRECT; + break; + case CFI_BP: + orc->sp_reg = ORC_REG_BP; + break; + case CFI_BP_INDIRECT: + orc->sp_reg = ORC_REG_BP_INDIRECT; + break; + case CFI_R10: + orc->sp_reg = ORC_REG_R10; + break; + case CFI_R13: + orc->sp_reg = ORC_REG_R13; + break; + case CFI_DI: + orc->sp_reg = ORC_REG_DI; + break; + case CFI_DX: + orc->sp_reg = ORC_REG_DX; + break; + default: + WARN_FUNC("unknown CFA base reg %d", + insn->sec, insn->offset, cfi->cfa.base); + return -1; + } - orc->sp_offset = cfa->offset; - orc->bp_offset = bp->offset; - orc->type = insn->cfi.type; + switch (bp->base) { + case CFI_UNDEFINED: + orc->bp_reg = ORC_REG_UNDEFINED; + break; + case CFI_CFA: + orc->bp_reg = ORC_REG_PREV_SP; + break; + case CFI_BP: + orc->bp_reg = ORC_REG_BP; + break; + default: + WARN_FUNC("unknown BP base reg %d", + insn->sec, insn->offset, bp->base); + return -1; } + orc->sp_offset = cfi->cfa.offset; + orc->bp_offset = bp->offset; + orc->type = cfi->type; + return 0; } -static int create_orc_entry(struct elf *elf, struct section *u_sec, struct section *ip_relocsec, - unsigned int idx, struct section *insn_sec, - unsigned long insn_off, struct orc_entry *o) +static int write_orc_entry(struct elf *elf, struct section *orc_sec, + struct section *ip_rsec, unsigned int idx, + struct section *insn_sec, unsigned long insn_off, + struct orc_entry *o) { struct orc_entry *orc; struct reloc *reloc; /* populate ORC data */ - orc = (struct orc_entry *)u_sec->data->d_buf + idx; + orc = (struct orc_entry *)orc_sec->data->d_buf + idx; memcpy(orc, o, sizeof(*orc)); orc->sp_offset = bswap_if_needed(orc->sp_offset); orc->bp_offset = bswap_if_needed(orc->bp_offset); @@ -117,102 +112,109 @@ static int create_orc_entry(struct elf *elf, struct section *u_sec, struct secti reloc->type = R_X86_64_PC32; reloc->offset = idx * sizeof(int); - reloc->sec = ip_relocsec; + reloc->sec = ip_rsec; elf_add_reloc(elf, reloc); return 0; } -int create_orc_sections(struct objtool_file *file) +struct orc_list_entry { + struct list_head list; + struct orc_entry orc; + struct section *insn_sec; + unsigned long insn_off; +}; + +static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc, + struct section *sec, unsigned long offset) +{ + struct orc_list_entry *entry = malloc(sizeof(*entry)); + + if (!entry) { + WARN("malloc failed"); + return -1; + } + + entry->orc = *orc; + entry->insn_sec = sec; + entry->insn_off = offset; + + list_add_tail(&entry->list, orc_list); + return 0; +} + +int orc_create(struct objtool_file *file) { - struct instruction *insn, *prev_insn; - struct section *sec, *u_sec, *ip_relocsec; - unsigned int idx; + struct section *sec, *ip_rsec, *orc_sec; + unsigned int nr = 0, idx = 0; + struct orc_list_entry *entry; + struct list_head orc_list; - struct orc_entry empty = { - .sp_reg = ORC_REG_UNDEFINED, + struct orc_entry null = { + .sp_reg = ORC_REG_UNDEFINED, .bp_reg = ORC_REG_UNDEFINED, .type = UNWIND_HINT_TYPE_CALL, }; - sec = find_section_by_name(file->elf, ".orc_unwind"); - if (sec) { - WARN("file already has .orc_unwind section, skipping"); - return -1; - } - - /* count the number of needed orcs */ - idx = 0; + /* Build a deduplicated list of ORC entries: */ + INIT_LIST_HEAD(&orc_list); for_each_sec(file, sec) { + struct orc_entry orc, prev_orc = {0}; + struct instruction *insn; + bool empty = true; + if (!sec->text) continue; - prev_insn = NULL; sec_for_each_insn(file, sec, insn) { - if (!prev_insn || - memcmp(&insn->orc, &prev_insn->orc, - sizeof(struct orc_entry))) { - idx++; - } - prev_insn = insn; + if (init_orc_entry(&orc, &insn->cfi)) + return -1; + if (!memcmp(&prev_orc, &orc, sizeof(orc))) + continue; + if (orc_list_add(&orc_list, &orc, sec, insn->offset)) + return -1; + nr++; + prev_orc = orc; + empty = false; } - /* section terminator */ - if (prev_insn) - idx++; + /* Add a section terminator */ + if (!empty) { + orc_list_add(&orc_list, &null, sec, sec->len); + nr++; + } } - if (!idx) - return -1; + if (!nr) + return 0; + /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */ + sec = find_section_by_name(file->elf, ".orc_unwind"); + if (sec) { + WARN("file already has .orc_unwind section, skipping"); + return -1; + } + orc_sec = elf_create_section(file->elf, ".orc_unwind", 0, + sizeof(struct orc_entry), nr); + if (!orc_sec) + return -1; - /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */ - sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), idx); + sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr); if (!sec) return -1; - - ip_relocsec = elf_create_reloc_section(file->elf, sec, SHT_RELA); - if (!ip_relocsec) + ip_rsec = elf_create_reloc_section(file->elf, sec, SHT_RELA); + if (!ip_rsec) return -1; - /* create .orc_unwind section */ - u_sec = elf_create_section(file->elf, ".orc_unwind", 0, - sizeof(struct orc_entry), idx); - - /* populate sections */ - idx = 0; - for_each_sec(file, sec) { - if (!sec->text) - continue; - - prev_insn = NULL; - sec_for_each_insn(file, sec, insn) { - if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc, - sizeof(struct orc_entry))) { - - if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx, - insn->sec, insn->offset, - &insn->orc)) - return -1; - - idx++; - } - prev_insn = insn; - } - - /* section terminator */ - if (prev_insn) { - if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx, - prev_insn->sec, - prev_insn->offset + prev_insn->len, - &empty)) - return -1; - - idx++; - } + /* Write ORC entries to sections: */ + list_for_each_entry(entry, &orc_list, list) { + if (write_orc_entry(file->elf, orc_sec, ip_rsec, idx++, + entry->insn_sec, entry->insn_off, + &entry->orc)) + return -1; } - if (elf_rebuild_reloc_section(file->elf, ip_relocsec)) + if (elf_rebuild_reloc_section(file->elf, ip_rsec)) return -1; return 0; diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c index f2716827cc30..8314e824db4a 100644 --- a/tools/objtool/weak.c +++ b/tools/objtool/weak.c @@ -25,12 +25,7 @@ int __weak orc_dump(const char *_objname) UNSUPPORTED("orc"); } -int __weak create_orc(struct objtool_file *file) -{ - UNSUPPORTED("orc"); -} - -int __weak create_orc_sections(struct objtool_file *file) +int __weak orc_create(struct objtool_file *file) { UNSUPPORTED("orc"); 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