Messages in this thread Patch in this message | | | Date | Fri, 26 Mar 2021 16:12:12 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v3 13/16] objtool: Keep track of retpoline call sites |
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Provide infrastructure for architectures to rewrite/augment compiler generated retpoline calls. Similar to what we do for static_call()s, keep track of the instructions that are retpoline calls.
Use the same list_head, since a retpoline call cannot also be a static_call.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- tools/objtool/check.c | 34 +++++++++++++++++++++++++++----- tools/objtool/include/objtool/arch.h | 2 + tools/objtool/include/objtool/check.h | 2 - tools/objtool/include/objtool/objtool.h | 1 tools/objtool/objtool.c | 1 5 files changed, 34 insertions(+), 6 deletions(-)
--- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -451,7 +451,7 @@ static int create_static_call_sections(s return 0; idx = 0; - list_for_each_entry(insn, &file->static_call_list, static_call_node) + list_for_each_entry(insn, &file->static_call_list, call_node) idx++; sec = elf_create_section(file->elf, ".static_call_sites", SHF_WRITE, @@ -460,7 +460,7 @@ static int create_static_call_sections(s return -1; idx = 0; - list_for_each_entry(insn, &file->static_call_list, static_call_node) { + list_for_each_entry(insn, &file->static_call_list, call_node) { site = (struct static_call_site *)sec->data->d_buf + idx; memset(site, 0, sizeof(struct static_call_site)); @@ -829,13 +829,16 @@ static int add_jump_destinations(struct else insn->type = INSN_JUMP_DYNAMIC_CONDITIONAL; + list_add_tail(&insn->call_node, + &file->retpoline_call_list); + insn->retpoline_safe = true; continue; } else if (insn->func) { /* internal or external sibling call (with reloc) */ insn->call_dest = reloc->sym; if (insn->call_dest->static_call_tramp) { - list_add_tail(&insn->static_call_node, + list_add_tail(&insn->call_node, &file->static_call_list); } continue; @@ -897,7 +900,7 @@ static int add_jump_destinations(struct /* internal sibling call (without reloc) */ insn->call_dest = insn->jump_dest->func; if (insn->call_dest->static_call_tramp) { - list_add_tail(&insn->static_call_node, + list_add_tail(&insn->call_node, &file->static_call_list); } } @@ -981,6 +984,9 @@ static int add_call_destinations(struct insn->type = INSN_CALL_DYNAMIC; insn->retpoline_safe = true; + list_add_tail(&insn->call_node, + &file->retpoline_call_list); + remove_insn_ops(insn); continue; @@ -988,7 +994,7 @@ static int add_call_destinations(struct insn->call_dest = reloc->sym; if (insn->call_dest && insn->call_dest->static_call_tramp) { - list_add_tail(&insn->static_call_node, + list_add_tail(&insn->call_node, &file->static_call_list); } @@ -1714,6 +1720,11 @@ static void mark_rodata(struct objtool_f file->rodata = found; } +__weak int arch_rewrite_retpolines(struct objtool_file *file) +{ + return 0; +} + static int decode_sections(struct objtool_file *file) { int ret; @@ -1742,6 +1753,10 @@ static int decode_sections(struct objtoo if (ret) return ret; + /* + * Must be before add_special_section_alts() as that depends on + * jump_dest being set. + */ ret = add_jump_destinations(file); if (ret) return ret; @@ -1778,6 +1793,15 @@ static int decode_sections(struct objtoo if (ret) return ret; + /* + * Must be after add_special_section_alts(), since this will emit + * alternatives. Must be after add_{jump,call}_destination(), since + * those create the call insn lists. + */ + ret = arch_rewrite_retpolines(file); + if (ret) + return ret; + return 0; } --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -87,4 +87,6 @@ int arch_decode_hint_reg(struct instruct bool arch_is_retpoline(struct symbol *sym); +int arch_rewrite_retpolines(struct objtool_file *file); + #endif /* _ARCH_H */ --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -39,7 +39,7 @@ struct alt_group { struct instruction { struct list_head list; struct hlist_node hash; - struct list_head static_call_node; + struct list_head call_node; struct list_head mcount_loc_node; struct section *sec; unsigned long offset; --- a/tools/objtool/include/objtool/objtool.h +++ b/tools/objtool/include/objtool/objtool.h @@ -18,6 +18,7 @@ struct objtool_file { struct elf *elf; struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 20); + struct list_head retpoline_call_list; struct list_head static_call_list; struct list_head mcount_loc_list; bool ignore_unreachables, c_file, hints, rodata; --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -125,6 +125,7 @@ struct objtool_file *objtool_open_read(c INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); + INIT_LIST_HEAD(&file.retpoline_call_list); INIT_LIST_HEAD(&file.static_call_list); INIT_LIST_HEAD(&file.mcount_loc_list); file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
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