Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 15 Sep 2022 13:11:09 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v3 30/59] objtool: Add .call_sites section |
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From: Peter Zijlstra <peterz@infradead.org>
In preparation for call depth tracking provide a section which collects all direct calls.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/kernel/vmlinux.lds.S | 7 ++++ tools/objtool/check.c | 51 ++++++++++++++++++++++++++++++++ tools/objtool/include/objtool/objtool.h | 1 tools/objtool/objtool.c | 1 4 files changed, 60 insertions(+)
--- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -291,6 +291,13 @@ SECTIONS *(.return_sites) __return_sites_end = .; } + + . = ALIGN(8); + .call_sites : AT(ADDR(.call_sites) - LOAD_OFFSET) { + __call_sites = .; + *(.call_sites) + __call_sites_end = .; + } #endif #ifdef CONFIG_X86_KERNEL_IBT --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -898,6 +898,49 @@ static int create_mcount_loc_sections(st return 0; } +static int create_direct_call_sections(struct objtool_file *file) +{ + struct instruction *insn; + struct section *sec; + unsigned int *loc; + int idx; + + sec = find_section_by_name(file->elf, ".call_sites"); + if (sec) { + INIT_LIST_HEAD(&file->call_list); + WARN("file already has .call_sites section, skipping"); + return 0; + } + + if (list_empty(&file->call_list)) + return 0; + + idx = 0; + list_for_each_entry(insn, &file->call_list, call_node) + idx++; + + sec = elf_create_section(file->elf, ".call_sites", 0, sizeof(unsigned int), idx); + if (!sec) + return -1; + + idx = 0; + list_for_each_entry(insn, &file->call_list, call_node) { + + loc = (unsigned int *)sec->data->d_buf + idx; + memset(loc, 0, sizeof(unsigned int)); + + if (elf_add_reloc_to_insn(file->elf, sec, + idx * sizeof(unsigned int), + R_X86_64_PC32, + insn->sec, insn->offset)) + return -1; + + idx++; + } + + return 0; +} + /* * Warnings shouldn't be reported for ignored functions. */ @@ -1252,6 +1295,9 @@ static void annotate_call_site(struct ob return; } + if (insn->type == INSN_CALL && !insn->sec->init) + list_add_tail(&insn->call_node, &file->call_list); + if (!sibling && dead_end_function(file, sym)) insn->dead_end = true; } @@ -4274,6 +4320,11 @@ int check(struct objtool_file *file) if (ret < 0) goto out; warnings += ret; + + ret = create_direct_call_sections(file); + if (ret < 0) + goto out; + warnings += ret; } if (opts.mcount) { --- a/tools/objtool/include/objtool/objtool.h +++ b/tools/objtool/include/objtool/objtool.h @@ -28,6 +28,7 @@ struct objtool_file { struct list_head static_call_list; struct list_head mcount_loc_list; struct list_head endbr_list; + struct list_head call_list; bool ignore_unreachables, hints, rodata; unsigned int nr_endbr; --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -106,6 +106,7 @@ struct objtool_file *objtool_open_read(c INIT_LIST_HEAD(&file.static_call_list); INIT_LIST_HEAD(&file.mcount_loc_list); INIT_LIST_HEAD(&file.endbr_list); + INIT_LIST_HEAD(&file.call_list); file.ignore_unreachables = opts.no_unreachable; file.hints = false;
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