| Message ID | 20200625200235.GQ4781@hirez.programming.kicks-ass.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] objtool,x86_64: Replace recordmcount with objtool | expand |
On Thu, Jun 25, 2020 at 1:02 PM Peter Zijlstra <peterz@infradead.org> wrote: > > On Thu, Jun 25, 2020 at 09:15:03AM -0700, Sami Tolvanen wrote: > > On Thu, Jun 25, 2020 at 09:45:30AM +0200, Peter Zijlstra wrote: > > > > At least for x86_64 I can do a really quick take for a recordmcount pass > > > in objtool, but I suppose you also need this for ARM64 ? > > > > Sure, sounds good. arm64 uses -fpatchable-function-entry with clang, so we > > don't need recordmcount there. > > This is on top of my local pile: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git master > > which notably includes the static_call series. > > Not boot tested, but it generates the required sections and they look > more or less as expected, ymmv. > > --- > arch/x86/Kconfig | 1 - > scripts/Makefile.build | 3 ++ > scripts/link-vmlinux.sh | 2 +- > tools/objtool/builtin-check.c | 9 ++--- > tools/objtool/builtin.h | 2 +- > tools/objtool/check.c | 81 +++++++++++++++++++++++++++++++++++++++++++ > tools/objtool/check.h | 1 + > tools/objtool/objtool.h | 1 + > 8 files changed, 91 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index a291823f3f26..189575c12434 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -174,7 +174,6 @@ config X86 > select HAVE_EXIT_THREAD > select HAVE_FAST_GUP > select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE > - select HAVE_FTRACE_MCOUNT_RECORD > select HAVE_FUNCTION_GRAPH_TRACER > select HAVE_FUNCTION_TRACER > select HAVE_GCC_PLUGINS > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 2e8810b7e5ed..c774befc57da 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -227,6 +227,9 @@ endif > ifdef CONFIG_X86_SMAP > objtool_args += --uaccess > endif > +ifdef CONFIG_DYNAMIC_FTRACE > + objtool_args += --mcount > +endif > > # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory > # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > index 92dd745906f4..00c6e4f28a1a 100755 > --- a/scripts/link-vmlinux.sh > +++ b/scripts/link-vmlinux.sh > @@ -60,7 +60,7 @@ objtool_link() > local objtoolopt; > > if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then > - objtoolopt="check" > + objtoolopt="check --vmlinux" > if [ -z "${CONFIG_FRAME_POINTER}" ]; then > objtoolopt="${objtoolopt} --no-fp" > fi > diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c > index 4896c5a89702..a6c3a3fba67d 100644 > --- a/tools/objtool/builtin-check.c > +++ b/tools/objtool/builtin-check.c > @@ -18,7 +18,7 @@ > #include "builtin.h" > #include "objtool.h" > > -bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu; > +bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, mcount; > > static const char * const check_usage[] = { > "objtool check [<options>] file.o", > @@ -36,12 +36,13 @@ const struct option check_options[] = { > OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"), > OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"), > OPT_BOOLEAN('F', "fpu", &fpu, "validate FPU context"), > + OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"), > OPT_END(), > }; > > int cmd_check(int argc, const char **argv) > { > - const char *objname, *s; > + const char *objname; > > argc = parse_options(argc, argv, check_options, check_usage, 0); > > @@ -50,9 +51,5 @@ int cmd_check(int argc, const char **argv) > > objname = argv[0]; > > - s = strstr(objname, "vmlinux.o"); > - if (s && !s[9]) > - vmlinux = true; > - > return check(objname, false); > } > diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h > index 7158e09d4cc9..b51d883ec245 100644 > --- a/tools/objtool/builtin.h > +++ b/tools/objtool/builtin.h > @@ -8,7 +8,7 @@ > #include <subcmd/parse-options.h> > > extern const struct option check_options[]; > -extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu; > +extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, mcount; > > extern int cmd_check(int argc, const char **argv); > extern int cmd_orc(int argc, const char **argv); > diff --git a/tools/objtool/check.c b/tools/objtool/check.c > index 6647a8d1545b..ee99566bdae9 100644 > --- a/tools/objtool/check.c > +++ b/tools/objtool/check.c > @@ -533,6 +533,65 @@ static int create_static_call_sections(struct objtool_file *file) > return 0; > } > > +static int create_mcount_loc_sections(struct objtool_file *file) > +{ > + struct section *sec, *reloc_sec; > + struct reloc *reloc; > + unsigned long *loc; > + struct instruction *insn; > + int idx; > + > + sec = find_section_by_name(file->elf, "__mcount_loc"); > + if (sec) { > + INIT_LIST_HEAD(&file->mcount_loc_list); > + WARN("file already has __mcount_loc section, skipping"); > + return 0; > + } > + > + if (list_empty(&file->mcount_loc_list)) > + return 0; > + > + idx = 0; > + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) > + idx++; > + > + sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx); > + if (!sec) > + return -1; > + > + reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA); > + if (!reloc_sec) > + return -1; > + > + idx = 0; > + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) { > + > + loc = (unsigned long *)sec->data->d_buf + idx; > + memset(loc, 0, sizeof(unsigned long)); > + > + reloc = malloc(sizeof(*reloc)); > + if (!reloc) { > + perror("malloc"); > + return -1; > + } > + memset(reloc, 0, sizeof(*reloc)); calloc(1, sizeof(*reloc))? > + > + reloc->sym = insn->sec->sym; > + reloc->addend = insn->offset; > + reloc->type = R_X86_64_64; > + reloc->offset = idx * sizeof(unsigned long); > + reloc->sec = reloc_sec; > + elf_add_reloc(file->elf, reloc); > + > + idx++; > + } > + > + if (elf_rebuild_reloc_section(file->elf, reloc_sec)) > + return -1; > + > + return 0; > +} > + > /* > * Warnings shouldn't be reported for ignored functions. > */ > @@ -892,6 +951,22 @@ static int add_call_destinations(struct objtool_file *file) > insn->type = INSN_NOP; > } > > + if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) { > + if (reloc) { > + reloc->type = R_NONE; > + elf_write_reloc(file->elf, reloc); > + } > + > + elf_write_insn(file->elf, insn->sec, > + insn->offset, insn->len, > + arch_nop_insn(insn->len)); > + > + insn->type = INSN_NOP; > + > + list_add_tail(&insn->mcount_loc_node, > + &file->mcount_loc_list); > + } > + > /* > * Whatever stack impact regular CALLs have, should be undone > * by the RETURN of the called function. > @@ -3004,6 +3079,7 @@ int check(const char *_objname, bool orc) > INIT_LIST_HEAD(&file.insn_list); > hash_init(file.insn_hash); > 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"); > file.ignore_unreachables = no_unreachable; > file.hints = false; > @@ -3056,6 +3132,11 @@ int check(const char *_objname, bool orc) > goto out; > warnings += ret; > > + ret = create_mcount_loc_sections(&file); > + if (ret < 0) > + goto out; > + warnings += ret; > + > if (orc) { > ret = create_orc(&file); > if (ret < 0) > diff --git a/tools/objtool/check.h b/tools/objtool/check.h > index cd95fca0d237..01f11b5da5dd 100644 > --- a/tools/objtool/check.h > +++ b/tools/objtool/check.h > @@ -24,6 +24,7 @@ struct instruction { > struct list_head list; > struct hlist_node hash; > struct list_head static_call_node; > + struct list_head mcount_loc_node; > struct section *sec; > unsigned long offset; > unsigned int len; > diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h > index 9a7cd0b88bd8..f604b22d22cc 100644 > --- a/tools/objtool/objtool.h > +++ b/tools/objtool/objtool.h > @@ -17,6 +17,7 @@ struct objtool_file { > struct list_head insn_list; > DECLARE_HASHTABLE(insn_hash, 20); > struct list_head static_call_list; > + struct list_head mcount_loc_list; > bool ignore_unreachables, c_file, hints, rodata; > }; >
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a291823f3f26..189575c12434 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -174,7 +174,6 @@ config X86 select HAVE_EXIT_THREAD select HAVE_FAST_GUP select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE - select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_GCC_PLUGINS diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 2e8810b7e5ed..c774befc57da 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -227,6 +227,9 @@ endif ifdef CONFIG_X86_SMAP objtool_args += --uaccess endif +ifdef CONFIG_DYNAMIC_FTRACE + objtool_args += --mcount +endif # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 92dd745906f4..00c6e4f28a1a 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -60,7 +60,7 @@ objtool_link() local objtoolopt; if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then - objtoolopt="check" + objtoolopt="check --vmlinux" if [ -z "${CONFIG_FRAME_POINTER}" ]; then objtoolopt="${objtoolopt} --no-fp" fi diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 4896c5a89702..a6c3a3fba67d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -18,7 +18,7 @@ #include "builtin.h" #include "objtool.h" -bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu; +bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, mcount; static const char * const check_usage[] = { "objtool check [<options>] file.o", @@ -36,12 +36,13 @@ const struct option check_options[] = { OPT_BOOLEAN('d', "duplicate", &validate_dup, "duplicate validation for vmlinux.o"), OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"), OPT_BOOLEAN('F', "fpu", &fpu, "validate FPU context"), + OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"), OPT_END(), }; int cmd_check(int argc, const char **argv) { - const char *objname, *s; + const char *objname; argc = parse_options(argc, argv, check_options, check_usage, 0); @@ -50,9 +51,5 @@ int cmd_check(int argc, const char **argv) objname = argv[0]; - s = strstr(objname, "vmlinux.o"); - if (s && !s[9]) - vmlinux = true; - return check(objname, false); } diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h index 7158e09d4cc9..b51d883ec245 100644 --- a/tools/objtool/builtin.h +++ b/tools/objtool/builtin.h @@ -8,7 +8,7 @@ #include <subcmd/parse-options.h> extern const struct option check_options[]; -extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu; +extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, fpu, mcount; extern int cmd_check(int argc, const char **argv); extern int cmd_orc(int argc, const char **argv); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 6647a8d1545b..ee99566bdae9 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -533,6 +533,65 @@ static int create_static_call_sections(struct objtool_file *file) return 0; } +static int create_mcount_loc_sections(struct objtool_file *file) +{ + struct section *sec, *reloc_sec; + struct reloc *reloc; + unsigned long *loc; + struct instruction *insn; + int idx; + + sec = find_section_by_name(file->elf, "__mcount_loc"); + if (sec) { + INIT_LIST_HEAD(&file->mcount_loc_list); + WARN("file already has __mcount_loc section, skipping"); + return 0; + } + + if (list_empty(&file->mcount_loc_list)) + return 0; + + idx = 0; + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) + idx++; + + sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx); + if (!sec) + return -1; + + reloc_sec = elf_create_reloc_section(file->elf, sec, SHT_RELA); + if (!reloc_sec) + return -1; + + idx = 0; + list_for_each_entry(insn, &file->mcount_loc_list, mcount_loc_node) { + + loc = (unsigned long *)sec->data->d_buf + idx; + memset(loc, 0, sizeof(unsigned long)); + + reloc = malloc(sizeof(*reloc)); + if (!reloc) { + perror("malloc"); + return -1; + } + memset(reloc, 0, sizeof(*reloc)); + + reloc->sym = insn->sec->sym; + reloc->addend = insn->offset; + reloc->type = R_X86_64_64; + reloc->offset = idx * sizeof(unsigned long); + reloc->sec = reloc_sec; + elf_add_reloc(file->elf, reloc); + + idx++; + } + + if (elf_rebuild_reloc_section(file->elf, reloc_sec)) + return -1; + + return 0; +} + /* * Warnings shouldn't be reported for ignored functions. */ @@ -892,6 +951,22 @@ static int add_call_destinations(struct objtool_file *file) insn->type = INSN_NOP; } + if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) { + if (reloc) { + reloc->type = R_NONE; + elf_write_reloc(file->elf, reloc); + } + + elf_write_insn(file->elf, insn->sec, + insn->offset, insn->len, + arch_nop_insn(insn->len)); + + insn->type = INSN_NOP; + + list_add_tail(&insn->mcount_loc_node, + &file->mcount_loc_list); + } + /* * Whatever stack impact regular CALLs have, should be undone * by the RETURN of the called function. @@ -3004,6 +3079,7 @@ int check(const char *_objname, bool orc) INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); 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"); file.ignore_unreachables = no_unreachable; file.hints = false; @@ -3056,6 +3132,11 @@ int check(const char *_objname, bool orc) goto out; warnings += ret; + ret = create_mcount_loc_sections(&file); + if (ret < 0) + goto out; + warnings += ret; + if (orc) { ret = create_orc(&file); if (ret < 0) diff --git a/tools/objtool/check.h b/tools/objtool/check.h index cd95fca0d237..01f11b5da5dd 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -24,6 +24,7 @@ struct instruction { struct list_head list; struct hlist_node hash; struct list_head static_call_node; + struct list_head mcount_loc_node; struct section *sec; unsigned long offset; unsigned int len; diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 9a7cd0b88bd8..f604b22d22cc 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -17,6 +17,7 @@ struct objtool_file { struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 20); struct list_head static_call_list; + struct list_head mcount_loc_list; bool ignore_unreachables, c_file, hints, rodata; };