| Message ID | 20220318105140.43914-3-sv@linux.ibm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | objtool: Add mcount sub-command | expand |
Le 18/03/2022 à 11:51, Sathvika Vasireddy a écrit : > This patch adds 'mcount' as a subcommand to objtool, and enables > the same for x86. objtool is built if CONFIG_FTRACE_MCOUNT_USE_OBJTOOL > is selected. Additionally, architectures can select HAVE_NOP_MCOUNT > if they choose to nop out mcount call sites. If that config option is > selected, then --mnop is passed as an option to 'objtool mcount' > > Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> > --- > Makefile | 6 ++ > arch/x86/Kconfig | 3 +- > scripts/Makefile.build | 12 +++ > tools/objtool/Build | 2 + > tools/objtool/Makefile | 4 +- > tools/objtool/builtin-mcount.c | 74 +++++++++++++ > tools/objtool/include/objtool/builtin.h | 4 +- > tools/objtool/include/objtool/objtool.h | 1 + > tools/objtool/mcount.c | 138 ++++++++++++++++++++++++ > tools/objtool/objtool.c | 1 + > tools/objtool/weak.c | 5 + > 11 files changed, 247 insertions(+), 3 deletions(-) > create mode 100644 tools/objtool/builtin-mcount.c > create mode 100644 tools/objtool/mcount.c > > diff --git a/Makefile b/Makefile > index 55a30ca69350..316f7d08b30a 100644 > --- a/Makefile > +++ b/Makefile > @@ -846,7 +846,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC > endif > endif > ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL > + ifdef CONFIG_HAVE_NOP_MCOUNT > CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT > + endif > endif > ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT > ifdef CONFIG_HAVE_C_RECORDMCOUNT > @@ -1303,6 +1305,10 @@ ifdef CONFIG_STACK_VALIDATION > prepare: tools/objtool > endif > > +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL > +prepare: tools/objtool > +endif I don't think that will work for powerpc. See arch/powerpc/Makefile powerpc builds the VDSO under prepare: , and powerpc has CONFIG_HAVE_GENERIC_VDSO so there are some C files in that step that seem to use objtool, allthough that looks odd to me. Must be something to fix somewhere. powerpc64-linux-gcc -Wp,-MMD,arch/powerpc/kernel/vdso/.vgettimeofday-64.o.d -nostdinc -I./arch/powerpc/include -I./arch/powerpc/include/generated -I./include -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -I ./arch/powerpc -DHAVE_AS_ATHIGH=1 -fmacro-prefix-map=./= -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 -mbig-endian -m64 -msoft-float -pipe -mtraceback=no -mabi=elfv1 -mcall-aixdesc -mcmodel=medium -mno-pointers-to-nested-functions -mtune=power7 -mcpu=power5 -mno-altivec -mno-vsx -fno-asynchronous-unwind-tables -mno-string -Wa,-maltivec -Wa,-mpower4 -Wa,-many -mabi=elfv1 -mcall-aixdesc -mbig-endian -mstack-protector-guard=tls -mstack-protector-guard-reg=r13 -fno-delete-null-pointer-checks -Wno-frame-address -Wno-format-truncation -Wno-format-overflow -Wno-address-of-packed-member -O2 -fno-allow-store-data-races -Wframe-larger-than=2048 -fstack-protector-strong -Wimplicit-fallthrough=5 -Wno-main -Wno-unused-but-set-variable -Wno-unused-const-variable -fno-stack-clash-protection -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wcast-function-type -Wno-stringop-truncation -Wno-zero-length-bounds -Wno-array-bounds -Wno-stringop-overflow -Wno-restrict -Wno-maybe-uninitialized -Wno-alloc-size-larger-than -fno-strict-overflow -fno-stack-check -fconserve-stack -Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init -Wno-packed-not-aligned -mstack-protector-guard-offset=3200 -shared -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both -include /home/chleroy/linux-powerpc/lib/vdso/gettimeofday.c -fno-stack-protector -DDISABLE_BRANCH_PROFILING -ffreestanding -fasynchronous-unwind-tables -ffixed-r30 -DKBUILD_MODFILE='"arch/powerpc/kernel/vdso/vgettimeofday-64"' -DKBUILD_BASENAME='"vgettimeofday_64"' -DKBUILD_MODNAME='"vgettimeofday_64"' -D__KBUILD_MODNAME=kmod_vgettimeofday_64 -c -o arch/powerpc/kernel/vdso/vgettimeofday-64.o arch/powerpc/kernel/vdso/vgettimeofday.c ; ./tools/objtool/objtool mcount arch/powerpc/kernel/vdso/vgettimeofday-64.o > + > ifdef CONFIG_BPF > ifdef CONFIG_DEBUG_INFO_BTF > prepare: tools/bpf/resolve_btfids
Christophe Leroy wrote: > > > Le 18/03/2022 à 11:51, Sathvika Vasireddy a écrit : >> This patch adds 'mcount' as a subcommand to objtool, and enables >> the same for x86. objtool is built if CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >> is selected. Additionally, architectures can select HAVE_NOP_MCOUNT >> if they choose to nop out mcount call sites. If that config option is >> selected, then --mnop is passed as an option to 'objtool mcount' >> >> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> >> --- >> Makefile | 6 ++ >> arch/x86/Kconfig | 3 +- >> scripts/Makefile.build | 12 +++ >> tools/objtool/Build | 2 + >> tools/objtool/Makefile | 4 +- >> tools/objtool/builtin-mcount.c | 74 +++++++++++++ >> tools/objtool/include/objtool/builtin.h | 4 +- >> tools/objtool/include/objtool/objtool.h | 1 + >> tools/objtool/mcount.c | 138 ++++++++++++++++++++++++ >> tools/objtool/objtool.c | 1 + >> tools/objtool/weak.c | 5 + >> 11 files changed, 247 insertions(+), 3 deletions(-) >> create mode 100644 tools/objtool/builtin-mcount.c >> create mode 100644 tools/objtool/mcount.c >> >> diff --git a/Makefile b/Makefile >> index 55a30ca69350..316f7d08b30a 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -846,7 +846,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC >> endif >> endif >> ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >> + ifdef CONFIG_HAVE_NOP_MCOUNT >> CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT >> + endif >> endif >> ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT >> ifdef CONFIG_HAVE_C_RECORDMCOUNT >> @@ -1303,6 +1305,10 @@ ifdef CONFIG_STACK_VALIDATION >> prepare: tools/objtool >> endif >> >> +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >> +prepare: tools/objtool >> +endif > > I don't think that will work for powerpc. > > See arch/powerpc/Makefile > > powerpc builds the VDSO under prepare: , and powerpc has > CONFIG_HAVE_GENERIC_VDSO so there are some C files in that step that > seem to use objtool, allthough that looks odd to me. Must be something > to fix somewhere. > > powerpc64-linux-gcc > -Wp,-MMD,arch/powerpc/kernel/vdso/.vgettimeofday-64.o.d -nostdinc > -I./arch/powerpc/include -I./arch/powerpc/include/generated -I./include > -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi > -I./include/uapi -I./include/generated/uapi -include > ./include/linux/compiler-version.h -include ./include/linux/kconfig.h > -include ./include/linux/compiler_types.h -D__KERNEL__ -I ./arch/powerpc > -DHAVE_AS_ATHIGH=1 -fmacro-prefix-map=./= -Wall -Wundef > -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing > -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration > -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 > -mbig-endian -m64 -msoft-float -pipe -mtraceback=no -mabi=elfv1 > -mcall-aixdesc -mcmodel=medium -mno-pointers-to-nested-functions > -mtune=power7 -mcpu=power5 -mno-altivec -mno-vsx > -fno-asynchronous-unwind-tables -mno-string -Wa,-maltivec -Wa,-mpower4 > -Wa,-many -mabi=elfv1 -mcall-aixdesc -mbig-endian > -mstack-protector-guard=tls -mstack-protector-guard-reg=r13 > -fno-delete-null-pointer-checks -Wno-frame-address > -Wno-format-truncation -Wno-format-overflow > -Wno-address-of-packed-member -O2 -fno-allow-store-data-races > -Wframe-larger-than=2048 -fstack-protector-strong > -Wimplicit-fallthrough=5 -Wno-main -Wno-unused-but-set-variable > -Wno-unused-const-variable -fno-stack-clash-protection > -Wdeclaration-after-statement -Wvla -Wno-pointer-sign > -Wcast-function-type -Wno-stringop-truncation -Wno-zero-length-bounds > -Wno-array-bounds -Wno-stringop-overflow -Wno-restrict > -Wno-maybe-uninitialized -Wno-alloc-size-larger-than > -fno-strict-overflow -fno-stack-check -fconserve-stack -Werror=date-time > -Werror=incompatible-pointer-types -Werror=designated-init > -Wno-packed-not-aligned -mstack-protector-guard-offset=3200 -shared > -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both -include > /home/chleroy/linux-powerpc/lib/vdso/gettimeofday.c -fno-stack-protector > -DDISABLE_BRANCH_PROFILING -ffreestanding -fasynchronous-unwind-tables > -ffixed-r30 > -DKBUILD_MODFILE='"arch/powerpc/kernel/vdso/vgettimeofday-64"' > -DKBUILD_BASENAME='"vgettimeofday_64"' > -DKBUILD_MODNAME='"vgettimeofday_64"' > -D__KBUILD_MODNAME=kmod_vgettimeofday_64 -c -o > arch/powerpc/kernel/vdso/vgettimeofday-64.o > arch/powerpc/kernel/vdso/vgettimeofday.c ; ./tools/objtool/objtool > mcount arch/powerpc/kernel/vdso/vgettimeofday-64.o We don't enable ftrace for vdso, so I suspect objtool run above will be a no-op. This needs to be confirmed, of course. - Naveen
Le 21/03/2022 à 09:19, Naveen N. Rao a écrit : > Christophe Leroy wrote: >> >> >> Le 18/03/2022 à 11:51, Sathvika Vasireddy a écrit : >>> This patch adds 'mcount' as a subcommand to objtool, and enables >>> the same for x86. objtool is built if CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >>> is selected. Additionally, architectures can select HAVE_NOP_MCOUNT >>> if they choose to nop out mcount call sites. If that config option is >>> selected, then --mnop is passed as an option to 'objtool mcount' >>> >>> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> >>> --- >>> Makefile | 6 ++ >>> arch/x86/Kconfig | 3 +- >>> scripts/Makefile.build | 12 +++ >>> tools/objtool/Build | 2 + >>> tools/objtool/Makefile | 4 +- >>> tools/objtool/builtin-mcount.c | 74 +++++++++++++ >>> tools/objtool/include/objtool/builtin.h | 4 +- >>> tools/objtool/include/objtool/objtool.h | 1 + >>> tools/objtool/mcount.c | 138 ++++++++++++++++++++++++ >>> tools/objtool/objtool.c | 1 + >>> tools/objtool/weak.c | 5 + >>> 11 files changed, 247 insertions(+), 3 deletions(-) >>> create mode 100644 tools/objtool/builtin-mcount.c >>> create mode 100644 tools/objtool/mcount.c >>> >>> diff --git a/Makefile b/Makefile >>> index 55a30ca69350..316f7d08b30a 100644 >>> --- a/Makefile >>> +++ b/Makefile >>> @@ -846,7 +846,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC >>> endif >>> endif >>> ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >>> + ifdef CONFIG_HAVE_NOP_MCOUNT >>> CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT >>> + endif >>> endif >>> ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT >>> ifdef CONFIG_HAVE_C_RECORDMCOUNT >>> @@ -1303,6 +1305,10 @@ ifdef CONFIG_STACK_VALIDATION >>> prepare: tools/objtool >>> endif >>> +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL >>> +prepare: tools/objtool >>> +endif >> >> I don't think that will work for powerpc. >> >> See arch/powerpc/Makefile >> >> powerpc builds the VDSO under prepare: , and powerpc has >> CONFIG_HAVE_GENERIC_VDSO so there are some C files in that step that >> seem to use objtool, allthough that looks odd to me. Must be something >> to fix somewhere. >> >> powerpc64-linux-gcc >> -Wp,-MMD,arch/powerpc/kernel/vdso/.vgettimeofday-64.o.d -nostdinc >> -I./arch/powerpc/include -I./arch/powerpc/include/generated >> -I./include -I./arch/powerpc/include/uapi >> -I./arch/powerpc/include/generated/uapi -I./include/uapi >> -I./include/generated/uapi -include ./include/linux/compiler-version.h >> -include ./include/linux/kconfig.h -include >> ./include/linux/compiler_types.h -D__KERNEL__ -I ./arch/powerpc >> -DHAVE_AS_ATHIGH=1 -fmacro-prefix-map=./= -Wall -Wundef >> -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing >> -fno-common -fshort-wchar -fno-PIE >> -Werror=implicit-function-declaration -Werror=implicit-int >> -Werror=return-type -Wno-format-security -std=gnu89 -mbig-endian -m64 >> -msoft-float -pipe -mtraceback=no -mabi=elfv1 -mcall-aixdesc >> -mcmodel=medium -mno-pointers-to-nested-functions -mtune=power7 >> -mcpu=power5 -mno-altivec -mno-vsx -fno-asynchronous-unwind-tables >> -mno-string -Wa,-maltivec -Wa,-mpower4 -Wa,-many -mabi=elfv1 >> -mcall-aixdesc -mbig-endian -mstack-protector-guard=tls >> -mstack-protector-guard-reg=r13 -fno-delete-null-pointer-checks >> -Wno-frame-address -Wno-format-truncation -Wno-format-overflow >> -Wno-address-of-packed-member -O2 -fno-allow-store-data-races >> -Wframe-larger-than=2048 -fstack-protector-strong >> -Wimplicit-fallthrough=5 -Wno-main -Wno-unused-but-set-variable >> -Wno-unused-const-variable -fno-stack-clash-protection >> -Wdeclaration-after-statement -Wvla -Wno-pointer-sign >> -Wcast-function-type -Wno-stringop-truncation -Wno-zero-length-bounds >> -Wno-array-bounds -Wno-stringop-overflow -Wno-restrict >> -Wno-maybe-uninitialized -Wno-alloc-size-larger-than >> -fno-strict-overflow -fno-stack-check -fconserve-stack >> -Werror=date-time -Werror=incompatible-pointer-types >> -Werror=designated-init -Wno-packed-not-aligned >> -mstack-protector-guard-offset=3200 -shared -fno-common -fno-builtin >> -nostdlib -Wl,--hash-style=both -include >> /home/chleroy/linux-powerpc/lib/vdso/gettimeofday.c >> -fno-stack-protector -DDISABLE_BRANCH_PROFILING -ffreestanding >> -fasynchronous-unwind-tables -ffixed-r30 >> -DKBUILD_MODFILE='"arch/powerpc/kernel/vdso/vgettimeofday-64"' >> -DKBUILD_BASENAME='"vgettimeofday_64"' >> -DKBUILD_MODNAME='"vgettimeofday_64"' >> -D__KBUILD_MODNAME=kmod_vgettimeofday_64 -c -o >> arch/powerpc/kernel/vdso/vgettimeofday-64.o >> arch/powerpc/kernel/vdso/vgettimeofday.c ; ./tools/objtool/objtool >> mcount arch/powerpc/kernel/vdso/vgettimeofday-64.o > > We don't enable ftrace for vdso, so I suspect objtool run above will be > a no-op. This needs to be confirmed, of course. > I just checked without the series: recordmcount isn't run for VDSO, so objtool shouldn't be run either when the series is applied. Christophe
Christophe Leroy wrote: > > > Le 21/03/2022 à 09:19, Naveen N. Rao a écrit : >> Christophe Leroy wrote: >> >> We don't enable ftrace for vdso, so I suspect objtool run above will be >> a no-op. This needs to be confirmed, of course. >> > > I just checked without the series: recordmcount isn't run for VDSO, so > objtool shouldn't be run either when the series is applied. Agree. I was only pointing out that it would be harmless, but it is good to ensure objtool is skipped for files/directories where ftrace isn't enabled. recordmcount keys off the presence of CC_FLAGS_FTRACE, and we should do the same for 'objtool --mcount'. - Naveen
diff --git a/Makefile b/Makefile index 55a30ca69350..316f7d08b30a 100644 --- a/Makefile +++ b/Makefile @@ -846,7 +846,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC endif endif ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + ifdef CONFIG_HAVE_NOP_MCOUNT CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT + endif endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT ifdef CONFIG_HAVE_C_RECORDMCOUNT @@ -1303,6 +1305,10 @@ ifdef CONFIG_STACK_VALIDATION prepare: tools/objtool endif +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL +prepare: tools/objtool +endif + ifdef CONFIG_BPF ifdef CONFIG_DEBUG_INFO_BTF prepare: tools/bpf/resolve_btfids diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9f5bd41bf660..eecfe588cd9f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -185,7 +185,8 @@ config X86 select HAVE_CONTEXT_TRACKING if X86_64 select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING select HAVE_C_RECORDMCOUNT - select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION + select HAVE_OBJTOOL_MCOUNT + select HAVE_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT select HAVE_BUILDTIME_MCOUNT_SORT select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_CONTIGUOUS diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a4b89b757287..6a09b4ba14a1 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -242,6 +242,18 @@ cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(o endif # CONFIG_STACK_VALIDATION +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + +objtool := $(objtree)/tools/objtool/objtool + +objtool_args := mcount +objtool_args += $(if $(CONFIG_HAVE_NOP_MCOUNT), --mnop) + +cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) +cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) + +endif # CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + ifdef CONFIG_LTO_CLANG # Skip objtool for LLVM bitcode diff --git a/tools/objtool/Build b/tools/objtool/Build index 161fd451241a..0b9b8bd0ee92 100644 --- a/tools/objtool/Build +++ b/tools/objtool/Build @@ -2,12 +2,14 @@ objtool-y += arch/$(SRCARCH)/ objtool-y += weak.o +objtool-$(SUBCMD_MCOUNT) += mcount.o objtool-$(SUBCMD_CHECK) += check.o objtool-$(SUBCMD_CHECK) += special.o objtool-$(SUBCMD_ORC) += check.o objtool-$(SUBCMD_ORC) += orc_gen.o objtool-$(SUBCMD_ORC) += orc_dump.o +objtool-y += builtin-mcount.o objtool-y += builtin-check.o objtool-y += builtin-orc.o objtool-y += elf.o diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile index 92ce4fce7bc7..8404cf696954 100644 --- a/tools/objtool/Makefile +++ b/tools/objtool/Makefile @@ -41,13 +41,15 @@ AWK = awk SUBCMD_CHECK := n SUBCMD_ORC := n +SUBCMD_MCOUNT := n ifeq ($(SRCARCH),x86) SUBCMD_CHECK := y SUBCMD_ORC := y + SUBCMD_MCOUNT := y endif -export SUBCMD_CHECK SUBCMD_ORC +export SUBCMD_CHECK SUBCMD_ORC SUBCMD_MCOUNT export srctree OUTPUT CFLAGS SRCARCH AWK include $(srctree)/tools/build/Makefile.include diff --git a/tools/objtool/builtin-mcount.c b/tools/objtool/builtin-mcount.c new file mode 100644 index 000000000000..f203d118cffa --- /dev/null +++ b/tools/objtool/builtin-mcount.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <subcmd/parse-options.h> +#include <string.h> +#include <stdlib.h> +#include <objtool/builtin.h> +#include <objtool/objtool.h> + +bool mnop; + +static const char * const mcount_usage[] = { + "objtool mcount [<options>] file.o", + NULL, +}; + +static const char * const env_usage[] = { + "OBJTOOL_ARGS=\"<options>\"", + NULL, +}; + +const struct option mcount_options[] = { + OPT_BOOLEAN('N', "mnop", &mnop, "nop mcount call sites"), + OPT_END(), +}; + +int cmd_parse_options_mcount(int argc, const char **argv, const char * const usage[]) +{ + const char *envv[16] = { }; + char *env; + int envc; + + env = getenv("OBJTOOL_ARGS"); + if (env) { + envv[0] = "OBJTOOL_ARGS"; + for (envc = 1; envc < ARRAY_SIZE(envv); ) { + envv[envc++] = env; + env = strchr(env, ' '); + if (!env) + break; + *env = '\0'; + env++; + } + + parse_options(envc, envv, mcount_options, env_usage, 0); + } + + argc = parse_options(argc, argv, mcount_options, usage, 0); + if (argc != 1) + usage_with_options(usage, mcount_options); + return argc; +} + +int cmd_mcount(int argc, const char **argv) +{ + const char *objname; + struct objtool_file *file; + int ret; + + argc = cmd_parse_options_mcount(argc, argv, mcount_usage); + objname = argv[0]; + + file = objtool_open_read(objname); + if (!file) + return 1; + + ret = objtool_mcount(file); + if (ret) + return ret; + + if (file->elf->changed) + return elf_write(file->elf); + + return 0; +} diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index 89ba869ed08f..d7ed6ff65729 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -9,11 +9,13 @@ extern const struct option check_options[]; extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, - validate_dup, vmlinux, mcount, noinstr, backup, sls; + validate_dup, vmlinux, mcount, noinstr, backup, sls, mnop; extern int cmd_parse_options(int argc, const char **argv, const char * const usage[]); +extern int cmd_parse_options_mcount(int argc, const char **argv, const char * const usage[]); extern int cmd_check(int argc, const char **argv); extern int cmd_orc(int argc, const char **argv); +extern int cmd_mcount(int argc, const char **argv); #endif /* _BUILTIN_H */ diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h index f99fbc6078d5..edcf28d4407c 100644 --- a/tools/objtool/include/objtool/objtool.h +++ b/tools/objtool/include/objtool/objtool.h @@ -41,5 +41,6 @@ void objtool_pv_add(struct objtool_file *file, int idx, struct symbol *func); int check(struct objtool_file *file); int orc_dump(const char *objname); int orc_create(struct objtool_file *file); +int objtool_mcount(struct objtool_file *file); #endif /* _OBJTOOL_H */ diff --git a/tools/objtool/mcount.c b/tools/objtool/mcount.c new file mode 100644 index 000000000000..fc3d215671bf --- /dev/null +++ b/tools/objtool/mcount.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <string.h> +#include <stdlib.h> +#include <sys/mman.h> + +#include <arch/elf.h> +#include <objtool/builtin.h> +#include <objtool/cfi.h> +#include <objtool/arch.h> +#include <objtool/check.h> +#include <objtool/utils.h> +#include <objtool/special.h> +#include <objtool/warn.h> + +#include <linux/objtool.h> +#include <linux/hashtable.h> +#include <linux/kernel.h> +#include <linux/static_call_types.h> + +static int classify_symbols(struct objtool_file *file) +{ + struct section *sec; + struct symbol *func; + + for_each_sec(file, sec) { + list_for_each_entry(func, &sec->symbol_list, list) { + if (func->bind != STB_GLOBAL) + continue; + if ((!strcmp(func->name, "__fentry__")) || (!strcmp(func->name, "_mcount"))) + func->fentry = true; + } + } + + return 0; +} + +static void annotate_call_site(struct objtool_file *file, + struct instruction *insn, bool sibling) +{ + struct reloc *reloc = insn_reloc(file, insn); + struct symbol *sym = insn->call_dest; + + if (!sym) + sym = reloc->sym; + + if (sym->fentry) { + if (sibling) + WARN_FUNC("Tail call to _mcount !?!?", insn->sec, insn->offset); + if (mnop) { + 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->call_node, &file->mcount_loc_list); + return; + } +} + +static void add_call_dest(struct objtool_file *file, struct instruction *insn, + struct symbol *dest, bool sibling) +{ + insn->call_dest = dest; + if (!dest) + return; + + remove_insn_ops(insn); + + annotate_call_site(file, insn, sibling); +} +static int add_call_destinations(struct objtool_file *file) +{ + struct instruction *insn; + unsigned long dest_off; + struct symbol *dest; + struct reloc *reloc; + + for_each_insn(file, insn) { + if (insn->type != INSN_CALL) + continue; + + reloc = insn_reloc(file, insn); + if (!reloc) { + dest_off = arch_jump_destination(insn); + dest = find_call_destination(insn->sec, dest_off); + + add_call_dest(file, insn, dest, false); + + + } else { + add_call_dest(file, insn, reloc->sym, false); + } + } + + return 0; +} + +static int decode_sections(struct objtool_file *file) +{ + int ret; + + ret = decode_instructions(file); + if (ret) + return ret; + + ret = classify_symbols(file); + if (ret) + return ret; + + ret = add_call_destinations(file); + if (ret) + return ret; + + return 0; +} + + +int objtool_mcount(struct objtool_file *file) +{ + int ret, warnings = 0; + + ret = decode_sections(file); + if (ret < 0) + return 0; + + ret = create_mcount_loc_sections(file); + if (ret < 0) + return 0; + warnings += ret; + return 0; +} diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c index bdf699f6552b..e19851813d5b 100644 --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -37,6 +37,7 @@ static const char objtool_usage_string[] = static struct cmd_struct objtool_cmds[] = { {"check", cmd_check, "Perform stack metadata validation on an object file" }, + {"mcount", cmd_mcount, "Generate __mcount_loc section" }, {"orc", cmd_orc, "Generate in-place ORC unwind tables for an object file" }, }; diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c index 8314e824db4a..19b2dfcacf2e 100644 --- a/tools/objtool/weak.c +++ b/tools/objtool/weak.c @@ -29,3 +29,8 @@ int __weak orc_create(struct objtool_file *file) { UNSUPPORTED("orc"); } + +int __weak objtool_mcount(struct objtool_file *file) +{ + UNSUPPORTED("mcount subcommand"); +}
This patch adds 'mcount' as a subcommand to objtool, and enables the same for x86. objtool is built if CONFIG_FTRACE_MCOUNT_USE_OBJTOOL is selected. Additionally, architectures can select HAVE_NOP_MCOUNT if they choose to nop out mcount call sites. If that config option is selected, then --mnop is passed as an option to 'objtool mcount' Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> --- Makefile | 6 ++ arch/x86/Kconfig | 3 +- scripts/Makefile.build | 12 +++ tools/objtool/Build | 2 + tools/objtool/Makefile | 4 +- tools/objtool/builtin-mcount.c | 74 +++++++++++++ tools/objtool/include/objtool/builtin.h | 4 +- tools/objtool/include/objtool/objtool.h | 1 + tools/objtool/mcount.c | 138 ++++++++++++++++++++++++ tools/objtool/objtool.c | 1 + tools/objtool/weak.c | 5 + 11 files changed, 247 insertions(+), 3 deletions(-) create mode 100644 tools/objtool/builtin-mcount.c create mode 100644 tools/objtool/mcount.c