Messages in this thread | | | Date | Mon, 21 Mar 2022 13:49:28 +0530 | From | "Naveen N. Rao" <> | Subject | Re: [RFC PATCH 2/3] objtool: Enable and implement 'mcount' subcommand |
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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
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