Re: [RFC PATCH 2/3] objtool: Enable and implement 'mcount' subcommand
From: Christophe Leroy <hidden>
Date: 2022-03-21 07:06:22
Also in:
lkml
Le 18/03/2022 à 11:51, Sathvika Vasireddy a écrit :
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.cdiff --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