| 7f7f6f7a | 06-May-2024 |
Masahiro Yamada <[email protected]> |
Makefile: remove redundant tool coverage variables
Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.
Remove redundant variables.
Note:
This commit changes the covera
Makefile: remove redundant tool coverage variables
Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.
Remove redundant variables.
Note:
This commit changes the coverage for some objects:
- include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
- include arch/sparc/vdso/vdso-image-*.o into UBSAN
- include arch/sparc/vdso/vma.o into UBSAN
- include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
- include arch/x86/entry/vdso/vma.o into GCOV, KCOV
- include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
I believe these are positive effects because all of them are kernel
space objects.
Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Tested-by: Roberto Sassu <[email protected]>
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| 22235ef3 | 28-Apr-2020 |
Nathan Chancellor <[email protected]> |
MIPS: VDSO: Allow ld.lld to link the VDSO
Currently, when linking with ld.lld, this warning pops up:
arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25
CONFIG_LD_VERSION is set wi
MIPS: VDSO: Allow ld.lld to link the VDSO
Currently, when linking with ld.lld, this warning pops up:
arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25
CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific
to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does
not set.
ld.lld has a completely different versioning scheme (as it follows
LLVM's versioning) and it does not have the issue mentioned in the
comment block so it should be allowed to link the VDSO.
With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.
$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
00000024: R_MIPS_PC32 _start
000000b0: R_MIPS_PC32 _start
000002bc: R_MIPS_PC32 _start
0000036c: R_MIPS_PC32 _start
00000468: R_MIPS_PC32 _start
Reported-by: Dmitry Golovin <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/785
Link: https://github.com/llvm/llvm-project/commit/e364e2e9ce50c12eb2bf093560e1a1a8544d455a
Signed-off-by: Thomas Bogendoerfer <[email protected]>
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|
| 2ff90699 | 28-Apr-2020 |
Nathan Chancellor <[email protected]> |
MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO
Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variab
MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO
Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.
When clang is built in a default configuration, it first attempts to use
the target triple's default linker then the system's default linker,
unless told otherwise through -fuse-ld=... We do not use -fuse-ld=
because it can be brittle and we have support for invoking $(LD)
directly. See commit fe00e50b2db8c ("ARM: 8858/1: vdso: use $(LD)
instead of $(CC) to link VDSO") and commit 691efbedc60d2 ("arm64: vdso:
use $(LD) instead of $(CC) to link VDSO") for examples of doing this in
the VDSO.
Do the same thing here. Replace the custom linking logic with $(cmd_ld)
and ldflags-y so that $(LD) is respected. We need to explicitly add two
flags to the linker that were implicitly passed by the compiler:
-G 0 (which comes from ccflags-vdso) and --eh-frame-hdr.
Before this patch (generated by adding '-v' to VDSO_LDFLAGS):
<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \
-plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \
-plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \
-plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \
--eh-frame-hdr \
-G 0 \
-EB \
-mips64r2 \
-shared \
-melf64btsmip \
-o arch/mips/vdso/vdso.so.dbg.raw \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \
-L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \
-Bsymbolic \
--no-undefined \
-soname=linux-vdso.so.1 \
-EB \
--hash-style=sysv \
--build-id \
-T arch/mips/vdso/vdso.lds \
arch/mips/vdso/elf.o \
arch/mips/vdso/vgettimeofday.o \
arch/mips/vdso/sigreturn.o
After this patch:
<gcc_prefix>/bin/mips64-linux-ld \
-m elf64btsmip \
-Bsymbolic \
--no-undefined \
-soname=linux-vdso.so.1 \
-EB \
-nostdlib \
-shared \
-G 0 \
--eh-frame-hdr \
--hash-style=sysv \
--build-id \
-T arch/mips/vdso/vdso.lds \
arch/mips/vdso/elf.o \
arch/mips/vdso/vgettimeofday.o
arch/mips/vdso/sigreturn.o \
-o arch/mips/vdso/vdso.so.dbg.raw
Note that we leave behind -mips64r2. Turns out that ld ignores it (see
get_emulation in ld/ldmain.c). This is true of current trunk and 2.23,
which is the minimum supported version for the kernel:
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641
Before this patch, LD=ld.lld did nothing:
$ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//'
String dump of section '.comment':
[ 0] ClangBuiltLinux clang version 11.0.0
After this patch, it does:
$ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//'
String dump of section '.comment':
[ 0] Linker: LLD 11.0.0
[ 62] ClangBuiltLinux clang version 11.0.0
Link: https://github.com/ClangBuiltLinux/linux/issues/785
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
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| 72cf3b3d | 17-Feb-2020 |
Nathan Chancellor <[email protected]> |
MIPS: vdso: Wrap -mexplicit-relocs in cc-option
Clang does not support this option and errors out:
clang-11: error: unknown argument: '-mexplicit-relocs'
Clang does not appear to need this flag li
MIPS: vdso: Wrap -mexplicit-relocs in cc-option
Clang does not support this option and errors out:
clang-11: error: unknown argument: '-mexplicit-relocs'
Clang does not appear to need this flag like GCC does because the jalr
check that was added in commit 976c23af3ee5 ("mips: vdso: add build
time check that no 'jalr t9' calls left") passes just fine with
$ make ARCH=mips CC=clang CROSS_COMPILE=mipsel-linux-gnu- malta_defconfig arch/mips/vdso/
even before commit d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in
vdso code").
-mrelax-pic-calls has been supported since clang 9, which is the
earliest version that could build a working MIPS kernel, and it is the
default for clang so just leave it be.
Fixes: d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code")
Link: https://github.com/ClangBuiltLinux/linux/issues/890
Signed-off-by: Nathan Chancellor <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Tested-by: Nick Desaulniers <[email protected]>
Signed-off-by: Paul Burton <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
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