linux-dev/arch/powerpc/kernel/vdso32/Makefile, branch master

powerpc/vdso: Merge vdso64 and vdso32 into a single directory

2022-02-12T11:47:43Z

merge vdso64 into vdso32 and rename it vdso. Reported-by: kernel test robot Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/4dbe05cc130f6a0858d09ac72e436c373cb08b70.1642782130.git.christophe.leroy@csgroup.eu

powerpc/vdso: Rework VDSO32 makefile to add a prefix to object files

2022-02-12T11:47:43Z

In order to merge vdso32 and vdso64 build in following patch, rework Makefile is order to add -32 suffix to VDSO32 object files. Also change sigtramp.S to sigtramp32.S as VDSO64 sigtramp.S is too different to be squashed into VDSO32 sigtramp.S at the first place. gen_vdso_offsets.sh also becomes gen_vdso32_offsets.sh Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0c421b704a57b228e75a891512568339c53667ad.1642782130.git.christophe.leroy@csgroup.eu

powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o

2021-01-30T11:23:42Z

vgettimeofday.o is unnecessarily rebuilt. Adding it to 'targets' is not enough to fix the issue. Kbuild is correctly rebuilding it because the command line is changed. PowerPC builds each vdso directory twice; first in vdso_prepare to generate vdso{32,64}-offsets.h, second as part of the ordinary build process to embed vdso{32,64}.so.dbg into the kernel. The problem shows up when CONFIG_PPC_WERROR=y due to the following line in arch/powerpc/Kbuild: subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror In the preparation stage, Kbuild directly visits the vdso directories, hence it does not inherit subdir-ccflags-y. In the second descend, Kbuild adds -Werror, which results in the command line flipping with/without -Werror. It implies a potential danger; if a more critical flag that would impact the resulted vdso, the offsets recorded in the headers might be different from real offsets in the embedded vdso images. Removing the unneeded second descend solves the problem. Reported-by: Michael Ellerman Signed-off-by: Masahiro Yamada Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/linuxppc-dev/87tuslxhry.fsf@mpe.ellerman.id.au/ Link: https://lore.kernel.org/r/20201223171142.707053-1-masahiroy@kernel.org

powerpc/vdso: Don't pass 64-bit ABI cflags to 32-bit VDSO

2020-12-21T11:06:26Z

When building the 32-bit VDSO, we are building 32-bit code as part of a 64-bit kernel build. That requires us to tweak the cflags to trick the compiler into building 32-bit code for us. The main way we do that is by passing -m32, but there are other options that affect code generation and ABI selection. In particular when building vgettimeofday.c, we end up passing -mcall-aixdesc because it's in KBUILD_CFLAGS, which causes the compiler to generate function descriptors, and dot symbols, eg: $ nm arch/powerpc/kernel/vdso32/vgettimeofday.o 000005d0 T .__c_kernel_clock_getres 00000024 D __c_kernel_clock_getres ... We get away with that at the moment because we also use the DOTSYM macro, and that is also incorrectly prepending a '.' in 32-bit VDSO code due to a separate bug. But we shouldn't be generating function descriptors for this file, there's no 32-bit ABI that includes function descriptors, so the resulting object file is some frankenstein and it's surprising that it even links. So filter out all the ABI-related options we add to CFLAGS for 64-bit builds, so that they're not used when building 32-bit code. With that we only see regular text symbols: $ nm arch/powerpc/kernel/vdso32/vgettimeofday.o michael@alpine1-p1 000005d0 T __c_kernel_clock_getres 00000000 T __c_kernel_clock_gettime 00000200 T __c_kernel_clock_gettime64 00000410 T __c_kernel_gettimeofday 00000650 T __c_kernel_time Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.") Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201218111619.1206391-2-mpe@ellerman.id.au

powerpc/vdso: Block R_PPC_REL24 relocations

2020-12-21T11:06:25Z

Add R_PPC_REL24 relocations to the list of relocations we do NOT support in the VDSO. These are generated in some cases and we do not support relocating them at runtime, so if they appear then the VDSO will not work at runtime, therefore it's preferable to break the build if we see them. Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.") Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201218111619.1206391-1-mpe@ellerman.id.au

powerpc/vdso: Retrieve sigtramp offsets at buildtime

2020-12-03T14:01:17Z

This is copied from arm64. Instead of using runtime generated signal trampoline offsets, get offsets at buildtime. If the said trampoline doesn't exist, build will fail. So no need to check whether the trampoline exists or not in the VDSO. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f8bfd6812c3e3678b1cdb4d55a52f9eb022b40d3.1601197618.git.christophe.leroy@csgroup.eu

powerpc/vdso: Stripped VDSO is not needed, don't build it

2020-12-03T14:01:15Z

Since commit 24b659a13866 ("powerpc: Use unstripped VDSO image for more accurate profiling data"), only the unstripped VDSO image has been used. Partially revert commit 8150caad0226 ("[POWERPC] powerpc vDSO: install unstripped copies on disk") to avoid building the stripped version. And the unstripped version in $(MODLIB)/vdso/ is not required anymore as it is the one embedded in the kernel image. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/5986ca25be44fe6e9790486304507f240077d8c4.1601197618.git.christophe.leroy@csgroup.eu

powerpc/vdso: Switch VDSO to generic C implementation.

2020-12-03T14:01:10Z

With the C VDSO, the performance is slightly lower, but it is worth it as it will ease maintenance and evolution, and also brings clocks that are not supported with the ASM VDSO. On an 8xx at 132 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 828 nsec/call clock-getres-realtime-coarse: vdso: 391 nsec/call clock-gettime-realtime-coarse: vdso: 614 nsec/call clock-getres-realtime: vdso: 460 nsec/call clock-gettime-realtime: vdso: 876 nsec/call clock-getres-monotonic-coarse: vdso: 399 nsec/call clock-gettime-monotonic-coarse: vdso: 691 nsec/call clock-getres-monotonic: vdso: 460 nsec/call clock-gettime-monotonic: vdso: 1026 nsec/call On an 8xx at 132 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 955 nsec/call clock-getres-realtime-coarse: vdso: 545 nsec/call clock-gettime-realtime-coarse: vdso: 592 nsec/call clock-getres-realtime: vdso: 545 nsec/call clock-gettime-realtime: vdso: 941 nsec/call clock-getres-monotonic-coarse: vdso: 545 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call clock-getres-monotonic: vdso: 545 nsec/call clock-gettime-monotonic: vdso: 940 nsec/call It is even better for gettime with monotonic clocks. Unsupported clocks with ASM VDSO: clock-gettime-boottime: vdso: 3851 nsec/call clock-gettime-tai: vdso: 3852 nsec/call clock-gettime-monotonic-raw: vdso: 3396 nsec/call Same clocks with C VDSO: clock-gettime-tai: vdso: 941 nsec/call clock-gettime-monotonic-raw: vdso: 1001 nsec/call clock-gettime-monotonic-coarse: vdso: 591 nsec/call On an 8321E at 333 MHz, vdsotest with the ASM VDSO: gettimeofday: vdso: 220 nsec/call clock-getres-realtime-coarse: vdso: 102 nsec/call clock-gettime-realtime-coarse: vdso: 178 nsec/call clock-getres-realtime: vdso: 129 nsec/call clock-gettime-realtime: vdso: 235 nsec/call clock-getres-monotonic-coarse: vdso: 105 nsec/call clock-gettime-monotonic-coarse: vdso: 208 nsec/call clock-getres-monotonic: vdso: 129 nsec/call clock-gettime-monotonic: vdso: 274 nsec/call On an 8321E at 333 MHz, vdsotest with the C VDSO: gettimeofday: vdso: 272 nsec/call clock-getres-realtime-coarse: vdso: 160 nsec/call clock-gettime-realtime-coarse: vdso: 184 nsec/call clock-getres-realtime: vdso: 166 nsec/call clock-gettime-realtime: vdso: 281 nsec/call clock-getres-monotonic-coarse: vdso: 160 nsec/call clock-gettime-monotonic-coarse: vdso: 184 nsec/call clock-getres-monotonic: vdso: 169 nsec/call clock-gettime-monotonic: vdso: 275 nsec/call On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO: clock-gettime-monotonic: vdso: 35 nsec/call clock-getres-monotonic: vdso: 16 nsec/call clock-gettime-monotonic-coarse: vdso: 18 nsec/call clock-getres-monotonic-coarse: vdso: 522 nsec/call clock-gettime-monotonic-raw: vdso: 598 nsec/call clock-getres-monotonic-raw: vdso: 520 nsec/call clock-gettime-realtime: vdso: 34 nsec/call clock-getres-realtime: vdso: 16 nsec/call clock-gettime-realtime-coarse: vdso: 18 nsec/call clock-getres-realtime-coarse: vdso: 517 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 25 nsec/call And with the C VDSO: clock-gettime-monotonic: vdso: 37 nsec/call clock-getres-monotonic: vdso: 20 nsec/call clock-gettime-monotonic-coarse: vdso: 21 nsec/call clock-getres-monotonic-coarse: vdso: 19 nsec/call clock-gettime-monotonic-raw: vdso: 38 nsec/call clock-getres-monotonic-raw: vdso: 20 nsec/call clock-gettime-realtime: vdso: 37 nsec/call clock-getres-realtime: vdso: 20 nsec/call clock-gettime-realtime-coarse: vdso: 20 nsec/call clock-getres-realtime-coarse: vdso: 19 nsec/call getcpu: vdso: 8 nsec/call gettimeofday: vdso: 28 nsec/call Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au

Merge tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2020-10-22T20:13:57Z

Pull Kbuild updates from Masahiro Yamada: - Support 'make compile_commands.json' to generate the compilation database more easily, avoiding stale entries - Support 'make clang-analyzer' and 'make clang-tidy' for static checks using clang-tidy - Preprocess scripts/modules.lds.S to allow CONFIG options in the module linker script - Drop cc-option tests from compiler flags supported by our minimal GCC/Clang versions - Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y - Use sha1 build id for both BFD linker and LLD - Improve deb-pkg for reproducible builds and rootless builds - Remove stale, useless scripts/namespace.pl - Turn -Wreturn-type warning into error - Fix build error of deb-pkg when CONFIG_MODULES=n - Replace 'hostname' command with more portable 'uname -n' - Various Makefile cleanups * tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) kbuild: Use uname for LINUX_COMPILE_HOST detection kbuild: Only add -fno-var-tracking-assignments for old GCC versions kbuild: remove leftover comment for filechk utility treewide: remove DISABLE_LTO kbuild: deb-pkg: clean up package name variables kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n kbuild: enforce -Werror=return-type scripts: remove namespace.pl builddeb: Add support for all required debian/rules targets builddeb: Enable rootless builds builddeb: Pass -n to gzip for reproducible packages kbuild: split the build log of kallsyms kbuild: explicitly specify the build id style scripts/setlocalversion: make git describe output more reliable kbuild: remove cc-option test of -Werror=date-time kbuild: remove cc-option test of -fno-stack-check kbuild: remove cc-option test of -fno-strict-overflow kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan kbuild: do not create built-in objects for external module builds ...

arch: vdso: add vdso linker script to 'targets' instead of extra-y

2020-09-07T12:41:27Z

The vdso linker script is preprocessed on demand. Adding it to 'targets' is enough to include the .cmd file. Signed-off-by: Masahiro Yamada Acked-by: Catalin Marinas Acked-by: Greentime Hu