linux-dev/arch/arm64/kernel/vdso32/Makefile, branch master

arm64: vdso32: enable orphan handling for VDSO

2022-06-23T14:34:59Z

Like vmlinux, enable orphan-handling for the compat VDSO32. This can catch subtle errors that might arise from unexpected sections being included. Signed-off-by: Joey Gouly Cc: Catalin Marinas Cc: Will Deacon Cc: Masahiro Yamada Cc: Vincenzo Frascino Cc: Kees Cook Reviewed-by: Kees Cook Reviewed-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20220510095834.32394-5-joey.gouly@arm.com Signed-off-by: Will Deacon

arm64: vdso: fix makefile dependency on vdso.so

2022-05-10T11:08:40Z

There is currently no dependency for vdso*-wrap.S on vdso*.so, which means that you can get a build that uses a stale vdso*-wrap.o. In commit a5b8ca97fbf8, the file that includes the vdso.so was moved and renamed from arch/arm64/kernel/vdso/vdso.S to arch/arm64/kernel/vdso-wrap.S, when this happened the Makefile was not updated to force the dependcy on vdso.so. Fixes: a5b8ca97fbf8 ("arm64: do not descend to vdso directories twice") Signed-off-by: Joey Gouly Cc: Masahiro Yamada Cc: Vincenzo Frascino Cc: Catalin Marinas Cc: Will Deacon Link: https://lore.kernel.org/r/20220510102721.50811-1-joey.gouly@arm.com Signed-off-by: Will Deacon

Kbuild: move to -std=gnu11

2022-03-13T08:31:37Z

During a patch discussion, Linus brought up the option of changing the C standard version from gnu89 to gnu99, which allows using variable declaration inside of a for() loop. While the C99, C11 and later standards introduce many other features, most of these are already available in gnu89 as GNU extensions as well. An earlier attempt to do this when gcc-5 started defaulting to -std=gnu11 failed because at the time that caused warnings about designated initializers with older compilers. Now that gcc-5.1 is the minimum compiler version used for building kernels, that is no longer a concern. Similarly, the behavior of 'inline' functions changes between gnu89 using gnu_inline behavior and gnu11 using standard c99+ behavior, but this was taken care of by defining 'inline' to include __attribute__((gnu_inline)) in order to allow building with clang a while ago. Nathan Chancellor reported a new -Wdeclaration-after-statement warning that appears in a system header on arm, this still needs a workaround. The differences between gnu99, gnu11, gnu1x and gnu17 are fairly minimal and mainly impact warnings at the -Wpedantic level that the kernel never enables. Between these, gnu11 is the newest version that is supported by all supported compiler versions, though it is only the default on gcc-5, while all other supported versions of gcc or clang default to gnu1x/gnu17. Link: https://lore.kernel.org/lkml/CAHk-=wiyCH7xeHcmiFJ-YgXUy2Jaj7pnkdKpcovt8fYbVFW3TA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1603 Suggested-by: Linus Torvalds Acked-by: Marco Elver Acked-by: Jani Nikula Acked-by: David Sterba Tested-by: Sedat Dilek Reviewed-by: Alex Shi Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

Kbuild: use -Wdeclaration-after-statement

2022-03-13T08:31:10Z

The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting the use of additional C11 features such as for-loop initial declarations. One contentious aspect of C99 is that it permits mixed declarations and code, and for now at least, it seems preferable to enforce that declarations must come first. These warnings were already enabled in the kernel itself, but not for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses a separate set of CFLAGS. This patch fixes an existing violation in modpost.c, which is not reported because of the missing flag in KBUILD_USERCFLAGS: | scripts/mod/modpost.c: In function ‘match’: | scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] | 837 | const char *endp = p + strlen(p) - 1; | | ^~~~~ Signed-off-by: Mark Rutland [arnd: don't add a duplicate flag to the default set, update changelog] Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) Signed-off-by: Masahiro Yamada

arm64: vdso: remove -nostdlib compiler flag

2021-11-08T10:02:57Z

The -nostdlib option requests the compiler to not use the standard system startup files or libraries when linking. It is effective only when $(CC) is used as a linker driver. Since commit 691efbedc60d ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO"), $(LD) is directly used, hence -nostdlib is unneeded. Signed-off-by: Masahiro Yamada Link: https://lore.kernel.org/r/20211107161802.323125-1-masahiroy@kernel.org Signed-off-by: Will Deacon

arm64: vdso32: require CROSS_COMPILE_COMPAT for gcc+bfd

2021-10-21T09:31:39Z

Similar to commit 231ad7f409f1 ("Makefile: infer --target from ARCH for CC=clang") There really is no point in setting --target based on $CROSS_COMPILE_COMPAT for clang when the integrated assembler is being used, since commit ef94340583ee ("arm64: vdso32: drop -no-integrated-as flag"). Allows COMPAT_VDSO to be selected without setting $CROSS_COMPILE_COMPAT when using clang and lld together. Before: $ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y $ ARCH=arm64 make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config $ After: $ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y $ ARCH=arm64 make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y Reviewed-by: Nathan Chancellor Suggested-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20211019223646.1146945-5-ndesaulniers@google.com Signed-off-by: Will Deacon

arm64: vdso32: suppress error message for 'make mrproper'

2021-10-21T09:31:39Z

When running the following command without arm-linux-gnueabi-gcc in one's $PATH, the following warning is observed: $ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 mrproper make[1]: arm-linux-gnueabi-gcc: No such file or directory This is because KCONFIG is not run for mrproper, so CONFIG_CC_IS_CLANG is not set, and we end up eagerly evaluating various variables that try to invoke CC_COMPAT. This is a similar problem to what was observed in commit dc960bfeedb0 ("h8300: suppress error messages for 'make clean'") Reported-by: Lucas Henneman Suggested-by: Masahiro Yamada Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Link: https://lore.kernel.org/r/20211019223646.1146945-4-ndesaulniers@google.com Signed-off-by: Will Deacon

arm64: vdso32: drop test for -march=armv8-a

2021-10-21T09:31:38Z

As Arnd points out: gcc-4.8 already supported -march=armv8, and we require gcc-5.1 now, so both this #if/#else construct and the corresponding "cc32-option,-march=armv8-a" check should be obsolete now. Link: https://lore.kernel.org/lkml/CAK8P3a3UBEJ0Py2ycz=rHfgog8g3mCOeQOwO0Gmp-iz6Uxkapg@mail.gmail.com/ Suggested-by: Arnd Bergmann Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20211019223646.1146945-3-ndesaulniers@google.com Signed-off-by: Will Deacon

arm64: vdso32: drop the test for dmb ishld

2021-10-21T09:31:38Z

Binutils added support for this instruction in commit e797f7e0b2bedc9328d4a9a0ebc63ca7a2dbbebc which shipped in 2.24 (just missing the 2.23 release) but was cherry-picked into 2.23 in commit 27a50d6755bae906bc73b4ec1a8b448467f0bea1. Thanks to Christian and Simon for helping me with the patch archaeology. According to Documentation/process/changes.rst, the minimum supported version of binutils is 2.23. Since all supported versions of GAS support this instruction, drop the assembler invocation, preprocessor flags/guards, and the cross assembler macro that's now unused. This also avoids a recursive self reference in a follow up cleanup patch. Cc: Christian Biesinger Cc: Simon Marchi Signed-off-by: Nick Desaulniers Reviewed-by: Vincenzo Frascino Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20211019223646.1146945-2-ndesaulniers@google.com Signed-off-by: Will Deacon

arm64: vdso32: drop -no-integrated-as flag

2021-04-23T13:17:50Z

Clang can assemble these files just fine; this is a relic from the top level Makefile conditionally adding this. We no longer need --prefix, --gcc-toolchain, or -Qunused-arguments flags either with this change, so remove those too. To test building: $ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \ CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make LLVM=1 LLVM_IAS=1 \ defconfig arch/arm64/kernel/vdso32/ Suggested-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Reviewed-by: Vincenzo Frascino Tested-by: Stephen Boyd Acked-by: Will Deacon Link: https://lore.kernel.org/r/20210420174427.230228-1-ndesaulniers@google.com Signed-off-by: Catalin Marinas