kernel.git/arch/powerpc/kernel/vdso, branch linux-6.1.y

powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang

2024-12-14T18:54:25Z

[ Upstream commit d677ce521334d8f1f327cafc8b1b7854b0833158 ] Under certain conditions, the 64-bit '-mstack-protector-guard' flags may end up in the 32-bit vDSO flags, resulting in build failures due to the structure of clang's argument parsing of the stack protector options, which validates the arguments of the stack protector guard flags unconditionally in the frontend, choking on the 64-bit values when targeting 32-bit: clang: error: invalid value 'r13' in 'mstack-protector-guard-reg=', expected one of: r2 clang: error: invalid value 'r13' in 'mstack-protector-guard-reg=', expected one of: r2 make[3]: *** [arch/powerpc/kernel/vdso/Makefile:85: arch/powerpc/kernel/vdso/vgettimeofday-32.o] Error 1 make[3]: *** [arch/powerpc/kernel/vdso/Makefile:87: arch/powerpc/kernel/vdso/vgetrandom-32.o] Error 1 Remove these flags by adding them to the CC32FLAGSREMOVE variable, which already handles situations similar to this. Additionally, reformat and align a comment better for the expanding CONFIG_CC_IS_CLANG block. Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/20241030-powerpc-vdso-drop-stackp-flags-clang-v1-1-d95e7376d29c@kernel.org Signed-off-by: Sasha Levin

powerpc/vdso: Refactor CFLAGS for CVDSO build

2024-12-14T18:54:25Z

[ Upstream commit a6b67eb09963af29991625862cbb4f56b85954ed ] In order to avoid two much duplication when we add new VDSO functionnalities in C like getrandom, refactor common CFLAGS. Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman Signed-off-by: Jason A. Donenfeld Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Include CLANG_FLAGS explicitly in ldflags-y

2024-12-14T18:54:25Z

[ Upstream commit a7e5eb53bf9b800d086e2ebcfebd9a3bb16bd1b0 ] A future change will move CLANG_FLAGS from KBUILD_{A,C}FLAGS to KBUILD_CPPFLAGS so that '--target' is available while preprocessing. When that occurs, the following error appears when building the compat PowerPC vDSO: clang: error: unsupported option '-mbig-endian' for target 'x86_64-pc-linux-gnu' make[3]: *** [.../arch/powerpc/kernel/vdso/Makefile:76: arch/powerpc/kernel/vdso/vdso32.so.dbg] Error 1 Explicitly add CLANG_FLAGS to ldflags-y, so that '--target' will always be present. Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang

2024-12-14T18:54:25Z

[ Upstream commit 05e05bfc92d196669a3d087fc34d3998b6ddb758 ] When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it warns: clang-16: error: argument unused during compilation: '-fno-stack-clash-protection' [-Werror,-Wunused-command-line-argument] This warning happens because vgettimeofday-32.c gets its base CFLAGS from the main kernel, which may contain flags that are only supported on a 64-bit target but not a 32-bit one, which is the case here. -fstack-clash-protection and its negation are only suppported by the 64-bit powerpc target but that flag is included in an invocation for a 32-bit powerpc target, so clang points out that while the flag is one that it recognizes, it is not actually used by this compiler job. To eliminate the warning, remove -fno-stack-clash-protection from vgettimeofday-32.c's CFLAGS when using clang, as has been done for other flags previously. Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Linux Kernel Functional Testing Tested-by: Anders Roxell Signed-off-by: Masahiro Yamada Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Improve linker flags

2024-12-14T18:54:25Z

[ Upstream commit f0a42fbab447ed9f55bbd99751183e71f3a1f6ec ] When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, there are several warnings in the PowerPC vDSO: clang-16: error: -Wl,-soname=linux-vdso32.so.1: 'linker' input unused [-Werror,-Wunused-command-line-argument] clang-16: error: -Wl,--hash-style=both: 'linker' input unused [-Werror,-Wunused-command-line-argument] clang-16: error: argument unused during compilation: '-shared' [-Werror,-Wunused-command-line-argument] clang-16: error: argument unused during compilation: '-nostdinc' [-Werror,-Wunused-command-line-argument] clang-16: error: argument unused during compilation: '-Wa,-maltivec' [-Werror,-Wunused-command-line-argument] The first group of warnings point out that linker flags were being added to all invocations of $(CC), even though they will only be used during the final vDSO link. Move those flags to ldflags-y. The second group of warnings are compiler or assembler flags that will be unused during linking. Filter them out from KBUILD_CFLAGS so that they are not used during linking. Additionally, '-z noexecstack' was added directly to the ld_and_check rule in commit 1d53c0192b15 ("powerpc/vdso: link with -z noexecstack") but now that there is a common ldflags variable, it can be moved there. Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Linux Kernel Functional Testing Tested-by: Anders Roxell Signed-off-by: Masahiro Yamada Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Remove unused '-s' flag from ASFLAGS

2024-12-14T18:54:25Z

[ Upstream commit 024734d132846dcb27f07deb1ec5be64d4cbfae9 ] When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it warns: clang-16: error: argument unused during compilation: '-s' [-Werror,-Wunused-command-line-argument] The compiler's '-s' flag is a linking option (it is passed along to the linker directly), which means it does nothing when the linker is not invoked by the compiler. The kernel builds all .o files with '-c', which stops the compilation pipeline before linking, so '-s' can be safely dropped from ASFLAGS. Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Reviewed-by: Segher Boessenkool Tested-by: Linux Kernel Functional Testing Tested-by: Anders Roxell Acked-by: Michael Ellerman Signed-off-by: Masahiro Yamada Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Skip objtool from running on VDSO files

2024-12-14T18:54:25Z

[ Upstream commit d0160bd5d389da247fb5affb6a35ea393d22fedb ] Do not run objtool on VDSO files, by using OBJECT_FILES_NON_STANDARD. Suggested-by: Christophe Leroy Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Reviewed-by: Christophe Leroy Acked-by: Josh Poimboeuf Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-8-sv@linux.ibm.com Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin

powerpc/vdso: Fix VDSO data access when running in a non-root time namespace

2024-10-17T13:21:49Z

[ Upstream commit c73049389e58c01e2e3bbfae900c8daeee177191 ] When running in a non-root time namespace, the global VDSO data page is replaced by a dedicated namespace data page and the global data page is mapped next to it. Detailed explanations can be found at commit 660fd04f9317 ("lib/vdso: Prepare for time namespace support"). When it happens, __kernel_get_syscall_map and __kernel_get_tbfreq and __kernel_sync_dicache don't work anymore because they read 0 instead of the data they need. To address that, clock_mode has to be read. When it is set to VDSO_CLOCKMODE_TIMENS, it means it is a dedicated namespace data page and the global data is located on the following page. Add a macro called get_realdatapage which reads clock_mode and add PAGE_SIZE to the pointer provided by get_datapage macro when clock_mode is equal to VDSO_CLOCKMODE_TIMENS. Use this new macro instead of get_datapage macro except for time functions as they handle it internally. Fixes: 74205b3fc2ef ("powerpc/vdso: Add support for time namespaces") Reported-by: Jason A. Donenfeld Closes: https://lore.kernel.org/all/ZtnYqZI-nrsNslwy@zx2c4.com/ Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman Signed-off-by: Jason A. Donenfeld Signed-off-by: Sasha Levin

powerpc: Drops STABS_DEBUG from linker scripts

2022-09-30T08:35:52Z

No toolchain we support should be generating stabs debug information anymore. Drop the sections entirely from our linker scripts. We removed all the manual stabs annotations in commit 12318163737c ("powerpc/32: Remove remaining .stabs annotations"). Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220928130951.1732983-1-mpe@ellerman.id.au

powerpc/vdso: link with -z noexecstack

2022-09-05T07:28:25Z

With recent binutils, the following warning appears: VDSO32L arch/powerpc/kernel/vdso/vdso32.so.dbg /opt/gcc-12.2.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/12.2.0/../../../../powerpc64-linux/bin/ld: warning: arch/powerpc/kernel/vdso/getcpu-32.o: missing .note.GNU-stack section implies executable stack /opt/gcc-12.2.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/12.2.0/../../../../powerpc64-linux/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker To avoid that, explicitly tell the linker we don't want executable stack. For more explanations, see commit ffcf9c5700e4 ("x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/b95f2e3216a574837dd61208444e9515c3423da4.1662132312.git.christophe.leroy@csgroup.eu