kernel/linux.git/arch/powerpc/Makefile, branch v5.15.208

powerpc: remove checks for binutils older than 2.25

2024-01-25T22:52:32+00:00

[ Upstream commit 54a11654de163994e32b24e3aa90ef81f4a3184d ] Commit e4412739472b ("Documentation: raise minimum supported version of binutils to 2.25") allows us to remove the checks for old binutils. There is no more user for ld-ifversion. Remove it as well. Signed-off-by: Masahiro Yamada Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://msgid.link/20230119082250.151485-1-masahiroy@kernel.org Stable-dep-of: 1b1e38002648 ("powerpc: add crtsavres.o to always-y instead of extra-y") Signed-off-by: Sasha Levin

powerpc/toc: Future proof kernel toc

2024-01-25T22:52:32+00:00

[ Upstream commit a3ad84da076009c94969fa97f604257667e2980f ] This patch future-proofs the kernel against linker changes that might put the toc pointer at some location other than .got+0x8000, by replacing __toc_start+0x8000 with .TOC. throughout. If the kernel's idea of the toc pointer doesn't agree with the linker, bad things happen. prom_init.c code relocating its toc is also changed so that a symbolic __prom_init_toc_start toc-pointer relative address is calculated rather than assuming that it is always at toc-pointer - 0x8000. The length calculations loading values from the toc are also avoided. It's a little incestuous to do that with unreloc_toc picking up adjusted values (which is fine in practice, they both adjust by the same amount if all goes well). I've also changed the way .got is aligned in vmlinux.lds and zImage.lds, mostly so that dumping out section info by objdump or readelf plainly shows the alignment is 256. This linker script feature was added 2005-09-27, available in FSF binutils releases from 2.17 onwards. Should be safe to use in the kernel, I think. Finally, put *(.got) before the prom_init.o entry which only needs *(.toc), so that the GOT header goes in the correct place. I don't believe this makes any difference for the kernel as it would for dynamic objects being loaded by ld.so. That change is just to stop lusers who blindly copy kernel scripts being led astray. Of course, this change needs the prom_init.c changes. Some notes on .toc and .got. .toc is a compiler generated section of addresses. .got is a linker generated section of addresses, generally built when the linker sees R_*_*GOT* relocations. In the case of powerpc64 ld.bfd, there are multiple generated .got sections, one per input object file. So you can somewhat reasonably write in a linker script an input section statement like *prom_init.o(.got .toc) to mean "the .got and .toc section for files matching *prom_init.o". On other architectures that doesn't make sense, because the linker generally has just one .got section. Even on powerpc64, note well that the GOT entries for prom_init.o may be merged with GOT entries from other objects. That means that if prom_init.o references, say, _end via some GOT relocation, and some other object also references _end via a GOT relocation, the GOT entry for _end may be in the range __prom_init_toc_start to __prom_init_toc_end and if the kernel does something special to GOT/TOC entries in that range then the value of _end as seen by objects other than prom_init.o will be affected. On the other hand the GOT entry for _end may not be in the range __prom_init_toc_start to __prom_init_toc_end. Which way it turns out is deterministic but a detail of linker operation that should not be relied on. A feature of ld.bfd is that input .toc (and .got) sections matching one linker input section statement may be sorted, to put entries used by small-model code first, near the toc base. This is why scripts for powerpc64 normally use *(.got .toc) rather than *(.got) *(.toc), since the first form allows more freedom to sort. Another feature of ld.bfd is that indirect addressing sequences using the GOT/TOC may be edited by the linker to relative addressing. In many cases relative addressing would be emitted by gcc for -mcmodel=medium if you appropriately decorate variable declarations with non-default visibility. The original patch is here: https://lore.kernel.org/linuxppc-dev/20210310034813.GM6042@bubble.grove.modra.org/ Signed-off-by: Alan Modra [aik: removed non-relocatable which is gone in 24d33ac5b8ffb] [aik: added <=2.24 check] [aik: because of llvm-as, kernel_toc_addr() uses "mr" instead of global register variable] Signed-off-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211221055904.555763-2-aik@ozlabs.ru Stable-dep-of: 1b1e38002648 ("powerpc: add crtsavres.o to always-y instead of extra-y") Signed-off-by: Sasha Levin

powerpc: Fail build if using recordmcount with binutils v2.37

2023-07-23T11:47:47+00:00

commit 25ea739ea1d4d3de41acc4f4eb2d1a97eee0eb75 upstream. binutils v2.37 drops unused section symbols, which prevents recordmcount from capturing mcount locations in sections that have no non-weak symbols. This results in a build failure with a message such as: Cannot find symbol for section 12: .text.perf_callchain_kernel. kernel/events/callchain.o: failed The change to binutils was reverted for v2.38, so this behavior is specific to binutils v2.37: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c09c8b42021180eee9495bd50d8b35e683d3901b Objtool is able to cope with such sections, so this issue is specific to recordmcount. Fail the build and print a warning if binutils v2.37 is detected and if we are using recordmcount. Cc: stable@vger.kernel.org Suggested-by: Joel Stanley Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20230530061436.56925-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman

powerpc: Remove linker flag from KBUILD_AFLAGS

2023-03-10T08:39:44+00:00

[ Upstream commit 31f48f16264bc70962fb3e7ec62da64d0a2ba04a ] When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it points out that KBUILD_AFLAGS contains a linker flag, which will be unused: clang: error: -Wl,-a32: 'linker' input unused [-Werror,-Wunused-command-line-argument] This was likely supposed to be '-Wa,-a$(BITS)'. However, this change is unnecessary, as all supported versions of clang and gcc will pass '-a64' or '-a32' to GNU as based on the value of '-m'; the behavior of the latest stable release of the oldest supported major version of each compiler is shown below and each compiler's latest release exhibits the same behavior (GCC 12.2.0 and Clang 15.0.6). $ powerpc64-linux-gcc --version | head -1 powerpc64-linux-gcc (GCC) 5.5.0 $ powerpc64-linux-gcc -m64 -### -x assembler-with-cpp -c -o /dev/null /dev/null &| grep 'as ' .../as -a64 -mppc64 -many -mbig -o /dev/null /tmp/cctwuBzZ.s $ powerpc64-linux-gcc -m32 -### -x assembler-with-cpp -c -o /dev/null /dev/null &| grep 'as ' .../as -a32 -mppc -many -mbig -o /dev/null /tmp/ccaZP4mF.sg $ clang --version | head -1 Ubuntu clang version 11.1.0-++20211011094159+1fdec59bffc1-1~exp1~20211011214622.5 $ clang --target=powerpc64-linux-gnu -fno-integrated-as -m64 -### \ -x assembler-with-cpp -c -o /dev/null /dev/null &| grep gnu-as "/usr/bin/powerpc64-linux-gnu-as" "-a64" "-mppc64" "-many" "-o" "/dev/null" "/tmp/null-80267c.s" $ clang --target=powerpc64-linux-gnu -fno-integrated-as -m64 -### \ -x assembler-with-cpp -c -o /dev/null /dev/null &| grep gnu-as "/usr/bin/powerpc64-linux-gnu-as" "-a32" "-mppc" "-many" "-o" "/dev/null" "/tmp/null-ab8f8d.s" Remove this flag altogether to avoid future issues. Fixes: 1421dc6d4829 ("powerpc/kbuild: Use flags variables rather than overriding LD/CC/AS") Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Linux Kernel Functional Testing Tested-by: Anders Roxell Acked-by: Michael Ellerman Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

powerpc/64s: Fix GENERIC_CPU build flags for PPC970 / G5

2022-10-26T10:35:23+00:00

[ Upstream commit 58ec7f06b74e0d6e76c4110afce367c8b5f0837d ] Big-endian GENERIC_CPU supports 970, but builds with -mcpu=power5. POWER5 is ISA v2.02 whereas 970 is v2.01 plus Altivec. 2.02 added the popcntb instruction which a compiler might use. Use -mcpu=power4. Fixes: 471d7ff8b51b ("powerpc/64s: Remove POWER4 support") Signed-off-by: Nicholas Piggin Reviewed-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220921014103.587954-1-npiggin@gmail.com Signed-off-by: Sasha Levin

powerpc/32: Don't always pass -mcpu=powerpc to the compiler

2022-08-25T09:40:43+00:00

[ Upstream commit 446cda1b21d9a6b3697fe399c6a3a00ff4a285f5 ] Since commit 4bf4f42a2feb ("powerpc/kbuild: Set default generic machine type for 32-bit compile"), when building a 32 bits kernel with a bi-arch version of GCC, or when building a book3s/32 kernel, the option -mcpu=powerpc is passed to GCC at all time, relying on it being eventually overriden by a subsequent -mcpu=xxxx. But when building the same kernel with a 32 bits only version of GCC, that is not done, relying on gcc being built with the expected default CPU. This logic has two problems. First, it is a bit fragile to rely on whether the GCC version is bi-arch or not, because today we can have bi-arch versions of GCC configured with a 32 bits default. Second, there are some versions of GCC which don't support -mcpu=powerpc, for instance for e500 SPE-only versions. So, stop relying on this approximative logic and allow the user to decide whether he/she wants to use the toolchain's default CPU or if he/she wants to set one, and allow only possible CPUs based on the selected target. Reported-by: Pali Rohár Signed-off-by: Christophe Leroy Tested-by: Pali Rohár Reviewed-by: Arnd Bergmann Reviewed-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/d4df724691351531bf46d685d654689e5dfa0d74.1657549153.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin

powerpc/Makefile: Don't pass -mcpu=powerpc64 when building 32-bit

2022-04-08T12:23:36+00:00

[ Upstream commit 2863dd2db23e0407f6c50b8ba5c0e55abef894f1 ] When CONFIG_GENERIC_CPU=y (true for all our defconfigs) we pass -mcpu=powerpc64 to the compiler, even when we're building a 32-bit kernel. This happens because we have an ifdef CONFIG_PPC_BOOK3S_64/else block in the Makefile that was written before 32-bit supported GENERIC_CPU. Prior to that the else block only applied to 64-bit Book3E. The GCC man page says -mcpu=powerpc64 "[specifies] a pure ... 64-bit big endian PowerPC ... architecture machine [type], with an appropriate, generic processor model assumed for scheduling purposes." It's unclear how that interacts with -m32, which we are also passing, although obviously -m32 is taking precedence in some sense, as the 32-bit kernel only contains 32-bit instructions. This was noticed by inspection, not via any bug reports, but it does affect code generation. Comparing before/after code generation, there are some changes to instruction scheduling, and the after case (with -mcpu=powerpc64 removed) the compiler seems more keen to use r8. Fix it by making the else case only apply to Book3E 64, which excludes 32-bit. Fixes: 0e00a8c9fd92 ("powerpc: Allow CPU selection also on PPC32") Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220215112858.304779-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc: Add "-z notext" flag to disable diagnostic

2021-08-15T03:49:39+00:00

Object files used to link .tmp_vmlinux.kallsyms1 have many R_PPC64_ADDR64 relocations in non-SHF_WRITE sections. There are many text relocations (e.g. in .rela___ksymtab_gpl+* and .rela__mcount_loc sections) in a -pie link and are disallowed by LLD: ld.lld: error: can't create dynamic relocation R_PPC64_ADDR64 against local symbol in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output >>> defined in arch/powerpc/kernel/head_64.o >>> referenced by arch/powerpc/kernel/head_64.o:(__restart_table+0x10) Newer GNU ld configured with "--enable-textrel-check=error" will report an error as well: $ ld-new -EL -m elf64lppc -pie ... -o .tmp_vmlinux.kallsyms1 ... ld-new: read-only segment has dynamic relocations Add "-z notext" to suppress the errors. Non-CONFIG_RELOCATABLE builds use the default -no-pie mode and thus R_PPC64_ADDR64 relocations can be resolved at link-time. Reported-by: Itaru Kitayama Co-developed-by: Bill Wendling Signed-off-by: Fangrui Song Signed-off-by: Bill Wendling Reviewed-by: Nick Desaulniers Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210813200511.1905703-1-morbo@google.com

powerpc: move the install rule to arch/powerpc/Makefile

2021-08-04T00:53:39+00:00

Currently, the install target in arch/powerpc/Makefile descends into arch/powerpc/boot/Makefile to invoke the shell script, but there is no good reason to do so. arch/powerpc/Makefile can run the shell script directly. Signed-off-by: Masahiro Yamada Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210729141937.445051-3-masahiroy@kernel.org

Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2021-07-10T18:01:38+00:00

Pull Kbuild updates from Masahiro Yamada: - Increase the -falign-functions alignment for the debug option. - Remove ugly libelf checks from the top Makefile. - Make the silent build (-s) more silent. - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified. - Various script cleanups * tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits) scripts: add generic syscallnr.sh scripts: check duplicated syscall number in syscall table sparc: syscalls: use pattern rules to generate syscall headers parisc: syscalls: use pattern rules to generate syscall headers nds32: add arch/nds32/boot/.gitignore kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set kbuild: modpost: Explicitly warn about unprototyped symbols kbuild: remove trailing slashes from $(KBUILD_EXTMOD) kconfig.h: explain IS_MODULE(), IS_ENABLED() kconfig: constify long_opts scripts/setlocalversion: simplify the short version part scripts/setlocalversion: factor out 12-chars hash construction scripts/setlocalversion: add more comments to -dirty flag detection scripts/setlocalversion: remove workaround for old make-kpkg scripts/setlocalversion: remove mercurial, svn and git-svn supports kbuild: clean up ${quiet} checks in shell scripts kbuild: sink stdout from cmd for silent build init: use $(call cmd,) for generating include/generated/compile.h kbuild: merge scripts/mkmakefile to top Makefile sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild ...