kernel.git/arch/powerpc/Makefile, branch linux-4.19.y

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

2023-08-30T14:31:52Z

[ Upstream commit 25ea739ea1d4d3de41acc4f4eb2d1a97eee0eb75 ] 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: Sasha Levin

powerpc: remove leftover code of old GCC version checks

2023-08-30T14:31:52Z

[ Upstream commit bad96de8d31ba65dc26645af5550135315ea0b19 ] Clean up the leftover of commit f2910f0e6835 ("powerpc: remove old GCC version checks"). Signed-off-by: Masahiro Yamada Acked-by: Nicholas Piggin Signed-off-by: Michael Ellerman Stable-dep-of: 25ea739ea1d4 ("powerpc: Fail build if using recordmcount with binutils v2.37") Signed-off-by: Sasha Levin

powerpc/32: add stack protector support

2023-08-30T14:31:52Z

[ Upstream commit c3ff2a5193fa61b1b284cfb1d79628814ed0e95a ] This functionality was tentatively added in the past (commit 6533b7c16ee5 ("powerpc: Initial stack protector (-fstack-protector) support")) but had to be reverted (commit f2574030b0e3 ("powerpc: Revert the initial stack protector support") because of GCC implementing it differently whether it had been built with libc support or not. Now, GCC offers the possibility to manually set the stack-protector mode (global or tls) regardless of libc support. This time, the patch selects HAVE_STACKPROTECTOR only if -mstack-protector-guard=tls is supported by GCC. On PPC32, as register r2 points to current task_struct at all time, the stack_canary located inside task_struct can be used directly by using the following GCC options: -mstack-protector-guard=tls -mstack-protector-guard-reg=r2 -mstack-protector-guard-offset=offsetof(struct task_struct, stack_canary)) The protector is disabled for prom_init and bootx_init as it is too early to handle it properly. $ echo CORRUPT_STACK > /sys/kernel/debug/provoke-crash/DIRECT [ 134.943666] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: lkdtm_CORRUPT_STACK+0x64/0x64 [ 134.943666] [ 134.955414] CPU: 0 PID: 283 Comm: sh Not tainted 4.18.0-s3k-dev-12143-ga3272be41209 #835 [ 134.963380] Call Trace: [ 134.965860] [c6615d60] [c001f76c] panic+0x118/0x260 (unreliable) [ 134.971775] [c6615dc0] [c001f654] panic+0x0/0x260 [ 134.976435] [c6615dd0] [c032c368] lkdtm_CORRUPT_STACK_STRONG+0x0/0x64 [ 134.982769] [c6615e00] [ffffffff] 0xffffffff Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Stable-dep-of: 25ea739ea1d4 ("powerpc: Fail build if using recordmcount with binutils v2.37") Signed-off-by: Sasha Levin

powerpc: Fix defconfig choice logic when cross compiling

2023-06-21T13:39:59Z

commit af5cd05de5dd38cf25d14ea4d30ae9b791d2420b upstream. Our logic for choosing defconfig doesn't work well in some situations. For example if you're on a ppc64le machine but you specify a non-empty CROSS_COMPILE, in order to use a non-default toolchain, then defconfig will give you ppc64_defconfig (big endian): $ make CROSS_COMPILE=~/toolchains/gcc-8/bin/powerpc-linux- defconfig *** Default configuration is based on 'ppc64_defconfig' This is because we assume that CROSS_COMPILE being set means we can't be on a ppc machine and rather than checking we just default to ppc64_defconfig. We should just ignore CROSS_COMPILE, instead check the machine with uname and if it's one of ppc, ppc64 or ppc64le then use that defconfig. If it's none of those then we fall back to ppc64_defconfig. Signed-off-by: Michael Ellerman Signed-off-by: Alyssa Ross Signed-off-by: Greg Kroah-Hartman

powerpc: Remove linker flag from KBUILD_AFLAGS

2023-03-11T15:31:44Z

[ 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

2022-10-26T11:19:35Z

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

2022-04-15T12:14:49Z

[ 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: Drop -me200 addition to build flags

2020-12-30T10:25:38Z

[ Upstream commit e02152ba2810f7c88cb54e71cda096268dfa9241 ] Currently a build with CONFIG_E200=y will fail with: Error: invalid switch -me200 Error: unrecognized option -me200 Upstream binutils has never supported an -me200 option. Presumably it was supported at some point by either a fork or Freescale internal binutils. We can't support code that we can't even build test, so drop the addition of -me200 to the build flags, so we can at least build with CONFIG_E200=y. Reported-by: Németh Márton Reported-by: kernel test robot Signed-off-by: Michael Ellerman Reviewed-by: Nick Desaulniers Acked-by: Scott Wood Link: https://lore.kernel.org/r/20201116120913.165317-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc: vdso: Make vdso32 installation conditional in vdso_install

2020-01-27T13:50:40Z

[ Upstream commit ff6d27823f619892ab96f7461764840e0d786b15 ] The 32-bit vDSO is not needed and not normally built for 64-bit little-endian configurations. However, the vdso_install target still builds and installs it. Add the same config condition as is normally used for the build. Fixes: e0d005916994 ("powerpc/vdso: Disable building the 32-bit VDSO ...") Signed-off-by: Ben Hutchings Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc: Don't add -mabi= flags when building with Clang

2020-01-04T18:13:10Z

[ Upstream commit 465bfd9c44dea6b55962b5788a23ac87a467c923 ] When building pseries_defconfig, building vdso32 errors out: error: unknown target ABI 'elfv1' This happens because -m32 in clang changes the target to 32-bit, which does not allow the ABI to be changed. Commit 4dc831aa8813 ("powerpc: Fix compiling a BE kernel with a powerpc64le toolchain") added these flags to fix building big endian kernels with a little endian GCC. Clang doesn't need -mabi because the target triple controls the default value. -mlittle-endian and -mbig-endian manipulate the triple into either powerpc64-* or powerpc64le-*, which properly sets the default ABI. Adding a debug print out in the PPC64TargetInfo constructor after line 383 above shows this: $ echo | ./clang -E --target=powerpc64-linux -mbig-endian -o /dev/null - Default ABI: elfv1 $ echo | ./clang -E --target=powerpc64-linux -mlittle-endian -o /dev/null - Default ABI: elfv2 $ echo | ./clang -E --target=powerpc64le-linux -mbig-endian -o /dev/null - Default ABI: elfv1 $ echo | ./clang -E --target=powerpc64le-linux -mlittle-endian -o /dev/null - Default ABI: elfv2 Don't specify -mabi when building with clang to avoid the build error with -m32 and not change any code generation. -mcall-aixdesc is not an implemented flag in clang so it can be safely excluded as well, see commit 238abecde8ad ("powerpc: Don't use gcc specific options on clang"). pseries_defconfig successfully builds after this patch and powernv_defconfig and ppc44x_defconfig don't regress. Reviewed-by: Daniel Axtens Signed-off-by: Nathan Chancellor [mpe: Trim clang links in change log] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191119045712.39633-2-natechancellor@gmail.com Signed-off-by: Sasha Levin