linux-dev/arch/powerpc/xmon/Makefile, branch master

kbuild: introduce ccflags-remove-y and asflags-remove-y

2020-08-09T16:32:59Z

CFLAGS_REMOVE_.o filters out flags when compiling a particular object, but there is no convenient way to do that for every object in a directory. Add ccflags-remove-y and asflags-remove-y to make it easily. Use ccflags-remove-y to clean up some Makefiles. The add/remove order works as follows: [1] KBUILD_CFLAGS specifies compiler flags used globally [2] ccflags-y adds compiler flags for all objects in the current Makefile [3] ccflags-remove-y removes compiler flags for all objects in the current Makefile (New feature) [4] CFLAGS_ adds compiler flags per file. [5] CFLAGS_REMOVE_ removes compiler flags per file. Having [3] before [4] allows us to remove flags from most (but not all) objects in the current Makefile. For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE) from all objects in the directory, then adds it back to trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o The same applies to lib/livepatch/Makefile. Please note ccflags-remove-y has no effect to the sub-directories. In contrast, the previous notation got rid of compiler flags also from all the sub-directories. The following are not affected because they have no sub-directories: arch/arm/boot/compressed/ arch/powerpc/xmon/ arch/sh/ kernel/trace/ However, lib/ has several sub-directories. To keep the behavior, I added ccflags-remove-y to all Makefiles in subdirectories of lib/, except the following: lib/vdso/Makefile - Kbuild does not descend into this Makefile lib/raid/test/Makefile - This is not used for the kernel build I think commit 2464a609ded0 ("ftrace: do not trace library functions") excluded too much. In the next commit, I will remove ccflags-remove-y from the sub-directories of lib/. Suggested-by: Sami Tolvanen Signed-off-by: Masahiro Yamada Acked-by: Steven Rostedt (VMware) Acked-by: Michael Ellerman (powerpc) Acked-by: Brendan Higgins (KUnit) Tested-by: Anders Roxell

powerpc/xmon: Move breakpoints to text section

2020-05-18T14:10:36Z

The instructions for xmon's breakpoint are stored bpt_table[] which is in the data section. This is problematic as the data section may be marked as no execute. Move bpt_table[] to the text section. Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200506034050.24806-4-jniethe5@gmail.com

powerpc: Make setjmp/longjmp signature standard

2020-04-01T03:30:51Z

Declaring setjmp()/longjmp() as taking longs makes the signature non-standard, and makes clang complain. In the past, this has been worked around by adding -ffreestanding to the compile flags. The implementation looks like it only ever propagates the value (in longjmp) or sets it to 1 (in setjmp), and we only call longjmp with integer parameters. This allows removing -ffreestanding from the compilation flags. Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Clement Courbet Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200330080400.124803-1-courbet@google.com

powerpc: Avoid clang warnings around setjmp and longjmp

2019-11-25T10:45:43Z

Commit aea447141c7e ("powerpc: Disable -Wbuiltin-requires-header when setjmp is used") disabled -Wbuiltin-requires-header because of a warning about the setjmp and longjmp declarations. r367387 in clang added another diagnostic around this, complaining that there is no jmp_buf declaration. In file included from ../arch/powerpc/xmon/xmon.c:47: ../arch/powerpc/include/asm/setjmp.h:10:13: error: declaration of built-in function 'setjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header . [-Werror,-Wincomplete-setjmp-declaration] extern long setjmp(long *); ^ ../arch/powerpc/include/asm/setjmp.h:11:13: error: declaration of built-in function 'longjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header . [-Werror,-Wincomplete-setjmp-declaration] extern void longjmp(long *, long); ^ 2 errors generated. We are not using the standard library's longjmp/setjmp implementations for obvious reasons; make this clear to clang by using -ffreestanding on these files. Cc: stable@vger.kernel.org # 4.14+ Suggested-by: Segher Boessenkool Reviewed-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191119045712.39633-3-natechancellor@gmail.com

powerpc: disable KASAN instrumentation on early/critical files.

2019-05-02T15:20:26Z

All files containing functions run before kasan_early_init() is called must have KASAN instrumentation disabled. For those file, branch profiling also have to be disabled otherwise each if () generates a call to ftrace_likely_update(). Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc: Enable kcov

2019-02-23T10:04:32Z

kcov provides kernel coverage data that's useful for fuzzing tools like syzkaller. Wire up kcov support on powerpc. Disable kcov instrumentation on the same files where we currently disable gcov and UBSan instrumentation, plus some additional exclusions which appear necessary to boot on book3e machines. Signed-off-by: Andrew Donnellan Acked-by: Dmitry Vyukov Tested-by: Daniel Axtens # e6500 Signed-off-by: Michael Ellerman

powerpc/xmon: Relax frame size for clang

2018-10-31T09:39:25Z

When building with clang (8 trunk, 7.0 release) the frame size limit is hit: arch/powerpc/xmon/xmon.c:452:12: warning: stack frame size of 2576 bytes in function 'xmon_core' [-Wframe-larger-than=] Some investigation by Naveen indicates this is due to clang saving the addresses to printf format strings on the stack. While this issue is investigated, bump up the frame size limit for xmon when building with clang. Link: https://github.com/ClangBuiltLinux/linux/issues/252 Signed-off-by: Joel Stanley Signed-off-by: Michael Ellerman

powerpc: Add -Werror at arch/powerpc level

2018-10-18T13:56:17Z

Back when I added -Werror in commit ba55bd74360e ("powerpc: Add configurable -Werror for arch/powerpc") I did it by adding it to most of the arch Makefiles. At the time we excluded math-emu, because apparently it didn't build cleanly. But that seems to have been fixed somewhere in the interim. So move the -Werror addition to the top-level of the arch, this saves us from repeating it in every Makefile and means we won't forget to add it to any new sub-dirs. Signed-off-by: Michael Ellerman

powerpc: Disable -Wbuiltin-requires-header when setjmp is used

2018-10-13T11:21:25Z

The powerpc kernel uses setjmp which causes a warning when building with clang: In file included from arch/powerpc/xmon/xmon.c:51: ./arch/powerpc/include/asm/setjmp.h:15:13: error: declaration of built-in function 'setjmp' requires inclusion of the header [-Werror,-Wbuiltin-requires-header] extern long setjmp(long *); ^ ./arch/powerpc/include/asm/setjmp.h:16:13: error: declaration of built-in function 'longjmp' requires inclusion of the header [-Werror,-Wbuiltin-requires-header] extern void longjmp(long *, long); ^ This *is* the header and we're not using the built-in setjump but rather the one in arch/powerpc/kernel/misc.S. As the compiler warning does not make sense, it for the files where setjmp is used. Signed-off-by: Joel Stanley Reviewed-by: Nick Desaulniers [mpe: Move subdir-ccflags in xmon/Makefile to not clobber -Werror] Signed-off-by: Michael Ellerman

powerpc: consolidate -mno-sched-epilog into FTRACE flags

2018-09-19T12:01:56Z

Signed-off-by: Nicholas Piggin Reviewed-by: Joel Stanley Signed-off-by: Michael Ellerman