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| author | Michael Ellerman <mpe@ellerman.id.au> | 2017-01-24 16:36:57 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-01-25 13:36:10 +1100 |
| commit | b5fa0f7f88edcde37df1807fdf9ff10ec787a60e (patch) | |
| tree | 3f0c8e6904907d51ccaf858963bb597970266d05 /arch/powerpc/include/asm/mmu.h | |
| parent | f2574030b0e33263b8a1c28fa3c4fa9292283799 (diff) | |
| download | lwn-b5fa0f7f88edcde37df1807fdf9ff10ec787a60e.tar.gz lwn-b5fa0f7f88edcde37df1807fdf9ff10ec787a60e.zip | |
powerpc: Fix build failure with clang due to BUILD_BUG_ON()
Anton says: In commit 4db7327194db ("powerpc: Add option to use jump
label for cpu_has_feature()") and commit c12e6f24d413 ("powerpc: Add
option to use jump label for mmu_has_feature()") we added:
BUILD_BUG_ON(!__builtin_constant_p(feature))
to cpu_has_feature() and mmu_has_feature() in order to catch usage
issues (such as cpu_has_feature(cpu_has_feature(X), which has happened
once in the past). Unfortunately LLVM isn't smart enough to resolve
this, and it errors out.
I work around it in my clang/LLVM builds of the kernel, but I have just
discovered that it causes a lot of issues for the bcc (eBPF) trace tool
(which uses LLVM).
For now just #ifdef it away for clang builds.
Fixes: 4db7327194db ("powerpc: Add option to use jump label for cpu_has_feature()")
Fixes: c12e6f24d413 ("powerpc: Add option to use jump label for mmu_has_feature()")
Cc: stable@vger.kernel.org # v4.8+
Reported-by: Anton Blanchard <anton@samba.org>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/mmu.h')
| -rw-r--r-- | arch/powerpc/include/asm/mmu.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h index a34c764ca8dd..233a7e8cc8e3 100644 --- a/arch/powerpc/include/asm/mmu.h +++ b/arch/powerpc/include/asm/mmu.h @@ -160,7 +160,9 @@ static __always_inline bool mmu_has_feature(unsigned long feature) { int i; +#ifndef __clang__ /* clang can't cope with this */ BUILD_BUG_ON(!__builtin_constant_p(feature)); +#endif #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG if (!static_key_initialized) { |