[Buildroot] [PATCH v2] linux-tools/perf: Add dependency on 32-bit atomics

Thomas Petazzoni thomas.petazzoni at bootlin.com
Sat Apr 20 13:50:05 UTC 2019


On Thu, 18 Apr 2019 20:38:45 +0300
Alexey Brodkin <Alexey.Brodkin at synopsys.com> wrote:

> Atomic ops are strictly required by perf utility as it uses
> atomic_xxx() functions.
> Otherwise building fails like that:
> |.../output/host/opt/ext-toolchain/bin/../lib/gcc/arc-snps-linux-uclibc/8.2.1/../../../../arc-snps-linux-uclibc/bin/ld:
> |.../output/build/linux-5.0.7/tools/perf/libperf.a(libperf-in.o): in function `atomic_cmpxchg':
> |.../output/build/linux-5.0.7/tools/include/asm-generic/atomic-gcc.h:69: undefined reference to `__sync_val_compare_and_swap_4'
> Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com>
> Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>

I have applied to master, after doing one change, see below.

> +comment "perf needs 32-bit atomic ops"
> +	depends on !BR2_TOOLCHAIN_HAS_SYNC_4
> +

We typically don't add such comments, because it's an architecture
dependency. There is nothing the user can do about it, so there's no
point in having a comment.


Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering

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