Re: [PATCH 1/2] perf tools: allow building for ARM

[Jamie Iles]

On Fri, Dec 11, 2009 at 11:23:16AM +0100, Ingo Molnar wrote:
> cpu_relax() looks fine, but rmb() seems not to match the one that can be 
> found in arch/arm/:
> 
> arch/arm/include/asm/system.h:#define rmb()		dmb()
> arch/arm/include/asm/system.h:#define rmb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
> arch/arm/include/asm/system.h:#define smp_rmb()	rmb()
> 
> arch/arm/include/asm/system.h:#define dmb() __asm__ __volatile__ ("dmb" : : : "memory")
> arch/arm/include/asm/system.h:#define dmb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
> arch/arm/include/asm/system.h:#define dmb() __asm__ __volatile__ ("" : : : "memory")
> arch/arm/include/asm/system.h:#define dmb() __asm__ __volatile__ ("" : : : "memory")
The implementation of the barriers depend on the CPU arch revision which is
defined in the kernel config. As the perf tools don't use the kernel config,
we don't know here what arch revision we're building for. Perhaps we need a
LINUX_ARM_ARCH parameter when building for ARM so we can pick the correct one.

Jamie
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/