From 82a9f16adc12f51c3f8ea59a7c3c120241aff836 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Thu, 16 May 2013 20:27:31 +0000 Subject: powerpc/hw_breakpoints: Add DABRX cpu feature to fix 32-bit regression When introducing support for DABRX in 4474ef0, we broke older 32-bit CPUs that don't have that register. Some CPUs have a DABR but not DABRX. Configuration are: - No 32bit CPUs have DABRX but some have DABR. - POWER4+ and below have the DABR but no DABRX. - 970 and POWER5 and above have DABR and DABRX. - POWER8 has DAWR, hence no DABRX. This introduces CPU_FTR_DABRX and sets it on appropriate CPUs. We use the top 64 bits for CPU FTR bits since only 64 bit CPUs have this. Processors that don't have the DABRX will still work as they will fall back to software filtering these breakpoints via perf_exclude_event(). Signed-off-by: Michael Neuling Reported-by: "Gorelik, Jacob (335F)" cc: stable@vger.kernel.org (v3.9 only) Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/process.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index a902723fdc69..b0f3e3f77e72 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -399,7 +399,8 @@ static inline int __set_dabr(unsigned long dabr, unsigned long dabrx) static inline int __set_dabr(unsigned long dabr, unsigned long dabrx) { mtspr(SPRN_DABR, dabr); - mtspr(SPRN_DABRX, dabrx); + if (cpu_has_feature(CPU_FTR_DABRX)) + mtspr(SPRN_DABRX, dabrx); return 0; } #else -- cgit v1.2.3