On 08/10/15 16:08, Catalin Marinas wrote:
On Thu, Oct 08, 2015 at 12:56:28PM +0100, Suzuki K. Poulose wrote:
On 08/10/15 12:11, Catalin Marinas wrote:
On Mon, Oct 05, 2015 at 06:02:05PM +0100, Suzuki K. Poulose wrote:
@@ -137,13 +138,17 @@ extern struct pmu perf_ops_bp;
  /* Determine number of BRP registers available. */
  static inline int get_num_brps(void)
  {
-       return ((read_cpuid(ID_AA64DFR0_EL1) >> 12) & 0xf) + 1;
+       return 1 +
+               
cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1),
+                                               ID_AA64DFR0_BRPS_SHIFT);
  }

cpuid_feature_extract_field() is fine but we should we bother with
read_system_reg vs just read_cpuid?
Similar question for patch 17/22.

Well, we would have already TAINTed the kernel, if these fields are different.
It is just the matter of, whether we want to provide the safer value on a 
tainted
kernel or not. I am open to suggestions.

Ah, sorry, I mixed read_system_reg() with read_cpu_sysreg(). I think we

Oh, ok. I think we should rename it as you suggest below to avoid the
confusion.

need to rename the latter as it gets confusing. Maybe something like
read_native_sys_reg() or __raw_read_system_reg().



Thanks
Suzuki



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