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