Messages in this thread | | | Date | Tue, 16 Apr 2024 10:24:27 -0700 | Subject | Re: [PATCH] ACPI: CPPC: Fix bit_offset shift in MASK_VAL macro | From | Jarred White <> |
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On 4/8/2024 10:23 PM, Jarred White wrote: > Commit 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for > system memory accesses") neglected to properly wrap the bit_offset shift > when it comes to applying the mask. This may cause incorrect values to be > read and may cause the cpufreq module not be loaded. > > [ 11.059751] cpu_capacity: CPU0 missing/invalid highest performance. > [ 11.066005] cpu_capacity: partial information: fallback to 1024 for all CPUs > > Also, corrected the bitmask generation in GENMASK (extra bit being added). > > Fixes: 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses") > Signed-off-by: Jarred White <jarredwhite@linux.microsoft.com> > CC: Vanshidhar Konda <vanshikonda@os.amperecomputing.com> > CC: stable@vger.kernel.org #5.15+ > --- > drivers/acpi/cppc_acpi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 4bfbe55553f4..00a30ca35e78 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -170,8 +170,8 @@ show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time); > #define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width) > > /* Shift and apply the mask for CPC reads/writes */ > -#define MASK_VAL(reg, val) ((val) >> ((reg)->bit_offset & \ > - GENMASK(((reg)->bit_width), 0))) > +#define MASK_VAL(reg, val) (((val) >> (reg)->bit_offset) & \ > + GENMASK(((reg)->bit_width) - 1, 0)) > > static ssize_t show_feedback_ctrs(struct kobject *kobj, > struct kobj_attribute *attr, char *buf)
Hi Vanshi,
Could you review please?
Thanks, Jarred
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