6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jarred White jarredwhite@linux.microsoft.com
commit 05d92ee782eeb7b939bdd0189e6efcab9195bf95 upstream.
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: 5.15+ stable@vger.kernel.org # 5.15+ Reviewed-by: Vanshidhar Konda vanshikonda@os.amperecomputing.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/cppc_acpi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -167,8 +167,8 @@ show_cppc_data(cppc_get_perf_ctrs, cppc_ #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)