Patch "ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro" has been added to the 6.6-stable tree

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This is a note to let you know that I've just added the patch titled

    ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     acpi-cppc-fix-bit_offset-shift-in-mask_val-macro.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 05d92ee782eeb7b939bdd0189e6efcab9195bf95 Mon Sep 17 00:00:00 2001
From: Jarred White <jarredwhite@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 8 Apr 2024 22:23:09 -0700
Subject: ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro

From: Jarred White <jarredwhite@xxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxx>
Cc: 5.15+ <stable@xxxxxxxxxxxxxxx> # 5.15+
Reviewed-by: Vanshidhar Konda <vanshikonda@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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)


Patches currently in stable-queue which might be from jarredwhite@xxxxxxxxxxxxxxxxxxx are

queue-6.6/acpi-cppc-fix-access-width-used-for-pcc-registers.patch
queue-6.6/acpi-cppc-fix-bit_offset-shift-in-mask_val-macro.patch
queue-6.6/acpi-cppc-use-access_width-over-bit_width-for-system-memory-accesses.patch




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