From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>,
Jarred White <jarredwhite@linux.microsoft.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
Easwar Hariharan <eahariha@linux.microsoft.com>,
"open list:ACPI" <linux-acpi@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH] ACPI: CPPC: Fix bit_offset shift in MASK_VAL macro
Date: Mon, 22 Apr 2024 18:43:26 +0200 [thread overview]
Message-ID: <CAJZ5v0imiRbheOJgEf=Ua-JRhDTh1+SJ-=CjUC7vOQYffV50FA@mail.gmail.com> (raw)
In-Reply-To: <soawdod6cpcc73wrc35bvnah5toubf2cv4x7c3e6p53xtvllrs@6dtpn2v5t3di>
On Wed, Apr 17, 2024 at 7:37 PM Vanshidhar Konda
<vanshikonda@os.amperecomputing.com> wrote:
>
> Looks good to me.
>
> Reviewed-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
>
> On Mon, Apr 08, 2024 at 10:23:09PM -0700, 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)
> >--
Applied as 6.9-rc material, thanks!
prev parent reply other threads:[~2024-04-22 16:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 5:23 [PATCH] ACPI: CPPC: Fix bit_offset shift in MASK_VAL macro Jarred White
2024-04-16 17:24 ` Jarred White
2024-04-17 17:36 ` Vanshidhar Konda
2024-04-22 16:43 ` Rafael J. Wysocki [this message]
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