linux-stable.git/drivers/cpufreq, branch v6.1.78

cpufreq: intel_pstate: Refine computation of P-state for given frequency

2024-02-01T00:17:08+00:00

commit 192cdb1c907fd8df2d764c5bb17496e415e59391 upstream.

On systems using HWP, if a given frequency is equal to the maximum turbo
frequency or the maximum non-turbo frequency, the HWP performance level
corresponding to it is already known and can be used directly without
any computation.

Accordingly, adjust the code to use the known HWP performance levels in
the cases mentioned above.

This also helps to avoid limiting CPU capacity artificially in some
cases when the BIOS produces the HWP_CAP numbers using a different
E-core-to-P-core performance scaling factor than expected by the kernel.

Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores")
Cc: 6.1+  # 6.1+
Tested-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: scmi: process the result of devm_of_clk_add_hw_provider()

2024-01-25T23:27:20+00:00

[ Upstream commit c4a5118a3ae1eadc687d84eef9431f9e13eb015c ]

devm_of_clk_add_hw_provider() may return an errno, so
add a return value check

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 8410e7f3b31e ("cpufreq: scmi: Fix OPP addition failure with a dummy clock provider")
Signed-off-by: Alexandra Diupina 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: Use of_property_present() for testing DT property presence

2024-01-25T23:27:20+00:00

[ Upstream commit b8f3a396a7ee43e6079176cc0fb8de2b95a23681 ]

It is preferred to use typed property access functions (i.e.
of_property_read_ functions) rather than low-level
of_get_property/of_find_property functions for reading properties. As
part of this, convert of_get_property/of_find_property calls to the
recently added of_property_present() helper when we just want to test
for presence of a property and nothing more.

Signed-off-by: Rob Herring 
Signed-off-by: Viresh Kumar 
Stable-dep-of: c4a5118a3ae1 ("cpufreq: scmi: process the result of devm_of_clk_add_hw_provider()")
Signed-off-by: Sasha Levin

cpufreq: imx6q: Don't disable 792 Mhz OPP unnecessarily

2023-12-08T07:51:19+00:00

[ Upstream commit 2e4e0984c7d696cc74cf2fd7e7f62997f0e9ebe6 ]

For a 900MHz i.MX6ULL CPU the 792MHz OPP is disabled. There is no
convincing reason to disable this OPP. If a CPU can run at 900MHz,
it should also be able to cope with 792MHz. Looking at the voltage
level of 792MHz in [1] (page 24, table 10. "Operating Ranges") the
current defined OPP is above the minimum. So the voltage level
shouldn't be a problem. However in [2] (page 24, table 10.
"Operating Ranges"), it is not mentioned that 792MHz OPP isn't
allowed. Change it to only disable 792MHz OPP for i.MX6ULL types
below 792 MHz.

[1] https://www.nxp.com/docs/en/data-sheet/IMX6ULLIEC.pdf
[2] https://www.nxp.com/docs/en/data-sheet/IMX6ULLCEC.pdf

Fixes: 0aa9abd4c212 ("cpufreq: imx6q: check speed grades for i.MX6ULL")
Signed-off-by: Christoph Niedermaier 
Reviewed-by: Marek Vasut 
Reviewed-by: Fabio Estevam 
[ Viresh: Edited subject ]
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: imx6q: don't warn for disabling a non-existing frequency

2023-12-08T07:51:19+00:00

[ Upstream commit 11a3b0ac33d95aa84be426e801f800997262a225 ]

It is confusing if a warning is given for disabling a non-existent
frequency of the operating performance points (OPP). In this case
the function dev_pm_opp_disable() returns -ENODEV. Check the return
value and avoid the output of a warning in this case. Avoid code
duplication by using a separate function.

Signed-off-by: Christoph Niedermaier 
[ Viresh : Updated commit subject ]
Signed-off-by: Viresh Kumar 
Stable-dep-of: 2e4e0984c7d6 ("cpufreq: imx6q: Don't disable 792 Mhz OPP unnecessarily")
Signed-off-by: Sasha Levin

cpufreq/amd-pstate: Fix the return value of amd_pstate_fast_switch()

2023-12-08T07:51:15+00:00

commit bb87be267b8ee9b40917fb5bf51be5ddb33c37c2 upstream.

cpufreq_driver->fast_switch() callback expects a frequency as a return
value. amd_pstate_fast_switch() was returning the return value of
amd_pstate_update_freq(), which only indicates a success or failure.

Fix this by making amd_pstate_fast_switch() return the target_freq
when the call to amd_pstate_update_freq() is successful, and return
the current frequency from policy->cur when the call to
amd_pstate_update_freq() is unsuccessful.

Fixes: 4badf2eb1e98 ("cpufreq: amd-pstate: Add ->fast_switch() callback")
Acked-by: Huang Rui 
Reviewed-by: Wyes Karny 
Reviewed-by: Perry Yuan 
Cc: 6.4+  # v6.4+
Signed-off-by: Gautham R. Shenoy 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: stats: Fix buffer overflow detection in trans_stats()

2023-11-28T17:07:16+00:00

[ Upstream commit ea167a7fc2426f7685c3735e104921c1a20a6d3f ]

Commit 3c0897c180c6 ("cpufreq: Use scnprintf() for avoiding potential
buffer overflow") switched from snprintf to the more secure scnprintf
but never updated the exit condition for PAGE_SIZE.

As the commit say and as scnprintf document, what scnprintf returns what
is actually written not counting the '\0' end char. This results in the
case of len exceeding the size, len set to PAGE_SIZE - 1, as it can be
written at max PAGE_SIZE - 1 (as '\0' is not counted)

Because of len is never set to PAGE_SIZE, the function never break early,
never prints the warning and never return -EFBIG.

Fix this by changing the condition to PAGE_SIZE - 1 to correctly trigger
the error.

Cc: 5.10+  # 5.10+
Fixes: 3c0897c180c6 ("cpufreq: Use scnprintf() for avoiding potential buffer overflow")
Signed-off-by: Christian Marangi 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: brcmstb-avs-cpufreq: Fix -Warray-bounds bug

2023-09-13T07:43:04+00:00

commit e520d0b6be950ce3738cf4b9bd3b392be818f1dc upstream.

Allocate extra space for terminating element at:

drivers/cpufreq/brcmstb-avs-cpufreq.c:
449         table[i].frequency = CPUFREQ_TABLE_END;

and add code comment to make this clear.

This fixes the following -Warray-bounds warning seen after building
ARM with multi_v7_defconfig (GCC 13):
In function 'brcm_avs_get_freq_table',
    inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
drivers/cpufreq/brcmstb-avs-cpufreq.c:449:28: warning: array subscript 5 is outside array bounds of 'void[60]' [-Warray-bounds=]
  449 |         table[i].frequency = CPUFREQ_TABLE_END;
In file included from include/linux/node.h:18,
                 from include/linux/cpu.h:17,
                 from include/linux/cpufreq.h:12,
                 from drivers/cpufreq/brcmstb-avs-cpufreq.c:44:
In function 'devm_kmalloc_array',
    inlined from 'devm_kcalloc' at include/linux/device.h:328:9,
    inlined from 'brcm_avs_get_freq_table' at drivers/cpufreq/brcmstb-avs-cpufreq.c:437:10,
    inlined from 'brcm_avs_cpufreq_init' at drivers/cpufreq/brcmstb-avs-cpufreq.c:623:15:
include/linux/device.h:323:16: note: at offset 60 into object of size 60 allocated by 'devm_kmalloc'
  323 |         return devm_kmalloc(dev, bytes, flags);
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -Warray-bounds.

Link: https://github.com/KSPP/linux/issues/324
Fixes: de322e085995 ("cpufreq: brcmstb-avs-cpufreq: AVS CPUfreq driver for Broadcom STB SoCs")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva 
Reviewed-by: Florian Fainelli 
Signed-off-by: Viresh Kumar 
Signed-off-by: Greg Kroah-Hartman

cpufreq: Fix the race condition while updating the transition_task of policy

2023-09-13T07:42:59+00:00

[ Upstream commit 61bfbf7951ba561dcbdd5357702d3cbc2d447812 ]

The field 'transition_task' of policy structure is used to track the
task which is performing the frequency transition. Using this field to
print a warning once detect a case where the same task is calling
_begin() again before completing the preivous frequency transition via
the _end().

However, there is a potential race condition in _end() and _begin() APIs
while updating the field 'transition_task' of policy, the scenario is
depicted below:

             Task A                            Task B

        /* 1st freq transition */
        Invoke _begin() {
                ...
                ...
        }
                                        /* 2nd freq transition */
                                        Invoke _begin() {
                                                ... //waiting for A to
                                                ... //clear
                                                ... //transition_ongoing
                                                ... //in _end() for
                                                ... //the 1st transition
                                                        |
        Change the frequency                            |
                                                        |
        Invoke _end() {                                 |
                ...                                     |
                ...                                     |
                transition_ongoing = false;             V
                                                transition_ongoing = true;
                                                transition_task = current;
                transition_task = NULL;
                ... //A overwrites the task
                ... //performing the transition
                ... //result in error warning.
        }

To fix this race condition, the transition_lock of policy structure is
now acquired before updating policy structure in _end() API. Which ensure
that only one task can update the 'transition_task' field at a time.

Link: https://lore.kernel.org/all/b3c61d8a-d52d-3136-fbf0-d1de9f1ba411@huawei.com/
Fixes: ca654dc3a93d ("cpufreq: Catch double invocations of cpufreq_freq_transition_begin/end")
Signed-off-by: Liao Chang 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: powernow-k8: Use related_cpus instead of cpus in driver.exit()

2023-09-13T07:42:30+00:00

[ Upstream commit 03997da042dac73c69e60d91942c727c76828b65 ]

Since the 'cpus' field of policy structure will become empty in the
cpufreq core API, it is better to use 'related_cpus' in the exit()
callback of driver.

Fixes: c3274763bfc3 ("cpufreq: powernow-k8: Initialize per-cpu data-structures properly")
Signed-off-by: Liao Chang 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin