The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023052858-overgrown-profile-8066@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

4badf2eb1e98 ("cpufreq: amd-pstate: Add ->fast_switch() callback") 2dd6d0ebf740 ("cpufreq: amd-pstate: Add guided autonomous mode") 3e6e07805764 ("Documentation: cpufreq: amd-pstate: Move amd_pstate param to alphabetical order") 5014603e409b ("Documentation: introduce amd pstate active mode kernel command line options") ffa5096a7c33 ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors") 36c5014e5460 ("cpufreq: amd-pstate: optimize driver working mode selection in amd_pstate_param()") 4f3085f87b51 ("cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4badf2eb1e986bdbf34dd2f5d4c979553a86fe54 Mon Sep 17 00:00:00 2001 From: "Gautham R. Shenoy" gautham.shenoy@amd.com Date: Wed, 17 May 2023 16:28:15 +0000 Subject: [PATCH] cpufreq: amd-pstate: Add ->fast_switch() callback

Schedutil normally calls the adjust_perf callback for drivers with adjust_perf callback available and fast_switch_possible flag set. However, when frequency invariance is disabled and schedutil tries to invoke fast_switch. So, there is a chance of kernel crash if this function pointer is not set. To protect against this scenario add fast_switch callback to amd_pstate driver.

Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State") Signed-off-by: Gautham R. Shenoy gautham.shenoy@amd.com Signed-off-by: Wyes Karny wyes.karny@amd.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 5a3d4aa0f45a..45711fc0a856 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -444,9 +444,8 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy) return 0; }

-static int amd_pstate_target(struct cpufreq_policy *policy, - unsigned int target_freq, - unsigned int relation) +static int amd_pstate_update_freq(struct cpufreq_policy *policy, + unsigned int target_freq, bool fast_switch) { struct cpufreq_freqs freqs; struct amd_cpudata *cpudata = policy->driver_data; @@ -465,14 +464,37 @@ static int amd_pstate_target(struct cpufreq_policy *policy, des_perf = DIV_ROUND_CLOSEST(target_freq * cap_perf, cpudata->max_freq);

- cpufreq_freq_transition_begin(policy, &freqs); + WARN_ON(fast_switch && !policy->fast_switch_enabled); + /* + * If fast_switch is desired, then there aren't any registered + * transition notifiers. See comment for + * cpufreq_enable_fast_switch(). + */ + if (!fast_switch) + cpufreq_freq_transition_begin(policy, &freqs); + amd_pstate_update(cpudata, min_perf, des_perf, - max_perf, false, policy->governor->flags); - cpufreq_freq_transition_end(policy, &freqs, false); + max_perf, fast_switch, policy->governor->flags); + + if (!fast_switch) + cpufreq_freq_transition_end(policy, &freqs, false);

return 0; }

+static int amd_pstate_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + return amd_pstate_update_freq(policy, target_freq, false); +} + +static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + return amd_pstate_update_freq(policy, target_freq, true); +} + static void amd_pstate_adjust_perf(unsigned int cpu, unsigned long _min_perf, unsigned long target_perf, @@ -715,6 +737,7 @@ static int amd_pstate_cpu_exit(struct cpufreq_policy *policy)

freq_qos_remove_request(&cpudata->req[1]); freq_qos_remove_request(&cpudata->req[0]); + policy->fast_switch_possible = false; kfree(cpudata);

return 0; @@ -1309,6 +1332,7 @@ static struct cpufreq_driver amd_pstate_driver = { .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, .verify = amd_pstate_verify, .target = amd_pstate_target, + .fast_switch = amd_pstate_fast_switch, .init = amd_pstate_cpu_init, .exit = amd_pstate_cpu_exit, .suspend = amd_pstate_cpu_suspend,