| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20241205222847.7889-14-mario.limonciello@amd.com>
Date: Thu, 5 Dec 2024 16:28:45 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>
CC: Perry Yuan <perry.yuan@....com>, <linux-kernel@...r.kernel.org>,
<linux-pm@...r.kernel.org>, Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH 13/15] cpufreq/amd-pstate: Check if CPPC request has changed before writing to the MSR or shared memory
Move the common MSR field formatting code to msr_update_perf() from
its callers.
Ensure that the MSR write is necessary before flushing a write out.
Also drop the comparison from the passive flow tracing.
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
drivers/cpufreq/amd-pstate-trace.h | 7 +----
drivers/cpufreq/amd-pstate.c | 47 +++++++++++-------------------
2 files changed, 18 insertions(+), 36 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate-trace.h b/drivers/cpufreq/amd-pstate-trace.h
index e2221a4b6901c..8d692415d9050 100644
--- a/drivers/cpufreq/amd-pstate-trace.h
+++ b/drivers/cpufreq/amd-pstate-trace.h
@@ -32,7 +32,6 @@ TRACE_EVENT(amd_pstate_perf,
u64 aperf,
u64 tsc,
unsigned int cpu_id,
- bool changed,
bool fast_switch
),
@@ -44,7 +43,6 @@ TRACE_EVENT(amd_pstate_perf,
aperf,
tsc,
cpu_id,
- changed,
fast_switch
),
@@ -57,7 +55,6 @@ TRACE_EVENT(amd_pstate_perf,
__field(unsigned long long, aperf)
__field(unsigned long long, tsc)
__field(unsigned int, cpu_id)
- __field(bool, changed)
__field(bool, fast_switch)
),
@@ -70,11 +67,10 @@ TRACE_EVENT(amd_pstate_perf,
__entry->aperf = aperf;
__entry->tsc = tsc;
__entry->cpu_id = cpu_id;
- __entry->changed = changed;
__entry->fast_switch = fast_switch;
),
- TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s fast_switch=%s",
+ TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u fast_switch=%s",
(unsigned long)__entry->min_perf,
(unsigned long)__entry->target_perf,
(unsigned long)__entry->capacity,
@@ -83,7 +79,6 @@ TRACE_EVENT(amd_pstate_perf,
(unsigned long long)__entry->aperf,
(unsigned long long)__entry->tsc,
(unsigned int)__entry->cpu_id,
- (__entry->changed) ? "true" : "false",
(__entry->fast_switch) ? "true" : "false"
)
);
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 8598f50e18b58..06464e2dd905f 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -224,15 +224,26 @@ static s16 shmem_get_epp(struct amd_cpudata *cpudata)
static int msr_update_perf(struct amd_cpudata *cpudata, u32 min_perf,
u32 des_perf, u32 max_perf, u32 epp, bool fast_switch)
{
- u64 value;
+ u64 value, prev;
+
+ value = prev = READ_ONCE(cpudata->cppc_req_cached);
+
+ value &= ~(AMD_PSTATE_MAX_PERF_MASK | AMD_PSTATE_MIN_PERF_MASK |
+ AMD_PSTATE_DES_PERF_MASK | AMD_PSTATE_EPP_PERF_MASK);
+ value |= FIELD_PREP(AMD_PSTATE_MAX_PERF_MASK, max_perf);
+ value |= FIELD_PREP(AMD_PSTATE_DES_PERF_MASK, des_perf);
+ value |= FIELD_PREP(AMD_PSTATE_MIN_PERF_MASK, min_perf);
+ value |= FIELD_PREP(AMD_PSTATE_EPP_PERF_MASK, epp);
+
+ if (value == prev)
+ return 0;
- value = READ_ONCE(cpudata->cppc_req_cached);
if (fast_switch) {
- wrmsrl(MSR_AMD_CPPC_REQ, READ_ONCE(cpudata->cppc_req_cached));
+ wrmsrl(MSR_AMD_CPPC_REQ, value);
return 0;
} else {
- int ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
- READ_ONCE(cpudata->cppc_req_cached));
+ int ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+
if (ret)
return ret;
}
@@ -528,9 +539,7 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
{
unsigned long max_freq;
struct cpufreq_policy *policy = cpufreq_cpu_get(cpudata->cpu);
- u64 prev = READ_ONCE(cpudata->cppc_req_cached);
u32 nominal_perf = READ_ONCE(cpudata->nominal_perf);
- u64 value = prev;
des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
@@ -546,27 +555,14 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
if (!cpudata->boost_supported)
max_perf = min_t(unsigned long, nominal_perf, max_perf);
- value &= ~(AMD_PSTATE_MAX_PERF_MASK | AMD_PSTATE_MIN_PERF_MASK |
- AMD_PSTATE_DES_PERF_MASK);
- value |= FIELD_PREP(AMD_PSTATE_MAX_PERF_MASK, max_perf);
- value |= FIELD_PREP(AMD_PSTATE_DES_PERF_MASK, des_perf);
- value |= FIELD_PREP(AMD_PSTATE_MIN_PERF_MASK, min_perf);
-
if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) {
trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq,
cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,
- cpudata->cpu, (value != prev), fast_switch);
+ cpudata->cpu, fast_switch);
}
- if (value == prev)
- goto cpufreq_policy_put;
-
- WRITE_ONCE(cpudata->cppc_req_cached, value);
-
amd_pstate_update_perf(cpudata, min_perf, des_perf, max_perf, 0, fast_switch);
-cpufreq_policy_put:
-
cpufreq_cpu_put(policy);
}
@@ -1564,19 +1560,10 @@ static void amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
{
struct amd_cpudata *cpudata = policy->driver_data;
- u64 value;
u32 epp;
amd_pstate_update_min_max_limit(policy);
- value = READ_ONCE(cpudata->cppc_req_cached);
-
- value &= ~(AMD_PSTATE_MAX_PERF_MASK | AMD_PSTATE_MIN_PERF_MASK |
- AMD_PSTATE_DES_PERF_MASK | AMD_PSTATE_EPP_PERF_MASK);
- value |= FIELD_PREP(AMD_PSTATE_MAX_PERF_MASK, cpudata->max_limit_perf);
- value |= FIELD_PREP(AMD_PSTATE_DES_PERF_MASK, 0);
- value |= FIELD_PREP(AMD_PSTATE_MIN_PERF_MASK, cpudata->min_limit_perf);
-
if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
epp = 0;
else
--
2.43.0
Powered by blists - more mailing lists