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Message-Id: <1458564569-19672-4-git-send-email-prarit@redhat.com>
Date: Mon, 21 Mar 2016 08:49:29 -0400
From: Prarit Bhargava <prarit@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Prarit Bhargava <prarit@...hat.com>
Subject: [PATCH 3/3] cpuidle, Prevent users from enabling cstates that are disabled in Hardware
The current codebase allows a user to enable a cstate even though the
hardware has disabled it. This patch adds state checking and prevents
userspace from setting a hardware disabled cstate to enabled.
Signed-off-by: Prarit Bhargava <prarit@...hat.com>
---
drivers/cpuidle/governors/ladder.c | 3 +++
drivers/cpuidle/governors/menu.c | 4 ++++
drivers/cpuidle/sysfs.c | 34 ++++++++++++++++++++++++++++++++--
drivers/idle/intel_idle.c | 6 ++++--
include/linux/cpuidle.h | 10 ++++++++--
5 files changed, 51 insertions(+), 6 deletions(-)
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 63bd5a4..680e5ee 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -144,6 +144,9 @@ static int ladder_enable_device(struct cpuidle_driver *drv,
state = &drv->states[i];
lstate = &ldev->states[i];
+ /* Some states may be disabled by hardware */
+ dev->states_usage[i].disable = drv->states[i].disabled;
+
lstate->stats.promotion_count = 0;
lstate->stats.demotion_count = 0;
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 0742b32..7351e0d 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -466,6 +466,10 @@ static int menu_enable_device(struct cpuidle_driver *drv,
for(i = 0; i < BUCKETS; i++)
data->correction_factor[i] = RESOLUTION * DECAY;
+ /* Some states may be disabled by hardware */
+ for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++)
+ dev->states_usage[i].disable = drv->states[i].disabled;
+
return 0;
}
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 832a2c3..313d1aa 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -274,6 +274,38 @@ static ssize_t store_state_##_name(struct cpuidle_state *state, \
return size; \
}
+static ssize_t store_state_disable(struct cpuidle_state *state,
+ struct cpuidle_state_usage *state_usage,
+ const char *buf, size_t size)
+{
+ unsigned long long value;
+ int err;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (state_usage->disable == CPUIDLE_STATE_HW_DISABLE) {
+ pr_info("cpuidle: state %s is disabled by hardware.\n",
+ state->name);
+ return -EINVAL;
+ }
+
+ err = kstrtoull(buf, 0, &value);
+ if (err)
+ return err;
+ if (value)
+ state_usage->disable = CPUIDLE_STATE_DISABLE;
+ else
+ state_usage->disable = CPUIDLE_STATE_ENABLE;
+ return size;
+}
+
+static ssize_t show_state_disable(struct cpuidle_state *state,
+ struct cpuidle_state_usage *state_usage,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", !!state_usage->disable);
+}
+
#define define_show_state_ull_function(_name) \
static ssize_t show_state_##_name(struct cpuidle_state *state, \
struct cpuidle_state_usage *state_usage, \
@@ -299,8 +331,6 @@ define_show_state_ull_function(usage)
define_show_state_ull_function(time)
define_show_state_str_function(name)
define_show_state_str_function(desc)
-define_show_state_ull_function(disable)
-define_store_state_ull_function(disable)
define_one_state_ro(name, show_state_name);
define_one_state_ro(desc, show_state_desc);
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 58bc913..f23d0f6 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -1142,10 +1142,12 @@ static int __init intel_idle_cpuidle_driver_init(void)
/* Has this state been disabled in hardware? */
if (limit < cpuidle_state_table[cstate].limit) {
- cpuidle_state_table[cstate].disabled = 1;
- pr_debug(PREFIX "state %s (0x%x) is disabled. Max Package limit is 0x%x.\n",
+ cpuidle_state_table[cstate].disabled =
+ CPUIDLE_STATE_HW_DISABLE;
+ pr_debug(PREFIX "state %s (0x%x) is disabled and set to %d. Max Package limit is 0x%x.\n",
cpuidle_state_table[cstate].name,
cpuidle_state_table[cstate].limit,
+ cpuidle_state_table[cstate].disabled,
limit);
}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 8bcfabb..0e59e17 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -29,8 +29,14 @@ struct cpuidle_driver;
* CPUIDLE DEVICE INTERFACE *
****************************/
+enum cpuidle_state_disable {
+ CPUIDLE_STATE_ENABLE = 0,
+ CPUIDLE_STATE_DISABLE = 1,
+ CPUIDLE_STATE_HW_DISABLE = 2,
+};
+
struct cpuidle_state_usage {
- unsigned long long disable;
+ enum cpuidle_state_disable disable;
unsigned long long usage;
unsigned long long time; /* in US */
};
@@ -44,7 +50,7 @@ struct cpuidle_state {
unsigned int exit_latency; /* in US */
int power_usage; /* in mW */
unsigned int target_residency; /* in US */
- bool disabled; /* disabled on all CPUs */
+ enum cpuidle_state_disable disabled; /* disabled on all CPUs */
int (*enter) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
--
1.7.9.3
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