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Subject[PATCH 5.4 106/309] crypto: ccree - fix PM race condition
Date
From: Gilad Ben-Yossef <gilad@benyossef.com>

commit 15fd2566bf54ee4d4781d8f170acfc9472a1541f upstream.

The PM code was racy, possibly causing the driver to submit
requests to a powered down device. Fix the race and while
at it simplify the PM code.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Fixes: 1358c13a48c4 ("crypto: ccree - fix resume race condition on init")
Cc: stable@kernel.org # v4.20
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/ccree/cc_driver.h | 1
drivers/crypto/ccree/cc_pm.c | 28 ++++---------------
drivers/crypto/ccree/cc_request_mgr.c | 50 ----------------------------------
drivers/crypto/ccree/cc_request_mgr.h | 8 -----
4 files changed, 7 insertions(+), 80 deletions(-)

--- a/drivers/crypto/ccree/cc_driver.h
+++ b/drivers/crypto/ccree/cc_driver.h
@@ -161,6 +161,7 @@ struct cc_drvdata {
int std_bodies;
bool sec_disabled;
u32 comp_mask;
+ bool pm_on;
};

struct cc_crypto_alg {
--- a/drivers/crypto/ccree/cc_pm.c
+++ b/drivers/crypto/ccree/cc_pm.c
@@ -22,14 +22,8 @@ const struct dev_pm_ops ccree_pm = {
int cc_pm_suspend(struct device *dev)
{
struct cc_drvdata *drvdata = dev_get_drvdata(dev);
- int rc;

dev_dbg(dev, "set HOST_POWER_DOWN_EN\n");
- rc = cc_suspend_req_queue(drvdata);
- if (rc) {
- dev_err(dev, "cc_suspend_req_queue (%x)\n", rc);
- return rc;
- }
fini_cc_regs(drvdata);
cc_iowrite(drvdata, CC_REG(HOST_POWER_DOWN_EN), POWER_DOWN_ENABLE);
cc_clk_off(drvdata);
@@ -63,13 +57,6 @@ int cc_pm_resume(struct device *dev)
/* check if tee fips error occurred during power down */
cc_tee_handle_fips_error(drvdata);

- rc = cc_resume_req_queue(drvdata);
- if (rc) {
- dev_err(dev, "cc_resume_req_queue (%x)\n", rc);
- return rc;
- }
-
- /* must be after the queue resuming as it uses the HW queue*/
cc_init_hash_sram(drvdata);

return 0;
@@ -80,10 +67,8 @@ int cc_pm_get(struct device *dev)
int rc = 0;
struct cc_drvdata *drvdata = dev_get_drvdata(dev);

- if (cc_req_queue_suspended(drvdata))
+ if (drvdata->pm_on)
rc = pm_runtime_get_sync(dev);
- else
- pm_runtime_get_noresume(dev);

return (rc == 1 ? 0 : rc);
}
@@ -93,14 +78,11 @@ int cc_pm_put_suspend(struct device *dev
int rc = 0;
struct cc_drvdata *drvdata = dev_get_drvdata(dev);

- if (!cc_req_queue_suspended(drvdata)) {
+ if (drvdata->pm_on) {
pm_runtime_mark_last_busy(dev);
rc = pm_runtime_put_autosuspend(dev);
- } else {
- /* Something wrong happens*/
- dev_err(dev, "request to suspend already suspended queue");
- rc = -EBUSY;
}
+
return rc;
}

@@ -117,7 +99,7 @@ int cc_pm_init(struct cc_drvdata *drvdat
/* must be before the enabling to avoid resdundent suspending */
pm_runtime_set_autosuspend_delay(dev, CC_SUSPEND_TIMEOUT);
pm_runtime_use_autosuspend(dev);
- /* activate the PM module */
+ /* set us as active - note we won't do PM ops until cc_pm_go()! */
return pm_runtime_set_active(dev);
}

@@ -125,9 +107,11 @@ int cc_pm_init(struct cc_drvdata *drvdat
void cc_pm_go(struct cc_drvdata *drvdata)
{
pm_runtime_enable(drvdata_to_dev(drvdata));
+ drvdata->pm_on = true;
}

void cc_pm_fini(struct cc_drvdata *drvdata)
{
pm_runtime_disable(drvdata_to_dev(drvdata));
+ drvdata->pm_on = false;
}
--- a/drivers/crypto/ccree/cc_request_mgr.c
+++ b/drivers/crypto/ccree/cc_request_mgr.c
@@ -41,7 +41,6 @@ struct cc_req_mgr_handle {
#else
struct tasklet_struct comptask;
#endif
- bool is_runtime_suspended;
};

struct cc_bl_item {
@@ -678,52 +677,3 @@ static void comp_handler(unsigned long d
cc_proc_backlog(drvdata);
dev_dbg(dev, "Comp. handler done.\n");
}
-
-/*
- * resume the queue configuration - no need to take the lock as this happens
- * inside the spin lock protection
- */
-#if defined(CONFIG_PM)
-int cc_resume_req_queue(struct cc_drvdata *drvdata)
-{
- struct cc_req_mgr_handle *request_mgr_handle =
- drvdata->request_mgr_handle;
-
- spin_lock_bh(&request_mgr_handle->hw_lock);
- request_mgr_handle->is_runtime_suspended = false;
- spin_unlock_bh(&request_mgr_handle->hw_lock);
-
- return 0;
-}
-
-/*
- * suspend the queue configuration. Since it is used for the runtime suspend
- * only verify that the queue can be suspended.
- */
-int cc_suspend_req_queue(struct cc_drvdata *drvdata)
-{
- struct cc_req_mgr_handle *request_mgr_handle =
- drvdata->request_mgr_handle;
-
- /* lock the send_request */
- spin_lock_bh(&request_mgr_handle->hw_lock);
- if (request_mgr_handle->req_queue_head !=
- request_mgr_handle->req_queue_tail) {
- spin_unlock_bh(&request_mgr_handle->hw_lock);
- return -EBUSY;
- }
- request_mgr_handle->is_runtime_suspended = true;
- spin_unlock_bh(&request_mgr_handle->hw_lock);
-
- return 0;
-}
-
-bool cc_req_queue_suspended(struct cc_drvdata *drvdata)
-{
- struct cc_req_mgr_handle *request_mgr_handle =
- drvdata->request_mgr_handle;
-
- return request_mgr_handle->is_runtime_suspended;
-}
-
-#endif
--- a/drivers/crypto/ccree/cc_request_mgr.h
+++ b/drivers/crypto/ccree/cc_request_mgr.h
@@ -40,12 +40,4 @@ void complete_request(struct cc_drvdata

void cc_req_mgr_fini(struct cc_drvdata *drvdata);

-#if defined(CONFIG_PM)
-int cc_resume_req_queue(struct cc_drvdata *drvdata);
-
-int cc_suspend_req_queue(struct cc_drvdata *drvdata);
-
-bool cc_req_queue_suspended(struct cc_drvdata *drvdata);
-#endif
-
#endif /*__REQUEST_MGR_H__*/

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