linux-kernel - [PATCH AUTOSEL 4.18 101/131] drm/amd/display: Prevent PSR from being enabled if initialization fails

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180902064601.183036-101-alexander.levin@microsoft.com>
Date:   Sun, 2 Sep 2018 13:05:10 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "anthony.koo@....com" <anthony.koo@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 101/131] drm/amd/display: Prevent PSR from being
 enabled if initialization fails

From: Anthony Koo <Anthony.Koo@....com>

[ Upstream commit 9907704174e0ad4ed02766fac4049971e583323d ]

[Why]
PSR_SET command is sent to the microcontroller in order to initialize
parameters needed for PSR feature, such as telling the microcontroller
which pipe is driving the PSR supported panel. When this command is
skipped or fails, the microcontroller may program the wrong thing if
driver tries to enable PSR.

[How]
If PSR_SET fails, do not set psr_enable flag to indicate the feature is
not yet initialized.

Signed-off-by: Anthony Koo <Anthony.Koo@....com>
Reviewed-by: Aric Cyr <Aric.Cyr@....com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c | 38 +++++++++++--------
 drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h  |  2 +-
 2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
index a576b8bbb3cd..dea40b322191 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
@@ -150,7 +150,7 @@ static void dce_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 	}
 }
 
-static void dce_dmcu_setup_psr(struct dmcu *dmcu,
+static bool dce_dmcu_setup_psr(struct dmcu *dmcu,
 		struct dc_link *link,
 		struct psr_context *psr_context)
 {
@@ -261,6 +261,8 @@ static void dce_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
+
+	return true;
 }
 
 static bool dce_is_dmcu_initialized(struct dmcu *dmcu)
@@ -545,24 +547,25 @@ static void dcn10_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 	 *  least a few frames. Should never hit the max retry assert below.
 	 */
 	if (wait == true) {
-	for (retryCount = 0; retryCount <= 1000; retryCount++) {
-		dcn10_get_dmcu_psr_state(dmcu, &psr_state);
-		if (enable) {
-			if (psr_state != 0)
-				break;
-		} else {
-			if (psr_state == 0)
-				break;
+		for (retryCount = 0; retryCount <= 1000; retryCount++) {
+			dcn10_get_dmcu_psr_state(dmcu, &psr_state);
+			if (enable) {
+				if (psr_state != 0)
+					break;
+			} else {
+				if (psr_state == 0)
+					break;
+			}
+			udelay(500);
 		}
-		udelay(500);
-	}
 
-	/* assert if max retry hit */
-	ASSERT(retryCount <= 1000);
+		/* assert if max retry hit */
+		if (retryCount >= 1000)
+			ASSERT(0);
 	}
 }
 
-static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
+static bool dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 		struct dc_link *link,
 		struct psr_context *psr_context)
 {
@@ -577,7 +580,7 @@ static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* If microcontroller is not running, do nothing */
 	if (dmcu->dmcu_state != DMCU_RUNNING)
-		return;
+		return false;
 
 	link->link_enc->funcs->psr_program_dp_dphy_fast_training(link->link_enc,
 			psr_context->psrExitLinkTrainingRequired);
@@ -677,6 +680,11 @@ static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
+
+	/* waitDMCUReadyForCmd */
+	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0, 1, 10000);
+
+	return true;
 }
 
 static void dcn10_psr_wait_loop(
diff --git a/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h b/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
index de60f940030d..4550747fb61c 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
@@ -48,7 +48,7 @@ struct dmcu_funcs {
 			const char *src,
 			unsigned int bytes);
 	void (*set_psr_enable)(struct dmcu *dmcu, bool enable, bool wait);
-	void (*setup_psr)(struct dmcu *dmcu,
+	bool (*setup_psr)(struct dmcu *dmcu,
 			struct dc_link *link,
 			struct psr_context *psr_context);
 	void (*get_psr_state)(struct dmcu *dmcu, uint32_t *psr_state);
-- 
2.17.1