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From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: gregkh@linuxfoundation.org
Cc: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 13/23] coresight: tmc: Fix TMC mode read in tmc_read_prepare_etb()
Date: Mon, 18 May 2020 12:02:32 -0600
Message-ID: <20200518180242.7916-14-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20200518180242.7916-1-mathieu.poirier@linaro.org>

From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>

On some QCOM platforms like SC7180, SDM845 and SM8150,
reading TMC mode register without proper coresight power
management can lead to async exceptions like the one in
the call trace below in tmc_read_prepare_etb(). This can
happen if the user tries to read the TMC etf data via
device node without setting up source and the sink first.
Fix this by having a check for coresight sysfs mode
before reading TMC mode management register.

 Kernel panic - not syncing: Asynchronous SError Interrupt
 CPU: 7 PID: 2605 Comm: hexdump Tainted: G S                5.4.30 #122
 Call trace:
  dump_backtrace+0x0/0x188
  show_stack+0x20/0x2c
  dump_stack+0xdc/0x144
  panic+0x168/0x36c
  panic+0x0/0x36c
  arm64_serror_panic+0x78/0x84
  do_serror+0x130/0x138
  el1_error+0x84/0xf8
  tmc_read_prepare_etb+0x88/0xb8
  tmc_open+0x40/0xd8
  misc_open+0x120/0x158
  chrdev_open+0xb8/0x1a4
  do_dentry_open+0x268/0x3a0
  vfs_open+0x34/0x40
  path_openat+0x39c/0xdf4
  do_filp_open+0x90/0x10c
  do_sys_open+0x150/0x3e8
  __arm64_compat_sys_openat+0x28/0x34
  el0_svc_common+0xa8/0x160
  el0_svc_compat_handler+0x2c/0x38
  el0_svc_compat+0x8/0x10

Fixes: 4525412a5046 ("coresight: tmc: making prepare/unprepare functions generic")
Reported-by: Stephen Boyd <swboyd@chromium.org>
Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index d0cc3985b72a..36cce2bfb744 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -596,13 +596,6 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
 		goto out;
 	}
 
-	/* There is no point in reading a TMC in HW FIFO mode */
-	mode = readl_relaxed(drvdata->base + TMC_MODE);
-	if (mode != TMC_MODE_CIRCULAR_BUFFER) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	/* Don't interfere if operated from Perf */
 	if (drvdata->mode == CS_MODE_PERF) {
 		ret = -EINVAL;
@@ -616,8 +609,15 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
 	}
 
 	/* Disable the TMC if need be */
-	if (drvdata->mode == CS_MODE_SYSFS)
+	if (drvdata->mode == CS_MODE_SYSFS) {
+		/* There is no point in reading a TMC in HW FIFO mode */
+		mode = readl_relaxed(drvdata->base + TMC_MODE);
+		if (mode != TMC_MODE_CIRCULAR_BUFFER) {
+			ret = -EINVAL;
+			goto out;
+		}
 		__tmc_etb_disable_hw(drvdata);
+	}
 
 	drvdata->reading = true;
 out:
-- 
2.20.1


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  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18 18:02 [PATCH 00/23] coresight: next for v5.8 Mathieu Poirier
2020-05-18 18:02 ` [PATCH 01/23] coresight: Pass coresight_device for coresight_release_platform_data Mathieu Poirier
2020-05-18 18:02 ` [PATCH 02/23] coresight: Add return value for fixup connections Mathieu Poirier
2020-05-18 18:02 ` [PATCH 03/23] coresight: Add generic sysfs link creation functions Mathieu Poirier
2020-05-18 18:02 ` [PATCH 04/23] coresight: Expose device connections via sysfs Mathieu Poirier
2020-05-18 18:02 ` [PATCH 05/23] coresight: cti: Add in sysfs links to other coresight devices Mathieu Poirier
2020-05-18 18:02 ` [PATCH 06/23] coresight: docs: Add information about the topology representations Mathieu Poirier
2020-05-18 18:02 ` [PATCH 07/23] docs: trace: coresight-ect.rst: Fix a build warning Mathieu Poirier
2020-05-18 18:02 ` [PATCH 08/23] coresight: etm4x: Add support for Qualcomm SC7180 SoC Mathieu Poirier
2020-05-18 18:02 ` [PATCH 09/23] coresight: etm4x: Replace ETM PIDs with UCI IDs for Kryo385 Mathieu Poirier
2020-05-18 18:02 ` [PATCH 10/23] coresight: cti: Make some symbols static Mathieu Poirier
2020-05-18 18:02 ` [PATCH 11/23] coresight: etb10: Make coresight_etb_groups static Mathieu Poirier
2020-05-18 18:02 ` [PATCH 12/23] coresight: Fix support for sparsely populated ports Mathieu Poirier
2020-05-18 18:02 ` Mathieu Poirier [this message]
2020-05-18 18:02 ` [PATCH 14/23] coresight: etmv4: Update default filter and initialisation Mathieu Poirier
2020-05-18 18:02 ` [PATCH 15/23] coresight: etm4x: Add support for Neoverse N1 ETM Mathieu Poirier
2020-05-18 18:02 ` [PATCH 16/23] coresight: Mark some functions static Mathieu Poirier
2020-05-18 18:02 ` [PATCH 17/23] coresight: Don't initialize variables unnecessarily Mathieu Poirier
2020-05-18 18:02 ` [PATCH 18/23] coresight: Initialize arg in sparse friendly way Mathieu Poirier
2020-05-18 18:02 ` [PATCH 19/23] coresight: Include required headers in C files Mathieu Poirier
2020-05-18 18:02 ` [PATCH 20/23] coresight: Avoid casting void pointers Mathieu Poirier
2020-05-18 18:02 ` [PATCH 21/23] coresight: etm4x: Fix use-after-free of per-cpu etm drvdata Mathieu Poirier
2020-05-19 14:32   ` Greg KH
2020-05-18 18:02 ` [PATCH 22/23] coresight: cti: Add CPU Hotplug handling to CTI driver Mathieu Poirier
2020-05-18 18:02 ` [PATCH 23/23] coresight: cti: Add CPU idle pm notifer to CTI devices Mathieu Poirier

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