6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Linu Cherian <lcherian@xxxxxxxxxxx>
commit bd2767ec3df2775bc336f441f9068a989ccb919d upstream.
Fix the below warning by avoding calls to tmc_etr_enable_hw,
if we are reusing the ETR buffer for multiple sources in sysfs mode.
echo 1 > /sys/bus/coresight/devices/tmc_etr0/enable_sink
echo 1 > /sys/bus/coresight/devices/ete1/enable_source
echo 1 > /sys/bus/coresight/devices/ete2/enable_source
[ 166.918290] ------------[ cut here ]------------
[ 166.922905] WARNING: CPU: 4 PID: 2288 at
drivers/hwtracing/coresight/coresight-tmc-etr.c:1037
tmc_etr_enable_hw+0xb0/0xc8
[ 166.933862] Modules linked in:
[ 166.936911] CPU: 4 PID: 2288 Comm: bash Not tainted 6.5.0-rc7 #132
[ 166.943084] Hardware name: Marvell CN106XX board (DT)
[ 166.948127] pstate: 834000c9 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS
BTYPE=--)
[ 166.955083] pc : tmc_etr_enable_hw+0xb0/0xc8
[ 166.959345] lr : tmc_enable_etr_sink+0x134/0x210
snip..
167.038545] Call trace:
[ 167.040982] tmc_etr_enable_hw+0xb0/0xc8
[ 167.044897] tmc_enable_etr_sink+0x134/0x210
[ 167.049160] coresight_enable_path+0x160/0x278
[ 167.053596] coresight_enable+0xd4/0x298
[ 167.057510] enable_source_store+0x54/0xa0
[ 167.061598] dev_attr_store+0x20/0x40
[ 167.065254] sysfs_kf_write+0x4c/0x68
[ 167.068909] kernfs_fop_write_iter+0x128/0x200
[ 167.073345] vfs_write+0x1ac/0x2f8
[ 167.076739] ksys_write+0x74/0x110
[ 167.080132] __arm64_sys_write+0x24/0x38
[ 167.084045] invoke_syscall.constprop.0+0x58/0xf8
[ 167.088744] do_el0_svc+0x60/0x160
[ 167.092137] el0_svc+0x40/0x170
[ 167.095273] el0t_64_sync_handler+0x100/0x130
[ 167.099621] el0t_64_sync+0x190/0x198
[ 167.103277] ---[ end trace 0000000000000000 ]---
-bash: echo: write error: Device or resource busy
Fixes: 296b01fd106e ("coresight: Refactor out buffer allocation function for ETR")
Signed-off-by: Linu Cherian <lcherian@xxxxxxxxxxx>
Reviewed-by: James Clark <james.clark@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Link: https://lore.kernel.org/r/20230823042948.12879-1-lcherian@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
.../hwtracing/coresight/coresight-tmc-etr.c | 24 ++++++++++---------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 66dc5f97a009..6132c5b3db9c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1173,16 +1173,6 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev)
goto out;
}
- /*
- * In sysFS mode we can have multiple writers per sink. Since this
- * sink is already enabled no memory is needed and the HW need not be
- * touched, even if the buffer size has changed.
- */
- if (drvdata->mode == CS_MODE_SYSFS) {
- atomic_inc(&csdev->refcnt);
- goto out;
- }
-
/*
* If we don't have a buffer or it doesn't match the requested size,
* use the buffer allocated above. Otherwise reuse the existing buffer.
@@ -1204,7 +1194,7 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev)
static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
{
- int ret;
+ int ret = 0;
unsigned long flags;
struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
struct etr_buf *sysfs_buf = tmc_etr_get_sysfs_buffer(csdev);
@@ -1213,12 +1203,24 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
return PTR_ERR(sysfs_buf);
spin_lock_irqsave(&drvdata->spinlock, flags);
+
+ /*
+ * In sysFS mode we can have multiple writers per sink. Since this
+ * sink is already enabled no memory is needed and the HW need not be
+ * touched, even if the buffer size has changed.
+ */
+ if (drvdata->mode == CS_MODE_SYSFS) {
+ atomic_inc(&csdev->refcnt);
+ goto out;
+ }
+
ret = tmc_etr_enable_hw(drvdata, sysfs_buf);
if (!ret) {
drvdata->mode = CS_MODE_SYSFS;
atomic_inc(&csdev->refcnt);
}
+out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
if (!ret)
--
2.42.0
