linux-toradex-rt_4.14-2.0.x: prevent bug backtraces

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

3 files changed, 89 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0001-imx_sc_thermal-prevent-BUG-with-rt-patch.patch b/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0001-imx_sc_thermal-prevent-BUG-with-rt-patch.patch
new file mode 100644
index 0000000..c796fa4
--- /dev/null
+++ b/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0001-imx_sc_thermal-prevent-BUG-with-rt-patch.patch
@@ -0,0 +1,53 @@
+From 4e6114a23a21db5741375070add8ccc16697db67 Mon Sep 17 00:00:00 2001
+From: Max Krummenacher <max.krummenacher@toradex.com>
+Date: Tue, 24 Sep 2019 14:15:50 +0200
+Subject: [PATCH 1/2] imx_sc_thermal: prevent BUG() with rt patch
+
+With the RT patch applied the kernel prints a BUG backtrace during boot:
+
+| BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
+
+Prevent this by avoiding the smp_processor_id call and just check the both
+CPU clusters which may be there in a i.MX8 series SoC.
+
+Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
+---
+ drivers/thermal/imx_sc_thermal.c | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+diff --git a/drivers/thermal/imx_sc_thermal.c b/drivers/thermal/imx_sc_thermal.c
+index 8c5049020cd8..51a6c73315ba 100644
+--- a/drivers/thermal/imx_sc_thermal.c
++++ b/drivers/thermal/imx_sc_thermal.c
+@@ -58,6 +58,7 @@ sc_ipc_t tsens_ipcHandle;
+ static int imx_sc_tsens_get_temp(void *data, int *temp)
+ {
+ 	struct imx_sc_sensor *sensor = data;
++	int hw_id;
+ 	sc_err_t sciErr;
+ 	int16_t celsius;
+ 	int8_t tenths;
+@@ -65,14 +66,14 @@ static int imx_sc_tsens_get_temp(void *data, int *temp)
+ 	sciErr = sc_misc_get_temp(tsens_ipcHandle, sensor->hw_id,
+ 			SC_C_TEMP, &celsius, &tenths);
+ 	/*
+-	 * if the SS power domain is down, read temp will fail, so
+-	 * we can return the temp of CPU domain instead.
++	 * if the SS power domain is down, read temp will fail,
++	 * try the temp of the potentially two CPU domains instead.
+ 	 */
+-	if (sciErr != SC_ERR_NONE) {
+-		sciErr = sc_misc_get_temp(tsens_ipcHandle,
+-			sensor_hw_id[topology_physical_package_id(smp_processor_id())],
++	hw_id = 0;
++	while (sciErr != SC_ERR_NONE) {
++		sciErr = sc_misc_get_temp(tsens_ipcHandle, sensor_hw_id[hw_id++],
+ 			SC_C_TEMP, &celsius, &tenths);
+-		if (sciErr != SC_ERR_NONE) {
++		if (hw_id > 1) {
+ 			pr_err("read temp sensor:%d failed\n", sensor->hw_id);
+ 			return -EINVAL;
+ 		}
+-- 
+2.20.1
+
diff --git a/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0002-ddr-perf-prevent-BUG-with-rt-patch.patch b/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0002-ddr-perf-prevent-BUG-with-rt-patch.patch
new file mode 100644
index 0000000..9296878
--- /dev/null
+++ b/recipes-kernel/linux/linux-toradex-rt-4.14-2.0.x/0002-ddr-perf-prevent-BUG-with-rt-patch.patch
@@ -0,0 +1,34 @@
+From 066e66d9222f70d3e21a7df077ac6b623881c9cc Mon Sep 17 00:00:00 2001
+From: Max Krummenacher <max.krummenacher@toradex.com>
+Date: Tue, 24 Sep 2019 14:19:24 +0200
+Subject: [PATCH 2/2] ddr-perf: prevent BUG() with rt patch
+
+With the RT patch applied the kernel prints a BUG backtrace during boot:
+
+| BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
+
+Prevent this by replacing the smp_processor_id() call with a get_cpu() ..
+put_cpu() construct.
+
+Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
+---
+ drivers/perf/ddr-perf.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/perf/ddr-perf.c b/drivers/perf/ddr-perf.c
+index 73fe52ee8b95..744a6454d6a4 100644
+--- a/drivers/perf/ddr-perf.c
++++ b/drivers/perf/ddr-perf.c
+@@ -470,7 +470,8 @@ static int ddr_perf_probe(struct platform_device *pdev)
+ 
+ 	pmu->devtype = (struct fsl_ddr_devtype_data *)of_id->data;
+ 
+-	cpumask_set_cpu(smp_processor_id(), &pmu->cpu);
++	cpumask_set_cpu(get_cpu(), &pmu->cpu);
++	put_cpu();
+ 	ret = perf_pmu_register(&(pmu->pmu), name, -1);
+ 	if (ret)
+ 		goto ddr_perf_err;
+-- 
+2.20.1
+
diff --git a/recipes-kernel/linux/linux-toradex-rt_4.14-2.0.x.bb b/recipes-kernel/linux/linux-toradex-rt_4.14-2.0.x.bb
index f69e1e2..e2ebd82 100644
--- a/recipes-kernel/linux/linux-toradex-rt_4.14-2.0.x.bb
+++ b/recipes-kernel/linux/linux-toradex-rt_4.14-2.0.x.bb
@@ -8,6 +8,8 @@ SUMMARY = "Real-Time Linux kernel for Toradex Freescale i.MX based modules"
 MIRRORS += "${KERNELORG_MIRROR}/linux/kernel/projects/rt/4.14/older/ ${KERNELORG_MIRROR}/linux/kernel/projects/rt/4.14/"
 SRC_URI += " \
     ${KERNELORG_MIRROR}/linux/kernel/projects/rt/4.14/older/patch-4.14.126-rt62.patch.xz;name=rt-patch \
+    file://0001-imx_sc_thermal-prevent-BUG-with-rt-patch.patch \
+    file://0002-ddr-perf-prevent-BUG-with-rt-patch.patch \
 "
 
 SRC_URI[rt-patch.md5sum] = "47f2bb663112711d7270902e7e42cd16"