[PATCH 2/3] perf/arm_cspmu: nvidia: handle empty resource list in PCIE-TGT init

[PATCH 2/3] perf/arm_cspmu: nvidia: handle empty resource list in PCIE-TGT init

[Saurav Sachidanand]

When acpi_dev_get_memory_resources() returns success but the resource
list is empty (rentry is NULL), addr_filter_reg remains NULL from
devm_kzalloc. Since IS_ERR(NULL) is false, the function proceeds
without error and later dereferences the NULL pointer in
pcie_tgt_pmu_config_addr_filter().

Set addr_filter_reg to ERR_PTR(-ENODEV) when the resource list is
empty so the existing IS_ERR check catches it.

Fixes: 3dd73022306b ("perf/arm_cspmu: nvidia: Add Tegra410 PCIE-TGT PMU")
Signed-off-by: Saurav Sachidanand <sauravsc@amazon.com>
---
 drivers/perf/arm_cspmu/nvidia_cspmu.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/arm_cspmu/nvidia_cspmu.c b/drivers/perf/arm_cspmu/nvidia_cspmu.c
index bac83e424d6dc..bae722e263e91 100644
--- a/drivers/perf/arm_cspmu/nvidia_cspmu.c
+++ b/drivers/perf/arm_cspmu/nvidia_cspmu.c
@@ -555,14 +555,16 @@ static int pcie_tgt_init_data(struct arm_cspmu *cspmu)
 
 	rentry = list_first_entry_or_null(
 		&resource_list, struct resource_entry, node);
-	if (rentry) {
+	if (rentry)
 		data->addr_filter_reg = devm_ioremap_resource(dev, rentry->res);
-		ret = 0;
-	}
+	else
+		data->addr_filter_reg = ERR_PTR(-ENODEV);
 
 	if (IS_ERR(data->addr_filter_reg)) {
 		dev_err(dev, "failed to get address filter resource\n");
 		ret = PTR_ERR(data->addr_filter_reg);
+	} else {
+		ret = 0;
 	}
 
 	acpi_dev_free_resource_list(&resource_list);
-- 
2.47.3

[PATCH 3/3] perf/arm_cspmu: nvidia: fix BDF calculation examples in PCIE PMU docs

[Saurav Sachidanand]

The BDF hex values in the documentation examples are inconsistent with
the stated formula (bus << 8) + (device << 3) + (function):

  - BDF 27:01.1: documented as 0x2781, correct value is 0x2709
    (0x27 << 8) + (0x01 << 3) + 0x1 = 0x2709
  - BDF 01:01.0: documented as 0x0180, correct value is 0x0108
    (0x01 << 8) + (0x01 << 3) + 0x0 = 0x0108

It appears (device << 7) was used instead of (device << 3) when
computing the example values.

Fixes: bf585ba14726 ("perf/arm_cspmu: nvidia: Add Tegra410 PCIE PMU")
Signed-off-by: Saurav Sachidanand <sauravsc@amazon.com>
---
 Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
index 0656223b61d47..24f0e801d7b80 100644
--- a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
+++ b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
@@ -170,7 +170,7 @@ The list of event filters:
     devices in root port 0 to 3.
   * src_bdf: the BDF that will be monitored. This is a 16-bit value that
     follows formula: (bus << 8) + (device << 3) + (function). For example, the
-    value of BDF 27:01.1 is 0x2781.
+    value of BDF 27:01.1 is 0x2709.
   * src_bdf_en: enable the BDF filter. If this is set, the BDF filter value in
     "src_bdf" is used to filter the traffic.
 
@@ -215,7 +215,7 @@ Example usage:
 * Count event id 0x4 from BDF 01:01.0 of PCIE RC-4 on socket 0 targeting all
   destinations::
 
-    perf stat -a -e nvidia_pcie_pmu_0_rc_4/event=0x4,src_bdf=0x0180,src_bdf_en=0x1/
+    perf stat -a -e nvidia_pcie_pmu_0_rc_4/event=0x4,src_bdf=0x0108,src_bdf_en=0x1/
 
 .. _NVIDIA_T410_PCIE_PMU_RC_Mapping_Section:
 
-- 
2.47.3