[PATCH 5/5] perf/x86/uncore: Don't WARN_ON_ONCE() for a broken discovery table

kan.liang
2022-11-29T19:11:04Z

The kernel warning message is triggered, when SPR MCC is used.

[ 17.945331] ------------[ cut here ]------------
[ 17.946305] WARNING: CPU: 65 PID: 1 at
arch/x86/events/intel/uncore_discovery.c:184
intel_uncore_has_discovery_tables+0x4c0/0x65c
[ 17.946305] Modules linked in:
[ 17.946305] CPU: 65 PID: 1 Comm: swapper/0 Not tainted
5.4.17-2136.313.1-X10-2c+ #4

It's caused by the broken discovery table of UPI.

The discovery tables are from hardware. Except for dropping the broken
information, there is nothing Linux can do. Using WARN_ON_ONCE() is
overkilled.

Use the pr_info() to replace WARN_ON_ONCE(), and specify what uncore unit
is dropped and the reason.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/events/intel/uncore_discovery.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index abb51191f5af..cb488e41807c 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -128,13 +128,21 @@ uncore_insert_box_info(struct uncore_unit_discovery *unit,
unsigned int *box_offset, *ids;
int i;

- if (WARN_ON_ONCE(!unit->ctl || !unit->ctl_offset || !unit->ctr_offset))
+ if (!unit->ctl || !unit->ctl_offset || !unit->ctr_offset) {
+ pr_info("Invalid address is detected for uncore type %d box %d, "
+ "Disable the uncore unit.\n",
+ unit->box_type, unit->box_id);
return;
+ }

if (parsed) {
type = search_uncore_discovery_type(unit->box_type);
- if (WARN_ON_ONCE(!type))
+ if (!type) {
+ pr_info("A spurious uncore type %d is detected, "
+ "Disable the uncore type.\n",
+ unit->box_type);
return;
+ }
/* Store the first box of each die */
if (!type->box_ctrl_die[die])
type->box_ctrl_die[die] = unit->ctl;
@@ -169,8 +177,12 @@ uncore_insert_box_info(struct uncore_unit_discovery *unit,
ids[i] = type->ids[i];
box_offset[i] = type->box_offset[i];

- if (WARN_ON_ONCE(unit->box_id == ids[i]))
+ if (unit->box_id == ids[i]) {
+ pr_info("Duplicate uncore type %d box ID %d is detected, "
+ "Drop the duplicate uncore unit.\n",
+ unit->box_type, unit->box_id);
goto free_ids;
+ }
}
ids[i] = unit->box_id;
box_offset[i] = unit->ctl - type->box_ctrl;
--
2.35.1