linux-kernel - [PATCH 1/2] thermal: intel: Prevent accidental clearing of HFI status

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Message-Id: <20221116024949.2590043-1-srinivas.pandruvada@linux.intel.com>
Date:   Tue, 15 Nov 2022 18:49:48 -0800
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     afael@...nel.org, daniel.lezcano@...aro.org, amitk@...nel.org,
        rui.zhang@...el.com
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Subject: [PATCH 1/2] thermal: intel: Prevent accidental clearing of HFI status

When there is a package thermal interrupt with PROCHOT log, it will be
processed and cleared. It is possible that there is an active HFI event
status, which is about to get processed or getting processed. While
clearing PROCHOT log bit, it will also clear HFI status bit. This means
that hardware is free to update HFI memory.

When clearing a package thermal interrupt, some processors will generate
a "general protection fault" when any of the read only bit is set to 1.
The driver maintains a mask of all read-write bits which can be set.
This mask doesn't include HFI status bit. This bit will also be cleared,
as it will be assumed read-only bit. So, add HFI status bit 26 to the
mask.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Reviewed-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
---
 drivers/thermal/intel/therm_throt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/intel/therm_throt.c b/drivers/thermal/intel/therm_throt.c
index 8352083b87c7..9e8ab31d756e 100644
--- a/drivers/thermal/intel/therm_throt.c
+++ b/drivers/thermal/intel/therm_throt.c
@@ -197,7 +197,7 @@ static const struct attribute_group thermal_attr_group = {
 #define THERM_STATUS_PROCHOT_LOG	BIT(1)

 #define THERM_STATUS_CLEAR_CORE_MASK (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11) | BIT(13) | BIT(15))
-#define THERM_STATUS_CLEAR_PKG_MASK  (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11))
+#define THERM_STATUS_CLEAR_PKG_MASK  (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11) | BIT(26))

 static void clear_therm_status_log(int level)
 {
-- 
2.31.1