linux-kernel - [PATCH] platform/x86/intel/pmc: Alder Lake PCH slp_s0

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230320212029.3154407-1-david.e.box@linux.intel.com>
Date:   Mon, 20 Mar 2023 14:20:29 -0700
From:   "David E. Box" <david.e.box@...ux.intel.com>
To:     irenic.rajneesh@...il.com, rajvi.jingar@...ux.intel.com,
        david.e.box@...ux.intel.com, hdegoede@...hat.com,
        markgross@...nel.org, andy.shevchenko@...il.com
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Subject: [PATCH] platform/x86/intel/pmc: Alder Lake PCH slp_s0_residency fix

From: Rajvi Jingar <rajvi.jingar@...ux.intel.com>

For platforms with Alder Lake PCH (Alder Lake S and Raptor Lake S) the
slp_s0_residency attribute has been reporting the wrong value. Unlike other
platforms, ADL PCH does not have a counter for the time that the SLP_S0
signal was asserted. Instead, firmware uses the aggregate of the Low Power
Mode (LPM) substate counters as the S0ix value.  Since the LPM counters run
at a different frequency, this lead to misreporting of the S0ix time.

Add a check for Alder Lake PCH and adjust the frequency accordingly when
display slp_s0_residency.

Fixes: bbab31101f44 ("platform/x86/intel: pmc/core: Add Alderlake support to pmc core driver")
Signed-off-by: Rajvi Jingar <rajvi.jingar@...ux.intel.com>
Signed-off-by: David E. Box <david.e.box@...ux.intel.com>
---
 drivers/platform/x86/intel/pmc/core.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/pmc/core.c b/drivers/platform/x86/intel/pmc/core.c
index e489d2175e42..61ca7c37fb02 100644
--- a/drivers/platform/x86/intel/pmc/core.c
+++ b/drivers/platform/x86/intel/pmc/core.c
@@ -66,7 +66,18 @@ static inline void pmc_core_reg_write(struct pmc_dev *pmcdev, int reg_offset,
 
 static inline u64 pmc_core_adjust_slp_s0_step(struct pmc_dev *pmcdev, u32 value)
 {
-	return (u64)value * pmcdev->map->slp_s0_res_counter_step;
+	/*
+	 * ADL PCH does not have the SLP_S0 counter and LPM Residency counters are
+	 * used as a workaround which uses 30.5 usec tick. All other client
+	 * programs have the legacy SLP_S0 residency counter that is using the 122
+	 * usec tick.
+	 */
+	const int lpm_adj_x2 = pmcdev->map->lpm_res_counter_step_x2;
+
+	if (pmcdev->map == &adl_reg_map)
+		return (u64)value * GET_X2_COUNTER((u64)lpm_adj_x2);
+	else
+		return (u64)value * pmcdev->map->slp_s0_res_counter_step;
 }
 
 static int set_etr3(struct pmc_dev *pmcdev)

base-commit: 02c464b73645404654359ad21f368a13735e2850
-- 
2.34.1