linux-kernel - [PATCH 2/2] watchdog: sp5100_tco: Enable watchdog on Family 17h devices if disabled

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20200910163109.235136-2-linux@roeck-us.net>
Date:   Thu, 10 Sep 2020 09:31:09 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>,
        Jan Kiszka <jan.kiszka@...mens.com>
Subject: [PATCH 2/2] watchdog: sp5100_tco: Enable watchdog on Family 17h devices if disabled

On Family 17h (Ryzen) devices, the WatchdogTmrEn bit of PmDecodeEn not only
enables watchdog memory decoding at 0xfeb00000, it also enables the
watchdog hardware itself. Use this information to enable the watchdog if
it is not already enabled.

Cc: Jan Kiszka <jan.kiszka@...mens.com>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/sp5100_tco.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 85e9664318c9..a730ecbf78cd 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -17,6 +17,12 @@
  *	    AMD Publication 51192 "AMD Bolton FCH Register Reference Guide"
  *	    AMD Publication 52740 "BIOS and Kernel Developer’s Guide (BKDG)
  *				for AMD Family 16h Models 30h-3Fh Processors"
+ *	    AMD Publication 55570-B1-PUB "Processor Programming Reference (PPR)
+ *				for AMD Family 17h Model 18h, Revision B1
+ *				Processors (PUB)
+ *	    AMD Publication 55772-A1-PUB "Processor Programming Reference (PPR)
+ *				for AMD Family 17h Model 20h, Revision A1
+ *				Processors (PUB)
  */
 
 /*
@@ -241,6 +247,18 @@ static int sp5100_tco_setupdevice(struct device *dev,
 		break;
 	case efch:
 		dev_name = SB800_DEVNAME;
+		/*
+		 * On Family 17h devices, the EFCH_PM_DECODEEN_WDT_TMREN bit of
+		 * EFCH_PM_DECODEEN not only enables the EFCH_PM_WDT_ADDR memory
+		 * region, it also enables the watchdog itself.
+		 */
+		if (boot_cpu_data.x86 == 0x17) {
+			val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
+			if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
+				sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN, 0xff,
+							  EFCH_PM_DECODEEN_WDT_TMREN);
+			}
+		}
 		val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
 		if (val & EFCH_PM_DECODEEN_WDT_TMREN)
 			mmio_addr = EFCH_PM_WDT_ADDR;
-- 
2.17.1