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From:   Prasad Sodagudi <psodagud@codeaurora.org>
To:     sudeep.holla@arm.com, julien.thierry@arm.com, will.deacon@arm.com,
        catalin.marinas@arm.com, mark.rutland@arm.com,
        lorenzo.pieralisi@arm.com, akpm@linux-foundation.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Prasad Sodagudi <psodagud@codeaurora.org>
Subject: [PATCH] kernel/panic: Use SYSTEM_RESET2 command for warm reset
Date:   Wed,  8 May 2019 18:47:12 -0700
Message-Id: <1557366432-352469-1-git-send-email-psodagud@codeaurora.org>
In-Reply-To: <ce0b66f5d00e760f87ddeeacbc40b956@codeaurora.org>
References: <ce0b66f5d00e760f87ddeeacbc40b956@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Some platforms may need warm reboot support when kernel crashed
for post mortem analysis instead of cold reboot. So use config
CONFIG_WARM_REBOOT_ON_PANIC and SYSTEM_RESET2 psci command
support for warm reset.

Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
---
 kernel/panic.c    |  4 ++++
 lib/Kconfig.debug | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/kernel/panic.c b/kernel/panic.c
index c1fcaad..6ab6675 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -198,6 +198,10 @@ void panic(const char *fmt, ...)
 
 	console_verbose();
 	bust_spinlocks(1);
+#ifdef CONFIG_WARM_REBOOT_ON_PANIC
+	/* Configure for warm reboot instead of cold reboot. */
+	reboot_mode = REBOOT_WARM;
+#endif
 	va_start(args, fmt);
 	len = vscnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d695ec1..2a727d8 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1000,6 +1000,16 @@ config PANIC_TIMEOUT
 	  value n > 0 will wait n seconds before rebooting, while a timeout
 	  value n < 0 will reboot immediately.
 
+config WARM_REBOOT_ON_PANIC
+	bool "Warm reboot instead of cold reboot for panic"
+	default n
+	help
+	  Some vendor platform may need warm reboot instead of cold reboot
+	  for debugging. Before vendor specific power off driver is
+	  probed, platform always gets cold reset. By setting Y here and
+	  support for PSCI V1.1 is present from firmware, platform would
+	  get warm reset instead of cold reset.
+
 config SCHED_DEBUG
 	bool "Collect scheduler debugging info"
 	depends on DEBUG_KERNEL && PROC_FS
-- 
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