linux-kernel - [RFC][PATCH 08/10] pstore: register kmsg into directly mapped zones if available

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Message-ID: <20250217101706.2104498-9-eugen.hristev@linaro.org>
Date: Mon, 17 Feb 2025 12:17:04 +0200
From: Eugen Hristev <eugen.hristev@...aro.org>
To: linux-arm-msm@...r.kernel.org,
	linux-hardening@...r.kernel.org,
	kees@...nel.org
Cc: linux-kernel@...r.kernel.org,
	johannes@...solutions.net,
	gregkh@...uxfoundation.org,
	rafael@...nel.org,
	dakr@...nel.org,
	andersson@...nel.org,
	konradybcio@...nel.org,
	tony.luck@...el.com,
	gpiccoli@...lia.com,
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	rostedt@...dmis.org,
	john.ogness@...utronix.de,
	senozhatsky@...omium.org,
	quic_mojha@...cinc.com,
	linux-arm-kernel@...ts.infradead.org,
	kernel@...cinc.com,
	Eugen Hristev <eugen.hristev@...aro.org>
Subject: [RFC][PATCH 08/10] pstore: register kmsg into directly mapped zones if available

If dmapped zones are available, register the log buffer into one zone.

Signed-off-by: Eugen Hristev <eugen.hristev@...aro.org>
---
 fs/pstore/platform.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 32448d9dd316..9a5c1d6d5031 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -452,11 +452,22 @@ static void pstore_register_kmsg(void)
 	kmsg_dump_register(&pstore_dumper);
 }
 
+static int pstore_register_kmsg_dmapped(void)
+{
+	return pstore_register_core_area("dmesg", log_buf_addr_get(),
+					 log_buf_len_get());
+}
+
 static void pstore_unregister_kmsg(void)
 {
 	kmsg_dump_unregister(&pstore_dumper);
 }
 
+static int pstore_unregister_kmsg_dmapped(void)
+{
+	return pstore_unregister_core_area("dmesg", log_buf_addr_get(),
+					   log_buf_len_get());
+}
 #ifdef CONFIG_PSTORE_CONSOLE
 static void pstore_console_write(struct console *con, const char *s, unsigned c)
 {
@@ -582,6 +593,9 @@ int pstore_register(struct pstore_info *psi)
 		pstore_dumper.max_reason = psinfo->max_reason;
 		pstore_register_kmsg();
 	}
+	if (psi->flags & PSTORE_FLAGS_DMAPPED)
+		if (pstore_register_kmsg_dmapped())
+			pr_warn("Registering kmsg as dmapped failed.\n");
 	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_register_console();
 	if (psi->flags & PSTORE_FLAGS_FTRACE)
@@ -628,6 +642,8 @@ void pstore_unregister(struct pstore_info *psi)
 		pstore_unregister_console();
 	if (psi->flags & PSTORE_FLAGS_DMESG)
 		pstore_unregister_kmsg();
+	if (psi->flags & PSTORE_FLAGS_DMAPPED)
+		pstore_unregister_kmsg_dmapped();
 
 	/* Stop timer and make sure all work has finished. */
 	del_timer_sync(&pstore_timer);
-- 
2.43.0