linux-kernel - [PATCH] powerpc/fadump: when fadump is supported register the fadump sysfs files.

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Date:   Tue, 20 Aug 2019 17:06:16 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     Michal Suchanek <msuchanek@...e.de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Hari Bathini <hbathini@...ux.vnet.ibm.com>,
        Christophe Leroy <christophe.leroy@....fr>,
        Yangtao Li <tiny.windzz@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc/fadump: when fadump is supported register the fadump sysfs files.

Currently it is not possible to distinguish the case when fadump is
supported by firmware and disabled in kernel and completely unsupported
using the kernel sysfs interface. User can investigate the devicetree
but it is more reasonable to provide sysfs files in case we get some
fadumpv2 in the future.

With this patch sysfs files are available whenever fadump is supported
by firmware.

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
 arch/powerpc/kernel/fadump.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 4eab97292cc2..f35ab2433a9b 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1671,13 +1671,9 @@ static void fadump_init_files(void)
  */
 int __init setup_fadump(void)
 {
-	if (!fw_dump.fadump_enabled)
-		return 0;
-
-	if (!fw_dump.fadump_supported) {
+	if (!fw_dump.fadump_supported && fw_dump.fadump_enabled) {
 		printk(KERN_ERR "Firmware-assisted dump is not supported on"
 			" this hardware\n");
-		return 0;
 	}
 
 	fadump_show_config();
@@ -1685,18 +1681,26 @@ int __init setup_fadump(void)
 	 * If dump data is available then see if it is valid and prepare for
 	 * saving it to the disk.
 	 */
-	if (fw_dump.dump_active) {
+	if (fw_dump.fadump_enabled) {
+		if (fw_dump.dump_active) {
+			/*
+			 * if dump process fails then invalidate the
+			 * registration and release memory before proceeding
+			 * for re-registration.
+			 */
+			if (process_fadump(fdm_active) < 0)
+				fadump_invalidate_release_mem();
+		}
 		/*
-		 * if dump process fails then invalidate the registration
-		 * and release memory before proceeding for re-registration.
+		 * Initialize the kernel dump memory structure for FAD
+		 * registration.
 		 */
-		if (process_fadump(fdm_active) < 0)
-			fadump_invalidate_release_mem();
+		else if (fw_dump.reserve_dump_area_size)
+			init_fadump_mem_struct(&fdm,
+					fw_dump.reserve_dump_area_start);
 	}
-	/* Initialize the kernel dump memory structure for FAD registration. */
-	else if (fw_dump.reserve_dump_area_size)
-		init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
-	fadump_init_files();
+	if (fw_dump.fadump_supported)
+		fadump_init_files();
 
 	return 1;
 }
-- 
2.22.0