linux-kernel - [PATCH v9 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr_boot

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Date:   Wed, 28 Feb 2018 18:51:03 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <hpa@...or.com>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bhe@...hat.com>,
        <keescook@...omium.org>, <yasu.isimatu@...il.com>
CC:     <indou.takao@...fujitsu.com>, <lcapitulino@...hat.com>,
        Chao Fan <fanc.fnst@...fujitsu.com>
Subject: [PATCH v9 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr_boot_mem=

Since only 'movable_node' specified without 'kaslr_boot_mem=' may
break memory hotplug, so reconmmend users using 'kaslr_boot_mem='
when 'movable_node' specified.

Signed-off-by: Chao Fan <fanc.fnst@...fujitsu.com>
Acked-by: Baoquan He <bhe@...hat.com>
---
 arch/x86/boot/compressed/kaslr.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index eb47502fbe54..9fb86248d5c5 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -288,6 +288,16 @@ static int handle_mem_filter(void)
 	    !strstr(args, "kaslr_boot_mem="))
 		return 0;
 
+#ifdef CONFIG_MEMORY_HOTPLUG
+	/*
+	 * Check if 'kaslr_boot_mem=' specified when 'movable_node' found.
+	 * If not, just give a warrning. Otherwise memory hotplug could be
+	 * affected if kernel is put on movable memory regions.
+	 */
+	if (strstr(args, "movable_node") && !strstr(args, "kaslr_boot_mem="))
+		warn("'kaslr_boot_mem=' should be specified when using 'movable_node'.\n");
+#endif
+
 	tmp_cmdline = malloc(len + 1);
 	if (!tmp_cmdline)
 		error("Failed to allocate space for tmp_cmdline");
-- 
2.14.3