From: Andi Kleen <ak@suse.de>
Date: Wed, 30 Jan 2008 12:33:42 +0000 (+0100)
Subject: c_p_a(): do a simple self test at boot
X-Git-Tag: v2.6.25-rc1~1143^2~142
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0c42f392767d3592e1cf676857d398ef69be7c9c;p=linux-2.6

c_p_a(): do a simple self test at boot

When CONFIG_DEBUG_RODATA is enabled undo the ro mapping and redo it again.
This gives some simple testing for change_page_attr().

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 9bb61e1aed..38211ff044 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -204,4 +204,9 @@ config DEBUG_BOOT_PARAMS
 	help
 	  This option will cause struct boot_params to be exported via debugfs.
 
+config CPA_DEBUG
+	bool "CPA self test code"
+	help
+	  Do change_page_attr self tests at boot.
+
 endmenu
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 459b384acd..724a5eff6f 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -799,6 +799,20 @@ void mark_rodata_ro(void)
 		change_page_attr(virt_to_page(start),
 		                 size >> PAGE_SHIFT, PAGE_KERNEL_RX);
 		printk("Write protecting the kernel text: %luk\n", size >> 10);
+
+#ifdef CONFIG_CPA_DEBUG
+		global_flush_tlb();
+
+		printk("Testing CPA: Reverting %lx-%lx\n", start, start+size);
+		change_page_attr(virt_to_page(start), size>>PAGE_SHIFT,
+				 PAGE_KERNEL_EXEC);
+		global_flush_tlb();
+
+		printk("Testing CPA: write protecting again\n");
+		change_page_attr(virt_to_page(start), size>>PAGE_SHIFT,
+				PAGE_KERNEL_RX);
+		global_flush_tlb();
+#endif
 	}
 #endif
 	start += size;
@@ -815,6 +829,18 @@ void mark_rodata_ro(void)
 	 * of who is the culprit.
 	 */
 	global_flush_tlb();
+
+#ifdef CONFIG_CPA_DEBUG
+	printk("Testing CPA: undo %lx-%lx\n", start, start + size);
+	change_page_attr(virt_to_page(start), size >> PAGE_SHIFT,
+				PAGE_KERNEL);
+	global_flush_tlb();
+
+	printk("Testing CPA: write protecting again\n");
+	change_page_attr(virt_to_page(start), size >> PAGE_SHIFT,
+				PAGE_KERNEL_RO);
+	global_flush_tlb();
+#endif
 }
 #endif
 
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 8198840c3d..0fd9d7f777 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -606,6 +606,16 @@ void mark_rodata_ro(void)
 	 * of who is the culprit.
 	 */
 	global_flush_tlb();
+
+#ifdef CONFIG_CPA_DEBUG
+	printk("Testing CPA: undo %lx-%lx\n", start, end);
+	change_page_attr_addr(start, (end - start) >> PAGE_SHIFT, PAGE_KERNEL);
+	global_flush_tlb();
+
+	printk("Testing CPA: again\n");
+	change_page_attr_addr(start, (end - start) >> PAGE_SHIFT, PAGE_KERNEL_RO);
+	global_flush_tlb();
+#endif
 }
 #endif