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 9bb61e1..38211ff 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -204,4 +204,9 @@
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 459b384..724a5ef 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -799,6 +799,20 @@
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 @@
* 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 8198840..0fd9d7f 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -606,6 +606,16 @@
* 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