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Commit 0c42f392 authored by Andi Kleen's avatar Andi Kleen Committed by Ingo Molnar
Browse files

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: default avatarAndi Kleen <ak@suse.de>
Acked-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent b4416a1b

arch/x86/Kconfig.debug

+5 −0
Original line number Original line Diff line number Diff line
@@ -204,4 +204,9 @@ config DEBUG_BOOT_PARAMS 
	help

	help

	  This option will cause struct boot_params to be exported via debugfs.

	  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
 
endmenu

arch/x86/mm/init_32.c

+26 −0
Original line number Original line Diff line number Diff line
@@ -799,6 +799,20 @@ void mark_rodata_ro(void) 
		change_page_attr(virt_to_page(start),

		change_page_attr(virt_to_page(start),

		                 size >> PAGE_SHIFT, PAGE_KERNEL_RX);

		                 size >> PAGE_SHIFT, PAGE_KERNEL_RX);

		printk("Write protecting the kernel text: %luk\n", size >> 10);

		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

#endif

	start += size;

	start += size;
@@ -815,6 +829,18 @@ void mark_rodata_ro(void) 
	 * of who is the culprit.

	 * of who is the culprit.

	 */

	 */

	global_flush_tlb();

	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

#endif

arch/x86/mm/init_64.c

+10 −0
Original line number Original line Diff line number Diff line
@@ -606,6 +606,16 @@ void mark_rodata_ro(void) 
	 * of who is the culprit.

	 * of who is the culprit.

	 */

	 */

	global_flush_tlb();

	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

#endif