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c_p_a(): do a simple self test at boot

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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>
This commit is contained in:
Andi Kleen 2008-01-30 13:33:42 +01:00 committed by Ingo Molnar
parent b4416a1be8
commit 0c42f39276
3 changed files with 41 additions and 0 deletions
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5
arch/x86/Kconfig.debug
View file

@ -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

26
arch/x86/mm/init_32.c
View file

@ -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

10
arch/x86/mm/init_64.c
View file

@ -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