From 0c42f392767d3592e1cf676857d398ef69be7c9c Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 30 Jan 2008 13:33:42 +0100 Subject: [PATCH] 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 Acked-by: Jan Beulich Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/Kconfig.debug | 5 +++++ arch/x86/mm/init_32.c | 26 ++++++++++++++++++++++++++ arch/x86/mm/init_64.c | 10 ++++++++++ 3 files changed, 41 insertions(+) diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 9bb61e1aed69..38211ff0447f 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 459b384acda9..724a5eff6f34 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 8198840c3dcb..0fd9d7f77786 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 -- 2.20.1