From 2a25dc7c79c92c6cba45c6218c49395173be80bf Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 17 Sep 2018 16:29:07 +0200 Subject: [PATCH] x86/mm/init32: Mark text and rodata RO in one go The sequence of marking text and rodata read-only in 32bit init is: set_ro(text); kernel_set_to_readonly = 1; set_ro(rodata); When kernel_set_to_readonly is 1 it enables the protection mechanism in CPA for the read only regions. With the upcoming checks for existing mappings this consequently triggers the warning about an existing mapping being incorrect vs. static protections because rodata has not been converted yet. There is no technical reason to split the two, so just combine the RO protection to convert text and rodata in one go. Convert the printks to pr_info while at it. Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Reviewed-by: Dave Hansen Cc: Peter Zijlstra Cc: Bin Yang Cc: Mark Gross Link: https://lkml.kernel.org/r/20180917143545.731701535@linutronix.de --- arch/x86/mm/init_32.c | 23 ++++------------------- 1 file changed, 4 insertions(+), 19 deletions(-) diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 979e0a0..142c7d9 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -923,34 +923,19 @@ static void mark_nxdata_nx(void) void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_text); - unsigned long size = PFN_ALIGN(_etext) - start; + unsigned long size = (unsigned long)__end_rodata - start; set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); - printk(KERN_INFO "Write protecting the kernel text: %luk\n", + pr_info("Write protecting kernel text and read-only data: %luk\n", size >> 10); kernel_set_to_readonly = 1; #ifdef CONFIG_CPA_DEBUG - printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", - start, start+size); - set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); - - printk(KERN_INFO "Testing CPA: write protecting again\n"); - set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); -#endif - - start += size; - size = (unsigned long)__end_rodata - start; - set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); - printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", - size >> 10); - -#ifdef CONFIG_CPA_DEBUG - printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); + pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); - printk(KERN_INFO "Testing CPA: write protecting again\n"); + pr_info("Testing CPA: write protecting again\n"); set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); #endif mark_nxdata_nx(); -- 2.7.4