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Commit ee01f112 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: init memory debugging 



debug incorrect/late access to init memory, by permanently unmapping
the init memory ranges. Depends on CONFIG_DEBUG_PAGEALLOC=y.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 1a487252

arch/x86/mm/init_32.c

+11 −0
Original line number Diff line number Diff line
@@ -783,6 +783,16 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) 
{

	unsigned long addr;



#ifdef CONFIG_DEBUG_PAGEALLOC

	/*

	 * If debugging page accesses then do not free this memory but

	 * mark them not present - any buggy init-section access will

	 * create a kernel page fault:

	 */

	printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",

		begin, PAGE_ALIGN(end));

	set_memory_np(begin, (end - begin) >> PAGE_SHIFT);

#else

	/*

	 * We just marked the kernel text read only above, now that

	 * we are going to free part of that, we need to make that
@@ -798,6 +808,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) 
		totalram_pages++;

	}

	printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);

#endif

}



void free_initmem(void)

arch/x86/mm/init_64.c

+11 −0
Original line number Diff line number Diff line
@@ -550,6 +550,16 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) 
	if (begin >= end)

		return;



	/*

	 * If debugging page accesses then do not free this memory but

	 * mark them not present - any buggy init-section access will

	 * create a kernel page fault:

	 */

#ifdef CONFIG_DEBUG_PAGEALLOC

	printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",

		begin, PAGE_ALIGN(end));

	set_memory_np(begin, (end - begin) >> PAGE_SHIFT);

#else

	printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);

	for (addr = begin; addr < end; addr += PAGE_SIZE) {

		ClearPageReserved(virt_to_page(addr));
@@ -575,6 +585,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) 
		set_memory_nx(begin, (end - begin)/PAGE_SIZE);

	}

#endif

#endif

}



void free_initmem(void)