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Commit 0a694067 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/mem_detect: add DAT sanity check 



Add sanity check: verify if the passed in array resides in vmalloc space.
If so print a warning and return to caller.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent d009f4d8

arch/s390/mm/mem_detect.c

+13 −1
Original line number Diff line number Diff line
@@ -50,16 +50,28 @@ void detect_memory_layout(struct mem_chunk chunk[]) 
	unsigned long flags, flags_dat, cr0;



	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));

	/* Disable IRQs, DAT and low address protection so tprot does the

	/*

	 * Disable IRQs, DAT and low address protection so tprot does the

	 * right thing and we don't get scheduled away with low address

	 * protection disabled.

	 */

	local_irq_save(flags);

	flags_dat = __arch_local_irq_stnsm(0xfb);

	/*

	 * In case DAT was enabled, make sure chunk doesn't reside in vmalloc

	 * space. We have disabled DAT and any access to vmalloc area will

	 * cause an exception.

	 * If DAT was disabled we are called from early ipl code.

	 */

	if (test_bit(5, &flags_dat)) {

		if (WARN_ON_ONCE(is_vmalloc_or_module_addr(chunk)))

			goto out;

	}

	__ctl_store(cr0, 0, 0);

	__ctl_clear_bit(0, 28);

	find_memory_chunks(chunk);

	__ctl_load(cr0, 0, 0);

out:

	__arch_local_irq_ssm(flags_dat);

	local_irq_restore(flags);

}