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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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2013-04-27 13:07:17 +02:00 committed by Martin Schwidefsky
parent d009f4d886
commit 0a69406711
1 changed files with 13 additions and 1 deletions
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14
arch/s390/mm/mem_detect.c
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@ -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);
}