From 0a694067111e8fcd3eda430f8fa2d0277edd231f Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Sat, 27 Apr 2013 13:07:17 +0200
Subject: [PATCH] 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>
---
arch/s390/mm/mem_detect.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/s390/mm/mem_detect.c b/arch/s390/mm/mem_detect.c
index fb216e11c25d2..854c08448de12 100644
--- a/arch/s390/mm/mem_detect.c
+++ b/arch/s390/mm/mem_detect.c
@@ -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);
}
--
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