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authorWill Deacon <will.deacon@arm.com>2012-04-12 17:15:08 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-04-15 22:00:30 +0100
commite5ab85800820edd907d3f43f285e1232f84d5a41 (patch)
tree24a227ba56d28b732975b5ca96fbce70ece1eeac
parent9f85550347f51c79a917b2aec04c90691c11e20a (diff)
ARM: 7382/1: mm: truncate memory banks to fit in 4GB space for classic MMU
If a bank of memory spanning the 4GB boundary is added on a !CONFIG_LPAE kernel then we will hang early during boot since the memory bank will have wrapped around to zero. This patch truncates memory banks for !LPAE configurations when the end address is not representable in 32 bits. Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/setup.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index b91411371ae1..ebfac782593f 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -523,7 +523,21 @@ int __init arm_add_memory(phys_addr_t start, unsigned long size)
*/
size -= start & ~PAGE_MASK;
bank->start = PAGE_ALIGN(start);
- bank->size = size & PAGE_MASK;
+
+#ifndef CONFIG_LPAE
+ if (bank->start + size < bank->start) {
+ printk(KERN_CRIT "Truncating memory at 0x%08llx to fit in "
+ "32-bit physical address space\n", (long long)start);
+ /*
+ * To ensure bank->start + bank->size is representable in
+ * 32 bits, we use ULONG_MAX as the upper limit rather than 4GB.
+ * This means we lose a page after masking.
+ */
+ size = ULONG_MAX - bank->start;
+ }
+#endif
+
+ bank->size = size & PAGE_MASK;
/*
* Check whether this memory region has non-zero size or