[RFC PATCH 14/18] ARM: LPAE: mark memory banks with start > ULONG_MAX as highmem

[Catalin Marinas]

From: Will Deacon <will.deacon at arm.com>

Memory banks living outside of the 32-bit physical address
space do not have a 1:1 pa <-> va mapping and therefore the
__va macro may wrap.

This patch ensures that such banks are marked as highmem so
that the Kernel doesn't try to split them up when it sees that
the wrapped virtual address overlaps the vmalloc space.

Signed-off-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
---
 arch/arm/mm/mmu.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index c060d82..f8f8e06 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -787,7 +787,8 @@ static void __init sanity_check_meminfo(void)
 
 #ifdef CONFIG_HIGHMEM
 		if (__va(bank->start) > vmalloc_min ||
-		    __va(bank->start) < (void *)PAGE_OFFSET)
+		    __va(bank->start) < (void *)PAGE_OFFSET ||
+		    bank->start > ULONG_MAX)
 			highmem = 1;
 
 		bank->highmem = highmem;
@@ -796,7 +797,7 @@ static void __init sanity_check_meminfo(void)
 		 * Split those memory banks which are partially overlapping
 		 * the vmalloc area greatly simplifying things later.
 		 */
-		if (__va(bank->start) < vmalloc_min &&
+		if (!highmem && __va(bank->start) < vmalloc_min &&
 		    bank->size > vmalloc_min - __va(bank->start)) {
 			if (meminfo.nr_banks >= NR_BANKS) {
 				printk(KERN_CRIT "NR_BANKS too low, "