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ARM: 8432/1: move VMALLOC_END from 0xff000000 to 0xff800000 

There is a 12MB unused region in our memory map between the vmalloc and
fixmap areas. This became unused with commit e9da6e9905, confirmed
with commit 64d3b6a3f4.

We also have a 8MB guard area before the vmalloc area.  With the default
240MB vmalloc area size and the current VMALLOC_END definition, that
means the end of low memory ends up at 0xef800000 which is unfortunate
for 768MB machines where 8MB of RAM is lost to himem.

Let's move VMALLOC_END to 0xff800000 so the guard area won't chop the
top of the 768MB low memory area while keeping the default vmalloc area
size unchanged and still preserving a gap between the vmalloc and fixmap
areas.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Nicolas Pitre 2015-09-13 03:25:26 +01:00 committed by Russell King
parent 803e3dbcb4
commit 6ff0966052
2 changed files with 2 additions and 2 deletions
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2
Documentation/arm/memory.txt
View File

@ -54,7 +54,7 @@ VMALLOC_START VMALLOC_END-1 vmalloc() / ioremap() space.
located here through iotable_init().
VMALLOC_START is based upon the value
of the high_memory variable, and VMALLOC_END
is equal to 0xff000000.
is equal to 0xff800000.
PAGE_OFFSET high_memory-1 Kernel direct-mapped RAM region.
This maps the platforms RAM, and typically

2
arch/arm/include/asm/pgtable.h
View File

@ -43,7 +43,7 @@
*/
#define VMALLOC_OFFSET (8*1024*1024)
#define VMALLOC_START (((unsigned long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
#define VMALLOC_END 0xff000000UL
#define VMALLOC_END 0xff800000UL
#define LIBRARY_TEXT_START 0x0c000000