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[ARM] Fix some corner cases in new mm initialisation 

Document that the VMALLOC_END address must be aligned to 2MB since
it must align with a PGD boundary.

Allocate the vectors page early so that the flush_cache_all() later
will cause any dirty cache lines in the direct mapping will be safely
written back.

Move the flush_cache_all() to the second local_flush_cache_tlb() and
remove the now redundant first local_flush_cache_tlb().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2005-11-17 22:43:30 +00:00 committed by Russell King
parent 67a1901ff4
commit 02b3083922
2 changed files with 16 additions and 12 deletions
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4
Documentation/arm/memory.txt
View File

@ -1,7 +1,7 @@
Kernel Memory Layout on ARM Linux
Russell King <rmk@arm.linux.org.uk>
May 21, 2004 (2.6.6)
November 17, 2005 (2.6.15)
This document describes the virtual memory layout which the Linux
kernel uses for ARM processors. It indicates which regions are
@ -37,6 +37,8 @@ ff000000 ffbfffff Reserved for future expansion of DMA
mapping region.
VMALLOC_END feffffff Free for platform use, recommended.
VMALLOC_END must be aligned to a 2MB
boundary.
VMALLOC_START VMALLOC_END-1 vmalloc() / ioremap() space.
Memory returned by vmalloc/ioremap will

24
arch/arm/mm/init.c
View File

@ -420,7 +420,8 @@ static void __init bootmem_init(struct meminfo *mi)
* Set up device the mappings. Since we clear out the page tables for all
* mappings above VMALLOC_END, we will remove any debug device mappings.
* This means you have to be careful how you debug this function, or any
* called function. (Do it by code inspection!)
* called function. This means you can't use any function or debugging
* method which may touch any device, otherwise the kernel _will_ crash.
*/
static void __init devicemaps_init(struct machine_desc *mdesc)
{
@ -428,6 +429,12 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
unsigned long addr;
void *vectors;
/*
* Allocate the vector page early.
*/
vectors = alloc_bootmem_low_pages(PAGE_SIZE);
BUG_ON(!vectors);
for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
@ -461,12 +468,6 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
create_mapping(&map);
#endif
flush_cache_all();
local_flush_tlb_all();
vectors = alloc_bootmem_low_pages(PAGE_SIZE);
BUG_ON(!vectors);
/*
* Create a mapping for the machine vectors at the high-vectors
* location (0xffff0000). If we aren't using high-vectors, also
@ -491,12 +492,13 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
mdesc->map_io();
/*
* Finally flush the tlb again - this ensures that we're in a
* consistent state wrt the writebuffer if the writebuffer needs
* draining. After this point, we can start to touch devices
* again.
* Finally flush the caches and tlb to ensure that we're in a
* consistent state wrt the writebuffer. This also ensures that
* any write-allocated cache lines in the vector page are written
* back. After this point, we can start to touch devices again.
*/
local_flush_tlb_all();
flush_cache_all();
}
/*