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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 Kernel Memory Layout on ARM Linux
Russell King <rmk@arm.linux.org.uk> 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 This document describes the virtual memory layout which the Linux
kernel uses for ARM processors. It indicates which regions are kernel uses for ARM processors. It indicates which regions are
@ -37,6 +37,8 @@ ff000000 ffbfffff Reserved for future expansion of DMA
mapping region. mapping region.
VMALLOC_END feffffff Free for platform use, recommended. 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. VMALLOC_START VMALLOC_END-1 vmalloc() / ioremap() space.
Memory returned by vmalloc/ioremap will 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 * 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. * 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 * 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) 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; unsigned long addr;
void *vectors; 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) for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr)); pmd_clear(pmd_off_k(addr));
@ -461,12 +468,6 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
create_mapping(&map); create_mapping(&map);
#endif #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 * Create a mapping for the machine vectors at the high-vectors
* location (0xffff0000). If we aren't using high-vectors, also * 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(); mdesc->map_io();
/* /*
* Finally flush the tlb again - this ensures that we're in a * Finally flush the caches and tlb to ensure that we're in a
* consistent state wrt the writebuffer if the writebuffer needs * consistent state wrt the writebuffer. This also ensures that
* draining. After this point, we can start to touch devices * any write-allocated cache lines in the vector page are written
* again. * back. After this point, we can start to touch devices again.
*/ */
local_flush_tlb_all(); local_flush_tlb_all();
flush_cache_all();
} }
/* /*