[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>
diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt
index 4b1c93a..dc60455 100644
--- a/Documentation/arm/memory.txt
+++ b/Documentation/arm/memory.txt
@@ -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 @@
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
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index c168f32..8b276ee 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -420,7 +420,8 @@
* 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 @@
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 @@
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 @@
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();
}
/*