path: root/arch/ia64/kernel/efi.c
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authorJes Sorensen <jes@wildopensource.com>2005-06-21 17:15:02 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-21 18:46:18 -0700
commitf14f75b81187cdbe10cc53a521bf9fdf97b59f8c (patch)
tree5c0d48c8a3338e6f1747e6cd55f699be96ffef1a /arch/ia64/kernel/efi.c
parent2caaad41e4aa8f5dd999695b4ddeaa0e7f3912a4 (diff)
[PATCH] ia64 uncached alloc
This patch contains the ia64 uncached page allocator and the generic allocator (genalloc). The uncached allocator was formerly part of the SN2 mspec driver but there are several other users of it so it has been split off from the driver. The generic allocator can be used by device driver to manage special memory etc. The generic allocator is based on the allocator from the sym53c8xx_2 driver. Various users on ia64 needs uncached memory. The SGI SN architecture requires it for inter-partition communication between partitions within a large NUMA cluster. The specific user for this is the XPC code. Another application is large MPI style applications which use it for synchronization, on SN this can be done using special 'fetchop' operations but it also benefits non SN hardware which may use regular uncached memory for this purpose. Performance of doing this through uncached vs cached memory is pretty substantial. This is handled by the mspec driver which I will push out in a seperate patch. Rather than creating a specific allocator for just uncached memory I came up with genalloc which is a generic purpose allocator that can be used by device drivers and other subsystems as they please. For instance to handle onboard device memory. It was derived from the sym53c7xx_2 driver's allocator which is also an example of a potential user (I am refraining from modifying sym2 right now as it seems to have been under fairly heavy development recently). On ia64 memory has various properties within a granule, ie. it isn't safe to access memory as uncached within the same granule as currently has memory accessed in cached mode. The regular system therefore doesn't utilize memory in the lower granules which is mixed in with device PAL code etc. The uncached driver walks the EFI memmap and pulls out the spill uncached pages and sticks them into the uncached pool. Only after these chunks have been utilized, will it start converting regular cached memory into uncached memory. Hence the reason for the EFI related code additions. Signed-off-by: Jes Sorensen <jes@wildopensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/ia64/kernel/efi.c')
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 4a3b1aac43e7..179f230816ed 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -410,6 +410,38 @@ efi_memmap_walk (efi_freemem_callback_t callback, void *arg)
+ * Walk the EFI memory map to pull out leftover pages in the lower
+ * memory regions which do not end up in the regular memory map and
+ * stick them into the uncached allocator
+ *
+ * The regular walk function is significantly more complex than the
+ * uncached walk which means it really doesn't make sense to try and
+ * marge the two.
+ */
+void __init
+efi_memmap_walk_uc (efi_freemem_callback_t callback)
+ void *efi_map_start, *efi_map_end, *p;
+ efi_memory_desc_t *md;
+ u64 efi_desc_size, start, end;
+ efi_map_start = __va(ia64_boot_param->efi_memmap);
+ efi_map_end = efi_map_start + ia64_boot_param->efi_memmap_size;
+ efi_desc_size = ia64_boot_param->efi_memdesc_size;
+ for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
+ md = p;
+ if (md->attribute == EFI_MEMORY_UC) {
+ start = PAGE_ALIGN(md->phys_addr);
+ end = PAGE_ALIGN((md->phys_addr+(md->num_pages << EFI_PAGE_SHIFT)) & PAGE_MASK);
+ if ((*callback)(start, end, NULL) < 0)
+ return;
+ }
+ }
* Look for the PAL_CODE region reported by EFI and maps it using an
* ITR to enable safe PAL calls in virtual mode. See IA-64 Processor
* Abstraction Layer chapter 11 in ADAG

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