diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-05-06 08:06:44 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-11 09:45:14 +0200 |
| commit | 45fbe3ee01b8e463b28c2751b5dcc0cbdc142d90 (patch) | |
| tree | e90eb280684631d342ab34fdea298eb9badcd7d7 /arch/x86/kernel/e820.c | |
| parent | 134cbf35c739bf89c51fd975a33a6b87507482c4 (diff) | |
x86, e820, pci: reserve extra free space near end of RAM
The point is to take all RAM resources we have, and
_after_ we've added all the resources we've seen in
the E820 tree, we then _also_ try to add fake reserved
entries for any "round up to X" at the end of the RAM
resources.
[ Impact: improve PCI mem-resource allocation robustness, protect "stolen RAM" ]
Reported-by: Yannick Roehlly <yannick.roehlly@free.fr>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: yannick.roehlly@free.fr
LKML-Reference: <4A01A784.2050407@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/e820.c')
| -rw-r--r-- | arch/x86/kernel/e820.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 00628130292..a2335d9de05 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1371,6 +1371,23 @@ void __init e820_reserve_resources(void) } } +/* How much should we pad RAM ending depending on where it is? */ +static unsigned long ram_alignment(resource_size_t pos) +{ + unsigned long mb = pos >> 20; + + /* To 64kB in the first megabyte */ + if (!mb) + return 64*1024; + + /* To 1MB in the first 16MB */ + if (mb < 16) + return 1024*1024; + + /* To 32MB for anything above that */ + return 32*1024*1024; +} + void __init e820_reserve_resources_late(void) { int i; @@ -1382,6 +1399,24 @@ void __init e820_reserve_resources_late(void) insert_resource_expand_to_fit(&iomem_resource, res); res++; } + + /* + * Try to bump up RAM regions to reasonable boundaries to + * avoid stolen RAM: + */ + for (i = 0; i < e820.nr_map; i++) { + struct e820entry *entry = &e820_saved.map[i]; + resource_size_t start, end; + + if (entry->type != E820_RAM) + continue; + start = entry->addr + entry->size; + end = round_up(start, ram_alignment(start)); + if (start == end) + continue; + reserve_region_with_split(&iomem_resource, start, + end - 1, "RAM buffer"); + } } char *__init default_machine_specific_memory_setup(void) |