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authorLinus Torvalds <torvalds@linux-foundation.org>2009-05-06 08:06:44 -0700
committerIngo Molnar <mingo@elte.hu>2009-05-11 09:45:14 +0200
commit45fbe3ee01b8e463b28c2751b5dcc0cbdc142d90 (patch)
treee90eb280684631d342ab34fdea298eb9badcd7d7 /arch/x86/kernel/e820.c
parent134cbf35c739bf89c51fd975a33a6b87507482c4 (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.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 006281302925..a2335d9de052 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)