This is a note to let you know that I've just added the patch titled
x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct
mapping.
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-exclude-e820_reserved-regions-and-memory-holes-above-4-gb-from-direct-mapping.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a Mon Sep 17 00:00:00 2001
From: Jacob Shin <[email protected]>
Date: Thu, 20 Oct 2011 16:15:26 -0500
Subject: x86: Exclude E820_RESERVED regions and memory holes above 4 GB from
direct mapping.
From: Jacob Shin <[email protected]>
commit 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a upstream.
On systems with very large memory (1 TB in our case), BIOS may report a
reserved region or a hole in the E820 map, even above the 4 GB range. Exclude
these from the direct mapping.
[ hpa: this should be done not just for > 4 GB but for everything above the
legacy
region (1 MB), at the very least. That, however, turns out to require
significant
restructuring. That work is well underway, but is not suitable for
rc/stable. ]
Signed-off-by: Jacob Shin <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/setup.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -927,8 +927,21 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_X86_64
if (max_pfn > max_low_pfn) {
- max_pfn_mapped = init_memory_mapping(1UL<<32,
- max_pfn<<PAGE_SHIFT);
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+
+ if (ei->addr + ei->size <= 1UL << 32)
+ continue;
+
+ if (ei->type == E820_RESERVED)
+ continue;
+
+ max_pfn_mapped = init_memory_mapping(
+ ei->addr < 1UL << 32 ? 1UL << 32 : ei->addr,
+ ei->addr + ei->size);
+ }
+
/* can we preseve max_low_pfn ?*/
max_low_pfn = max_pfn;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/x86-exclude-e820_reserved-regions-and-memory-holes-above-4-gb-from-direct-mapping.patch
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