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authorH. Peter Anvin <hpa@linux.intel.com>2010-12-16 19:11:09 -0800
committerH. Peter Anvin <hpa@linux.intel.com>2010-12-16 19:11:09 -0800
commit147dd5610c8d1bacb88a6c1dfdaceaf257946ed0 (patch)
tree7c803d44985e61879018dd76db52f77922e1b772 /arch
parent7f99d946e71e71d484b7543b49e990508e70d0c0 (diff)
downloadop-kernel-dev-147dd5610c8d1bacb88a6c1dfdaceaf257946ed0.zip
op-kernel-dev-147dd5610c8d1bacb88a6c1dfdaceaf257946ed0.tar.gz
x86-32: Make sure we can map all of lowmem if we need to
A relocatable kernel can be anywhere in lowmem -- and in the case of a kdump kernel, is likely to be fairly high. Since the early page tables map everything from address zero up we need to make sure we allocate enough brk that we can map all of lowmem if we need to. Reported-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Tested-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <4D0AD3ED.8070607@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/boot/compressed/misc.c2
-rw-r--r--arch/x86/kernel/head_32.S12
2 files changed, 8 insertions, 6 deletions
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 23f315c..325c052 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -355,7 +355,7 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
if (heap > 0x3fffffffffffUL)
error("Destination address too large");
#else
- if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
+ if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
error("Destination address too large");
#endif
#ifndef CONFIG_RELOCATABLE
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index bcece91..d7cdf5b 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -60,16 +60,18 @@
#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
#endif
+/* Number of possible pages in the lowmem region */
+LOWMEM_PAGES = (((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT)
+
/* Enough space to fit pagetables for the low memory linear map */
-MAPPING_BEYOND_END = \
- PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT
+MAPPING_BEYOND_END = PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT
/*
* Worst-case size of the kernel mapping we need to make:
- * the worst-case size of the kernel itself, plus the extra we need
- * to map for the linear map.
+ * a relocatable kernel can live anywhere in lowmem, so we need to be able
+ * to map all of lowmem.
*/
-KERNEL_PAGES = (KERNEL_IMAGE_SIZE + MAPPING_BEYOND_END)>>PAGE_SHIFT
+KERNEL_PAGES = LOWMEM_PAGES
INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE_asm
RESERVE_BRK(pagetables, INIT_MAP_SIZE)
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