aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-03-16 12:07:54 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2009-03-17 11:42:05 -0700
commitc090f532db3ab5b7be503f8ac84b0d33a18646c6 (patch)
treeabac222a32abc03730ccfa260d28af88581f6fb6
parent2bd2753ff46346543ab92e80df9d96366e21baa5 (diff)
x86-32: make sure we map enough to fit linear map pagetables
Impact: crash fix head_32.S needs to map the kernel itself, and enough space so that mm/init.c can allocate space from the e820 allocator for the linear map of low memory. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
-rw-r--r--arch/x86/kernel/head_32.S29
1 files changed, 19 insertions, 10 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index c79741cfb07..d383a7c0e49 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -38,8 +38,8 @@
#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
/*
- * This is how much memory *in addition to the memory covered up to
- * and including _end* we need mapped initially.
+ * This is how much memory in addition to the memory covered up to
+ * and including _end we need mapped initially.
* We need:
* (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
* (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
@@ -52,16 +52,25 @@
* KERNEL_IMAGE_SIZE should be greater than pa(_end)
* and small than max_low_pfn, otherwise will waste some page table entries
*/
-LOW_PAGES = (KERNEL_IMAGE_SIZE + PAGE_SIZE_asm - 1)>>PAGE_SHIFT
#if PTRS_PER_PMD > 1
-PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PMD) + PTRS_PER_PGD
+#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
#else
-PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PGD)
+#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
#endif
ALLOCATOR_SLOP = 4
-INIT_MAP_SIZE = (PAGE_TABLE_SIZE + ALLOCATOR_SLOP) * PAGE_SIZE_asm
+/* Enough space to fit pagetables for the low memory linear map */
+MAPPING_BEYOND_END = (PAGE_TABLE_SIZE(1 << (32 - PAGE_SHIFT)) * PAGE_SIZE)
+
+/*
+ * 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.
+ */
+KERNEL_PAGES = (KERNEL_IMAGE_SIZE + MAPPING_BEYOND_END)>>PAGE_SHIFT
+
+INIT_MAP_SIZE = (PAGE_TABLE_SIZE(KERNEL_PAGES) + ALLOCATOR_SLOP) * PAGE_SIZE_asm
RESERVE_BRK(pagetables, INIT_MAP_SIZE)
/*
@@ -197,9 +206,9 @@ default_entry:
loop 11b
/*
- * End condition: we must map up to the end.
+ * End condition: we must map up to the end + MAPPING_BEYOND_END.
*/
- movl $pa(_end) + PTE_IDENT_ATTR, %ebp
+ movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
cmpl %ebp,%eax
jb 10b
1:
@@ -229,9 +238,9 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
addl $0x1000,%eax
loop 11b
/*
- * End condition: we must map up to end
+ * End condition: we must map up to the end + MAPPING_BEYOND_END.
*/
- movl $pa(_end) + PTE_IDENT_ATTR, %ebp
+ movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
cmpl %ebp,%eax
jb 10b
addl $__PAGE_OFFSET, %edi