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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>
This commit is contained in:
Jeremy Fitzhardinge 2009-03-16 12:07:54 -07:00 committed by H. Peter Anvin
parent 2bd2753ff4
commit c090f532db
1 changed files with 19 additions and 10 deletions
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29
arch/x86/kernel/head_32.S
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@ -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