Commit-ID: c090f532db3ab5b7be503f8ac84b0d33a18646c6 Gitweb: http://git.kernel.org/tip/c090f532db3ab5b7be503f8ac84b0d33a18646c6 Author: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx> AuthorDate: Mon, 16 Mar 2009 12:07:54 -0700 Commit: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> CommitDate: Tue, 17 Mar 2009 11:42:05 -0700 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@xxxxxxxxxx> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> --- arch/x86/kernel/head_32.S | 29 +++++++++++++++++++---------- 1 files changed, 19 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index c79741c..d383a7c 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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