x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C
The new Xen PVH entry point requires page tables to be setup by the kernel since it is entered with paging disabled. Pull the common code out of head_32.S so that mk_early_pgtbl_32() can be invoked from both the new Xen entry point and the existing startup_32() code. Convert resulting common code to C. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: matt@codeblueprint.co.uk Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1481215471-9639-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Boris Ostrovsky
Ingo Molnar
parent
b4ed1d15b4
commit
1e620f9b23
@ -27,6 +27,7 @@ struct vm_area_struct;
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extern pgd_t swapper_pg_dir[1024];
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extern pgd_t initial_page_table[1024];
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extern pmd_t initial_pg_pmd[];
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static inline void pgtable_cache_init(void) { }
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static inline void check_pgt_cache(void) { }
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@ -75,4 +76,35 @@ do { \
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#define kern_addr_valid(kaddr) (0)
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#endif
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/*
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* This is how much memory in addition to the memory covered up to
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* and including _end we need mapped initially.
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* We need:
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* (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
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* (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
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*
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* Modulo rounding, each megabyte assigned here requires a kilobyte of
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* memory, which is currently unreclaimed.
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*
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* This should be a multiple of a page.
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*
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* KERNEL_IMAGE_SIZE should be greater than pa(_end)
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* and small than max_low_pfn, otherwise will waste some page table entries
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*/
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#if PTRS_PER_PMD > 1
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#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
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#else
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#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
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#endif
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/*
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* Number of possible pages in the lowmem region.
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*
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* We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
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* gas warning about overflowing shift count when gas has been compiled
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* with only a host target support using a 32-bit type for internal
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* representation.
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*/
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#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
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#endif /* _ASM_X86_PGTABLE_32_H */
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@ -49,3 +49,65 @@ asmlinkage __visible void __init i386_start_kernel(void)
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start_kernel();
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}
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/*
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* Initialize page tables. This creates a PDE and a set of page
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* tables, which are located immediately beyond __brk_base. The variable
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* _brk_end is set up to point to the first "safe" location.
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* Mappings are created both at virtual address 0 (identity mapping)
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* and PAGE_OFFSET for up to _end.
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*
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* In PAE mode initial_page_table is statically defined to contain
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* enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
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* entries). The identity mapping is handled by pointing two PGD entries
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* to the first kernel PMD. Note the upper half of each PMD or PTE are
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* always zero at this stage.
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*/
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void __init mk_early_pgtbl_32(void)
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{
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#ifdef __pa
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#undef __pa
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#endif
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#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
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pte_t pte, *ptep;
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int i;
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unsigned long *ptr;
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/* Enough space to fit pagetables for the low memory linear map */
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const unsigned long limit = __pa(_end) +
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(PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
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#ifdef CONFIG_X86_PAE
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pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
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#define SET_PL2(pl2, val) { (pl2).pmd = (val); }
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#else
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pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
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#define SET_PL2(pl2, val) { (pl2).pgd = (val); }
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#endif
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ptep = (pte_t *)__pa(__brk_base);
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pte.pte = PTE_IDENT_ATTR;
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while ((pte.pte & PTE_PFN_MASK) < limit) {
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SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
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*pl2p = pl2;
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#ifndef CONFIG_X86_PAE
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/* Kernel PDE entry */
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*(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
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#endif
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for (i = 0; i < PTRS_PER_PTE; i++) {
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*ptep = pte;
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pte.pte += PAGE_SIZE;
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ptep++;
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}
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pl2p++;
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}
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ptr = (unsigned long *)__pa(&max_pfn_mapped);
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/* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
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*ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
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ptr = (unsigned long *)__pa(&_brk_end);
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*ptr = (unsigned long)ptep + PAGE_OFFSET;
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}
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@ -24,6 +24,7 @@
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#include <asm/nops.h>
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#include <asm/bootparam.h>
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#include <asm/export.h>
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#include <asm/pgtable_32.h>
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/* Physical address */
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#define pa(X) ((X) - __PAGE_OFFSET)
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@ -41,43 +42,9 @@
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#define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability
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#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
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/*
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* This is how much memory in addition to the memory covered up to
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* and including _end we need mapped initially.
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* We need:
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* (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
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* (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
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*
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* Modulo rounding, each megabyte assigned here requires a kilobyte of
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* memory, which is currently unreclaimed.
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*
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* This should be a multiple of a page.
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*
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* KERNEL_IMAGE_SIZE should be greater than pa(_end)
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* and small than max_low_pfn, otherwise will waste some page table entries
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*/
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#if PTRS_PER_PMD > 1
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#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
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#else
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#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
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#endif
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#define SIZEOF_PTREGS 17*4
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/*
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* Number of possible pages in the lowmem region.
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*
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* We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
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* gas warning about overflowing shift count when gas has been compiled
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* with only a host target support using a 32-bit type for internal
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* representation.
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*/
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LOWMEM_PAGES = (((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)
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/* Enough space to fit pagetables for the low memory linear map */
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MAPPING_BEYOND_END = PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT
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/*
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* Worst-case size of the kernel mapping we need to make:
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* a relocatable kernel can live anywhere in lowmem, so we need to be able
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@ -160,90 +127,15 @@ ENTRY(startup_32)
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call load_ucode_bsp
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#endif
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/*
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* Initialize page tables. This creates a PDE and a set of page
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* tables, which are located immediately beyond __brk_base. The variable
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* _brk_end is set up to point to the first "safe" location.
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* Mappings are created both at virtual address 0 (identity mapping)
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* and PAGE_OFFSET for up to _end.
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*/
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#ifdef CONFIG_X86_PAE
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/*
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* In PAE mode initial_page_table is statically defined to contain
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* enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
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* entries). The identity mapping is handled by pointing two PGD entries
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* to the first kernel PMD.
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*
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* Note the upper half of each PMD or PTE are always zero at this stage.
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*/
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/* Create early pagetables. */
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call mk_early_pgtbl_32
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/* Do early initialization of the fixmap area */
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movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
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#ifdef CONFIG_X86_PAE
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#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
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xorl %ebx,%ebx /* %ebx is kept at zero */
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movl $pa(__brk_base), %edi
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movl $pa(initial_pg_pmd), %edx
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movl $PTE_IDENT_ATTR, %eax
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10:
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leal PDE_IDENT_ATTR(%edi),%ecx /* Create PMD entry */
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movl %ecx,(%edx) /* Store PMD entry */
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/* Upper half already zero */
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addl $8,%edx
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movl $512,%ecx
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11:
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stosl
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xchgl %eax,%ebx
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stosl
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xchgl %eax,%ebx
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addl $0x1000,%eax
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loop 11b
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/*
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* End condition: we must map up to the end + MAPPING_BEYOND_END.
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*/
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movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
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cmpl %ebp,%eax
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jb 10b
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1:
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addl $__PAGE_OFFSET, %edi
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movl %edi, pa(_brk_end)
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shrl $12, %eax
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movl %eax, pa(max_pfn_mapped)
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/* Do early initialization of the fixmap area */
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movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
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movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
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#else /* Not PAE */
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page_pde_offset = (__PAGE_OFFSET >> 20);
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movl $pa(__brk_base), %edi
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movl $pa(initial_page_table), %edx
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movl $PTE_IDENT_ATTR, %eax
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10:
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leal PDE_IDENT_ATTR(%edi),%ecx /* Create PDE entry */
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movl %ecx,(%edx) /* Store identity PDE entry */
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movl %ecx,page_pde_offset(%edx) /* Store kernel PDE entry */
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addl $4,%edx
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movl $1024, %ecx
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11:
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stosl
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addl $0x1000,%eax
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loop 11b
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/*
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* End condition: we must map up to the end + MAPPING_BEYOND_END.
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*/
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movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
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cmpl %ebp,%eax
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jb 10b
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addl $__PAGE_OFFSET, %edi
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movl %edi, pa(_brk_end)
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shrl $12, %eax
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movl %eax, pa(max_pfn_mapped)
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/* Do early initialization of the fixmap area */
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movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
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#else
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movl %eax,pa(initial_page_table+0xffc)
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#endif
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@ -666,6 +558,7 @@ ENTRY(setup_once_ref)
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__PAGE_ALIGNED_BSS
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.align PAGE_SIZE
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#ifdef CONFIG_X86_PAE
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.globl initial_pg_pmd
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initial_pg_pmd:
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.fill 1024*KPMDS,4,0
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#else
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