x86, mm: Initialize initial_page_table before paravirt jumps
v2.6.36-rc8-54-gb40827f (x86-32, mm: Add an initial page table
for core bootstrapping) made x86 boot using initial_page_table
and broke lguest.
For 2.6.37 we simply cut & paste the initialization code into
lguest (da32dac101 "lguest: populate initial_page_table"), now
we fix it properly by doing that initialization before the
paravirt jump.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: lguest <lguest@ozlabs.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <201101041720.54535.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rusty Russell
Ingo Molnar
parent
387c31c7e5
commit
d50d8fe192
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@ -139,39 +139,6 @@ ENTRY(startup_32)
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movl %eax, pa(olpc_ofw_pgd)
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#endif
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#ifdef CONFIG_PARAVIRT
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/* This is can only trip for a broken bootloader... */
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cmpw $0x207, pa(boot_params + BP_version)
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jb default_entry
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/* Paravirt-compatible boot parameters. Look to see what architecture
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we're booting under. */
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movl pa(boot_params + BP_hardware_subarch), %eax
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cmpl $num_subarch_entries, %eax
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jae bad_subarch
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movl pa(subarch_entries)(,%eax,4), %eax
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subl $__PAGE_OFFSET, %eax
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jmp *%eax
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bad_subarch:
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WEAK(lguest_entry)
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WEAK(xen_entry)
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/* Unknown implementation; there's really
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nothing we can do at this point. */
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ud2a
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__INITDATA
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subarch_entries:
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.long default_entry /* normal x86/PC */
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.long lguest_entry /* lguest hypervisor */
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.long xen_entry /* Xen hypervisor */
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.long default_entry /* Moorestown MID */
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num_subarch_entries = (. - subarch_entries) / 4
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.previous
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#endif /* CONFIG_PARAVIRT */
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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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@ -181,7 +148,6 @@ num_subarch_entries = (. - subarch_entries) / 4
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*
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* Note that the stack is not yet set up!
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*/
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default_entry:
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#ifdef CONFIG_X86_PAE
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/*
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@ -261,7 +227,42 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
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movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
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movl %eax,pa(initial_page_table+0xffc)
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#endif
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jmp 3f
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#ifdef CONFIG_PARAVIRT
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/* This is can only trip for a broken bootloader... */
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cmpw $0x207, pa(boot_params + BP_version)
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jb default_entry
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/* Paravirt-compatible boot parameters. Look to see what architecture
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we're booting under. */
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movl pa(boot_params + BP_hardware_subarch), %eax
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cmpl $num_subarch_entries, %eax
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jae bad_subarch
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movl pa(subarch_entries)(,%eax,4), %eax
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subl $__PAGE_OFFSET, %eax
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jmp *%eax
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bad_subarch:
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WEAK(lguest_entry)
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WEAK(xen_entry)
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/* Unknown implementation; there's really
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nothing we can do at this point. */
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ud2a
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__INITDATA
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subarch_entries:
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.long default_entry /* normal x86/PC */
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.long lguest_entry /* lguest hypervisor */
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.long xen_entry /* Xen hypervisor */
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.long default_entry /* Moorestown MID */
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num_subarch_entries = (. - subarch_entries) / 4
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.previous
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#else
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jmp default_entry
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#endif /* CONFIG_PARAVIRT */
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/*
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* Non-boot CPU entry point; entered from trampoline.S
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* We can't lgdt here, because lgdt itself uses a data segment, but
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@ -282,7 +283,7 @@ ENTRY(startup_32_smp)
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movl %eax,%fs
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movl %eax,%gs
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#endif /* CONFIG_SMP */
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3:
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default_entry:
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/*
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* New page tables may be in 4Mbyte page mode and may
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@ -622,13 +623,13 @@ ENTRY(initial_code)
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__PAGE_ALIGNED_BSS
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.align PAGE_SIZE_asm
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#ifdef CONFIG_X86_PAE
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ENTRY(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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ENTRY(initial_page_table)
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.fill 1024,4,0
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#endif
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ENTRY(initial_pg_fixmap)
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initial_pg_fixmap:
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.fill 1024,4,0
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ENTRY(empty_zero_page)
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.fill 4096,1,0
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@ -4,7 +4,6 @@
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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#include <asm/processor-flags.h>
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#include <asm/pgtable.h>
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/*G:020
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* Our story starts with the kernel booting into startup_32 in
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@ -38,113 +37,9 @@ ENTRY(lguest_entry)
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/* Set up the initial stack so we can run C code. */
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movl $(init_thread_union+THREAD_SIZE),%esp
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call init_pagetables
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/* Jumps are relative: we're running __PAGE_OFFSET too low. */
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jmp lguest_init+__PAGE_OFFSET
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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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* FIXME: This code is taken verbatim from arch/x86/kernel/head_32.S: they
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* don't have a stack at this point, so we can't just use call and ret.
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*/
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init_pagetables:
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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 pa(X) ((X) - __PAGE_OFFSET)
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/* Enough space to fit pagetables for the low memory linear map */
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MAPPING_BEYOND_END = \
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PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT
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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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#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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movl %eax,pa(initial_page_table+0xffc)
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#endif
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ret
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/*G:055
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* We create a macro which puts the assembler code between lgstart_ and lgend_
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* markers. These templates are put in the .text section: they can't be
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