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 (da32dac10126 "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>

1 files changed, 0 insertions, 105 deletions

diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S
index e7d5382ef263..4f420c2f2d55 100644
--- a/arch/x86/lguest/i386_head.S
+++ b/arch/x86/lguest/i386_head.S
@@ -4,7 +4,6 @@
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/processor-flags.h>
-#include <asm/pgtable.h>
 
 /*G:020
  * Our story starts with the kernel booting into startup_32 in
@@ -38,113 +37,9 @@ ENTRY(lguest_entry)
         /* Set up the initial stack so we can run C code. */
         movl $(init_thread_union+THREAD_SIZE),%esp
 
-        call init_pagetables
-
         /* Jumps are relative: we're running __PAGE_OFFSET too low. */
         jmp lguest_init+__PAGE_OFFSET
 
-/*
- * Initialize page tables.  This creates a PDE and a set of page
- * tables, which are located immediately beyond __brk_base.  The variable
- * _brk_end is set up to point to the first "safe" location.
- * Mappings are created both at virtual address 0 (identity mapping)
- * and PAGE_OFFSET for up to _end.
- *
- * FIXME: This code is taken verbatim from arch/x86/kernel/head_32.S: they
- * don't have a stack at this point, so we can't just use call and ret.
- */
-init_pagetables:
-#if PTRS_PER_PMD > 1
-#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
-#else
-#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
-#endif
-#define pa(X) ((X) - __PAGE_OFFSET)
-
-/* Enough space to fit pagetables for the low memory linear map */
-MAPPING_BEYOND_END = \
-        PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT
-#ifdef CONFIG_X86_PAE
-
-        /*
-         * In PAE mode initial_page_table is statically defined to contain
-         * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
-         * entries). The identity mapping is handled by pointing two PGD entries
-         * to the first kernel PMD.
-         *
-         * Note the upper half of each PMD or PTE are always zero at this stage.
-         */
-
-#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
-
-        xorl %ebx,%ebx                          /* %ebx is kept at zero */
-
-        movl $pa(__brk_base), %edi
-        movl $pa(initial_pg_pmd), %edx
-        movl $PTE_IDENT_ATTR, %eax
-10:
-        leal PDE_IDENT_ATTR(%edi),%ecx          /* Create PMD entry */
-        movl %ecx,(%edx)                        /* Store PMD entry */
-                                                /* Upper half already zero */
-        addl $8,%edx
-        movl $512,%ecx
-11:
-        stosl
-        xchgl %eax,%ebx
-        stosl
-        xchgl %eax,%ebx
-        addl $0x1000,%eax
-        loop 11b
-
-        /*
-         * End condition: we must map up to the end + MAPPING_BEYOND_END.
-         */
-        movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
-        cmpl %ebp,%eax
-        jb 10b
-1:
-        addl $__PAGE_OFFSET, %edi
-        movl %edi, pa(_brk_end)
-        shrl $12, %eax
-        movl %eax, pa(max_pfn_mapped)
-
-        /* Do early initialization of the fixmap area */
-        movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
-        movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
-#else   /* Not PAE */
-
-page_pde_offset = (__PAGE_OFFSET >> 20);
-
-        movl $pa(__brk_base), %edi
-        movl $pa(initial_page_table), %edx
-        movl $PTE_IDENT_ATTR, %eax
-10:
-        leal PDE_IDENT_ATTR(%edi),%ecx          /* Create PDE entry */
-        movl %ecx,(%edx)                        /* Store identity PDE entry */
-        movl %ecx,page_pde_offset(%edx)         /* Store kernel PDE entry */
-        addl $4,%edx
-        movl $1024, %ecx
-11:
-        stosl
-        addl $0x1000,%eax
-        loop 11b
-        /*
-         * End condition: we must map up to the end + MAPPING_BEYOND_END.
-         */
-        movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
-        cmpl %ebp,%eax
-        jb 10b
-        addl $__PAGE_OFFSET, %edi
-        movl %edi, pa(_brk_end)
-        shrl $12, %eax
-        movl %eax, pa(max_pfn_mapped)
-
-        /* Do early initialization of the fixmap area */
-        movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
-        movl %eax,pa(initial_page_table+0xffc)
-#endif
-        ret
-
 /*G:055
  * We create a macro which puts the assembler code between lgstart_ and lgend_
  * markers.  These templates are put in the .text section: they can't be