Commit b3444d16 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus 

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  lguest: populate initial_page_table
  lguest: restore boot speed
  lguest: fix crash lguest_time_init
parents 4ef5c68f da32dac1

arch/x86/kernel/head_32.S

+2 −2
Original line number Diff line number Diff line
@@ -620,13 +620,13 @@ ENTRY(initial_code) 
__PAGE_ALIGNED_BSS

	.align PAGE_SIZE_asm

#ifdef CONFIG_X86_PAE

initial_pg_pmd:

ENTRY(initial_pg_pmd)

	.fill 1024*KPMDS,4,0

#else

ENTRY(initial_page_table)

	.fill 1024,4,0

#endif

initial_pg_fixmap:

ENTRY(initial_pg_fixmap)

	.fill 1024,4,0

ENTRY(empty_zero_page)

	.fill 4096,1,0

arch/x86/lguest/boot.c

+8 −8
Original line number Diff line number Diff line
@@ -531,6 +531,9 @@ static void lguest_write_cr3(unsigned long cr3) 
{

	lguest_data.pgdir = cr3;

	lazy_hcall1(LHCALL_NEW_PGTABLE, cr3);



	/* These two page tables are simple, linear, and used during boot */

	if (cr3 != __pa(swapper_pg_dir) && cr3 != __pa(initial_page_table))

		cr3_changed = true;

}
@@ -703,9 +706,9 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) 
 * to forget all of them.  Fortunately, this is very rare.

 *

 * ... except in early boot when the kernel sets up the initial pagetables,

 * which makes booting astonishingly slow: 1.83 seconds!  So we don't even tell

 * the Host anything changed until we've done the first page table switch,

 * which brings boot back to 0.25 seconds.

 * which makes booting astonishingly slow: 48 seconds!  So we don't even tell

 * the Host anything changed until we've done the first real page table switch,

 * which brings boot back to 4.3 seconds.

 */

static void lguest_set_pte(pte_t *ptep, pte_t pteval)

{
@@ -1002,7 +1005,7 @@ static void lguest_time_init(void) 
	clockevents_register_device(&lguest_clockevent);



	/* Finally, we unblock the timer interrupt. */

	enable_lguest_irq(0);

	clear_bit(0, lguest_data.blocked_interrupts);

}



/*
@@ -1349,9 +1352,6 @@ __init void lguest_init(void) 
	 */

	switch_to_new_gdt(0);



	/* We actually boot with all memory mapped, but let's say 128MB. */

	max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT;



	/*

	 * The Host<->Guest Switcher lives at the top of our address space, and

	 * the Host told us how big it is when we made LGUEST_INIT hypercall:

arch/x86/lguest/i386_head.S

+105 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#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
@@ -37,9 +38,113 @@ 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