Commit 67dcbb6b authored by Vivek Goyal's avatar Vivek Goyal Committed by Andi Kleen
Browse files

[PATCH] x86-64: Clean up the early boot page table 



- Merge physmem_pgt and ident_pgt, removing physmem_pgt.  The merge
  is broken as soon as mm/init.c:init_memory_mapping is run.
- As physmem_pgt is gone don't export it in pgtable.h.
- Use defines from pgtable.h for page permissions.
- Fix the physical memory identity mapping so it is at the correct
  address.
- Remove the physical memory mapping from wakeup_level4_pgt it
  is at the wrong address so we can't possibly be usinging it.
- Simply NEXT_PAGE the work to calculate the phys_ alias
  of the labels was very cool.  Unfortuantely it was a brittle
  special purpose hack that makes maitenance more difficult.
  Instead just use label - __START_KERNEL_map like we do
  everywhere else in assembly.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent dafe41ee

arch/x86_64/kernel/head.S

+28 −33
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/init.h>

#include <asm/desc.h>

#include <asm/segment.h>

#include <asm/pgtable.h>

#include <asm/page.h>

#include <asm/msr.h>

#include <asm/cache.h>
@@ -260,52 +261,48 @@ ljumpvector: 
ENTRY(stext)

ENTRY(_stext)



	$page = 0

#define NEXT_PAGE(name) \

	$page = $page + 1; \

	.org $page * 0x1000; \

	phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \

	.balign	PAGE_SIZE; \

ENTRY(name)



/* Automate the creation of 1 to 1 mapping pmd entries */

#define PMDS(START, PERM, COUNT)		\

	i = 0 ;					\

	.rept (COUNT) ;				\

	.quad	(START) + (i << 21) + (PERM) ;	\

	i = i + 1 ;				\

	.endr



NEXT_PAGE(init_level4_pgt)

	/* This gets initialized in x86_64_start_kernel */

	.fill	512,8,0



NEXT_PAGE(level3_ident_pgt)

	.quad	phys_level2_ident_pgt | 0x007

	.quad	level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	511,8,0



NEXT_PAGE(level3_kernel_pgt)

	.fill	510,8,0

	/* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */

	.quad	phys_level2_kernel_pgt | 0x007

	.quad	level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	1,8,0



NEXT_PAGE(level2_ident_pgt)

	/* 40MB for bootup. 	*/

	i = 0

	.rept 20

	.quad	i << 21 | 0x083

	i = i + 1

	.endr

	.fill	492,8,0

	/* Since I easily can, map the first 1G.

	 * Don't set NX because code runs from these pages.

	 */

	PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD)

	

NEXT_PAGE(level2_kernel_pgt)

	/* 40MB kernel mapping. The kernel code cannot be bigger than that.

	   When you change this change KERNEL_TEXT_SIZE in page.h too. */

	/* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */

	i = 0

	.rept 20

	.quad	i << 21 | 0x183

	i = i + 1

	.endr

	PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL,

		KERNEL_TEXT_SIZE/PMD_SIZE)

	/* Module mapping starts here */

	.fill	492,8,0



NEXT_PAGE(level3_physmem_pgt)

	.quad	phys_level2_kernel_pgt | 0x007	/* so that __va works even before pagetable_init */

	.fill	511,8,0

	.fill	(PTRS_PER_PMD - (KERNEL_TEXT_SIZE/PMD_SIZE)),8,0



#undef PMDS

#undef NEXT_PAGE



	.data
@@ -313,12 +310,10 @@ NEXT_PAGE(level3_physmem_pgt) 
#ifdef CONFIG_ACPI_SLEEP

	.align PAGE_SIZE

ENTRY(wakeup_level4_pgt)

	.quad	phys_level3_ident_pgt | 0x007

	.fill	255,8,0

	.quad	phys_level3_physmem_pgt | 0x007

	.fill	254,8,0

	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	510,8,0

	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */

	.quad	phys_level3_kernel_pgt | 0x007

	.quad	level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE

#endif



#ifndef CONFIG_HOTPLUG_CPU
@@ -332,12 +327,12 @@ ENTRY(wakeup_level4_pgt) 
	 */

	.align PAGE_SIZE

ENTRY(boot_level4_pgt)

	.quad	phys_level3_ident_pgt | 0x007

	.fill	255,8,0

	.quad	phys_level3_physmem_pgt | 0x007

	.fill	254,8,0

	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	257,8,0

	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE

	.fill	252,8,0

	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */

	.quad	phys_level3_kernel_pgt | 0x007

	.quad	level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE



	.data

include/asm-x86_64/pgtable.h

+0 −1
Original line number Diff line number Diff line
@@ -14,7 +14,6 @@ 
#include <asm/pda.h>



extern pud_t level3_kernel_pgt[512];

extern pud_t level3_physmem_pgt[512];

extern pud_t level3_ident_pgt[512];

extern pmd_t level2_kernel_pgt[512];

extern pgd_t init_level4_pgt[];

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