arch/x86/include/asm/pgtable_32_areas.h

Source file repositories/reference/linux-study-clean/arch/x86/include/asm/pgtable_32_areas.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/pgtable_32_areas.h
Extension
.h
Size
1583 bytes
Lines
54
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_X86_PGTABLE_32_AREAS_H
#define _ASM_X86_PGTABLE_32_AREAS_H

#include <asm/cpu_entry_area.h>

/*
 * Just any arbitrary offset to the start of the vmalloc VM area: the
 * current 8MB value just means that there will be a 8MB "hole" after the
 * physical memory until the kernel virtual memory starts.  That means that
 * any out-of-bounds memory accesses will hopefully be caught.
 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
 * area for the same reason. ;)
 */
#define VMALLOC_OFFSET	(8 * 1024 * 1024)

#ifndef __ASSEMBLER__
extern bool __vmalloc_start_set; /* set once high_memory is set */
#endif

#define VMALLOC_START	((unsigned long)high_memory + VMALLOC_OFFSET)
#ifdef CONFIG_X86_PAE
#define LAST_PKMAP 512
#else
#define LAST_PKMAP 1024
#endif

#define CPU_ENTRY_AREA_PAGES		(NR_CPUS * DIV_ROUND_UP(sizeof(struct cpu_entry_area), PAGE_SIZE))

/* The +1 is for the readonly IDT page: */
#define CPU_ENTRY_AREA_BASE	\
	((FIXADDR_TOT_START - PAGE_SIZE*(CPU_ENTRY_AREA_PAGES+1)) & PMD_MASK)

#define LDT_BASE_ADDR		\
	((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)

#define LDT_END_ADDR		(LDT_BASE_ADDR + PMD_SIZE)

#define PKMAP_BASE		\
	((LDT_BASE_ADDR - PAGE_SIZE) & PMD_MASK)

#ifdef CONFIG_HIGHMEM
# define VMALLOC_END	(PKMAP_BASE - 2 * PAGE_SIZE)
#else
# define VMALLOC_END	(LDT_BASE_ADDR - 2 * PAGE_SIZE)
#endif

#define MODULES_VADDR	VMALLOC_START
#define MODULES_END	VMALLOC_END
#define MODULES_LEN	(MODULES_VADDR - MODULES_END)

#define MAXMEM	(VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)

#endif /* _ASM_X86_PGTABLE_32_AREAS_H */

Annotation

Implementation Notes