arch/x86/include/asm/fixmap.h

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

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/fixmap.h
Extension
.h
Size
6096 bytes
Lines
201
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_FIXMAP_H
#define _ASM_X86_FIXMAP_H

#include <asm/kmap_size.h>

/*
 * Exposed to assembly code for setting up initial page tables. Cannot be
 * calculated in assembly code (fixmap entries are an enum), but is sanity
 * checked in the actual fixmap C code to make sure that the fixmap is
 * covered fully.
 */
#ifndef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
# define FIXMAP_PMD_NUM	2
#else
# define KM_PMDS	(KM_MAX_IDX * ((CONFIG_NR_CPUS + 511) / 512))
# define FIXMAP_PMD_NUM (KM_PMDS + 2)
#endif
/* fixmap starts downwards from the 507th entry in level2_fixmap_pgt */
#define FIXMAP_PMD_TOP	507

#ifndef __ASSEMBLER__
#include <linux/kernel.h>
#include <asm/apicdef.h>
#include <asm/page.h>
#include <asm/pgtable_types.h>
#ifdef CONFIG_X86_32
#include <linux/threads.h>
#else
#include <uapi/asm/vsyscall.h>
#endif

/*
 * We can't declare FIXADDR_TOP as variable for x86_64 because vsyscall
 * uses fixmaps that relies on FIXADDR_TOP for proper address calculation.
 * Because of this, FIXADDR_TOP x86 integration was left as later work.
 */
#ifdef CONFIG_X86_32
/*
 * Leave one empty page between vmalloc'ed areas and
 * the start of the fixmap.
 */
extern unsigned long __FIXADDR_TOP;
#define FIXADDR_TOP	((unsigned long)__FIXADDR_TOP)
#else
#define FIXADDR_TOP	(round_up(VSYSCALL_ADDR + PAGE_SIZE, 1<<PMD_SHIFT) - \
			 PAGE_SIZE)
#endif

/*
 * Here we define all the compile-time 'special' virtual
 * addresses. The point is to have a constant address at
 * compile time, but to set the physical address only
 * in the boot process.
 * for x86_32: We allocate these special addresses
 * from the end of virtual memory (0xfffff000) backwards.
 * Also this lets us do fail-safe vmalloc(), we
 * can guarantee that these special addresses and
 * vmalloc()-ed addresses never overlap.
 *
 * These 'compile-time allocated' memory buffers are
 * fixed-size 4k pages (or larger if used with an increment
 * higher than 1). Use set_fixmap(idx,phys) to associate
 * physical memory with fixmap indices.
 *
 * TLB entries of such buffers will not be flushed across
 * task switches.
 */
enum fixed_addresses {
#ifdef CONFIG_X86_32
	FIX_HOLE,
#else
#ifdef CONFIG_X86_VSYSCALL_EMULATION
	VSYSCALL_PAGE = (FIXADDR_TOP - VSYSCALL_ADDR) >> PAGE_SHIFT,
#endif
#endif
	FIX_DBGP_BASE,
	FIX_EARLYCON_MEM_BASE,
#ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
	FIX_OHCI1394_BASE,
#endif
#ifdef CONFIG_X86_LOCAL_APIC
	FIX_APIC_BASE,	/* local (CPU) APIC) -- required for SMP or not */
#endif
#ifdef CONFIG_X86_IO_APIC
	FIX_IO_APIC_BASE_0,
	FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
#endif
#ifdef CONFIG_KMAP_LOCAL
	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,

Annotation

Implementation Notes