arch/um/kernel/mem.c

Source file repositories/reference/linux-study-clean/arch/um/kernel/mem.c

File Facts

System
Linux kernel
Corpus path
arch/um/kernel/mem.c
Extension
.c
Size
3489 bytes
Lines
140
Domain
Architecture Layer
Bucket
arch/um
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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */

#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <asm/sections.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <as-layout.h>
#include <init.h>
#include <kern.h>
#include <kern_util.h>
#include <mem_user.h>
#include <os.h>
#include <um_malloc.h>
#include <linux/sched/task.h>
#include <linux/kasan.h>

#ifdef CONFIG_KASAN
void __init kasan_init(void)
{
	/*
	 * kasan_map_memory will map all of the required address space and
	 * the host machine will allocate physical memory as necessary.
	 */
	kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE);
	init_task.kasan_depth = 0;
	/*
	 * Since kasan_init() is called before main(),
	 * KASAN is initialized but the enablement is deferred after
	 * jump_label_init(). See arch_mm_preinit().
	 */
}

static void (*kasan_init_ptr)(void)
__section(".kasan_init") __used
= kasan_init;
#endif

/*
 * Initialized during boot, and readonly for initializing page tables
 * afterwards
 */
pgd_t swapper_pg_dir[PTRS_PER_PGD];

/* Initialized at boot time, and readonly after that */
int kmalloc_ok = 0;

/* Used during early boot */
static unsigned long brk_end;

void __init arch_mm_preinit(void)
{
	/* Safe to call after jump_label_init(). Enables KASAN. */
	kasan_init_generic();

	/* Map in the area just after the brk now that kmalloc is about
	 * to be turned on.
	 */
	brk_end = PAGE_ALIGN((unsigned long) sbrk(0));
	map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
	memblock_free((void *)brk_end, uml_reserved - brk_end);
	uml_reserved = brk_end;
	min_low_pfn = PFN_UP(__pa(uml_reserved));
	max_pfn = max_low_pfn;
}

void __init mem_init(void)
{
	kmalloc_ok = 1;
}

void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
{
	max_zone_pfns[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT;
}

/*
 * This can't do anything because nothing in the kernel image can be freed
 * since it's not in kernel physical memory.
 */

void free_initmem(void)

Annotation

Implementation Notes