ramdisk.c File Reference

The RAM disk: the initial RAM disk the boot loader loaded, as block device 1, 0. More...

#include <core/system.h>
#include <core/panic.h>
#include <core/arch.h>
#include <core/module.h>
#include <core/string.h>
#include <boot/boot.h>
#include <dev/dev.h>
#include <mm/vm.h>

Go to the source code of this file.

Functions
static ssize_t	rd_read (struct devid *dd, off_t offset, size_t size, void *buf)
	Reads from the RAM disk: up to size bytes at offset, fewer at its end.
static ssize_t	rd_write (struct devid *dd, off_t offset, size_t size, void *buf)
	Writes to the RAM disk: up to size bytes at offset, fewer at its end.
static int	rd_probe ()
	Maps the RAM disk the boot loader loaded, and registers it as block device 1.
static size_t	rd_getbs (struct devid *dd)
	Returns the RAM disk's block size: 1, it is read byte by byte.

Variables
static void *	rd_addr = NULL
size_t	rd_size = 0
struct dev	rddev

Detailed Description

The RAM disk: the initial RAM disk the boot loader loaded, as block device 1, 0.

The boot loader puts the RAM disk (the first module) in memory; this driver maps it, and reads and writes it with plain copies. The kernel then unpacks the archive it holds as the first root filesystem (see load_ramdisk()). Without a module, the root is on a disk, and there is no RAM disk.

Definition in file ramdisk.c.

Function Documentation

rd_getbs()

size_t rd_getbs ( struct devid * dd )

static

Returns the RAM disk's block size: 1, it is read byte by byte.

Definition at line 88 of file ramdisk.c.

References rd_getbs().

Referenced by rd_getbs().

rd_probe()

int rd_probe ( )

static

Maps the RAM disk the boot loader loaded, and registers it as block device 1.

Without one (the root is on a disk), it does nothing.

Definition at line 65 of file ramdisk.c.

References __kboot, arch_phys_map(), kdev_blkdev_register(), boot::modules, boot::modules_count, module_t::paddr, panic, rd_addr, rd_probe(), rd_size, rddev, and module_t::size.

Referenced by rd_probe().

rd_read()

ssize_t rd_read ( struct devid * dd, off_t offset, size_t size, void * buf )

static

Reads from the RAM disk: up to size bytes at offset, fewer at its end.

Returns how many were read, 0 past the end.

Definition at line 29 of file ramdisk.c.

References memcpy(), MIN, rd_addr, rd_read(), and rd_size.

Referenced by rd_read().

rd_write()

ssize_t rd_write ( struct devid * dd, off_t offset, size_t size, void * buf )

static

Writes to the RAM disk: up to size bytes at offset, fewer at its end.

Returns how many were written, 0 past the end.

Definition at line 47 of file ramdisk.c.

References memcpy(), MIN, rd_addr, rd_size, and rd_write().

Referenced by rd_write().

Variable Documentation

rd_addr

void* rd_addr = NULL

static

Definition at line 22 of file ramdisk.c.

Referenced by rd_probe(), rd_read(), and rd_write().

rd_size

size_t rd_size = 0

Definition at line 25 of file ramdisk.c.

Referenced by load_ramdisk(), rd_probe(), rd_read(), and rd_write().

rddev

struct dev rddev

Initial value:

         = {
    .name  = "ramdisk",
    .probe = rd_probe,
    .bread  = rd_read,
    .bwrite = rd_write,
    .getbs = rd_getbs,
}

Definition at line 93 of file ramdisk.c.

Referenced by rd_probe().