/* * ramdisk.c - Multiple RAM disk driver - gzip-loading version - v. 0.8 beta. * * (C) Chad Page, Theodore Ts'o, et. al, 1995. * * This RAM disk is designed to have filesystems created on it and mounted * just like a regular floppy disk. * * It also does something suggested by Linus: use the buffer cache as the * RAM disk data. This makes it possible to dynamically allocate the RAM disk * buffer - with some consequences I have to deal with as I write this. * * This code is based on the original ramdisk.c, written mostly by * Theodore Ts'o (TYT) in 1991. The code was largely rewritten by * Chad Page to use the buffer cache to store the RAM disk data in * 1995; Theodore then took over the driver again, and cleaned it up * for inclusion in the mainline kernel. * * The original CRAMDISK code was written by Richard Lyons, and * adapted by Chad Page to use the new RAM disk interface. Theodore * Ts'o rewrote it so that both the compressed RAM disk loader and the * kernel decompressor uses the same inflate.c codebase. The RAM disk * loader now also loads into a dynamic (buffer cache based) RAM disk, * not the old static RAM disk. Support for the old static RAM disk has * been completely removed. * * Loadable module support added by Tom Dyas. * * Further cleanups by Chad Page (page0588@sundance.sjsu.edu): * Cosmetic changes in #ifdef MODULE, code movement, etc. * When the RAM disk module is removed, free the protected buffers * Default RAM disk size changed to 2.88 MB * * Added initrd: Werner Almesberger & Hans Lermen, Feb '96 * * 4/25/96 : Made RAM disk size a parameter (default is now 4 MB) * - Chad Page * * Add support for fs images split across >1 disk, Paul Gortmaker, Mar '98 * * Make block size and block size shift for RAM disks a global macro * and set blk_size for -ENOSPC, Werner Fink , Apr '99 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern void wait_for_keypress(void); /* * 35 has been officially registered as the RAMDISK major number, but * so is the original MAJOR number of 1. We're using 1 in * include/linux/major.h for now */ #define MAJOR_NR RAMDISK_MAJOR #include #include /* The RAM disk size is now a parameter */ #define NUM_RAMDISKS 16 /* This cannot be overridden (yet) */ #ifndef MODULE /* We don't have to load RAM disks or gunzip them in a module. */ #define RD_LOADER #define BUILD_CRAMDISK void rd_load(void); static int crd_load(struct file *fp, struct file *outfp); #ifdef CONFIG_BLK_DEV_INITRD static int initrd_users = 0; #endif #endif /* Various static variables go here. Most are used only in the RAM disk code. */ static unsigned long rd_length[NUM_RAMDISKS]; /* Size of RAM disks in bytes */ static int rd_hardsec[NUM_RAMDISKS]; /* Size of real blocks in bytes */ static int rd_blocksizes[NUM_RAMDISKS]; /* Size of 1024 byte blocks :) */ static int rd_kbsize[NUM_RAMDISKS]; /* Size in blocks of 1024 bytes */ /* * Parameters for the boot-loading of the RAM disk. These are set by * init/main.c (from arguments to the kernel command line) or from the * architecture-specific setup routine (from the stored boot sector * information). */ int rd_size = 4096; /* Size of the RAM disks */ /* * It would be very desiderable to have a soft-blocksize (that in the case * of the ramdisk driver is also the hardblocksize ;) of PAGE_SIZE because * doing that we'll achieve a far better MM footprint. Using a rd_blocksize of * BLOCK_SIZE in the worst case we'll make PAGE_SIZE/BLOCK_SIZE buffer-pages * unfreeable. With a rd_blocksize of PAGE_SIZE instead we are sure that only * 1 page will be protected. Depending on the size of the ramdisk you * may want to change the ramdisk blocksize to achieve a better or worse MM * behaviour. The default is still BLOCK_SIZE (needed by rd_load_image that * supposes the filesystem in the image uses a BLOCK_SIZE blocksize). */ int rd_blocksize = BLOCK_SIZE; /* Size of the RAM disks */ #ifndef MODULE int rd_doload = 0; /* 1 = load RAM disk, 0 = don't load */ int rd_prompt = 1; /* 1 = prompt for RAM disk, 0 = don't prompt */ int rd_image_start = 0; /* starting block # of image */ #ifdef CONFIG_BLK_DEV_INITRD unsigned long initrd_start,initrd_end; int mount_initrd = 1; /* zero if initrd should not be mounted */ int initrd_below_start_ok = 0; static int __init no_initrd(char *str) { mount_initrd = 0; return 1; } __setup("noinitrd", no_initrd); #endif static int __init ramdisk_start_setup(char *str) { rd_image_start = simple_strtol(str,NULL,0); return 1; } static int __init load_ramdisk(char *str) { rd_doload = simple_strtol(str,NULL,0) & 3; return 1; } static int __init prompt_ramdisk(char *str) { rd_prompt = simple_strtol(str,NULL,0) & 1; return 1; } static int __init ramdisk_size(char *str) { rd_size = simple_strtol(str,NULL,0); return 1; } static int __init ramdisk_size2(char *str) { return ramdisk_size(str); } __setup("ramdisk_start=", ramdisk_start_setup); __setup("load_ramdisk=", load_ramdisk); __setup("prompt_ramdisk=", prompt_ramdisk); __setup("ramdisk=", ramdisk_size); __setup("ramdisk_size=", ramdisk_size2); #endif /* * Basically, my strategy here is to set up a buffer-head which can't be * deleted, and make that my Ramdisk. If the request is outside of the * allocated size, we must get rid of it... * */ static void rd_request(request_queue_t * q) { unsigned int minor; unsigned long offset, len; struct buffer_head *rbh; struct buffer_head *sbh; repeat: INIT_REQUEST; minor = MINOR(CURRENT->rq_dev); if (minor >= NUM_RAMDISKS) { end_request(0); goto repeat; } offset = CURRENT->sector << 9; len = CURRENT->current_nr_sectors << 9; if ((offset + len) > rd_length[minor]) { end_request(0); goto repeat; } if ((CURRENT->cmd != READ) && (CURRENT->cmd != WRITE)) { printk(KERN_INFO "RAMDISK: bad command: %d\n", CURRENT->cmd); end_request(0); goto repeat; } /* * This has become somewhat more complicated with the addition of * the page cache. The problem is that in some cases the furnished * buffer is "real", i.e., part of the existing ramdisk, while in * others it is "unreal", e.g., part of a page. In the first case * not much needs to be done, while in the second, some kind of * transfer is needed. * * The two cases are distinguished here by checking whether the * real buffer is already in the buffer cache, and whether it is * the same as the one supplied. * * There are three cases with read/write to consider: * * 1. Supplied buffer matched one in the buffer cache: * Read - Clear the buffer, as it wasn't already valid. * Write - Mark the buffer as "Protected". * * 2. Supplied buffer mismatched one in the buffer cache: * Read - Copy the data from the buffer cache entry. * Write - Copy the data to the buffer cache entry. * * 3 No buffer cache entry existed: * Read - Clear the supplied buffer, but do not create a real * one. * Write - Create a real buffer, copy the data to it, and mark * it as "Protected". * * NOTE: There seems to be some schizophrenia here - the logic * using "len" seems to assume arbitrary request lengths, while * the "protect" logic assumes a single buffer cache entry. * This seems to be left over from the ancient contiguous ramdisk * logic. */ sbh = CURRENT->bh; rbh = get_hash_table(sbh->b_dev, sbh->b_blocknr, sbh->b_size); if (sbh == rbh) { if (CURRENT->cmd == READ) memset(CURRENT->buffer, 1, len); } else if (rbh) { if (CURRENT->cmd == READ) memcpy(CURRENT->buffer, rbh->b_data, rbh->b_size); else memcpy(rbh->b_data, CURRENT->buffer, rbh->b_size); } else { /* !rbh */ if (CURRENT->cmd == READ) memset(sbh->b_data, 2, len); else { rbh = getblk(sbh->b_dev, sbh->b_blocknr, sbh->b_size); if (rbh) memcpy(rbh->b_data, CURRENT->buffer, rbh->b_size); else BUG(); /* No buffer, what to do here? */ } } if (rbh) { set_bit(BH_Protected, &rbh->b_state); brelse(rbh); } end_request(1); goto repeat; } static int rd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { unsigned int minor; if (!inode || !inode->i_rdev) return -EINVAL; minor = MINOR(inode->i_rdev); switch (cmd) { case BLKFLSBUF: if (!capable(CAP_SYS_ADMIN)) return -EACCES; invalidate_buffers(inode->i_rdev); break; case BLKGETSIZE: /* Return device size */ if (!arg) return -EINVAL; return put_user(rd_kbsize[minor] << 1, (long *) arg); case BLKROSET: case BLKROGET: case BLKSSZGET: return blk_ioctl(inode->i_rdev, cmd, arg); default: return -EINVAL; }; return 0; } #ifdef CONFIG_BLK_DEV_INITRD static ssize_t initrd_read(struct file *file, char *buf, size_t count, loff_t *ppos) { int left; left = initrd_end - initrd_start - *ppos; if (count > left) count = left; if (count == 0) return 0; copy_to_user(buf, (char *)initrd_start + *ppos, count); *ppos += count; return count; } static int initrd_release(struct inode *inode,struct file *file) { extern void free_initrd_mem(unsigned long, unsigned long); if (--initrd_users) return 0; free_initrd_mem(initrd_start, initrd_end); initrd_start = 0; return 0; } static struct file_operations initrd_fops = { NULL, /* lseek */ initrd_read, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* poll */ NULL, /* ioctl */ NULL, /* mmap */ NULL, /* open */ NULL, /* flush */ initrd_release, /* release */ NULL /* fsync */ }; #endif static int rd_open(struct inode * inode, struct file * filp) { #ifdef CONFIG_BLK_DEV_INITRD if (DEVICE_NR(inode->i_rdev) == INITRD_MINOR) { if (!initrd_start) return -ENODEV; initrd_users++; filp->f_op = &initrd_fops; return 0; } #endif if (DEVICE_NR(inode->i_rdev) >= NUM_RAMDISKS) return -ENXIO; MOD_INC_USE_COUNT; return 0; } static int rd_release(struct inode * inode, struct file * filp) { MOD_DEC_USE_COUNT; return 0; } static struct block_device_operations fd_fops = { open: rd_open, release: rd_release, ioctl: rd_ioctl, }; /* Before freeing the module, invalidate all of the protected buffers! */ static void __exit rd_cleanup (void) { int i; for (i = 0 ; i < NUM_RAMDISKS; i++) invalidate_buffers(MKDEV(MAJOR_NR, i)); unregister_blkdev( MAJOR_NR, "ramdisk" ); blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR)); } /* This is the registration and initialization section of the RAM disk driver */ int __init rd_init (void) { int i; if (rd_blocksize > PAGE_SIZE || rd_blocksize < 512 || (rd_blocksize & (rd_blocksize-1))) { printk("RAMDISK: wrong blocksize %d, reverting to defaults\n", rd_blocksize); rd_blocksize = BLOCK_SIZE; } if (register_blkdev(MAJOR_NR, "ramdisk", &fd_fops)) { printk("RAMDISK: Could not get major %d", MAJOR_NR); return -EIO; } blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), &rd_request); for (i = 0; i < NUM_RAMDISKS; i++) { /* rd_size is given in kB */ rd_length[i] = rd_size << 10; rd_hardsec[i] = rd_blocksize; rd_blocksizes[i] = rd_blocksize; rd_kbsize[i] = rd_size; } hardsect_size[MAJOR_NR] = rd_hardsec; /* Size of the RAM disk blocks */ blksize_size[MAJOR_NR] = rd_blocksizes; /* Avoid set_blocksize() check */ blk_size[MAJOR_NR] = rd_kbsize; /* Size of the RAM disk in kB */ printk("RAMDISK driver initialized: " "%d RAM disks of %dK size %d blocksize\n", NUM_RAMDISKS, rd_size, rd_blocksize); return 0; } #ifdef MODULE module_init(rd_init); #endif module_exit(rd_cleanup); /* loadable module support */ MODULE_PARM (rd_size, "1i"); MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes."); MODULE_PARM (rd_blocksize, "i"); MODULE_PARM_DESC(rd_blocksize, "Blocksize of each RAM disk in bytes."); /* End of non-loading portions of the RAM disk driver */ #ifdef RD_LOADER /* * This routine tries to find a RAM disk image to load, and returns the * number of blocks to read for a non-compressed image, 0 if the image * is a compressed image, and -1 if an image with the right magic * numbers could not be found. * * We currently check for the following magic numbers: * minix * ext2 * romfs * gzip */ int __init identify_ramdisk_image(kdev_t device, struct file *fp, int start_block) { const int size = 512; struct minix_super_block *minixsb; struct ext2_super_block *ext2sb; struct romfs_super_block *romfsb; int nblocks = -1; unsigned char *buf; buf = kmalloc(size, GFP_KERNEL); if (buf == 0) return -1; minixsb = (struct minix_super_block *) buf; ext2sb = (struct ext2_super_block *) buf; romfsb = (struct romfs_super_block *) buf; memset(buf, 0xe5, size); /* * Read block 0 to test for gzipped kernel */ if (fp->f_op->llseek) fp->f_op->llseek(fp, start_block * BLOCK_SIZE, 0); fp->f_pos = start_block * BLOCK_SIZE; fp->f_op->read(fp, buf, size, &fp->f_pos); /* * If it matches the gzip magic numbers, return -1 */ if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) { printk(KERN_NOTICE "RAMDISK: Compressed image found at block %d\n", start_block); nblocks = 0; goto done; } /* romfs is at block zero too */ if (romfsb->word0 == ROMSB_WORD0 && romfsb->word1 == ROMSB_WORD1) { printk(KERN_NOTICE "RAMDISK: romfs filesystem found at block %d\n", start_block); nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS; goto done; } /* * Read block 1 to test for minix and ext2 superblock */ if (fp->f_op->llseek) fp->f_op->llseek(fp, (start_block+1) * BLOCK_SIZE, 0); fp->f_pos = (start_block+1) * BLOCK_SIZE; fp->f_op->read(fp, buf, size, &fp->f_pos); /* Try minix */ if (minixsb->s_magic == MINIX_SUPER_MAGIC || minixsb->s_magic == MINIX_SUPER_MAGIC2) { printk(KERN_NOTICE "RAMDISK: Minix filesystem found at block %d\n", start_block); nblocks = minixsb->s_nzones << minixsb->s_log_zone_size; goto done; } /* Try ext2 */ if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) { printk(KERN_NOTICE "RAMDISK: ext2 filesystem found at block %d\n", start_block); nblocks = le32_to_cpu(ext2sb->s_blocks_count); goto done; } printk(KERN_NOTICE "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n", start_block); done: if (fp->f_op->llseek) fp->f_op->llseek(fp, start_block * BLOCK_SIZE, 0); fp->f_pos = start_block * BLOCK_SIZE; kfree(buf); return nblocks; } /* * This routine loads in the RAM disk image. */ static void __init rd_load_image(kdev_t device, int offset, int unit) { struct inode inode, out_inode; struct file infile, outfile; struct dentry in_dentry, out_dentry; mm_segment_t fs; kdev_t ram_device; int nblocks, i; char *buf; unsigned short rotate = 0; unsigned short devblocks = 0; char rotator[4] = { '|' , '/' , '-' , '\\' }; ram_device = MKDEV(MAJOR_NR, unit); memset(&infile, 0, sizeof(infile)); memset(&inode, 0, sizeof(inode)); memset(&in_dentry, 0, sizeof(in_dentry)); inode.i_rdev = device; init_waitqueue_head(&inode.i_wait); infile.f_mode = 1; /* read only */ infile.f_dentry = &in_dentry; in_dentry.d_inode = &inode; memset(&outfile, 0, sizeof(outfile)); memset(&out_inode, 0, sizeof(out_inode)); memset(&out_dentry, 0, sizeof(out_dentry)); out_inode.i_rdev = ram_device; init_waitqueue_head(&out_inode.i_wait); outfile.f_mode = 3; /* read/write */ outfile.f_dentry = &out_dentry; out_dentry.d_inode = &out_inode; if (blkdev_open(&inode, &infile) != 0) return; if (blkdev_open(&out_inode, &outfile) != 0) return; fs = get_fs(); set_fs(KERNEL_DS); nblocks = identify_ramdisk_image(device, &infile, offset); if (nblocks < 0) goto done; if (nblocks == 0) { #ifdef BUILD_CRAMDISK if (crd_load(&infile, &outfile) == 0) goto successful_load; #else printk(KERN_NOTICE "RAMDISK: Kernel does not support compressed " "RAM disk images\n"); #endif goto done; } /* * NOTE NOTE: nblocks suppose that the blocksize is BLOCK_SIZE, so * rd_load_image will work only with filesystem BLOCK_SIZE wide! * So make sure to use 1k blocksize while generating ext2fs * ramdisk-images. */ if (nblocks > (rd_length[unit] >> BLOCK_SIZE_BITS)) { printk("RAMDISK: image too big! (%d/%ld blocks)\n", nblocks, rd_length[unit] >> BLOCK_SIZE_BITS); goto done; } /* * OK, time to copy in the data */ buf = kmalloc(BLOCK_SIZE, GFP_KERNEL); if (buf == 0) { printk(KERN_ERR "RAMDISK: could not allocate buffer\n"); goto done; } if (blk_size[MAJOR(device)]) devblocks = blk_size[MAJOR(device)][MINOR(device)]; #ifdef CONFIG_BLK_DEV_INITRD if (MAJOR(device) == MAJOR_NR && MINOR(device) == INITRD_MINOR) devblocks = nblocks; #endif if (devblocks == 0) { printk(KERN_ERR "RAMDISK: could not determine device size\n"); goto done; } printk(KERN_NOTICE "RAMDISK: Loading %d blocks [%d disk%s] into ram disk... ", nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : ""); for (i=0; i < nblocks; i++) { if (i && (i % devblocks == 0)) { printk("done disk #%d.\n", i/devblocks); rotate = 0; invalidate_buffers(device); if (infile.f_op->release) infile.f_op->release(&inode, &infile); printk("Please insert disk #%d and press ENTER\n", i/devblocks+1); wait_for_keypress(); if (blkdev_open(&inode, &infile) != 0) { printk("Error opening disk.\n"); goto done; } infile.f_pos = 0; printk("Loading disk #%d... ", i/devblocks+1); } infile.f_op->read(&infile, buf, BLOCK_SIZE, &infile.f_pos); outfile.f_op->write(&outfile, buf, BLOCK_SIZE, &outfile.f_pos); if (!(i % 16)) { printk("%c\b", rotator[rotate & 0x3]); rotate++; } } printk("done.\n"); kfree(buf); successful_load: invalidate_buffers(device); ROOT_DEV = MKDEV(MAJOR_NR, unit); done: if (infile.f_op->release) infile.f_op->release(&inode, &infile); set_fs(fs); } static void __init rd_load_disk(int n) { #ifdef CONFIG_BLK_DEV_INITRD extern kdev_t real_root_dev; #endif if (rd_doload == 0) return; if (MAJOR(ROOT_DEV) != FLOPPY_MAJOR #ifdef CONFIG_BLK_DEV_INITRD && MAJOR(real_root_dev) != FLOPPY_MAJOR #endif ) return; if (rd_prompt) { #ifdef CONFIG_BLK_DEV_FD floppy_eject(); #endif printk(KERN_NOTICE "VFS: Insert root floppy disk to be loaded into RAM disk and press ENTER\n"); wait_for_keypress(); } rd_load_image(ROOT_DEV,rd_image_start, n); } void __init rd_load(void) { rd_load_disk(0); } void __init rd_load_secondary(void) { rd_load_disk(1); } #ifdef CONFIG_BLK_DEV_INITRD void __init initrd_load(void) { rd_load_image(MKDEV(MAJOR_NR, INITRD_MINOR),rd_image_start,0); } #endif #endif /* RD_LOADER */ #ifdef BUILD_CRAMDISK /* * gzip declarations */ #define OF(args) args #ifndef memzero #define memzero(s, n) memset ((s), 0, (n)) #endif typedef unsigned char uch; typedef unsigned short ush; typedef unsigned long ulg; #define INBUFSIZ 4096 #define WSIZE 0x8000 /* window size--must be a power of two, and */ /* at least 32K for zip's deflate method */ static uch *inbuf; static uch *window; static unsigned insize = 0; /* valid bytes in inbuf */ static unsigned inptr = 0; /* index of next byte to be processed in inbuf */ static unsigned outcnt = 0; /* bytes in output buffer */ static int exit_code = 0; static long bytes_out = 0; static struct file *crd_infp, *crd_outfp; #define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf()) /* Diagnostic functions (stubbed out) */ #define Assert(cond,msg) #define Trace(x) #define Tracev(x) #define Tracevv(x) #define Tracec(c,x) #define Tracecv(c,x) #define STATIC static static int fill_inbuf(void); static void flush_window(void); static void *malloc(int size); static void free(void *where); static void error(char *m); static void gzip_mark(void **); static void gzip_release(void **); #include "../../lib/inflate.c" static void __init *malloc(int size) { return kmalloc(size, GFP_KERNEL); } static void __init free(void *where) { kfree(where); } static void __init gzip_mark(void **ptr) { } static void __init gzip_release(void **ptr) { } /* =========================================================================== * Fill the input buffer. This is called only when the buffer is empty * and at least one byte is really needed. */ static int __init fill_inbuf(void) { if (exit_code) return -1; insize = crd_infp->f_op->read(crd_infp, inbuf, INBUFSIZ, &crd_infp->f_pos); if (insize == 0) return -1; inptr = 1; return inbuf[0]; } /* =========================================================================== * Write the output window window[0..outcnt-1] and update crc and bytes_out. * (Used for the decompressed data only.) */ static void __init flush_window(void) { ulg c = crc; /* temporary variable */ unsigned n; uch *in, ch; crd_outfp->f_op->write(crd_outfp, window, outcnt, &crd_outfp->f_pos); in = window; for (n = 0; n < outcnt; n++) { ch = *in++; c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8); } crc = c; bytes_out += (ulg)outcnt; outcnt = 0; } static void __init error(char *x) { printk(KERN_ERR "%s", x); exit_code = 1; } static int __init crd_load(struct file * fp, struct file *outfp) { int result; insize = 0; /* valid bytes in inbuf */ inptr = 0; /* index of next byte to be processed in inbuf */ outcnt = 0; /* bytes in output buffer */ exit_code = 0; bytes_out = 0; crc = (ulg)0xffffffffL; /* shift register contents */ crd_infp = fp; crd_outfp = outfp; inbuf = kmalloc(INBUFSIZ, GFP_KERNEL); if (inbuf == 0) { printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n"); return -1; } window = kmalloc(WSIZE, GFP_KERNEL); if (window == 0) { printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n"); kfree(inbuf); return -1; } makecrc(); result = gunzip(); kfree(inbuf); kfree(window); return result; } #endif /* BUILD_CRAMDISK */