cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mtdram.c (4324B)


      1/*
      2 * mtdram - a test mtd device
      3 * Author: Alexander Larsson <alex@cendio.se>
      4 *
      5 * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
      6 * Copyright (c) 2005 Joern Engel <joern@wh.fh-wedel.de>
      7 *
      8 * This code is GPL
      9 *
     10 */
     11
     12#include <linux/module.h>
     13#include <linux/slab.h>
     14#include <linux/ioport.h>
     15#include <linux/vmalloc.h>
     16#include <linux/mm.h>
     17#include <linux/init.h>
     18#include <linux/mtd/mtd.h>
     19#include <linux/mtd/mtdram.h>
     20
     21static unsigned long total_size = CONFIG_MTDRAM_TOTAL_SIZE;
     22static unsigned long erase_size = CONFIG_MTDRAM_ERASE_SIZE;
     23static unsigned long writebuf_size = 64;
     24#define MTDRAM_TOTAL_SIZE (total_size * 1024)
     25#define MTDRAM_ERASE_SIZE (erase_size * 1024)
     26
     27module_param(total_size, ulong, 0);
     28MODULE_PARM_DESC(total_size, "Total device size in KiB");
     29module_param(erase_size, ulong, 0);
     30MODULE_PARM_DESC(erase_size, "Device erase block size in KiB");
     31module_param(writebuf_size, ulong, 0);
     32MODULE_PARM_DESC(writebuf_size, "Device write buf size in Bytes (Default: 64)");
     33
     34// We could store these in the mtd structure, but we only support 1 device..
     35static struct mtd_info *mtd_info;
     36
     37static int check_offs_len(struct mtd_info *mtd, loff_t ofs, uint64_t len)
     38{
     39	int ret = 0;
     40
     41	/* Start address must align on block boundary */
     42	if (mtd_mod_by_eb(ofs, mtd)) {
     43		pr_debug("%s: unaligned address\n", __func__);
     44		ret = -EINVAL;
     45	}
     46
     47	/* Length must align on block boundary */
     48	if (mtd_mod_by_eb(len, mtd)) {
     49		pr_debug("%s: length not block aligned\n", __func__);
     50		ret = -EINVAL;
     51	}
     52
     53	return ret;
     54}
     55
     56static int ram_erase(struct mtd_info *mtd, struct erase_info *instr)
     57{
     58	if (check_offs_len(mtd, instr->addr, instr->len))
     59		return -EINVAL;
     60	memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
     61
     62	return 0;
     63}
     64
     65static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,
     66		size_t *retlen, void **virt, resource_size_t *phys)
     67{
     68	*virt = mtd->priv + from;
     69	*retlen = len;
     70
     71	if (phys) {
     72		/* limit retlen to the number of contiguous physical pages */
     73		unsigned long page_ofs = offset_in_page(*virt);
     74		void *addr = *virt - page_ofs;
     75		unsigned long pfn1, pfn0 = vmalloc_to_pfn(addr);
     76
     77		*phys = __pfn_to_phys(pfn0) + page_ofs;
     78		len += page_ofs;
     79		while (len > PAGE_SIZE) {
     80			len -= PAGE_SIZE;
     81			addr += PAGE_SIZE;
     82			pfn0++;
     83			pfn1 = vmalloc_to_pfn(addr);
     84			if (pfn1 != pfn0) {
     85				*retlen = addr - *virt;
     86				break;
     87			}
     88		}
     89	}
     90
     91	return 0;
     92}
     93
     94static int ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
     95{
     96	return 0;
     97}
     98
     99static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
    100		size_t *retlen, u_char *buf)
    101{
    102	memcpy(buf, mtd->priv + from, len);
    103	*retlen = len;
    104	return 0;
    105}
    106
    107static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
    108		size_t *retlen, const u_char *buf)
    109{
    110	memcpy((char *)mtd->priv + to, buf, len);
    111	*retlen = len;
    112	return 0;
    113}
    114
    115static void __exit cleanup_mtdram(void)
    116{
    117	if (mtd_info) {
    118		mtd_device_unregister(mtd_info);
    119		vfree(mtd_info->priv);
    120		kfree(mtd_info);
    121	}
    122}
    123
    124int mtdram_init_device(struct mtd_info *mtd, void *mapped_address,
    125		unsigned long size, const char *name)
    126{
    127	memset(mtd, 0, sizeof(*mtd));
    128
    129	/* Setup the MTD structure */
    130	mtd->name = name;
    131	mtd->type = MTD_RAM;
    132	mtd->flags = MTD_CAP_RAM;
    133	mtd->size = size;
    134	mtd->writesize = 1;
    135	mtd->writebufsize = writebuf_size;
    136	mtd->erasesize = MTDRAM_ERASE_SIZE;
    137	mtd->priv = mapped_address;
    138
    139	mtd->owner = THIS_MODULE;
    140	mtd->_erase = ram_erase;
    141	mtd->_point = ram_point;
    142	mtd->_unpoint = ram_unpoint;
    143	mtd->_read = ram_read;
    144	mtd->_write = ram_write;
    145
    146	if (mtd_device_register(mtd, NULL, 0))
    147		return -EIO;
    148
    149	return 0;
    150}
    151
    152static int __init init_mtdram(void)
    153{
    154	void *addr;
    155	int err;
    156
    157	if (!total_size)
    158		return -EINVAL;
    159
    160	/* Allocate some memory */
    161	mtd_info = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
    162	if (!mtd_info)
    163		return -ENOMEM;
    164
    165	addr = vmalloc(MTDRAM_TOTAL_SIZE);
    166	if (!addr) {
    167		kfree(mtd_info);
    168		mtd_info = NULL;
    169		return -ENOMEM;
    170	}
    171	err = mtdram_init_device(mtd_info, addr, MTDRAM_TOTAL_SIZE, "mtdram test device");
    172	if (err) {
    173		vfree(addr);
    174		kfree(mtd_info);
    175		mtd_info = NULL;
    176		return err;
    177	}
    178	memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);
    179	return err;
    180}
    181
    182module_init(init_mtdram);
    183module_exit(cleanup_mtdram);
    184
    185MODULE_LICENSE("GPL");
    186MODULE_AUTHOR("Alexander Larsson <alexl@redhat.com>");
    187MODULE_DESCRIPTION("Simulated MTD driver for testing");