| /* |
| * linux/drivers/char/mem.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * Added devfs support. |
| * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> |
| * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/miscdevice.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| #include <linux/mman.h> |
| #include <linux/random.h> |
| #include <linux/init.h> |
| #include <linux/raw.h> |
| #include <linux/tty.h> |
| #include <linux/capability.h> |
| #include <linux/ptrace.h> |
| #include <linux/device.h> |
| #include <linux/highmem.h> |
| #include <linux/crash_dump.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bootmem.h> |
| #include <linux/splice.h> |
| #include <linux/pfn.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| |
| #ifdef CONFIG_IA64 |
| # include <linux/efi.h> |
| #endif |
| |
| static inline unsigned long size_inside_page(unsigned long start, |
| unsigned long size) |
| { |
| unsigned long sz; |
| |
| sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); |
| |
| return min(sz, size); |
| } |
| |
| #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
| static inline int valid_phys_addr_range(unsigned long addr, size_t count) |
| { |
| if (addr + count > __pa(high_memory)) |
| return 0; |
| |
| return 1; |
| } |
| |
| static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
| { |
| return 1; |
| } |
| #endif |
| |
| #ifdef CONFIG_STRICT_DEVMEM |
| static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
| { |
| u64 from = ((u64)pfn) << PAGE_SHIFT; |
| u64 to = from + size; |
| u64 cursor = from; |
| |
| while (cursor < to) { |
| if (!devmem_is_allowed(pfn)) { |
| printk(KERN_INFO |
| "Program %s tried to access /dev/mem between %Lx->%Lx.\n", |
| current->comm, from, to); |
| return 0; |
| } |
| cursor += PAGE_SIZE; |
| pfn++; |
| } |
| return 1; |
| } |
| #else |
| static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
| { |
| return 1; |
| } |
| #endif |
| |
| void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
| { |
| } |
| |
| /* |
| * This funcion reads the *physical* memory. The f_pos points directly to the |
| * memory location. |
| */ |
| static ssize_t read_mem(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| ssize_t read, sz; |
| char *ptr; |
| |
| if (!valid_phys_addr_range(p, count)) |
| return -EFAULT; |
| read = 0; |
| #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE) { |
| sz = size_inside_page(p, count); |
| if (sz > 0) { |
| if (clear_user(buf, sz)) |
| return -EFAULT; |
| buf += sz; |
| p += sz; |
| count -= sz; |
| read += sz; |
| } |
| } |
| #endif |
| |
| while (count > 0) { |
| unsigned long remaining; |
| |
| sz = size_inside_page(p, count); |
| |
| if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
| return -EPERM; |
| |
| /* |
| * On ia64 if a page has been mapped somewhere as uncached, then |
| * it must also be accessed uncached by the kernel or data |
| * corruption may occur. |
| */ |
| ptr = xlate_dev_mem_ptr(p); |
| if (!ptr) |
| return -EFAULT; |
| |
| remaining = copy_to_user(buf, ptr, sz); |
| unxlate_dev_mem_ptr(p, ptr); |
| if (remaining) |
| return -EFAULT; |
| |
| buf += sz; |
| p += sz; |
| count -= sz; |
| read += sz; |
| } |
| |
| *ppos += read; |
| return read; |
| } |
| |
| static ssize_t write_mem(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| ssize_t written, sz; |
| unsigned long copied; |
| void *ptr; |
| |
| if (!valid_phys_addr_range(p, count)) |
| return -EFAULT; |
| |
| written = 0; |
| |
| #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE) { |
| sz = size_inside_page(p, count); |
| /* Hmm. Do something? */ |
| buf += sz; |
| p += sz; |
| count -= sz; |
| written += sz; |
| } |
| #endif |
| |
| while (count > 0) { |
| sz = size_inside_page(p, count); |
| |
| if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
| return -EPERM; |
| |
| /* |
| * On ia64 if a page has been mapped somewhere as uncached, then |
| * it must also be accessed uncached by the kernel or data |
| * corruption may occur. |
| */ |
| ptr = xlate_dev_mem_ptr(p); |
| if (!ptr) { |
| if (written) |
| break; |
| return -EFAULT; |
| } |
| |
| copied = copy_from_user(ptr, buf, sz); |
| unxlate_dev_mem_ptr(p, ptr); |
| if (copied) { |
| written += sz - copied; |
| if (written) |
| break; |
| return -EFAULT; |
| } |
| |
| buf += sz; |
| p += sz; |
| count -= sz; |
| written += sz; |
| } |
| |
| *ppos += written; |
| return written; |
| } |
| |
| int __weak phys_mem_access_prot_allowed(struct file *file, |
| unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
| { |
| return 1; |
| } |
| |
| #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
| |
| /* |
| * Architectures vary in how they handle caching for addresses |
| * outside of main memory. |
| * |
| */ |
| #ifdef pgprot_noncached |
| static int uncached_access(struct file *file, unsigned long addr) |
| { |
| #if defined(CONFIG_IA64) |
| /* |
| * On ia64, we ignore O_DSYNC because we cannot tolerate memory |
| * attribute aliases. |
| */ |
| return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); |
| #elif defined(CONFIG_MIPS) |
| { |
| extern int __uncached_access(struct file *file, |
| unsigned long addr); |
| |
| return __uncached_access(file, addr); |
| } |
| #else |
| /* |
| * Accessing memory above the top the kernel knows about or through a |
| * file pointer |
| * that was marked O_DSYNC will be done non-cached. |
| */ |
| if (file->f_flags & O_DSYNC) |
| return 1; |
| return addr >= __pa(high_memory); |
| #endif |
| } |
| #endif |
| |
| static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
| unsigned long size, pgprot_t vma_prot) |
| { |
| #ifdef pgprot_noncached |
| unsigned long offset = pfn << PAGE_SHIFT; |
| |
| if (uncached_access(file, offset)) |
| return pgprot_noncached(vma_prot); |
| #endif |
| return vma_prot; |
| } |
| #endif |
| |
| #ifndef CONFIG_MMU |
| static unsigned long get_unmapped_area_mem(struct file *file, |
| unsigned long addr, |
| unsigned long len, |
| unsigned long pgoff, |
| unsigned long flags) |
| { |
| if (!valid_mmap_phys_addr_range(pgoff, len)) |
| return (unsigned long) -EINVAL; |
| return pgoff << PAGE_SHIFT; |
| } |
| |
| /* can't do an in-place private mapping if there's no MMU */ |
| static inline int private_mapping_ok(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & VM_MAYSHARE; |
| } |
| #else |
| #define get_unmapped_area_mem NULL |
| |
| static inline int private_mapping_ok(struct vm_area_struct *vma) |
| { |
| return 1; |
| } |
| #endif |
| |
| static const struct vm_operations_struct mmap_mem_ops = { |
| #ifdef CONFIG_HAVE_IOREMAP_PROT |
| .access = generic_access_phys |
| #endif |
| }; |
| |
| static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
| { |
| size_t size = vma->vm_end - vma->vm_start; |
| |
| if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
| return -EINVAL; |
| |
| if (!private_mapping_ok(vma)) |
| return -ENOSYS; |
| |
| if (!range_is_allowed(vma->vm_pgoff, size)) |
| return -EPERM; |
| |
| if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
| &vma->vm_page_prot)) |
| return -EINVAL; |
| |
| vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
| size, |
| vma->vm_page_prot); |
| |
| vma->vm_ops = &mmap_mem_ops; |
| |
| /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ |
| if (remap_pfn_range(vma, |
| vma->vm_start, |
| vma->vm_pgoff, |
| size, |
| vma->vm_page_prot)) { |
| return -EAGAIN; |
| } |
| return 0; |
| } |
| |
| #ifdef CONFIG_DEVKMEM |
| static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
| { |
| unsigned long pfn; |
| |
| /* Turn a kernel-virtual address into a physical page frame */ |
| pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; |
| |
| /* |
| * RED-PEN: on some architectures there is more mapped memory than |
| * available in mem_map which pfn_valid checks for. Perhaps should add a |
| * new macro here. |
| * |
| * RED-PEN: vmalloc is not supported right now. |
| */ |
| if (!pfn_valid(pfn)) |
| return -EIO; |
| |
| vma->vm_pgoff = pfn; |
| return mmap_mem(file, vma); |
| } |
| #endif |
| |
| #ifdef CONFIG_CRASH_DUMP |
| /* |
| * Read memory corresponding to the old kernel. |
| */ |
| static ssize_t read_oldmem(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long pfn, offset; |
| size_t read = 0, csize; |
| int rc = 0; |
| |
| while (count) { |
| pfn = *ppos / PAGE_SIZE; |
| if (pfn > saved_max_pfn) |
| return read; |
| |
| offset = (unsigned long)(*ppos % PAGE_SIZE); |
| if (count > PAGE_SIZE - offset) |
| csize = PAGE_SIZE - offset; |
| else |
| csize = count; |
| |
| rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
| if (rc < 0) |
| return rc; |
| buf += csize; |
| *ppos += csize; |
| read += csize; |
| count -= csize; |
| } |
| return read; |
| } |
| #endif |
| |
| #ifdef CONFIG_DEVKMEM |
| /* |
| * This function reads the *virtual* memory as seen by the kernel. |
| */ |
| static ssize_t read_kmem(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| ssize_t low_count, read, sz; |
| char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
| int err = 0; |
| |
| read = 0; |
| if (p < (unsigned long) high_memory) { |
| low_count = count; |
| if (count > (unsigned long)high_memory - p) |
| low_count = (unsigned long)high_memory - p; |
| |
| #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE && low_count > 0) { |
| sz = size_inside_page(p, low_count); |
| if (clear_user(buf, sz)) |
| return -EFAULT; |
| buf += sz; |
| p += sz; |
| read += sz; |
| low_count -= sz; |
| count -= sz; |
| } |
| #endif |
| while (low_count > 0) { |
| sz = size_inside_page(p, low_count); |
| |
| /* |
| * On ia64 if a page has been mapped somewhere as |
| * uncached, then it must also be accessed uncached |
| * by the kernel or data corruption may occur |
| */ |
| kbuf = xlate_dev_kmem_ptr((char *)p); |
| |
| if (copy_to_user(buf, kbuf, sz)) |
| return -EFAULT; |
| buf += sz; |
| p += sz; |
| read += sz; |
| low_count -= sz; |
| count -= sz; |
| } |
| } |
| |
| if (count > 0) { |
| kbuf = (char *)__get_free_page(GFP_KERNEL); |
| if (!kbuf) |
| return -ENOMEM; |
| while (count > 0) { |
| sz = size_inside_page(p, count); |
| if (!is_vmalloc_or_module_addr((void *)p)) { |
| err = -ENXIO; |
| break; |
| } |
| sz = vread(kbuf, (char *)p, sz); |
| if (!sz) |
| break; |
| if (copy_to_user(buf, kbuf, sz)) { |
| err = -EFAULT; |
| break; |
| } |
| count -= sz; |
| buf += sz; |
| read += sz; |
| p += sz; |
| } |
| free_page((unsigned long)kbuf); |
| } |
| *ppos = p; |
| return read ? read : err; |
| } |
| |
| |
| static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| ssize_t written, sz; |
| unsigned long copied; |
| |
| written = 0; |
| #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE) { |
| sz = size_inside_page(p, count); |
| /* Hmm. Do something? */ |
| buf += sz; |
| p += sz; |
| count -= sz; |
| written += sz; |
| } |
| #endif |
| |
| while (count > 0) { |
| char *ptr; |
| |
| sz = size_inside_page(p, count); |
| |
| /* |
| * On ia64 if a page has been mapped somewhere as uncached, then |
| * it must also be accessed uncached by the kernel or data |
| * corruption may occur. |
| */ |
| ptr = xlate_dev_kmem_ptr((char *)p); |
| |
| copied = copy_from_user(ptr, buf, sz); |
| if (copied) { |
| written += sz - copied; |
| if (written) |
| break; |
| return -EFAULT; |
| } |
| buf += sz; |
| p += sz; |
| count -= sz; |
| written += sz; |
| } |
| |
| *ppos += written; |
| return written; |
| } |
| |
| /* |
| * This function writes to the *virtual* memory as seen by the kernel. |
| */ |
| static ssize_t write_kmem(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| ssize_t wrote = 0; |
| ssize_t virtr = 0; |
| char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
| int err = 0; |
| |
| if (p < (unsigned long) high_memory) { |
| unsigned long to_write = min_t(unsigned long, count, |
| (unsigned long)high_memory - p); |
| wrote = do_write_kmem(p, buf, to_write, ppos); |
| if (wrote != to_write) |
| return wrote; |
| p += wrote; |
| buf += wrote; |
| count -= wrote; |
| } |
| |
| if (count > 0) { |
| kbuf = (char *)__get_free_page(GFP_KERNEL); |
| if (!kbuf) |
| return wrote ? wrote : -ENOMEM; |
| while (count > 0) { |
| unsigned long sz = size_inside_page(p, count); |
| unsigned long n; |
| |
| if (!is_vmalloc_or_module_addr((void *)p)) { |
| err = -ENXIO; |
| break; |
| } |
| n = copy_from_user(kbuf, buf, sz); |
| if (n) { |
| err = -EFAULT; |
| break; |
| } |
| vwrite(kbuf, (char *)p, sz); |
| count -= sz; |
| buf += sz; |
| virtr += sz; |
| p += sz; |
| } |
| free_page((unsigned long)kbuf); |
| } |
| |
| *ppos = p; |
| return virtr + wrote ? : err; |
| } |
| #endif |
| |
| #ifdef CONFIG_DEVPORT |
| static ssize_t read_port(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long i = *ppos; |
| char __user *tmp = buf; |
| |
| if (!access_ok(VERIFY_WRITE, buf, count)) |
| return -EFAULT; |
| while (count-- > 0 && i < 65536) { |
| if (__put_user(inb(i), tmp) < 0) |
| return -EFAULT; |
| i++; |
| tmp++; |
| } |
| *ppos = i; |
| return tmp-buf; |
| } |
| |
| static ssize_t write_port(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long i = *ppos; |
| const char __user * tmp = buf; |
| |
| if (!access_ok(VERIFY_READ, buf, count)) |
| return -EFAULT; |
| while (count-- > 0 && i < 65536) { |
| char c; |
| if (__get_user(c, tmp)) { |
| if (tmp > buf) |
| break; |
| return -EFAULT; |
| } |
| outb(c, i); |
| i++; |
| tmp++; |
| } |
| *ppos = i; |
| return tmp-buf; |
| } |
| #endif |
| |
| static ssize_t read_null(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| return 0; |
| } |
| |
| static ssize_t write_null(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| return count; |
| } |
| |
| static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
| struct splice_desc *sd) |
| { |
| return sd->len; |
| } |
| |
| static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
| loff_t *ppos, size_t len, unsigned int flags) |
| { |
| return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); |
| } |
| |
| static ssize_t read_zero(struct file *file, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| size_t written; |
| |
| if (!count) |
| return 0; |
| |
| if (!access_ok(VERIFY_WRITE, buf, count)) |
| return -EFAULT; |
| |
| written = 0; |
| while (count) { |
| unsigned long unwritten; |
| size_t chunk = count; |
| |
| if (chunk > PAGE_SIZE) |
| chunk = PAGE_SIZE; /* Just for latency reasons */ |
| unwritten = __clear_user(buf, chunk); |
| written += chunk - unwritten; |
| if (unwritten) |
| break; |
| if (signal_pending(current)) |
| return written ? written : -ERESTARTSYS; |
| buf += chunk; |
| count -= chunk; |
| cond_resched(); |
| } |
| return written ? written : -EFAULT; |
| } |
| |
| static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
| { |
| #ifndef CONFIG_MMU |
| return -ENOSYS; |
| #endif |
| if (vma->vm_flags & VM_SHARED) |
| return shmem_zero_setup(vma); |
| return 0; |
| } |
| |
| static ssize_t write_full(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| return -ENOSPC; |
| } |
| |
| /* |
| * Special lseek() function for /dev/null and /dev/zero. Most notably, you |
| * can fopen() both devices with "a" now. This was previously impossible. |
| * -- SRB. |
| */ |
| static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
| { |
| return file->f_pos = 0; |
| } |
| |
| /* |
| * The memory devices use the full 32/64 bits of the offset, and so we cannot |
| * check against negative addresses: they are ok. The return value is weird, |
| * though, in that case (0). |
| * |
| * also note that seeking relative to the "end of file" isn't supported: |
| * it has no meaning, so it returns -EINVAL. |
| */ |
| static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
| { |
| loff_t ret; |
| |
| mutex_lock(&file->f_path.dentry->d_inode->i_mutex); |
| switch (orig) { |
| case SEEK_CUR: |
| offset += file->f_pos; |
| case SEEK_SET: |
| /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ |
| if ((unsigned long long)offset >= ~0xFFFULL) { |
| ret = -EOVERFLOW; |
| break; |
| } |
| file->f_pos = offset; |
| ret = file->f_pos; |
| force_successful_syscall_return(); |
| break; |
| default: |
| ret = -EINVAL; |
| } |
| mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
| return ret; |
| } |
| |
| static int open_port(struct inode * inode, struct file * filp) |
| { |
| return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; |
| } |
| |
| #define zero_lseek null_lseek |
| #define full_lseek null_lseek |
| #define write_zero write_null |
| #define read_full read_zero |
| #define open_mem open_port |
| #define open_kmem open_mem |
| #define open_oldmem open_mem |
| |
| static const struct file_operations mem_fops = { |
| .llseek = memory_lseek, |
| .read = read_mem, |
| .write = write_mem, |
| .mmap = mmap_mem, |
| .open = open_mem, |
| .get_unmapped_area = get_unmapped_area_mem, |
| }; |
| |
| #ifdef CONFIG_DEVKMEM |
| static const struct file_operations kmem_fops = { |
| .llseek = memory_lseek, |
| .read = read_kmem, |
| .write = write_kmem, |
| .mmap = mmap_kmem, |
| .open = open_kmem, |
| .get_unmapped_area = get_unmapped_area_mem, |
| }; |
| #endif |
| |
| static const struct file_operations null_fops = { |
| .llseek = null_lseek, |
| .read = read_null, |
| .write = write_null, |
| .splice_write = splice_write_null, |
| }; |
| |
| #ifdef CONFIG_DEVPORT |
| static const struct file_operations port_fops = { |
| .llseek = memory_lseek, |
| .read = read_port, |
| .write = write_port, |
| .open = open_port, |
| }; |
| #endif |
| |
| static const struct file_operations zero_fops = { |
| .llseek = zero_lseek, |
| .read = read_zero, |
| .write = write_zero, |
| .mmap = mmap_zero, |
| }; |
| |
| /* |
| * capabilities for /dev/zero |
| * - permits private mappings, "copies" are taken of the source of zeros |
| */ |
| static struct backing_dev_info zero_bdi = { |
| .name = "char/mem", |
| .capabilities = BDI_CAP_MAP_COPY, |
| }; |
| |
| static const struct file_operations full_fops = { |
| .llseek = full_lseek, |
| .read = read_full, |
| .write = write_full, |
| }; |
| |
| #ifdef CONFIG_CRASH_DUMP |
| static const struct file_operations oldmem_fops = { |
| .read = read_oldmem, |
| .open = open_oldmem, |
| .llseek = default_llseek, |
| }; |
| #endif |
| |
| static ssize_t kmsg_write(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| char *tmp; |
| ssize_t ret; |
| |
| tmp = kmalloc(count + 1, GFP_KERNEL); |
| if (tmp == NULL) |
| return -ENOMEM; |
| ret = -EFAULT; |
| if (!copy_from_user(tmp, buf, count)) { |
| tmp[count] = 0; |
| ret = printk("%s", tmp); |
| if (ret > count) |
| /* printk can add a prefix */ |
| ret = count; |
| } |
| kfree(tmp); |
| return ret; |
| } |
| |
| static const struct file_operations kmsg_fops = { |
| .write = kmsg_write, |
| .llseek = noop_llseek, |
| }; |
| |
| static const struct memdev { |
| const char *name; |
| mode_t mode; |
| const struct file_operations *fops; |
| struct backing_dev_info *dev_info; |
| } devlist[] = { |
| [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
| #ifdef CONFIG_DEVKMEM |
| [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
| #endif |
| [3] = { "null", 0666, &null_fops, NULL }, |
| #ifdef CONFIG_DEVPORT |
| [4] = { "port", 0, &port_fops, NULL }, |
| #endif |
| [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
| [7] = { "full", 0666, &full_fops, NULL }, |
| [8] = { "random", 0666, &random_fops, NULL }, |
| [9] = { "urandom", 0666, &urandom_fops, NULL }, |
| [11] = { "kmsg", 0, &kmsg_fops, NULL }, |
| #ifdef CONFIG_CRASH_DUMP |
| [12] = { "oldmem", 0, &oldmem_fops, NULL }, |
| #endif |
| }; |
| |
| static int memory_open(struct inode *inode, struct file *filp) |
| { |
| int minor; |
| const struct memdev *dev; |
| |
| minor = iminor(inode); |
| if (minor >= ARRAY_SIZE(devlist)) |
| return -ENXIO; |
| |
| dev = &devlist[minor]; |
| if (!dev->fops) |
| return -ENXIO; |
| |
| filp->f_op = dev->fops; |
| if (dev->dev_info) |
| filp->f_mapping->backing_dev_info = dev->dev_info; |
| |
| if (dev->fops->open) |
| return dev->fops->open(inode, filp); |
| |
| return 0; |
| } |
| |
| static const struct file_operations memory_fops = { |
| .open = memory_open, |
| .llseek = noop_llseek, |
| }; |
| |
| static char *mem_devnode(struct device *dev, mode_t *mode) |
| { |
| if (mode && devlist[MINOR(dev->devt)].mode) |
| *mode = devlist[MINOR(dev->devt)].mode; |
| return NULL; |
| } |
| |
| static struct class *mem_class; |
| |
| static int __init chr_dev_init(void) |
| { |
| int minor; |
| int err; |
| |
| err = bdi_init(&zero_bdi); |
| if (err) |
| return err; |
| |
| if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
| printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
| |
| mem_class = class_create(THIS_MODULE, "mem"); |
| if (IS_ERR(mem_class)) |
| return PTR_ERR(mem_class); |
| |
| mem_class->devnode = mem_devnode; |
| for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
| if (!devlist[minor].name) |
| continue; |
| device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
| NULL, devlist[minor].name); |
| } |
| |
| return tty_init(); |
| } |
| |
| fs_initcall(chr_dev_init); |