| /* |
| * 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 mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/mm.h> |
| #include <linux/miscdevice.h> |
| #include <linux/tpqic02.h> |
| #include <linux/ftape.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/smp_lock.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| #include <asm/pgalloc.h> |
| |
| #ifdef CONFIG_FB |
| extern void fbmem_init(void); |
| #endif |
| #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR) |
| extern void tapechar_init(void); |
| #endif |
| |
| static ssize_t do_write_mem(struct file * file, void *p, unsigned long realp, |
| const char * buf, size_t count, loff_t *ppos) |
| { |
| ssize_t written; |
| |
| written = 0; |
| #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU)) |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (realp < PAGE_SIZE) { |
| unsigned long sz = PAGE_SIZE-realp; |
| if (sz > count) sz = count; |
| /* Hmm. Do something? */ |
| buf+=sz; |
| p+=sz; |
| count-=sz; |
| written+=sz; |
| } |
| #endif |
| if (copy_from_user(p, buf, count)) |
| return -EFAULT; |
| written += count; |
| *ppos += written; |
| return written; |
| } |
| |
| |
| /* |
| * This funcion reads the *physical* memory. The f_pos points directly to the |
| * memory location. |
| */ |
| static ssize_t read_mem(struct file * file, char * buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| unsigned long end_mem; |
| ssize_t read; |
| |
| end_mem = __pa(high_memory); |
| if (p >= end_mem) |
| return 0; |
| if (count > end_mem - p) |
| count = end_mem - p; |
| read = 0; |
| #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU)) |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE) { |
| unsigned long sz = PAGE_SIZE-p; |
| if (sz > count) |
| sz = count; |
| if (sz > 0) { |
| if (clear_user(buf, sz)) |
| return -EFAULT; |
| buf += sz; |
| p += sz; |
| count -= sz; |
| read += sz; |
| } |
| } |
| #endif |
| if (copy_to_user(buf, __va(p), count)) |
| return -EFAULT; |
| read += count; |
| *ppos += read; |
| return read; |
| } |
| |
| static ssize_t write_mem(struct file * file, const char * buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| unsigned long end_mem; |
| |
| end_mem = __pa(high_memory); |
| if (p >= end_mem) |
| return 0; |
| if (count > end_mem - p) |
| count = end_mem - p; |
| return do_write_mem(file, __va(p), p, buf, count, ppos); |
| } |
| |
| #ifndef pgprot_noncached |
| |
| /* |
| * This should probably be per-architecture in <asm/pgtable.h> |
| */ |
| static inline pgprot_t pgprot_noncached(pgprot_t _prot) |
| { |
| unsigned long prot = pgprot_val(_prot); |
| |
| #if defined(__i386__) || defined(__x86_64__) |
| /* On PPro and successors, PCD alone doesn't always mean |
| uncached because of interactions with the MTRRs. PCD | PWT |
| means definitely uncached. */ |
| if (boot_cpu_data.x86 > 3) |
| prot |= _PAGE_PCD | _PAGE_PWT; |
| #elif defined(__powerpc__) |
| prot |= _PAGE_NO_CACHE | _PAGE_GUARDED; |
| #elif defined(__mc68000__) && defined(CONFIG_MMU) |
| #ifdef SUN3_PAGE_NOCACHE |
| if (MMU_IS_SUN3) |
| prot |= SUN3_PAGE_NOCACHE; |
| else |
| #endif |
| if (MMU_IS_851 || MMU_IS_030) |
| prot |= _PAGE_NOCACHE030; |
| /* Use no-cache mode, serialized */ |
| else if (MMU_IS_040 || MMU_IS_060) |
| prot = (prot & _CACHEMASK040) | _PAGE_NOCACHE_S; |
| #endif |
| |
| return __pgprot(prot); |
| } |
| |
| #endif /* !pgprot_noncached */ |
| |
| /* |
| * Architectures vary in how they handle caching for addresses |
| * outside of main memory. |
| */ |
| static inline int noncached_address(unsigned long addr) |
| { |
| #if defined(__i386__) |
| /* |
| * On the PPro and successors, the MTRRs are used to set |
| * memory types for physical addresses outside main memory, |
| * so blindly setting PCD or PWT on those pages is wrong. |
| * For Pentiums and earlier, the surround logic should disable |
| * caching for the high addresses through the KEN pin, but |
| * we maintain the tradition of paranoia in this code. |
| */ |
| return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || |
| test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || |
| test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || |
| test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) |
| && addr >= __pa(high_memory); |
| #else |
| return addr >= __pa(high_memory); |
| #endif |
| } |
| |
| static int mmap_mem(struct file * file, struct vm_area_struct * vma) |
| { |
| unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; |
| |
| /* |
| * Accessing memory above the top the kernel knows about or |
| * through a file pointer that was marked O_SYNC will be |
| * done non-cached. |
| */ |
| if (noncached_address(offset) || (file->f_flags & O_SYNC)) |
| vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
| |
| /* Don't try to swap out physical pages.. */ |
| vma->vm_flags |= VM_RESERVED; |
| |
| /* |
| * Don't dump addresses that are not real memory to a core file. |
| */ |
| if (offset >= __pa(high_memory) || (file->f_flags & O_SYNC)) |
| vma->vm_flags |= VM_IO; |
| |
| if (remap_page_range(vma, vma->vm_start, offset, vma->vm_end-vma->vm_start, |
| vma->vm_page_prot)) |
| return -EAGAIN; |
| return 0; |
| } |
| |
| extern long vread(char *buf, char *addr, unsigned long count); |
| extern long vwrite(char *buf, char *addr, unsigned long count); |
| |
| /* |
| * This function reads the *virtual* memory as seen by the kernel. |
| */ |
| static ssize_t read_kmem(struct file *file, char *buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long p = *ppos; |
| ssize_t read = 0; |
| ssize_t virtr = 0; |
| char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
| |
| if (p < (unsigned long) high_memory) { |
| read = count; |
| if (count > (unsigned long) high_memory - p) |
| read = (unsigned long) high_memory - p; |
| |
| #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU)) |
| /* we don't have page 0 mapped on sparc and m68k.. */ |
| if (p < PAGE_SIZE && read > 0) { |
| size_t tmp = PAGE_SIZE - p; |
| if (tmp > read) tmp = read; |
| if (clear_user(buf, tmp)) |
| return -EFAULT; |
| buf += tmp; |
| p += tmp; |
| read -= tmp; |
| count -= tmp; |
| } |
| #endif |
| if (copy_to_user(buf, (char *)p, read)) |
| return -EFAULT; |
| p += read; |
| buf += read; |
| count -= read; |
| } |
| |
| if (count > 0) { |
| kbuf = (char *)__get_free_page(GFP_KERNEL); |
| if (!kbuf) |
| return -ENOMEM; |
| while (count > 0) { |
| int len = count; |
| |
| if (len > PAGE_SIZE) |
| len = PAGE_SIZE; |
| len = vread(kbuf, (char *)p, len); |
| if (!len) |
| break; |
| if (copy_to_user(buf, kbuf, len)) { |
| free_page((unsigned long)kbuf); |
| return -EFAULT; |
| } |
| count -= len; |
| buf += len; |
| virtr += len; |
| p += len; |
| } |
| free_page((unsigned long)kbuf); |
| } |
| *ppos = p; |
| return virtr + read; |
| } |
| |
| /* |
| * This function writes to the *virtual* memory as seen by the kernel. |
| */ |
| static ssize_t write_kmem(struct file * file, const char * 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 */ |
| |
| if (p < (unsigned long) high_memory) { |
| wrote = count; |
| if (count > (unsigned long) high_memory - p) |
| wrote = (unsigned long) high_memory - p; |
| |
| wrote = do_write_mem(file, (void*)p, p, buf, wrote, ppos); |
| |
| p += wrote; |
| buf += wrote; |
| count -= wrote; |
| } |
| |
| if (count > 0) { |
| kbuf = (char *)__get_free_page(GFP_KERNEL); |
| if (!kbuf) |
| return -ENOMEM; |
| while (count > 0) { |
| int len = count; |
| |
| if (len > PAGE_SIZE) |
| len = PAGE_SIZE; |
| if (len && copy_from_user(kbuf, buf, len)) { |
| free_page((unsigned long)kbuf); |
| return -EFAULT; |
| } |
| len = vwrite(kbuf, (char *)p, len); |
| count -= len; |
| buf += len; |
| virtr += len; |
| p += len; |
| } |
| free_page((unsigned long)kbuf); |
| } |
| |
| *ppos = p; |
| return virtr + wrote; |
| } |
| |
| #if defined(CONFIG_ISA) || !defined(__mc68000__) |
| static ssize_t read_port(struct file * file, char * buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long i = *ppos; |
| char *tmp = buf; |
| |
| if (verify_area(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 * buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long i = *ppos; |
| const char * tmp = buf; |
| |
| if (verify_area(VERIFY_READ,buf,count)) |
| return -EFAULT; |
| while (count-- > 0 && i < 65536) { |
| char c; |
| if (__get_user(c, tmp)) |
| return -EFAULT; |
| outb(c,i); |
| i++; |
| tmp++; |
| } |
| *ppos = i; |
| return tmp-buf; |
| } |
| #endif |
| |
| static ssize_t read_null(struct file * file, char * buf, |
| size_t count, loff_t *ppos) |
| { |
| return 0; |
| } |
| |
| static ssize_t write_null(struct file * file, const char * buf, |
| size_t count, loff_t *ppos) |
| { |
| return count; |
| } |
| |
| #ifdef CONFIG_MMU |
| /* |
| * For fun, we are using the MMU for this. |
| */ |
| static inline size_t read_zero_pagealigned(char * buf, size_t size) |
| { |
| struct mm_struct *mm; |
| struct vm_area_struct * vma; |
| unsigned long addr=(unsigned long)buf; |
| |
| mm = current->mm; |
| /* Oops, this was forgotten before. -ben */ |
| down_read(&mm->mmap_sem); |
| |
| /* For private mappings, just map in zero pages. */ |
| for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { |
| unsigned long count; |
| |
| if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) |
| goto out_up; |
| if (vma->vm_flags & VM_SHARED) |
| break; |
| count = vma->vm_end - addr; |
| if (count > size) |
| count = size; |
| |
| zap_page_range(vma, addr, count); |
| zeromap_page_range(vma, addr, count, PAGE_COPY); |
| |
| size -= count; |
| buf += count; |
| addr += count; |
| if (size == 0) |
| goto out_up; |
| } |
| |
| up_read(&mm->mmap_sem); |
| |
| /* The shared case is hard. Let's do the conventional zeroing. */ |
| do { |
| unsigned long unwritten = clear_user(buf, PAGE_SIZE); |
| if (unwritten) |
| return size + unwritten - PAGE_SIZE; |
| cond_resched(); |
| buf += PAGE_SIZE; |
| size -= PAGE_SIZE; |
| } while (size); |
| |
| return size; |
| out_up: |
| up_read(&mm->mmap_sem); |
| return size; |
| } |
| |
| static ssize_t read_zero(struct file * file, char * buf, |
| size_t count, loff_t *ppos) |
| { |
| unsigned long left, unwritten, written = 0; |
| |
| if (!count) |
| return 0; |
| |
| if (!access_ok(VERIFY_WRITE, buf, count)) |
| return -EFAULT; |
| |
| left = count; |
| |
| /* do we want to be clever? Arbitrary cut-off */ |
| if (count >= PAGE_SIZE*4) { |
| unsigned long partial; |
| |
| /* How much left of the page? */ |
| partial = (PAGE_SIZE-1) & -(unsigned long) buf; |
| unwritten = clear_user(buf, partial); |
| written = partial - unwritten; |
| if (unwritten) |
| goto out; |
| left -= partial; |
| buf += partial; |
| unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); |
| written += (left & PAGE_MASK) - unwritten; |
| if (unwritten) |
| goto out; |
| buf += left & PAGE_MASK; |
| left &= ~PAGE_MASK; |
| } |
| unwritten = clear_user(buf, left); |
| written += left - unwritten; |
| out: |
| return written ? written : -EFAULT; |
| } |
| |
| static int mmap_zero(struct file * file, struct vm_area_struct * vma) |
| { |
| if (vma->vm_flags & VM_SHARED) |
| return shmem_zero_setup(vma); |
| if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) |
| return -EAGAIN; |
| return 0; |
| } |
| #else /* CONFIG_MMU */ |
| static ssize_t read_zero(struct file * file, char * buf, |
| size_t count, loff_t *ppos) |
| { |
| size_t todo = count; |
| |
| while (todo) { |
| size_t chunk = todo; |
| |
| if (chunk > 4096) |
| chunk = 4096; /* Just for latency reasons */ |
| if (clear_user(buf, chunk)) |
| return -EFAULT; |
| buf += chunk; |
| todo -= chunk; |
| cond_resched(); |
| } |
| return count; |
| } |
| |
| static int mmap_zero(struct file * file, struct vm_area_struct * vma) |
| { |
| return -ENOSYS; |
| } |
| #endif /* CONFIG_MMU */ |
| |
| static ssize_t write_full(struct file * file, const char * 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) |
| { |
| int ret; |
| |
| lock_kernel(); |
| switch (orig) { |
| case 0: |
| file->f_pos = offset; |
| ret = file->f_pos; |
| break; |
| case 1: |
| file->f_pos += offset; |
| ret = file->f_pos; |
| break; |
| default: |
| ret = -EINVAL; |
| } |
| unlock_kernel(); |
| return ret; |
| } |
| |
| static int open_port(struct inode * inode, struct file * filp) |
| { |
| return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; |
| } |
| |
| #define mmap_kmem mmap_mem |
| #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 |
| |
| static struct file_operations mem_fops = { |
| .llseek = memory_lseek, |
| .read = read_mem, |
| .write = write_mem, |
| .mmap = mmap_mem, |
| .open = open_mem, |
| }; |
| |
| static struct file_operations kmem_fops = { |
| .llseek = memory_lseek, |
| .read = read_kmem, |
| .write = write_kmem, |
| .mmap = mmap_kmem, |
| .open = open_kmem, |
| }; |
| |
| static struct file_operations null_fops = { |
| .llseek = null_lseek, |
| .read = read_null, |
| .write = write_null, |
| }; |
| |
| #if defined(CONFIG_ISA) || !defined(__mc68000__) |
| static struct file_operations port_fops = { |
| .llseek = memory_lseek, |
| .read = read_port, |
| .write = write_port, |
| .open = open_port, |
| }; |
| #endif |
| |
| static struct file_operations zero_fops = { |
| .llseek = zero_lseek, |
| .read = read_zero, |
| .write = write_zero, |
| .mmap = mmap_zero, |
| }; |
| |
| static struct file_operations full_fops = { |
| .llseek = full_lseek, |
| .read = read_full, |
| .write = write_full, |
| }; |
| |
| static ssize_t kmsg_write(struct file * file, const char * buf, |
| size_t count, loff_t *ppos) |
| { |
| char *tmp; |
| int 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); |
| } |
| kfree(tmp); |
| return ret; |
| } |
| |
| static struct file_operations kmsg_fops = { |
| .write = kmsg_write, |
| }; |
| |
| static int memory_open(struct inode * inode, struct file * filp) |
| { |
| switch (minor(inode->i_rdev)) { |
| case 1: |
| filp->f_op = &mem_fops; |
| break; |
| case 2: |
| filp->f_op = &kmem_fops; |
| break; |
| case 3: |
| filp->f_op = &null_fops; |
| break; |
| #if defined(CONFIG_ISA) || !defined(__mc68000__) |
| case 4: |
| filp->f_op = &port_fops; |
| break; |
| #endif |
| case 5: |
| filp->f_op = &zero_fops; |
| break; |
| case 7: |
| filp->f_op = &full_fops; |
| break; |
| case 8: |
| filp->f_op = &random_fops; |
| break; |
| case 9: |
| filp->f_op = &urandom_fops; |
| break; |
| case 11: |
| filp->f_op = &kmsg_fops; |
| break; |
| default: |
| return -ENXIO; |
| } |
| if (filp->f_op && filp->f_op->open) |
| return filp->f_op->open(inode,filp); |
| return 0; |
| } |
| |
| void __init memory_devfs_register (void) |
| { |
| /* These are never unregistered */ |
| static const struct { |
| unsigned short minor; |
| char *name; |
| umode_t mode; |
| struct file_operations *fops; |
| } list[] = { /* list of minor devices */ |
| {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, |
| {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, |
| {3, "null", S_IRUGO | S_IWUGO, &null_fops}, |
| #if defined(CONFIG_ISA) || !defined(__mc68000__) |
| {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, |
| #endif |
| {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, |
| {7, "full", S_IRUGO | S_IWUGO, &full_fops}, |
| {8, "random", S_IRUGO | S_IWUSR, &random_fops}, |
| {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, |
| {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, |
| }; |
| int i; |
| |
| for (i=0; i<(sizeof(list)/sizeof(*list)); i++) |
| devfs_register (NULL, list[i].name, DEVFS_FL_NONE, |
| MEM_MAJOR, list[i].minor, |
| list[i].mode | S_IFCHR, |
| list[i].fops, NULL); |
| } |
| |
| static struct file_operations memory_fops = { |
| .open = memory_open, /* just a selector for the real open */ |
| }; |
| |
| int __init chr_dev_init(void) |
| { |
| if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) |
| printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
| memory_devfs_register(); |
| rand_initialize(); |
| #if defined (CONFIG_FB) |
| fbmem_init(); |
| #endif |
| tty_init(); |
| #ifdef CONFIG_M68K_PRINTER |
| lp_m68k_init(); |
| #endif |
| misc_init(); |
| #ifdef CONFIG_FTAPE |
| ftape_init(); |
| #endif |
| #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR) |
| tapechar_init(); |
| #endif |
| return 0; |
| } |
| |
| __initcall(chr_dev_init); |