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-rw-r--r--linux-2.6-xen-sparse/drivers/char/mem.c733
1 files changed, 733 insertions, 0 deletions
diff --git a/linux-2.6-xen-sparse/drivers/char/mem.c b/linux-2.6-xen-sparse/drivers/char/mem.c
new file mode 100644
index 0000000000..8eae836f01
--- /dev/null
+++ b/linux-2.6-xen-sparse/drivers/char/mem.c
@@ -0,0 +1,733 @@
+/*
+ * 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/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 <linux/devfs_fs_kernel.h>
+#include <linux/ptrace.h>
+#include <linux/device.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#ifdef CONFIG_IA64
+# include <linux/efi.h>
+#endif
+
+#if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
+extern void tapechar_init(void);
+#endif
+
+/*
+ * Architectures vary in how they handle caching for addresses
+ * outside of main memory.
+ *
+ */
+static inline int uncached_access(struct file *file, 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.
+ */
+ if (file->f_flags & O_SYNC)
+ return 1;
+ 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);
+#elif defined(__x86_64__)
+ /*
+ * This is broken because it can generate memory type aliases,
+ * which can cause cache corruptions
+ * But it is only available for root and we have to be bug-to-bug
+ * compatible with i386.
+ */
+ if (file->f_flags & O_SYNC)
+ return 1;
+ /* same behaviour as i386. PAT always set to cached and MTRRs control the
+ caching behaviour.
+ Hopefully a full PAT implementation will fix that soon. */
+ return 0;
+#elif defined(CONFIG_IA64)
+ /*
+ * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
+ */
+ return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
+#elif defined(CONFIG_PPC64)
+ /* On PPC64, we always do non-cacheable access to the IO hole and
+ * cacheable elsewhere. Cache paradox can checkstop the CPU and
+ * the high_memory heuristic below is wrong on machines with memory
+ * above the IO hole... Ah, and of course, XFree86 doesn't pass
+ * O_SYNC when mapping us to tap IO space. Surprised ?
+ */
+ return !page_is_ram(addr >> PAGE_SHIFT);
+#else
+ /*
+ * 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 (file->f_flags & O_SYNC)
+ return 1;
+ return addr >= __pa(high_memory);
+#endif
+}
+
+#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
+static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
+{
+ unsigned long end_mem;
+
+ end_mem = __pa(high_memory);
+ if (addr >= end_mem)
+ return 0;
+
+ if (*count > end_mem - addr)
+ *count = end_mem - addr;
+
+ return 1;
+}
+#endif
+
+static ssize_t do_write_mem(void *p, unsigned long realp,
+ const char __user * buf, size_t count, loff_t *ppos)
+{
+ ssize_t written;
+ unsigned long copied;
+
+ 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
+ copied = copy_from_user(p, buf, count);
+ if (copied) {
+ ssize_t ret = written + (count - copied);
+
+ if (ret)
+ return ret;
+ return -EFAULT;
+ }
+ written += count;
+ *ppos += written;
+ return written;
+}
+
+#ifndef ARCH_HAS_DEV_MEM
+/*
+ * 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;
+
+ if (!valid_phys_addr_range(p, &count))
+ return -EFAULT;
+ 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 __user * buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long p = *ppos;
+
+ if (!valid_phys_addr_range(p, &count))
+ return -EFAULT;
+ return do_write_mem(__va(p), p, buf, count, ppos);
+}
+#endif
+
+static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
+{
+#ifdef pgprot_noncached
+ unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+ int uncached;
+
+ uncached = uncached_access(file, offset);
+ if (uncached)
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+#endif
+
+ /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
+ if (remap_pfn_range(vma,
+ vma->vm_start,
+ vma->vm_pgoff,
+ 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 __user *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 __user * buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long p = *ppos;
+ ssize_t wrote = 0;
+ ssize_t virtr = 0;
+ ssize_t written;
+ 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;
+
+ written = do_write_mem((void*)p, p, buf, wrote, ppos);
+ if (written != wrote)
+ return written;
+ wrote = written;
+ 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) {
+ int len = count;
+
+ if (len > PAGE_SIZE)
+ len = PAGE_SIZE;
+ if (len) {
+ written = copy_from_user(kbuf, buf, len);
+ if (written) {
+ ssize_t ret;
+
+ free_page((unsigned long)kbuf);
+ ret = wrote + virtr + (len - written);
+ return ret ? ret : -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 __user * buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long i = *ppos;
+ char __user *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 __user * buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long i = *ppos;
+ const char __user * 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 __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;
+}
+
+#ifdef CONFIG_MMU
+/*
+ * For fun, we are using the MMU for this.
+ */
+static inline size_t read_zero_pagealigned(char __user * 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 | VM_HUGETLB))
+ break;
+ count = vma->vm_end - addr;
+ if (count > size)
+ count = size;
+
+ zap_page_range(vma, addr, count, NULL);
+ 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 __user * 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 __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;
+
+ down(&file->f_dentry->d_inode->i_sem);
+ switch (orig) {
+ case 0:
+ file->f_pos = offset;
+ ret = file->f_pos;
+ force_successful_syscall_return();
+ break;
+ case 1:
+ file->f_pos += offset;
+ ret = file->f_pos;
+ force_successful_syscall_return();
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ up(&file->f_dentry->d_inode->i_sem);
+ return ret;
+}
+
+static int open_port(struct inode * inode, struct file * filp)
+{
+ return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
+}
+
+#define mmap_mem mmap_kmem
+#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
+
+#ifndef ARCH_HAS_DEV_MEM
+static struct file_operations mem_fops = {
+ .llseek = memory_lseek,
+ .read = read_mem,
+ .write = write_mem,
+ .mmap = mmap_mem,
+ .open = open_mem,
+};
+#else
+extern struct file_operations mem_fops;
+#endif
+
+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 __user * 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 (iminor(inode)) {
+ 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;
+}
+
+static struct file_operations memory_fops = {
+ .open = memory_open, /* just a selector for the real open */
+};
+
+static const struct {
+ unsigned int minor;
+ char *name;
+ umode_t mode;
+ struct file_operations *fops;
+} devlist[] = { /* 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},
+};
+
+static struct class_simple *mem_class;
+
+static int __init chr_dev_init(void)
+{
+ int i;
+
+ if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
+ printk("unable to get major %d for memory devs\n", MEM_MAJOR);
+
+ mem_class = class_simple_create(THIS_MODULE, "mem");
+ for (i = 0; i < ARRAY_SIZE(devlist); i++) {
+ class_simple_device_add(mem_class,
+ MKDEV(MEM_MAJOR, devlist[i].minor),
+ NULL, devlist[i].name);
+ devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
+ S_IFCHR | devlist[i].mode, devlist[i].name);
+ }
+
+ return 0;
+}
+
+fs_initcall(chr_dev_init);
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-28 06:41:39 +0000