diff options
Diffstat (limited to 'xenolinux-2.4.24-sparse/drivers/char/mem.c')
| -rw-r--r-- | xenolinux-2.4.24-sparse/drivers/char/mem.c | 815 |
1 files changed, 815 insertions, 0 deletions
diff --git a/xenolinux-2.4.24-sparse/drivers/char/mem.c b/xenolinux-2.4.24-sparse/drivers/char/mem.c new file mode 100644 index 0000000000..73e6d48713 --- /dev/null +++ b/xenolinux-2.4.24-sparse/drivers/char/mem.c @@ -0,0 +1,815 @@ +/* + * 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> + * + * MODIFIED FOR XENOLINUX by Keir Fraser, 10th July 2003. + * Xenolinux has strange semantics for /dev/mem and /dev/kmem!! + * 1. mmap will not work on /dev/kmem + * 2. mmap on /dev/mem interprets the 'file offset' as a machine address + * rather than a physical address. + * I don't believe anyone sane mmaps /dev/kmem, but /dev/mem is mmapped + * to get at memory-mapped I/O spaces (eg. the VESA X server does this). + * For this to work at all we need to expect machine addresses. + * Reading/writing of /dev/kmem expects kernel virtual addresses, as usual. + * Reading/writing of /dev/mem expects 'physical addresses' as usual -- this + * is because /dev/mem can only read/write existing kernel mappings, which + * will be normal RAM, and we should present pseudo-physical layout for all + * except I/O (which is the sticky case that mmap is hacked to deal with). + */ + +#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/ptrace.h> + +#include <asm/uaccess.h> +#include <asm/io.h> +#include <asm/pgalloc.h> + +#ifdef CONFIG_I2C +extern int i2c_init_all(void); +#endif +#ifdef CONFIG_FB +extern void fbmem_init(void); +#endif +#ifdef CONFIG_PROM_CONSOLE +extern void prom_con_init(void); +#endif +#ifdef CONFIG_MDA_CONSOLE +extern void mda_console_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__) + /* 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__) + /* 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__) +#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; + +#if defined(CONFIG_XENO) && defined(CONFIG_XENO_PRIV) + if (!(start_info.flags & SIF_PRIVILEGED)) + return -ENXIO; + + /* DONTCOPY is essential for Xenolinux as copy_page_range is broken. */ + vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + if (direct_remap_area_pages(vma->vm_mm, vma->vm_start, offset, + vma->vm_end-vma->vm_start, vma->vm_page_prot)) + return -EAGAIN; + return 0; +#elif defined(CONFIG_XENO) + return -ENXIO; +#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 (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->vm_start, offset, vma->vm_end-vma->vm_start, + vma->vm_page_prot)) + return -EAGAIN; + return 0; +#endif +} + +/* + * 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__) + /* 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; +} + +extern long vwrite(char *buf, char *addr, unsigned long count); + +/* + * 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; +} + +/* + * 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; +#if defined(CONFIG_XENO_PRIV) + if (vma->vm_flags & VM_IO) + break; +#endif + count = vma->vm_end - addr; + if (count > size) + count = size; + + zap_page_range(mm, addr, count); + zeromap_page_range(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; + if (current->need_resched) + schedule(); + 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->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) + return -EAGAIN; + return 0; +} + +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) +{ + loff_t ret; + + 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; + } + return ret; +} + +static int open_port(struct inode * inode, struct file * filp) +{ + return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; +} + +struct page *kmem_vm_nopage(struct vm_area_struct *vma, unsigned long address, int write) +{ + unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; + unsigned long kaddr; + pgd_t *pgd; + pmd_t *pmd; + pte_t *ptep, pte; + struct page *page = NULL; + + /* address is user VA; convert to kernel VA of desired page */ + kaddr = (address - vma->vm_start) + offset; + kaddr = VMALLOC_VMADDR(kaddr); + + spin_lock(&init_mm.page_table_lock); + + /* Lookup page structure for kernel VA */ + pgd = pgd_offset(&init_mm, kaddr); + if (pgd_none(*pgd) || pgd_bad(*pgd)) + goto out; + pmd = pmd_offset(pgd, kaddr); + if (pmd_none(*pmd) || pmd_bad(*pmd)) + goto out; + ptep = pte_offset(pmd, kaddr); + if (!ptep) + goto out; + pte = *ptep; + if (!pte_present(pte)) + goto out; + if (write && !pte_write(pte)) + goto out; + page = pte_page(pte); + if (!VALID_PAGE(page)) { + page = NULL; + goto out; + } + + /* Increment reference count on page */ + get_page(page); + +out: + spin_unlock(&init_mm.page_table_lock); + + return page; +} + +struct vm_operations_struct kmem_vm_ops = { + nopage: kmem_vm_nopage, +}; + +static int mmap_kmem(struct file * file, struct vm_area_struct * vma) +{ + unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; + unsigned long size = vma->vm_end - vma->vm_start; + +#if defined(CONFIG_XENO) + return -ENXIO; +#endif + + /* + * If the user is not attempting to mmap a high memory address then + * the standard mmap_mem mechanism will work. High memory addresses + * need special handling, as remap_page_range expects a physically- + * contiguous range of kernel addresses (such as obtained in kmalloc). + */ + if ((offset + size) < (unsigned long) high_memory) + return mmap_mem(file, vma); + + /* + * 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 do anything here; "nopage" will fill the holes */ + vma->vm_ops = &kmem_vm_ops; + + /* 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. + */ + vma->vm_flags |= VM_IO; + + return 0; +} + +#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 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: +#if defined(CONFIG_XENO) +#if defined(CONFIG_XENO_PRIV) + if (!(start_info.flags & SIF_PRIVILEGED)) +#endif + return -ENXIO; +#endif + 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; + 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} + }; + 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 (devfs_register_chrdev(MEM_MAJOR,"mem",&memory_fops)) + printk("unable to get major %d for memory devs\n", MEM_MAJOR); + memory_devfs_register(); + rand_initialize(); +#ifdef CONFIG_I2C + i2c_init_all(); +#endif +#if defined (CONFIG_FB) + fbmem_init(); +#endif +#if defined (CONFIG_PROM_CONSOLE) + prom_con_init(); +#endif +#if defined (CONFIG_MDA_CONSOLE) + mda_console_init(); +#endif + tty_init(); +#ifdef CONFIG_M68K_PRINTER + lp_m68k_init(); +#endif + misc_init(); +#if CONFIG_QIC02_TAPE + qic02_tape_init(); +#endif +#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); |