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![Zhang Yanfei](/assets/img/avatar_default.png)
/dev/oldmem provides the interface for us to access the "old memory" in the dump-capture kernel. Unfortunately, no one actually uses this interface. And this interface could actually cause some real problems if used on ia64 where the cached/uncached accesses are mixed. See the discussion from the link: https://lkml.org/lkml/2013/4/12/386. So Eric suggested that we should remove /dev/oldmem as an unused piece of code. [akpm@linux-foundation.org: mention /dev/oldmem obsolescence in devices.txt] Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Hansen <dave@sr71.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
902 lines
19 KiB
C
902 lines
19 KiB
C
/*
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* linux/drivers/char/mem.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Added devfs support.
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* Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
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* Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
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*/
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#include <linux/mm.h>
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#include <linux/miscdevice.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/mman.h>
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#include <linux/random.h>
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#include <linux/init.h>
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#include <linux/raw.h>
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#include <linux/tty.h>
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#include <linux/capability.h>
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#include <linux/ptrace.h>
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#include <linux/device.h>
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#include <linux/highmem.h>
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#include <linux/backing-dev.h>
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#include <linux/bootmem.h>
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#include <linux/splice.h>
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#include <linux/pfn.h>
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#include <linux/export.h>
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#include <linux/io.h>
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#include <linux/aio.h>
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#include <asm/uaccess.h>
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#ifdef CONFIG_IA64
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# include <linux/efi.h>
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#endif
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#define DEVPORT_MINOR 4
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static inline unsigned long size_inside_page(unsigned long start,
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unsigned long size)
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{
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unsigned long sz;
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sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
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return min(sz, size);
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}
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#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
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static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)
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{
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return addr + count <= __pa(high_memory);
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}
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static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
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{
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return 1;
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}
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#endif
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#ifdef CONFIG_STRICT_DEVMEM
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static inline int range_is_allowed(unsigned long pfn, unsigned long size)
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{
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u64 from = ((u64)pfn) << PAGE_SHIFT;
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u64 to = from + size;
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u64 cursor = from;
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while (cursor < to) {
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if (!devmem_is_allowed(pfn)) {
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printk(KERN_INFO
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"Program %s tried to access /dev/mem between %Lx->%Lx.\n",
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current->comm, from, to);
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return 0;
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}
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cursor += PAGE_SIZE;
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pfn++;
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}
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return 1;
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}
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#else
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static inline int range_is_allowed(unsigned long pfn, unsigned long size)
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{
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return 1;
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}
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#endif
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void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
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{
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}
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/*
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* This funcion reads the *physical* memory. The f_pos points directly to the
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* memory location.
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*/
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static ssize_t read_mem(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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phys_addr_t p = *ppos;
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ssize_t read, sz;
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char *ptr;
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if (!valid_phys_addr_range(p, count))
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return -EFAULT;
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read = 0;
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#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
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/* we don't have page 0 mapped on sparc and m68k.. */
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if (p < PAGE_SIZE) {
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sz = size_inside_page(p, count);
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if (sz > 0) {
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if (clear_user(buf, sz))
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return -EFAULT;
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buf += sz;
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p += sz;
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count -= sz;
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read += sz;
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}
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}
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#endif
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while (count > 0) {
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unsigned long remaining;
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sz = size_inside_page(p, count);
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if (!range_is_allowed(p >> PAGE_SHIFT, count))
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return -EPERM;
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/*
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* On ia64 if a page has been mapped somewhere as uncached, then
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* it must also be accessed uncached by the kernel or data
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* corruption may occur.
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*/
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ptr = xlate_dev_mem_ptr(p);
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if (!ptr)
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return -EFAULT;
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remaining = copy_to_user(buf, ptr, sz);
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unxlate_dev_mem_ptr(p, ptr);
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if (remaining)
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return -EFAULT;
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buf += sz;
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p += sz;
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count -= sz;
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read += sz;
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}
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*ppos += read;
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return read;
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}
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static ssize_t write_mem(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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phys_addr_t p = *ppos;
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ssize_t written, sz;
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unsigned long copied;
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void *ptr;
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if (!valid_phys_addr_range(p, count))
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return -EFAULT;
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written = 0;
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#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
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/* we don't have page 0 mapped on sparc and m68k.. */
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if (p < PAGE_SIZE) {
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sz = size_inside_page(p, count);
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/* Hmm. Do something? */
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buf += sz;
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p += sz;
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count -= sz;
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written += sz;
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}
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#endif
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while (count > 0) {
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sz = size_inside_page(p, count);
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if (!range_is_allowed(p >> PAGE_SHIFT, sz))
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return -EPERM;
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/*
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* On ia64 if a page has been mapped somewhere as uncached, then
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* it must also be accessed uncached by the kernel or data
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* corruption may occur.
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*/
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ptr = xlate_dev_mem_ptr(p);
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if (!ptr) {
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if (written)
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break;
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return -EFAULT;
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}
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copied = copy_from_user(ptr, buf, sz);
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unxlate_dev_mem_ptr(p, ptr);
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if (copied) {
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written += sz - copied;
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if (written)
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break;
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return -EFAULT;
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}
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buf += sz;
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p += sz;
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count -= sz;
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written += sz;
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}
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*ppos += written;
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return written;
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}
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int __weak phys_mem_access_prot_allowed(struct file *file,
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unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
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{
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return 1;
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}
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#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
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/*
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* Architectures vary in how they handle caching for addresses
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* outside of main memory.
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*
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*/
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#ifdef pgprot_noncached
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static int uncached_access(struct file *file, phys_addr_t addr)
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{
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#if defined(CONFIG_IA64)
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/*
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* On ia64, we ignore O_DSYNC because we cannot tolerate memory
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* attribute aliases.
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*/
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return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
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#elif defined(CONFIG_MIPS)
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{
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extern int __uncached_access(struct file *file,
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unsigned long addr);
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return __uncached_access(file, addr);
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}
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#else
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/*
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* Accessing memory above the top the kernel knows about or through a
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* file pointer
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* that was marked O_DSYNC will be done non-cached.
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*/
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if (file->f_flags & O_DSYNC)
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return 1;
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return addr >= __pa(high_memory);
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#endif
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}
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#endif
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static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
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unsigned long size, pgprot_t vma_prot)
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{
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#ifdef pgprot_noncached
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phys_addr_t offset = pfn << PAGE_SHIFT;
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if (uncached_access(file, offset))
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return pgprot_noncached(vma_prot);
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#endif
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return vma_prot;
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}
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#endif
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#ifndef CONFIG_MMU
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static unsigned long get_unmapped_area_mem(struct file *file,
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unsigned long addr,
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unsigned long len,
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unsigned long pgoff,
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unsigned long flags)
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{
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if (!valid_mmap_phys_addr_range(pgoff, len))
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return (unsigned long) -EINVAL;
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return pgoff << PAGE_SHIFT;
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}
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/* can't do an in-place private mapping if there's no MMU */
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static inline int private_mapping_ok(struct vm_area_struct *vma)
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{
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return vma->vm_flags & VM_MAYSHARE;
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}
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#else
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#define get_unmapped_area_mem NULL
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static inline int private_mapping_ok(struct vm_area_struct *vma)
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{
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return 1;
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}
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#endif
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static const struct vm_operations_struct mmap_mem_ops = {
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#ifdef CONFIG_HAVE_IOREMAP_PROT
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.access = generic_access_phys
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#endif
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};
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static int mmap_mem(struct file *file, struct vm_area_struct *vma)
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{
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size_t size = vma->vm_end - vma->vm_start;
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if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
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return -EINVAL;
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if (!private_mapping_ok(vma))
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return -ENOSYS;
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if (!range_is_allowed(vma->vm_pgoff, size))
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return -EPERM;
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if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
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&vma->vm_page_prot))
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return -EINVAL;
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vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
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size,
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vma->vm_page_prot);
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vma->vm_ops = &mmap_mem_ops;
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/* Remap-pfn-range will mark the range VM_IO */
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if (remap_pfn_range(vma,
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vma->vm_start,
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vma->vm_pgoff,
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size,
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vma->vm_page_prot)) {
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return -EAGAIN;
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}
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return 0;
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}
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#ifdef CONFIG_DEVKMEM
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static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
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{
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unsigned long pfn;
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/* Turn a kernel-virtual address into a physical page frame */
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pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
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/*
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* RED-PEN: on some architectures there is more mapped memory than
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* available in mem_map which pfn_valid checks for. Perhaps should add a
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* new macro here.
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*
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* RED-PEN: vmalloc is not supported right now.
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*/
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if (!pfn_valid(pfn))
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return -EIO;
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vma->vm_pgoff = pfn;
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return mmap_mem(file, vma);
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}
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#endif
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#ifdef CONFIG_DEVKMEM
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/*
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* This function reads the *virtual* memory as seen by the kernel.
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*/
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static ssize_t read_kmem(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned long p = *ppos;
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ssize_t low_count, read, sz;
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char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
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int err = 0;
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read = 0;
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if (p < (unsigned long) high_memory) {
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low_count = count;
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if (count > (unsigned long)high_memory - p)
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low_count = (unsigned long)high_memory - p;
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#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
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/* we don't have page 0 mapped on sparc and m68k.. */
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if (p < PAGE_SIZE && low_count > 0) {
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sz = size_inside_page(p, low_count);
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if (clear_user(buf, sz))
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return -EFAULT;
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buf += sz;
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p += sz;
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read += sz;
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low_count -= sz;
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count -= sz;
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}
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#endif
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while (low_count > 0) {
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sz = size_inside_page(p, low_count);
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/*
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* On ia64 if a page has been mapped somewhere as
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* uncached, then it must also be accessed uncached
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* by the kernel or data corruption may occur
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*/
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kbuf = xlate_dev_kmem_ptr((char *)p);
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if (copy_to_user(buf, kbuf, sz))
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return -EFAULT;
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buf += sz;
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p += sz;
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read += sz;
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low_count -= sz;
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count -= sz;
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}
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}
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if (count > 0) {
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kbuf = (char *)__get_free_page(GFP_KERNEL);
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if (!kbuf)
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return -ENOMEM;
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while (count > 0) {
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sz = size_inside_page(p, count);
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if (!is_vmalloc_or_module_addr((void *)p)) {
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err = -ENXIO;
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break;
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}
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sz = vread(kbuf, (char *)p, sz);
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if (!sz)
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break;
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if (copy_to_user(buf, kbuf, sz)) {
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err = -EFAULT;
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break;
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}
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count -= sz;
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buf += sz;
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read += sz;
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p += sz;
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}
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free_page((unsigned long)kbuf);
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}
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*ppos = p;
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return read ? read : err;
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}
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static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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ssize_t written, sz;
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unsigned long copied;
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written = 0;
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#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
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/* we don't have page 0 mapped on sparc and m68k.. */
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if (p < PAGE_SIZE) {
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sz = size_inside_page(p, count);
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/* Hmm. Do something? */
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buf += sz;
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p += sz;
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count -= sz;
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written += sz;
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}
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#endif
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while (count > 0) {
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char *ptr;
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sz = size_inside_page(p, count);
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/*
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* On ia64 if a page has been mapped somewhere as uncached, then
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* it must also be accessed uncached by the kernel or data
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* corruption may occur.
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*/
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ptr = xlate_dev_kmem_ptr((char *)p);
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copied = copy_from_user(ptr, buf, sz);
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if (copied) {
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written += sz - copied;
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if (written)
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break;
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return -EFAULT;
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}
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buf += sz;
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p += sz;
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count -= sz;
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written += sz;
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}
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*ppos += written;
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return written;
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}
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/*
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* This function writes to the *virtual* memory as seen by the kernel.
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*/
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static ssize_t write_kmem(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned long p = *ppos;
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ssize_t wrote = 0;
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ssize_t virtr = 0;
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char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
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int err = 0;
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if (p < (unsigned long) high_memory) {
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unsigned long to_write = min_t(unsigned long, count,
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(unsigned long)high_memory - p);
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wrote = do_write_kmem(p, buf, to_write, ppos);
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if (wrote != to_write)
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return wrote;
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p += wrote;
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buf += wrote;
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count -= wrote;
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}
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if (count > 0) {
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kbuf = (char *)__get_free_page(GFP_KERNEL);
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if (!kbuf)
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return wrote ? wrote : -ENOMEM;
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while (count > 0) {
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unsigned long sz = size_inside_page(p, count);
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unsigned long n;
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if (!is_vmalloc_or_module_addr((void *)p)) {
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err = -ENXIO;
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break;
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}
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n = copy_from_user(kbuf, buf, sz);
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if (n) {
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err = -EFAULT;
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break;
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}
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vwrite(kbuf, (char *)p, sz);
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count -= sz;
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buf += sz;
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virtr += sz;
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|
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 ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
return iov_length(iov, nr_segs);
|
|
}
|
|
|
|
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 ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
size_t written = 0;
|
|
unsigned long i;
|
|
ssize_t ret;
|
|
|
|
for (i = 0; i < nr_segs; i++) {
|
|
ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len,
|
|
&pos);
|
|
if (ret < 0)
|
|
break;
|
|
written += ret;
|
|
}
|
|
|
|
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_inode(file)->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 (IS_ERR_VALUE((unsigned long long)offset)) {
|
|
ret = -EOVERFLOW;
|
|
break;
|
|
}
|
|
file->f_pos = offset;
|
|
ret = file->f_pos;
|
|
force_successful_syscall_return();
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
mutex_unlock(&file_inode(file)->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 aio_write_zero aio_write_null
|
|
#define open_mem open_port
|
|
#define open_kmem 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,
|
|
.aio_read = aio_read_null,
|
|
.aio_write = aio_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,
|
|
.aio_read = aio_read_zero,
|
|
.aio_write = aio_write_zero,
|
|
.mmap = mmap_zero,
|
|
};
|
|
|
|
/*
|
|
* capabilities for /dev/zero
|
|
* - permits private mappings, "copies" are taken of the source of zeros
|
|
* - no writeback happens
|
|
*/
|
|
static struct backing_dev_info zero_bdi = {
|
|
.name = "char/mem",
|
|
.capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
|
|
};
|
|
|
|
static const struct file_operations full_fops = {
|
|
.llseek = full_lseek,
|
|
.read = read_full,
|
|
.write = write_full,
|
|
};
|
|
|
|
static const struct memdev {
|
|
const char *name;
|
|
umode_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 },
|
|
#ifdef CONFIG_PRINTK
|
|
[11] = { "kmsg", 0644, &kmsg_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;
|
|
|
|
/* Is /dev/mem or /dev/kmem ? */
|
|
if (dev->dev_info == &directly_mappable_cdev_bdi)
|
|
filp->f_mode |= FMODE_UNSIGNED_OFFSET;
|
|
|
|
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, umode_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;
|
|
|
|
/*
|
|
* Create /dev/port?
|
|
*/
|
|
if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
|
|
continue;
|
|
|
|
device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
|
|
NULL, devlist[minor].name);
|
|
}
|
|
|
|
return tty_init();
|
|
}
|
|
|
|
fs_initcall(chr_dev_init);
|