diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 133 |
1 files changed, 101 insertions, 32 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 20070b7c573..e83623ead44 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -41,36 +41,7 @@ */ static inline int uncached_access(struct file *file, unsigned long addr) { -#if defined(__i386__) && !defined(__arch_um__) - /* - * 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__) && !defined(__arch_um__) - /* - * 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) +#if defined(CONFIG_IA64) /* * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. */ @@ -108,6 +79,36 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) } #endif +#ifdef CONFIG_NONPROMISC_DEVMEM +static inline int range_is_allowed(unsigned long pfn, unsigned long size) +{ + u64 from = ((u64)pfn) << PAGE_SHIFT; + u64 to = from + size; + u64 cursor = from; + + while (cursor < to) { + if (!devmem_is_allowed(pfn)) { + printk(KERN_INFO + "Program %s tried to access /dev/mem between %Lx->%Lx.\n", + current->comm, from, to); + return 0; + } + cursor += PAGE_SIZE; + pfn++; + } + return 1; +} +#else +static inline int range_is_allowed(unsigned long pfn, unsigned long size) +{ + return 1; +} +#endif + +void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr) +{ +} + /* * This funcion reads the *physical* memory. The f_pos points directly to the * memory location. @@ -150,15 +151,25 @@ static ssize_t read_mem(struct file * file, char __user * buf, sz = min_t(unsigned long, sz, count); + if (!range_is_allowed(p >> PAGE_SHIFT, count)) + return -EPERM; + /* * On ia64 if a page has been mapped somewhere as * uncached, then it must also be accessed uncached * by the kernel or data corruption may occur */ ptr = xlate_dev_mem_ptr(p); + if (!ptr) + return -EFAULT; - if (copy_to_user(buf, ptr, sz)) + if (copy_to_user(buf, ptr, sz)) { + unxlate_dev_mem_ptr(p, ptr); return -EFAULT; + } + + unxlate_dev_mem_ptr(p, ptr); + buf += sz; p += sz; count -= sz; @@ -207,20 +218,32 @@ static ssize_t write_mem(struct file * file, const char __user * buf, sz = min_t(unsigned long, sz, count); + if (!range_is_allowed(p >> PAGE_SHIFT, sz)) + return -EPERM; + /* * On ia64 if a page has been mapped somewhere as * uncached, then it must also be accessed uncached * by the kernel or data corruption may occur */ ptr = xlate_dev_mem_ptr(p); + if (!ptr) { + if (written) + break; + return -EFAULT; + } copied = copy_from_user(ptr, buf, sz); if (copied) { written += sz - copied; + unxlate_dev_mem_ptr(p, ptr); if (written) break; return -EFAULT; } + + unxlate_dev_mem_ptr(p, ptr); + buf += sz; p += sz; count -= sz; @@ -231,6 +254,12 @@ static ssize_t write_mem(struct file * file, const char __user * buf, return written; } +int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file, + unsigned long pfn, unsigned long size, pgprot_t *vma_prot) +{ + return 1; +} + #ifndef __HAVE_PHYS_MEM_ACCESS_PROT static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) @@ -271,6 +300,35 @@ static inline int private_mapping_ok(struct vm_area_struct *vma) } #endif +void __attribute__((weak)) +map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) +{ + /* nothing. architectures can override. */ +} + +void __attribute__((weak)) +unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) +{ + /* nothing. architectures can override. */ +} + +static void mmap_mem_open(struct vm_area_struct *vma) +{ + map_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static void mmap_mem_close(struct vm_area_struct *vma) +{ + unmap_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static struct vm_operations_struct mmap_mem_ops = { + .open = mmap_mem_open, + .close = mmap_mem_close +}; + static int mmap_mem(struct file * file, struct vm_area_struct * vma) { size_t size = vma->vm_end - vma->vm_start; @@ -281,17 +339,28 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma) if (!private_mapping_ok(vma)) return -ENOSYS; + if (!range_is_allowed(vma->vm_pgoff, size)) + return -EPERM; + + if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, + &vma->vm_page_prot)) + return -EINVAL; + vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, size, vma->vm_page_prot); + vma->vm_ops = &mmap_mem_ops; + /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size, - vma->vm_page_prot)) + vma->vm_page_prot)) { + unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot); return -EAGAIN; + } return 0; } |