diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 56 |
1 files changed, 37 insertions, 19 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index f4cd55fdd..6eaa07d23 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -5,22 +5,17 @@ */ #include <linux/config.h> -#include <linux/types.h> -#include <linux/errno.h> -#include <linux/sched.h> -#include <linux/kernel.h> -#include <linux/major.h> -#include <linux/tty.h> +#include <linux/mm.h> #include <linux/miscdevice.h> #include <linux/tpqic02.h> #include <linux/ftape.h> #include <linux/malloc.h> #include <linux/vmalloc.h> #include <linux/mman.h> -#include <linux/mm.h> #include <linux/random.h> #include <linux/init.h> #include <linux/joystick.h> +#include <linux/i2c.h> #include <asm/uaccess.h> #include <asm/io.h> @@ -137,26 +132,49 @@ static ssize_t write_mem(struct file * file, const char * buf, return do_write_mem(file, __va(p), p, buf, count, ppos); } +/* + * This should probably be per-architecture in <asm/pgtable.h> + */ +static inline unsigned long pgprot_noncached(unsigned long prot) +{ +#if defined(__i386__) + if (boot_cpu_data.x86 > 3) + prot |= _PAGE_PCD; +#elif defined(__powerpc__) + prot |= _PAGE_NO_CACHE | _PAGE_GUARDED; +#elif defined(__mc68000__) + if (CPU_IS_020_OR_030) + prot |= _PAGE_NOCACHE030; + /* Use no-cache mode, serialized */ + if (CPU_IS_040_OR_060) + prot = (prot & _CACHEMASK040) | _PAGE_NOCACHE_S; +#elif defined(__mips__) + prot = (prot & ~_CACHE_MASK) | _CACHE_UNCACHED; +#endif + + return prot; +} + static int mmap_mem(struct file * file, struct vm_area_struct * vma) { unsigned long offset = vma->vm_offset; if (offset & ~PAGE_MASK) return -ENXIO; -#if defined(__i386__) + /* - * hmm.. This disables high-memory caching, as the XFree86 team - * wondered about that at one time. - * The surround logic should disable caching for the high device - * addresses anyway, but right now this seems still needed. + * Accessing memory above the top the kernel knows about or + * through a file pointer that was marked O_SYNC will be + * done non-cached. + * + * Set VM_IO, as this is likely a non-cached access to an + * I/O area, and we don't want to include that in a core + * file. */ - if (boot_cpu_data.x86 > 3 && offset >= __pa(high_memory)) - pgprot_val(vma->vm_page_prot) |= _PAGE_PCD; -#endif -#ifdef __powerpc__ - if (offset >= __pa(high_memory)) - pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE|_PAGE_GUARDED; -#endif + if (offset >= __pa(high_memory) || (file->f_flags & O_SYNC)) { + pgprot_val(vma->vm_page_prot) = pgprot_noncached(pgprot_val(vma->vm_page_prot)); + 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; |