Messages in this thread |  | | | Date | Wed, 8 Dec 2004 10:44:42 +0000 | | From | Christoph Hellwig <> | | Subject | Re: [4/6] Xen VMM #4: HAS_ARCH_DEV_MEM |
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On Wed, Dec 08, 2004 at 07:30:31AM +0000, Ian Pratt wrote: > This patch adds ARCH_HAS_DEV_MEM, enabling per-architecture > implementations of /dev/mem and thus avoids a number of messy > #ifdef's. Although the mmap case can be solved easily be simply using > io_remap_page_range instead of remap_pfn_range on all architecutres, > we need to support read/write of /dev/mem in order for dmidecode etc > to work. These changes are more messy, and we believe warrant making > /dev/mem arch specific, which also cleans up uncached_access too. > > Signed-off-by: ian.pratt@cl.cam.ac.uk > > --- > > > diff -Nurp pristine-linux-2.6.10-rc3/drivers/char/mem.c tmp-linux-2.6.10-rc3-xen.patch/drivers/char/mem.c > --- pristine-linux-2.6.10-rc3/drivers/char/mem.c 2004-12-03 21:53:47.000000000 +0000 > +++ tmp-linux-2.6.10-rc3-xen.patch/drivers/char/mem.c 2004-12-08 00:52:40.000000000 +0000 > @@ -143,7 +143,7 @@ static ssize_t do_write_mem(void *p, uns > return written; > } > > - > +#ifndef ARCH_HAS_DEV_MEM > /* > * This funcion reads the *physical* memory. The f_pos points directly to the > * memory location. > @@ -189,8 +189,9 @@ static ssize_t write_mem(struct file * f > return -EFAULT; > return do_write_mem(__va(p), p, buf, count, ppos); > } > +#endif > > -static int mmap_mem(struct file * file, struct vm_area_struct * vma) > +static int mmap_kmem(struct file * file, struct vm_area_struct * vma) > { > #ifdef pgprot_noncached > unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; > @@ -567,7 +568,7 @@ static int open_port(struct inode * inod > return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; > } > > -#define mmap_kmem mmap_mem > +#define mmap_mem mmap_kmem > #define zero_lseek null_lseek > #define full_lseek null_lseek > #define write_zero write_null > @@ -575,6 +576,7 @@ static int open_port(struct inode * inod > #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, > @@ -582,6 +584,9 @@ static struct file_operations mem_fops = > .mmap = mmap_mem, > .open = open_mem, > }; > +#else > +extern struct file_operations mem_fops; > +#endif
Any chance you could put the /dev/mem implementation into a separate file, ala drivers/char/devmem.c and avoid the ifdefs? ARCH_HAS_DEV_MEM would have to become a CONFIG option then
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