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From: "Hans J. Koch" <hjk@linutronix.de>
To: Johann Baudy <johaahn@gmail.com>
Cc: hjk@linutronix.de, gregkh@suse.de, linux-kernel@vger.kernel.org
Subject: Re: UIO: phys_mem_access_prot() miss?
Date: Tue, 13 May 2008 20:51:38 +0200	[thread overview]
Message-ID: <20080513185137.GA3342@local> (raw)
In-Reply-To: <7e0dd21a0805130655xd8b1c8ap9a329943e25fe6fb@mail.gmail.com>

On Tue, May 13, 2008 at 03:55:29PM +0200, Johann Baudy wrote:
> Hi Hans, Greg,
> 
> I need some help on UIO driver.
> I have to add this below workaround (in uio.c) to be able to access
> phys memory from user space.
> I'm currently using PPC arch.
> Am I wrong? or Is it a miss?
> 
> static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
> {
> 
> ...
> 	switch (idev->info->mem[mi].memtype) {
> 		case UIO_MEM_PHYS:
> +       	vma->vm_page_prot = phys_mem_access_prot(filep,
> +            idev->info->mem[mi].addr >> PAGE_SHIFT,
> +						 vma->vm_end - vma->vm_start,
> +						 vma->vm_page_prot);
> 			return uio_mmap_physical(vma);
> 		case UIO_MEM_LOGICAL:
> ...
> 
> }
> 
> FYI: I've copied those lines from mem char driver in mmap_mem().

Hi Johann,
what kernel are you using? Similar problems were reported before, and
we've already applied a patch that should fix it. I think it hit
mainline shortly before the 2.6.25 release. uio_mmap() should work with
kernels >= 2.6.25 for PPC.

Thanks,
Hans


  reply	other threads:[~2008-05-13 18:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-13 13:55 UIO: phys_mem_access_prot() miss? Johann Baudy
2008-05-13 18:51 ` Hans J. Koch [this message]
2008-05-15  7:45   ` Johann Baudy

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