[Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

Hello,

I am writing an RTDM driver to replace one that uses UIO. The device
resides in a physical address > 4 GB on a PPC440EPx. The UIO could
not handle this address so I made a proposal to address it, details at:
http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html

Function rtdm_iomap_to_user() has same issue with the physical I/O
address
   unsigned long src_addr

I am new to Xenomai and would like to get some ideas on how to solve
this
issue.

Thanks,

Luis G. Herrera-Bendezu

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Jan Kiszka]

Herrera-Bendezu, Luis wrote:
> Hello,
> 
> I am writing an RTDM driver to replace one that uses UIO. The device
> resides in a physical address > 4 GB on a PPC440EPx. The UIO could
> not handle this address so I made a proposal to address it, details at:
> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
> 
> Function rtdm_iomap_to_user() has same issue with the physical I/O
> address
>    unsigned long src_addr
> 
> I am new to Xenomai and would like to get some ideas on how to solve
> this
> issue.

I think UIO as well as RTDM suffers from the same problem here: The
kernel service used to remap the physical memory (remap_pfn_range)
accepts unsigned long, not phys_addr_t. How is this supposed to work?

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

 

>-----Original Message-----
>From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>Sent: Tuesday, November 10, 2009 12:03 PM
>To: Herrera-Bendezu, Luis
>Cc: xenomai@xenomai.org
>Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>
>
>Herrera-Bendezu, Luis wrote:
>> Hello,
>> 
>> I am writing an RTDM driver to replace one that uses UIO. The device
>> resides in a physical address > 4 GB on a PPC440EPx. The UIO could
>> not handle this address so I made a proposal to address it, 
>details at:
>> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>> 
>> Function rtdm_iomap_to_user() has same issue with the physical I/O
>> address
>>    unsigned long src_addr
>> 
>> I am new to Xenomai and would like to get some ideas on how to solve
>> this
>> issue.
>
>I think UIO as well as RTDM suffers from the same problem here: The
>kernel service used to remap the physical memory (remap_pfn_range)
>accepts unsigned long, not phys_addr_t. How is this supposed to work?
>
>Jan
>
>-- 
>Siemens AG, Corporate Technology, CT SE 2
>Corporate Competence Center Embedded Linux
>

Actually, remap_pfn_range() gets passed the physical address left
shifted by PAGE_SIZE in both UIO and RTDM (xnarch_remap_io_page_range,
wrap_remap_io_page_range).

Luis
		
	

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Jan Kiszka]

Herrera-Bendezu, Luis wrote:
>  
> 
>> -----Original Message-----
>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>> Sent: Tuesday, November 10, 2009 12:03 PM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai@xenomai.org
>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>
>>
>> Herrera-Bendezu, Luis wrote:
>>> Hello,
>>>
>>> I am writing an RTDM driver to replace one that uses UIO. The device
>>> resides in a physical address > 4 GB on a PPC440EPx. The UIO could
>>> not handle this address so I made a proposal to address it, 
>> details at:
>>> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>
>>> Function rtdm_iomap_to_user() has same issue with the physical I/O
>>> address
>>>    unsigned long src_addr
>>>
>>> I am new to Xenomai and would like to get some ideas on how to solve
>>> this
>>> issue.
>> I think UIO as well as RTDM suffers from the same problem here: The
>> kernel service used to remap the physical memory (remap_pfn_range)
>> accepts unsigned long, not phys_addr_t. How is this supposed to work?
>>
>> Jan
>>
>> -- 
>> Siemens AG, Corporate Technology, CT SE 2
>> Corporate Competence Center Embedded Linux
>>
> 
> Actually, remap_pfn_range() gets passed the physical address left
> shifted by PAGE_SIZE in both UIO and RTDM (xnarch_remap_io_page_range,
> wrap_remap_io_page_range).

No, the target address is expressed in pages, the source in bytes.

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

 

>-----Original Message-----
>From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>Sent: Tuesday, November 10, 2009 1:13 PM
>To: Herrera-Bendezu, Luis
>Cc: xenomai@xenomai.org
>Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>
>
>Herrera-Bendezu, Luis wrote:
>>  
>> 
>>> -----Original Message-----
>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>> To: Herrera-Bendezu, Luis
>>> Cc: xenomai@xenomai.org
>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>
>>>
>>> Herrera-Bendezu, Luis wrote:
>>>> Hello,
>>>>
>>>> I am writing an RTDM driver to replace one that uses UIO. 
>The device
>>>> resides in a physical address > 4 GB on a PPC440EPx. The UIO could
>>>> not handle this address so I made a proposal to address it, 
>>> details at:
>>>> 
>http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>
>>>> Function rtdm_iomap_to_user() has same issue with the physical I/O
>>>> address
>>>>    unsigned long src_addr
>>>>
>>>> I am new to Xenomai and would like to get some ideas on 
>how to solve
>>>> this
>>>> issue.
>>> I think UIO as well as RTDM suffers from the same problem here: The
>>> kernel service used to remap the physical memory (remap_pfn_range)
>>> accepts unsigned long, not phys_addr_t. How is this 
>supposed to work?
>>>
>>> Jan
>>>
>>> -- 
>>> Siemens AG, Corporate Technology, CT SE 2
>>> Corporate Competence Center Embedded Linux
>>>
>> 
>> Actually, remap_pfn_range() gets passed the physical address left
>> shifted by PAGE_SIZE in both UIO and RTDM 
>(xnarch_remap_io_page_range,
>> wrap_remap_io_page_range).
>
>No, the target address is expressed in pages, the source in bytes.
>
That is true for rtdm_mmap_to_user but not for rtdm_iomap_to_user. See
how
mmap_data struct is set in both functions.

Luis

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Jan Kiszka]

Herrera-Bendezu, Luis wrote:
>  
> 
>> -----Original Message-----
>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>> Sent: Tuesday, November 10, 2009 1:13 PM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai@xenomai.org
>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>
>>
>> Herrera-Bendezu, Luis wrote:
>>>  
>>>
>>>> -----Original Message-----
>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>> To: Herrera-Bendezu, Luis
>>>> Cc: xenomai@xenomai.org
>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>
>>>>
>>>> Herrera-Bendezu, Luis wrote:
>>>>> Hello,
>>>>>
>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>> The device
>>>>> resides in a physical address > 4 GB on a PPC440EPx. The UIO could
>>>>> not handle this address so I made a proposal to address it, 
>>>> details at:
>> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>> Function rtdm_iomap_to_user() has same issue with the physical I/O
>>>>> address
>>>>>    unsigned long src_addr
>>>>>
>>>>> I am new to Xenomai and would like to get some ideas on 
>> how to solve
>>>>> this
>>>>> issue.
>>>> I think UIO as well as RTDM suffers from the same problem here: The
>>>> kernel service used to remap the physical memory (remap_pfn_range)
>>>> accepts unsigned long, not phys_addr_t. How is this 
>> supposed to work?
>>>> Jan
>>>>
>>>> -- 
>>>> Siemens AG, Corporate Technology, CT SE 2
>>>> Corporate Competence Center Embedded Linux
>>>>
>>> Actually, remap_pfn_range() gets passed the physical address left
>>> shifted by PAGE_SIZE in both UIO and RTDM 
>> (xnarch_remap_io_page_range,
>>> wrap_remap_io_page_range).
>> No, the target address is expressed in pages, the source in bytes.
>>
> That is true for rtdm_mmap_to_user but not for rtdm_iomap_to_user. See
> how
> mmap_data struct is set in both functions.

        struct rtdm_mmap_data mmap_data =
                { NULL, src_addr, vm_ops, vm_private_data };

with src_addr = "physical I/O address to be mapped", setting
mmap_data.src_paddr -- are you looking at different code?

Besides this, the key is how remap_pfn_page interprets the source
address argument.

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

 

>-----Original Message-----
>From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>Sent: Tuesday, November 10, 2009 1:55 PM
>To: Herrera-Bendezu, Luis
>Cc: xenomai@xenomai.org
>Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>
>
>Herrera-Bendezu, Luis wrote:
>>  
>> 
>>> -----Original Message-----
>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>> Sent: Tuesday, November 10, 2009 1:13 PM
>>> To: Herrera-Bendezu, Luis
>>> Cc: xenomai@xenomai.org
>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>
>>>
>>> Herrera-Bendezu, Luis wrote:
>>>>  
>>>>
>>>>> -----Original Message-----
>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>>> To: Herrera-Bendezu, Luis
>>>>> Cc: xenomai@xenomai.org
>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>
>>>>>
>>>>> Herrera-Bendezu, Luis wrote:
>>>>>> Hello,
>>>>>>
>>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>>> The device
>>>>>> resides in a physical address > 4 GB on a PPC440EPx. The 
>UIO could
>>>>>> not handle this address so I made a proposal to address it, 
>>>>> details at:
>>> 
>http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>>> Function rtdm_iomap_to_user() has same issue with the 
>physical I/O
>>>>>> address
>>>>>>    unsigned long src_addr
>>>>>>
>>>>>> I am new to Xenomai and would like to get some ideas on 
>>> how to solve
>>>>>> this
>>>>>> issue.
>>>>> I think UIO as well as RTDM suffers from the same problem 
>here: The
>>>>> kernel service used to remap the physical memory (remap_pfn_range)
>>>>> accepts unsigned long, not phys_addr_t. How is this 
>>> supposed to work?
>>>>> Jan
>>>>>
>>>>> -- 
>>>>> Siemens AG, Corporate Technology, CT SE 2
>>>>> Corporate Competence Center Embedded Linux
>>>>>
>>>> Actually, remap_pfn_range() gets passed the physical address left
>>>> shifted by PAGE_SIZE in both UIO and RTDM 
>>> (xnarch_remap_io_page_range,
>>>> wrap_remap_io_page_range).
>>> No, the target address is expressed in pages, the source in bytes.
>>>
>> That is true for rtdm_mmap_to_user but not for 
>rtdm_iomap_to_user. See
>> how
>> mmap_data struct is set in both functions.
>
>        struct rtdm_mmap_data mmap_data =
>                { NULL, src_addr, vm_ops, vm_private_data };
>
>with src_addr = "physical I/O address to be mapped", setting
>mmap_data.src_paddr -- are you looking at different code?
>
No, that is the code.
>Besides this, the key is how remap_pfn_page interprets the source
>address argument.
>
I had used UIO with success (as described in link above). The equivalent
code in UIO is (uio.c):
static int uio_mmap_physical(struct vm_area_struct *vma)
{
	struct uio_device *idev = vma->vm_private_data;
	int mi = uio_find_mem_index(vma);
	if (mi < 0)
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_RESERVED;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	return remap_pfn_range(vma,
			       vma->vm_start,
			       idev->info->mem[mi].addr >> PAGE_SHIFT,
			       vma->vm_end - vma->vm_start,
			       vma->vm_page_prot);
}

where idev->info->mem[mi].addr, mem[.] is the list of mappable regions.
Note that for UIO, the user application needs to mmap these regions to
user space. This is a step that is not needed on RTDM, right?

Luis

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Jan Kiszka]

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Herrera-Bendezu, Luis wrote:
>  
> 
>> -----Original Message-----
>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>> Sent: Tuesday, November 10, 2009 1:55 PM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai@xenomai.org
>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>
>>
>> Herrera-Bendezu, Luis wrote:
>>>  
>>>
>>>> -----Original Message-----
>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>> Sent: Tuesday, November 10, 2009 1:13 PM
>>>> To: Herrera-Bendezu, Luis
>>>> Cc: xenomai@xenomai.org
>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>
>>>>
>>>> Herrera-Bendezu, Luis wrote:
>>>>>  
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>>>> To: Herrera-Bendezu, Luis
>>>>>> Cc: xenomai@xenomai.org
>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>
>>>>>>
>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>> Hello,
>>>>>>>
>>>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>>>> The device
>>>>>>> resides in a physical address > 4 GB on a PPC440EPx. The 
>> UIO could
>>>>>>> not handle this address so I made a proposal to address it, 
>>>>>> details at:
>> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>>>> Function rtdm_iomap_to_user() has same issue with the 
>> physical I/O
>>>>>>> address
>>>>>>>    unsigned long src_addr
>>>>>>>
>>>>>>> I am new to Xenomai and would like to get some ideas on 
>>>> how to solve
>>>>>>> this
>>>>>>> issue.
>>>>>> I think UIO as well as RTDM suffers from the same problem 
>> here: The
>>>>>> kernel service used to remap the physical memory (remap_pfn_range)
>>>>>> accepts unsigned long, not phys_addr_t. How is this 
>>>> supposed to work?
>>>>>> Jan
>>>>>>
>>>>>> -- 
>>>>>> Siemens AG, Corporate Technology, CT SE 2
>>>>>> Corporate Competence Center Embedded Linux
>>>>>>
>>>>> Actually, remap_pfn_range() gets passed the physical address left
>>>>> shifted by PAGE_SIZE in both UIO and RTDM 
>>>> (xnarch_remap_io_page_range,
>>>>> wrap_remap_io_page_range).
>>>> No, the target address is expressed in pages, the source in bytes.
>>>>
>>> That is true for rtdm_mmap_to_user but not for 
>> rtdm_iomap_to_user. See
>>> how
>>> mmap_data struct is set in both functions.
>>        struct rtdm_mmap_data mmap_data =
>>                { NULL, src_addr, vm_ops, vm_private_data };
>>
>> with src_addr = "physical I/O address to be mapped", setting
>> mmap_data.src_paddr -- are you looking at different code?
>>
> No, that is the code.

But there is nothing shifted, the shifting takes place in Xenomai's wrapper.

>> Besides this, the key is how remap_pfn_page interprets the source
>> address argument.
>>
> I had used UIO with success (as described in link above). The equivalent
> code in UIO is (uio.c):
> static int uio_mmap_physical(struct vm_area_struct *vma)
> {
> 	struct uio_device *idev = vma->vm_private_data;
> 	int mi = uio_find_mem_index(vma);
> 	if (mi < 0)
> 		return -EINVAL;
> 
> 	vma->vm_flags |= VM_IO | VM_RESERVED;
> 
> 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> 
> 	return remap_pfn_range(vma,
> 			       vma->vm_start,
> 			       idev->info->mem[mi].addr >> PAGE_SHIFT,
> 			       vma->vm_end - vma->vm_start,
> 			       vma->vm_page_prot);
> }
> 
> where idev->info->mem[mi].addr, mem[.] is the list of mappable regions.
> Note that for UIO, the user application needs to mmap these regions to
> user space. This is a step that is not needed on RTDM, right?

OK, now I got my mistake: Confused by the wrong argument names of our
wrap_remap_io_page_range (and probably others) I thought that the
destination is given as page number, not the source.

But before adding some fancy new service for this use case, I'd like to
understand how common it actually is (crazy embedded designs tend to pop
up and deprecate faster than such APIs...).

And what was the final conclusion on LKML? As far as I understood the
UIO maintainer, the proposal was rejected. Any different follow-ups on
this that I missed? Of course, if you have a special design you can
always patch your kernel and Xenomai to fit these special purposes. But
for upstream support, kernel or Xenomai, it requires a clean and
portable model.

Jan


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Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

 

>-----Original Message-----
>From: jan.kiszka@domain.hid [mailto:jan.kiszka@domain.hid
>Sent: Tuesday, November 10, 2009 4:22 PM
>To: Herrera-Bendezu, Luis
>Cc: xenomai@xenomai.org
>Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>
>Herrera-Bendezu, Luis wrote:
>>  
>> 
>>> -----Original Message-----
>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>> Sent: Tuesday, November 10, 2009 1:55 PM
>>> To: Herrera-Bendezu, Luis
>>> Cc: xenomai@xenomai.org
>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>
>>>
>>> Herrera-Bendezu, Luis wrote:
>>>>  
>>>>
>>>>> -----Original Message-----
>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>> Sent: Tuesday, November 10, 2009 1:13 PM
>>>>> To: Herrera-Bendezu, Luis
>>>>> Cc: xenomai@xenomai.org
>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>
>>>>>
>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>  
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>>>>> To: Herrera-Bendezu, Luis
>>>>>>> Cc: xenomai@xenomai.org
>>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>>
>>>>>>>
>>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>>>>> The device
>>>>>>>> resides in a physical address > 4 GB on a PPC440EPx. The 
>>> UIO could
>>>>>>>> not handle this address so I made a proposal to address it, 
>>>>>>> details at:
>>> 
>http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>>>>> Function rtdm_iomap_to_user() has same issue with the 
>>> physical I/O
>>>>>>>> address
>>>>>>>>    unsigned long src_addr
>>>>>>>>
>>>>>>>> I am new to Xenomai and would like to get some ideas on 
>>>>> how to solve
>>>>>>>> this
>>>>>>>> issue.
>>>>>>> I think UIO as well as RTDM suffers from the same problem 
>>> here: The
>>>>>>> kernel service used to remap the physical memory 
>(remap_pfn_range)
>>>>>>> accepts unsigned long, not phys_addr_t. How is this 
>>>>> supposed to work?
>>>>>>> Jan
>>>>>>>
>>>>>>> -- 
>>>>>>> Siemens AG, Corporate Technology, CT SE 2
>>>>>>> Corporate Competence Center Embedded Linux
>>>>>>>
>>>>>> Actually, remap_pfn_range() gets passed the physical address left
>>>>>> shifted by PAGE_SIZE in both UIO and RTDM 
>>>>> (xnarch_remap_io_page_range,
>>>>>> wrap_remap_io_page_range).
>>>>> No, the target address is expressed in pages, the source in bytes.
>>>>>
>>>> That is true for rtdm_mmap_to_user but not for 
>>> rtdm_iomap_to_user. See
>>>> how
>>>> mmap_data struct is set in both functions.
>>>        struct rtdm_mmap_data mmap_data =
>>>                { NULL, src_addr, vm_ops, vm_private_data };
>>>
>>> with src_addr = "physical I/O address to be mapped", setting
>>> mmap_data.src_paddr -- are you looking at different code?
>>>
>> No, that is the code.
>
>But there is nothing shifted, the shifting takes place in 
>Xenomai's wrapper.
>
>>> Besides this, the key is how remap_pfn_page interprets the source
>>> address argument.
>>>
>> I had used UIO with success (as described in link above). 
>The equivalent
>> code in UIO is (uio.c):
>> static int uio_mmap_physical(struct vm_area_struct *vma)
>> {
>> 	struct uio_device *idev = vma->vm_private_data;
>> 	int mi = uio_find_mem_index(vma);
>> 	if (mi < 0)
>> 		return -EINVAL;
>> 
>> 	vma->vm_flags |= VM_IO | VM_RESERVED;
>> 
>> 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>> 
>> 	return remap_pfn_range(vma,
>> 			       vma->vm_start,
>> 			       idev->info->mem[mi].addr >> PAGE_SHIFT,
>> 			       vma->vm_end - vma->vm_start,
>> 			       vma->vm_page_prot);
>> }
>> 
>> where idev->info->mem[mi].addr, mem[.] is the list of 
>mappable regions.
>> Note that for UIO, the user application needs to mmap these 
>regions to
>> user space. This is a step that is not needed on RTDM, right?
>
>OK, now I got my mistake: Confused by the wrong argument names of our
>wrap_remap_io_page_range (and probably others) I thought that the
>destination is given as page number, not the source.
>
>But before adding some fancy new service for this use case, I'd like to
>understand how common it actually is (crazy embedded designs 
>tend to pop
>up and deprecate faster than such APIs...).
I do not think this is a new service but a limitation in the design.
The kernel supports it (application can mmap the device using /dev/mem)
and the PPC (440EPx in particular) has PCI and internal peripherals
located at addresses above 4 GB (I2C, SPI, etc.).
>
>And what was the final conclusion on LKML? As far as I understood the
>UIO maintainer, the proposal was rejected. Any different follow-ups on
>this that I missed? Of course, if you have a special design you can
>always patch your kernel and Xenomai to fit these special purposes. But
>for upstream support, kernel or Xenomai, it requires a clean and
>portable model.
There were no follow-ups and the reply concerning the required changes
was:
"I guess you'd have to look at the whole memory management stuff of each
 architecture to find out which kind of memory can be mapped with
addresses
 above unsigned long. Hardware often needs more than one contigous
pages.
 It might well be possible that a certain arch could have RAM for user
virtual
 addresses above 4GB, but no hardware. I don't know PPC well enough to
say
 anything about its behaviour."

In the mean time, it would be helpful if you have some suggestions on
how to
change RTDM to handle this case.

Thanks,
Luis

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Jan Kiszka]

Herrera-Bendezu, Luis wrote:
>  
> 
>> -----Original Message-----
>> From: jan.kiszka@domain.hid [mailto:jan.kiszka@domain.hid] 
>> Sent: Tuesday, November 10, 2009 4:22 PM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai@xenomai.org
>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>
>> Herrera-Bendezu, Luis wrote:
>>>  
>>>
>>>> -----Original Message-----
>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>>>> Sent: Tuesday, November 10, 2009 1:55 PM
>>>> To: Herrera-Bendezu, Luis
>>>> Cc: xenomai@xenomai.org
>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>
>>>>
>>>> Herrera-Bendezu, Luis wrote:
>>>>>  
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>>>>>> Sent: Tuesday, November 10, 2009 1:13 PM
>>>>>> To: Herrera-Bendezu, Luis
>>>>>> Cc: xenomai@xenomai.org
>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>
>>>>>>
>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>>  
>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>>>>>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>>>>>> To: Herrera-Bendezu, Luis
>>>>>>>> Cc: xenomai@xenomai.org
>>>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>>>
>>>>>>>>
>>>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>>>> Hello,
>>>>>>>>>
>>>>>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>>>>>> The device
>>>>>>>>> resides in a physical address > 4 GB on a PPC440EPx. The 
>>>> UIO could
>>>>>>>>> not handle this address so I made a proposal to address it, 
>>>>>>>> details at:
>> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>>>>>> Function rtdm_iomap_to_user() has same issue with the 
>>>> physical I/O
>>>>>>>>> address
>>>>>>>>>    unsigned long src_addr
>>>>>>>>>
>>>>>>>>> I am new to Xenomai and would like to get some ideas on 
>>>>>> how to solve
>>>>>>>>> this
>>>>>>>>> issue.
>>>>>>>> I think UIO as well as RTDM suffers from the same problem 
>>>> here: The
>>>>>>>> kernel service used to remap the physical memory 
>> (remap_pfn_range)
>>>>>>>> accepts unsigned long, not phys_addr_t. How is this 
>>>>>> supposed to work?
>>>>>>>> Jan
>>>>>>>>
>>>>>>>> -- 
>>>>>>>> Siemens AG, Corporate Technology, CT SE 2
>>>>>>>> Corporate Competence Center Embedded Linux
>>>>>>>>
>>>>>>> Actually, remap_pfn_range() gets passed the physical address left
>>>>>>> shifted by PAGE_SIZE in both UIO and RTDM 
>>>>>> (xnarch_remap_io_page_range,
>>>>>>> wrap_remap_io_page_range).
>>>>>> No, the target address is expressed in pages, the source in bytes.
>>>>>>
>>>>> That is true for rtdm_mmap_to_user but not for 
>>>> rtdm_iomap_to_user. See
>>>>> how
>>>>> mmap_data struct is set in both functions.
>>>>        struct rtdm_mmap_data mmap_data =
>>>>                { NULL, src_addr, vm_ops, vm_private_data };
>>>>
>>>> with src_addr = "physical I/O address to be mapped", setting
>>>> mmap_data.src_paddr -- are you looking at different code?
>>>>
>>> No, that is the code.
>> But there is nothing shifted, the shifting takes place in 
>> Xenomai's wrapper.
>>
>>>> Besides this, the key is how remap_pfn_page interprets the source
>>>> address argument.
>>>>
>>> I had used UIO with success (as described in link above). 
>> The equivalent
>>> code in UIO is (uio.c):
>>> static int uio_mmap_physical(struct vm_area_struct *vma)
>>> {
>>> 	struct uio_device *idev = vma->vm_private_data;
>>> 	int mi = uio_find_mem_index(vma);
>>> 	if (mi < 0)
>>> 		return -EINVAL;
>>>
>>> 	vma->vm_flags |= VM_IO | VM_RESERVED;
>>>
>>> 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>>>
>>> 	return remap_pfn_range(vma,
>>> 			       vma->vm_start,
>>> 			       idev->info->mem[mi].addr >> PAGE_SHIFT,
>>> 			       vma->vm_end - vma->vm_start,
>>> 			       vma->vm_page_prot);
>>> }
>>>
>>> where idev->info->mem[mi].addr, mem[.] is the list of 
>> mappable regions.
>>> Note that for UIO, the user application needs to mmap these 
>> regions to
>>> user space. This is a step that is not needed on RTDM, right?
>> OK, now I got my mistake: Confused by the wrong argument names of our
>> wrap_remap_io_page_range (and probably others) I thought that the
>> destination is given as page number, not the source.
>>
>> But before adding some fancy new service for this use case, I'd like to
>> understand how common it actually is (crazy embedded designs 
>> tend to pop
>> up and deprecate faster than such APIs...).
> I do not think this is a new service but a limitation in the design.
> The kernel supports it (application can mmap the device using /dev/mem)
> and the PPC (440EPx in particular) has PCI and internal peripherals
> located at addresses above 4 GB (I2C, SPI, etc.).

I think /dev/mem works by chance as it uses off_t to address the source,
and that is 64 bit even on 32 bit hosts.

But I just collected the confirmation that this extension of the PPC's
physical address range is indeed an increasingly common thing. It's
still a fairly new one, so the kernel is obviously also still in the
conversion process. Maybe poking those people again makes some sense.

>> And what was the final conclusion on LKML? As far as I understood the
>> UIO maintainer, the proposal was rejected. Any different follow-ups on
>> this that I missed? Of course, if you have a special design you can
>> always patch your kernel and Xenomai to fit these special purposes. But
>> for upstream support, kernel or Xenomai, it requires a clean and
>> portable model.
> There were no follow-ups and the reply concerning the required changes
> was:
> "I guess you'd have to look at the whole memory management stuff of each
>  architecture to find out which kind of memory can be mapped with
> addresses
>  above unsigned long. Hardware often needs more than one contigous
> pages.
>  It might well be possible that a certain arch could have RAM for user
> virtual
>  addresses above 4GB, but no hardware. I don't know PPC well enough to
> say
>  anything about its behaviour."
> 
> In the mean time, it would be helpful if you have some suggestions on
> how to
> change RTDM to handle this case.
> 

I think we can change rtdm_iomap_to_user to take src_addr as phys_addr_t
and propagate this internally properly. We also need to add a wrapper
for phys_addr_t for kernels that doesn't support this (<2.6.28). To my
current understanding, this should be sufficient, right?

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4GB

[Herrera-Bendezu, Luis]

 

>-----Original Message-----
>From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>Sent: Wednesday, November 11, 2009 9:06 AM
>To: Herrera-Bendezu, Luis
>Cc: xenomai@xenomai.org
>Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>
>
>Herrera-Bendezu, Luis wrote:
>>  
>> 
>>> -----Original Message-----
>>> From: jan.kiszka@domain.hid [mailto:jan.kiszka@domain.hid
>>> Sent: Tuesday, November 10, 2009 4:22 PM
>>> To: Herrera-Bendezu, Luis
>>> Cc: xenomai@xenomai.org
>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>
>>> Herrera-Bendezu, Luis wrote:
>>>>  
>>>>
>>>>> -----Original Message-----
>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>> Sent: Tuesday, November 10, 2009 1:55 PM
>>>>> To: Herrera-Bendezu, Luis
>>>>> Cc: xenomai@xenomai.org
>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>
>>>>>
>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>  
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>>>> Sent: Tuesday, November 10, 2009 1:13 PM
>>>>>>> To: Herrera-Bendezu, Luis
>>>>>>> Cc: xenomai@xenomai.org
>>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>>
>>>>>>>
>>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>>>  
>>>>>>>>
>>>>>>>>> -----Original Message-----
>>>>>>>>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid
>>>>>>>>> Sent: Tuesday, November 10, 2009 12:03 PM
>>>>>>>>> To: Herrera-Bendezu, Luis
>>>>>>>>> Cc: xenomai@xenomai.org
>>>>>>>>> Subject: Re: rtdm_iomap_to_user with phys addr > 4GB
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Herrera-Bendezu, Luis wrote:
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> I am writing an RTDM driver to replace one that uses UIO. 
>>>>>>> The device
>>>>>>>>>> resides in a physical address > 4 GB on a PPC440EPx. The 
>>>>> UIO could
>>>>>>>>>> not handle this address so I made a proposal to address it, 
>>>>>>>>> details at:
>>> 
>http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-April/070097.html
>>>>>>>>>> Function rtdm_iomap_to_user() has same issue with the 
>>>>> physical I/O
>>>>>>>>>> address
>>>>>>>>>>    unsigned long src_addr
>>>>>>>>>>
>>>>>>>>>> I am new to Xenomai and would like to get some ideas on 
>>>>>>> how to solve
>>>>>>>>>> this
>>>>>>>>>> issue.
>>>>>>>>> I think UIO as well as RTDM suffers from the same problem 
>>>>> here: The
>>>>>>>>> kernel service used to remap the physical memory 
>>> (remap_pfn_range)
>>>>>>>>> accepts unsigned long, not phys_addr_t. How is this 
>>>>>>> supposed to work?
>>>>>>>>> Jan
>>>>>>>>>
>>>>>>>>> -- 
>>>>>>>>> Siemens AG, Corporate Technology, CT SE 2
>>>>>>>>> Corporate Competence Center Embedded Linux
>>>>>>>>>
>>>>>>>> Actually, remap_pfn_range() gets passed the physical 
>address left
>>>>>>>> shifted by PAGE_SIZE in both UIO and RTDM 
>>>>>>> (xnarch_remap_io_page_range,
>>>>>>>> wrap_remap_io_page_range).
>>>>>>> No, the target address is expressed in pages, the 
>source in bytes.
>>>>>>>
>>>>>> That is true for rtdm_mmap_to_user but not for 
>>>>> rtdm_iomap_to_user. See
>>>>>> how
>>>>>> mmap_data struct is set in both functions.
>>>>>        struct rtdm_mmap_data mmap_data =
>>>>>                { NULL, src_addr, vm_ops, vm_private_data };
>>>>>
>>>>> with src_addr = "physical I/O address to be mapped", setting
>>>>> mmap_data.src_paddr -- are you looking at different code?
>>>>>
>>>> No, that is the code.
>>> But there is nothing shifted, the shifting takes place in 
>>> Xenomai's wrapper.
>>>
>>>>> Besides this, the key is how remap_pfn_page interprets the source
>>>>> address argument.
>>>>>
>>>> I had used UIO with success (as described in link above). 
>>> The equivalent
>>>> code in UIO is (uio.c):
>>>> static int uio_mmap_physical(struct vm_area_struct *vma)
>>>> {
>>>> 	struct uio_device *idev = vma->vm_private_data;
>>>> 	int mi = uio_find_mem_index(vma);
>>>> 	if (mi < 0)
>>>> 		return -EINVAL;
>>>>
>>>> 	vma->vm_flags |= VM_IO | VM_RESERVED;
>>>>
>>>> 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
>>>>
>>>> 	return remap_pfn_range(vma,
>>>> 			       vma->vm_start,
>>>> 			       idev->info->mem[mi].addr >> PAGE_SHIFT,
>>>> 			       vma->vm_end - vma->vm_start,
>>>> 			       vma->vm_page_prot);
>>>> }
>>>>
>>>> where idev->info->mem[mi].addr, mem[.] is the list of 
>>> mappable regions.
>>>> Note that for UIO, the user application needs to mmap these 
>>> regions to
>>>> user space. This is a step that is not needed on RTDM, right?
>>> OK, now I got my mistake: Confused by the wrong argument 
>names of our
>>> wrap_remap_io_page_range (and probably others) I thought that the
>>> destination is given as page number, not the source.
>>>
>>> But before adding some fancy new service for this use case, 
>I'd like to
>>> understand how common it actually is (crazy embedded designs 
>>> tend to pop
>>> up and deprecate faster than such APIs...).
>> I do not think this is a new service but a limitation in the design.
>> The kernel supports it (application can mmap the device 
>using /dev/mem)
>> and the PPC (440EPx in particular) has PCI and internal peripherals
>> located at addresses above 4 GB (I2C, SPI, etc.).
>
>I think /dev/mem works by chance as it uses off_t to address 
>the source,
>and that is 64 bit even on 32 bit hosts.
>
>But I just collected the confirmation that this extension of the PPC's
>physical address range is indeed an increasingly common thing. It's
>still a fairly new one, so the kernel is obviously also still in the
>conversion process. Maybe poking those people again makes some sense.
>
>>> And what was the final conclusion on LKML? As far as I 
>understood the
>>> UIO maintainer, the proposal was rejected. Any different 
>follow-ups on
>>> this that I missed? Of course, if you have a special design you can
>>> always patch your kernel and Xenomai to fit these special 
>purposes. But
>>> for upstream support, kernel or Xenomai, it requires a clean and
>>> portable model.
>> There were no follow-ups and the reply concerning the 
>required changes
>> was:
>> "I guess you'd have to look at the whole memory management 
>stuff of each
>>  architecture to find out which kind of memory can be mapped with
>> addresses
>>  above unsigned long. Hardware often needs more than one contigous
>> pages.
>>  It might well be possible that a certain arch could have 
>RAM for user
>> virtual
>>  addresses above 4GB, but no hardware. I don't know PPC well 
>enough to
>> say
>>  anything about its behaviour."
>> 
>> In the mean time, it would be helpful if you have some suggestions on
>> how to
>> change RTDM to handle this case.
>> 
>
>I think we can change rtdm_iomap_to_user to take src_addr as 
>phys_addr_t
>and propagate this internally properly. We also need to add a wrapper
>for phys_addr_t for kernels that doesn't support this (<2.6.28). To my
>current understanding, this should be sufficient, right?
Yes, I will give it a try and discuss results.

Luis

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4G

[Herrera-Bendezu, Luis]

Jan,

>I think we can change rtdm_iomap_to_user to take src_addr as 
>phys_addr_t
>and propagate this internally properly. We also need to add a wrapper
>for phys_addr_t for kernels that doesn't support this (<2.6.28). To my
>current understanding, this should be sufficient, right?
>

This is a diff against Xenomai version 2.4.8 and Linux version 2.6.28 to
handle RTDM mapping to user space of devices located at addresses > 4
GB.
Rather than modifying existing rtdm_iomap_to_user() API a new one is
added, rtdm_iomap_to_user64() (to mimic mmap64()). Since this is a user
API it can not use phys_addr_t so unsigned long long is used for the
interface.

I tried to use rtdm_iomap_to_user() on a kernel module initialization
section of my RTDM driver and passing NULL to user_info argument. This
causes an invalid memory access and system panic. How can this
function be called from kernel intialization code?

diff --git a/include/asm-generic/xenomai/system.h
b/include/asm-generic/xenomai/system.h
index 020e763..f2a9424 100644
--- a/include/asm-generic/xenomai/system.h
+++ b/include/asm-generic/xenomai/system.h
@@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
vm_area_struct *vma,
 static inline int xnarch_remap_io_page_range(struct file *filp,
 					     struct vm_area_struct *vma,
 					     unsigned long from,
-					     unsigned long to,
+					     phys_addr_t to,
 					     unsigned long size,
 					     pgprot_t prot)
 {
diff --git a/include/asm-generic/xenomai/wrappers.h
b/include/asm-generic/xenomai/wrappers.h
index 943ed34..319ac0d 100644
--- a/include/asm-generic/xenomai/wrappers.h
+++ b/include/asm-generic/xenomai/wrappers.h
@@ -400,4 +400,9 @@ static inline int wrap_raise_cap(int cap)
 }
 #endif /* LINUX_VERSION_CODE >= 2.6.29 */
 
+/* For Linux versions < 2.6.28 */
+#ifndef phys_addr_t
+#define phys_addr_t unsigned long
+#endif
+
 #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
diff --git a/include/xenomai/rtdm/rtdm_driver.h
b/include/xenomai/rtdm/rtdm_driver.h
index 3026aff..181caef 100644
--- a/include/xenomai/rtdm/rtdm_driver.h
+++ b/include/xenomai/rtdm/rtdm_driver.h
@@ -1172,6 +1172,11 @@ int rtdm_iomap_to_user(rtdm_user_info_t
*user_info,
 		       int prot, void **pptr,
 		       struct vm_operations_struct *vm_ops,
 		       void *vm_private_data);
+int rtdm_iomap_to_user64(rtdm_user_info_t *user_info,
+			 unsigned long long src_addr, size_t len,
+			 int prot, void **pptr,
+			 struct vm_operations_struct *vm_ops,
+			 void *vm_private_data);
 int rtdm_munmap(rtdm_user_info_t *user_info, void *ptr, size_t len);
 
 static inline int rtdm_read_user_ok(rtdm_user_info_t *user_info,
diff --git a/kernel/xenomai/skins/rtdm/drvlib.c
b/kernel/xenomai/skins/rtdm/drvlib.c
index 65c630f..0a710ee 100644
--- a/kernel/xenomai/skins/rtdm/drvlib.c
+++ b/kernel/xenomai/skins/rtdm/drvlib.c
@@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
 #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
 struct rtdm_mmap_data {
 	void *src_vaddr;
-	unsigned long src_paddr;
+	phys_addr_t src_paddr;
 	struct vm_operations_struct *vm_ops;
 	void *vm_private_data;
 };
@@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
 static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
*vma)
 {
 	struct rtdm_mmap_data *mmap_data = filp->private_data;
-	unsigned long vaddr, paddr, maddr, size;
+	unsigned long vaddr, maddr, size;
+	phys_addr_t paddr;
 	int ret;
 
 	vma->vm_ops = mmap_data->vm_ops;
 	vma->vm_private_data = mmap_data->vm_private_data;
 
 	vaddr = (unsigned long)mmap_data->src_vaddr;
-	paddr = (unsigned long)mmap_data->src_paddr;
+	paddr = (phys_addr_t)mmap_data->src_paddr;
 	if (!paddr)
 		/* kmalloc memory */
 		paddr = virt_to_phys((void *)vaddr);
@@ -1995,6 +1996,20 @@ int rtdm_iomap_to_user(rtdm_user_info_t
*user_info,
 
 EXPORT_SYMBOL(rtdm_iomap_to_user);
 
+int rtdm_iomap_to_user64(rtdm_user_info_t *user_info,
+			 unsigned long long src_addr, size_t len,
+			 int prot, void **pptr,
+			 struct vm_operations_struct *vm_ops,
+			 void *vm_private_data)
+{
+	struct rtdm_mmap_data mmap_data =
+		{ NULL, src_addr, vm_ops, vm_private_data };
+
+	return rtdm_do_mmap(user_info, &mmap_data, len, prot, pptr);
+}
+
+EXPORT_SYMBOL(rtdm_iomap_to_user64);
+
 /**
  * Unmap a user memory range.
  *

Luis

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4G

[Jan Kiszka]

Herrera-Bendezu, Luis wrote:
> Jan,
> 
>> I think we can change rtdm_iomap_to_user to take src_addr as 
>> phys_addr_t
>> and propagate this internally properly. We also need to add a wrapper
>> for phys_addr_t for kernels that doesn't support this (<2.6.28). To my
>> current understanding, this should be sufficient, right?
>>
> 
> This is a diff against Xenomai version 2.4.8 and Linux version 2.6.28 to
> handle RTDM mapping to user space of devices located at addresses > 4
> GB.

Does it apply against git-head as well? Note that this won't make it
into stable 2.4.

> Rather than modifying existing rtdm_iomap_to_user() API a new one is
> added, rtdm_iomap_to_user64() (to mimic mmap64()). Since this is a user
> API it can not use phys_addr_t so unsigned long long is used for the
> interface.

64 bit is not related to phys_addr_t. It /may/ be 64 bit, but it may
also be less (or more one day...?). So let's switch the existing
interface, just like the kernel does.

And it is not a user API; it is used between the driver and RTDM only.
How the driver deals with this in its user interface is a different
story. I think there is currently no publicly available driver that maps
I/O space into a user application, thus there is probably no stable RTDM
profile that uses unsigned long to specify a physical address.

> 
> I tried to use rtdm_iomap_to_user() on a kernel module initialization
> section of my RTDM driver and passing NULL to user_info argument. This
> causes an invalid memory access and system panic. How can this
> function be called from kernel intialization code?

Not at all. It is supposed to be called on behalf of a user application,
asking the driver to map some area into its address space. Then you have
a valid user_info at hand.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Xenomai-core] rtdm_iomap_to_user with phys addr > 4G

[Jan Kiszka]

Please make sure to always preserve CCs.

Herrera-Bendezu, Luis wrote:
>> -----Original Message-----
>> From: Jan Kiszka [mailto:jan.kiszka@domain.hid] 
>> Sent: Wednesday, November 18, 2009 11:42 AM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai@xenomai.org
>> Subject: Re: rtdm_iomap_to_user with phys addr > 4G
>>
>>
>> Herrera-Bendezu, Luis wrote:
>>> Jan,
>>>
>>>> I think we can change rtdm_iomap_to_user to take src_addr as 
>>>> phys_addr_t
>>>> and propagate this internally properly. We also need to add 
>> a wrapper
>>>> for phys_addr_t for kernels that doesn't support this 
>> (<2.6.28). To my
>>>> current understanding, this should be sufficient, right?
>>>>
>>> This is a diff against Xenomai version 2.4.8 and Linux 
>> version 2.6.28 to
>>> handle RTDM mapping to user space of devices located at addresses > 4
>>> GB.
>> Does it apply against git-head as well? Note that this won't make it
>> into stable 2.4.
>>
> Yes, included bellow.
> 
>>> Rather than modifying existing rtdm_iomap_to_user() API a new one is
>>> added, rtdm_iomap_to_user64() (to mimic mmap64()). Since 
>> this is a user
>>> API it can not use phys_addr_t so unsigned long long is used for the
>>> interface.
>> 64 bit is not related to phys_addr_t. It /may/ be 64 bit, but it may
>> also be less (or more one day...?). So let's switch the existing
>> interface, just like the kernel does.
>>
>> And it is not a user API; it is used between the driver and RTDM only.
>> How the driver deals with this in its user interface is a different
>> story. I think there is currently no publicly available driver 
>> that maps
>> I/O space into a user application, thus there is probably no 
>> stable RTDM
>> profile that uses unsigned long to specify a physical address.
>>
> I was mislead by the function description on both accounts (only to
> be used by drivers and should be called from user application via
> driver, open, ioctl):
> Environments:
> 
> This service can be called from:
> 
>     * Kernel module initialization/cleanup code
>     * User-space task (non-RT)

Yeah, this can be confusing on first sight. It describes on behalf of
which calling context an RTDM driver can execute a service.

> 
>>> I tried to use rtdm_iomap_to_user() on a kernel module initialization
>>> section of my RTDM driver and passing NULL to user_info 
>> argument. This
>>> causes an invalid memory access and system panic. How can this
>>> function be called from kernel intialization code?
>> Not at all. It is supposed to be called on behalf of a user 
>> application,
>> asking the driver to map some area into its address space. 
>> Then you have
>> a valid user_info at hand.
>>
>> Jan
>>
>> -- 
>> Siemens AG, Corporate Technology, CT T DE IT 1
>> Corporate Competence Center Embedded Linux
>>
> 
> 
> diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h
> index 020e763..f2a9424 100644
> --- a/include/asm-generic/system.h
> +++ b/include/asm-generic/system.h
> @@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
> vm_area_struct *vma,
>  static inline int xnarch_remap_io_page_range(struct file *filp,
>  					     struct vm_area_struct *vma,
>  					     unsigned long from,
> -					     unsigned long to,
> +					     phys_addr_t to,
>  					     unsigned long size,
>  					     pgprot_t prot)
>  {
> diff --git a/include/asm-generic/wrappers.h
> b/include/asm-generic/wrappers.h
> index 943ed34..5dfef95 100644
> --- a/include/asm-generic/wrappers.h
> +++ b/include/asm-generic/wrappers.h
> @@ -400,4 +400,9 @@ static inline int wrap_raise_cap(int cap)
>  }
>  #endif /* LINUX_VERSION_CODE >= 2.6.29 */
>  
> +/* for Linux versions < 2.6.28 */
> +#ifndef CONFIG_PHYS_ADDR_T_64BIT
> +typedef unsigned long phys_addr_t;
> +#endif

Let's make this cleanly depend on the kernel version, not some other
define which may or may not be defined independent of this type.

> +
>  #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
> diff --git a/include/rtdm/rtdm_driver.h b/include/rtdm/rtdm_driver.h
> index 3026aff..0340de8 100644
> --- a/include/rtdm/rtdm_driver.h
> +++ b/include/rtdm/rtdm_driver.h
> @@ -1168,7 +1168,7 @@ int rtdm_mmap_to_user(rtdm_user_info_t *user_info,
>  		      struct vm_operations_struct *vm_ops,
>  		      void *vm_private_data);
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data);
> diff --git a/ksrc/skins/rtdm/drvlib.c b/ksrc/skins/rtdm/drvlib.c
> index 65c630f..525fe09 100644
> --- a/ksrc/skins/rtdm/drvlib.c
> +++ b/ksrc/skins/rtdm/drvlib.c
> @@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
>  #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
>  struct rtdm_mmap_data {
>  	void *src_vaddr;
> -	unsigned long src_paddr;
> +	phys_addr_t src_paddr;
>  	struct vm_operations_struct *vm_ops;
>  	void *vm_private_data;
>  };
> @@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
>  static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
> *vma)
>  {
>  	struct rtdm_mmap_data *mmap_data = filp->private_data;
> -	unsigned long vaddr, paddr, maddr, size;
> +	unsigned long vaddr, maddr, size;
> +	phys_addr_t paddr;
>  	int ret;
>  
>  	vma->vm_ops = mmap_data->vm_ops;
>  	vma->vm_private_data = mmap_data->vm_private_data;
>  
>  	vaddr = (unsigned long)mmap_data->src_vaddr;
> -	paddr = (unsigned long)mmap_data->src_paddr;
> +	paddr = (phys_addr_t)mmap_data->src_paddr;

A good chance to drop this typecast-nop (paddr and src_paddr are already
of the same type).

>  	if (!paddr)
>  		/* kmalloc memory */
>  		paddr = virt_to_phys((void *)vaddr);
> @@ -1982,7 +1983,7 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
>   * Rescheduling: possible.
>   */
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data)
> 
> Luis

Except for the minor remarks, I'm fine with the patch. Please repost in
a proper format: patch subject, a short description, a signed-off, and
then the diff.

Thanks,
Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

[Xenomai-core] [PATCH] rtdm: Extend rtdm_iomap_to_user to map phys addr > 4G

[Herrera-Bendezu, Luis]

rtdm_iomap_to_user does not handle I/O memory mapping of
physical I/O address grater than 4 GB.

This patch changes the src_addr argument and underlying
code to handle this case.

Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
---
diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h
index 020e763..f2a9424 100644
--- a/include/asm-generic/system.h
+++ b/include/asm-generic/system.h
@@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
vm_area_struct *vma,
 static inline int xnarch_remap_io_page_range(struct file *filp,
 					     struct vm_area_struct *vma,
 					     unsigned long from,
-					     unsigned long to,
+					     phys_addr_t to,
 					     unsigned long size,
 					     pgprot_t prot)
 {
diff --git a/include/asm-generic/wrappers.h
b/include/asm-generic/wrappers.h
index 943ed34..239eb93 100644
--- a/include/asm-generic/wrappers.h
+++ b/include/asm-generic/wrappers.h
@@ -400,4 +400,8 @@ static inline int wrap_raise_cap(int cap)
 }
 #endif /* LINUX_VERSION_CODE >= 2.6.29 */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
+typedef unsigned long phys_addr_t;
+#endif
+
 #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
diff --git a/include/rtdm/rtdm_driver.h b/include/rtdm/rtdm_driver.h
index 3026aff..0340de8 100644
--- a/include/rtdm/rtdm_driver.h
+++ b/include/rtdm/rtdm_driver.h
@@ -1168,7 +1168,7 @@ int rtdm_mmap_to_user(rtdm_user_info_t *user_info,
 		      struct vm_operations_struct *vm_ops,
 		      void *vm_private_data);
 int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
-		       unsigned long src_addr, size_t len,
+		       phys_addr_t src_addr, size_t len,
 		       int prot, void **pptr,
 		       struct vm_operations_struct *vm_ops,
 		       void *vm_private_data);
diff --git a/ksrc/skins/rtdm/drvlib.c b/ksrc/skins/rtdm/drvlib.c
index 65c630f..8922689 100644
--- a/ksrc/skins/rtdm/drvlib.c
+++ b/ksrc/skins/rtdm/drvlib.c
@@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
 #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
 struct rtdm_mmap_data {
 	void *src_vaddr;
-	unsigned long src_paddr;
+	phys_addr_t src_paddr;
 	struct vm_operations_struct *vm_ops;
 	void *vm_private_data;
 };
@@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
 static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
*vma)
 {
 	struct rtdm_mmap_data *mmap_data = filp->private_data;
-	unsigned long vaddr, paddr, maddr, size;
+	unsigned long vaddr, maddr, size;
+	phys_addr_t paddr;
 	int ret;
 
 	vma->vm_ops = mmap_data->vm_ops;
 	vma->vm_private_data = mmap_data->vm_private_data;
 
 	vaddr = (unsigned long)mmap_data->src_vaddr;
-	paddr = (unsigned long)mmap_data->src_paddr;
+	paddr = mmap_data->src_paddr;
 	if (!paddr)
 		/* kmalloc memory */
 		paddr = virt_to_phys((void *)vaddr);
@@ -1982,7 +1983,7 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
  * Rescheduling: possible.
  */
 int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
-		       unsigned long src_addr, size_t len,
+		       phys_addr_t src_addr, size_t len,
 		       int prot, void **pptr,
 		       struct vm_operations_struct *vm_ops,
 		       void *vm_private_data)
---

Re: [Xenomai-core] [PATCH] rtdm: Extend rtdm_iomap_to_user to map phys addr > 4G

[Jan Kiszka]

[-- Attachment #1: Type: text/plain, Size: 3997 bytes --]

Herrera-Bendezu, Luis wrote:
> rtdm_iomap_to_user does not handle I/O memory mapping of
> physical I/O address grater than 4 GB.
> 
> This patch changes the src_addr argument and underlying
> code to handle this case.
> 
> Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
                                                ^^^^^^^^^^^
Something made your mail address unreadable. This is pointless (your
address is already archived on this list). Moreover, we need a proper
signature as a declaration that you are authorized to contribute this
patch. One may argue that the patch is trivial and not "copyrightable",
but we better avoid being sloppy even in that case.

Besides this, the patch is unfortunately line wrap. Make sure that
wrapping is switched off or use a different mailer.

Thanks,
Jan

> ---
> diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h
> index 020e763..f2a9424 100644
> --- a/include/asm-generic/system.h
> +++ b/include/asm-generic/system.h
> @@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
> vm_area_struct *vma,
>  static inline int xnarch_remap_io_page_range(struct file *filp,
>  					     struct vm_area_struct *vma,
>  					     unsigned long from,
> -					     unsigned long to,
> +					     phys_addr_t to,
>  					     unsigned long size,
>  					     pgprot_t prot)
>  {
> diff --git a/include/asm-generic/wrappers.h
> b/include/asm-generic/wrappers.h
> index 943ed34..239eb93 100644
> --- a/include/asm-generic/wrappers.h
> +++ b/include/asm-generic/wrappers.h
> @@ -400,4 +400,8 @@ static inline int wrap_raise_cap(int cap)
>  }
>  #endif /* LINUX_VERSION_CODE >= 2.6.29 */
>  
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
> +typedef unsigned long phys_addr_t;
> +#endif
> +
>  #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
> diff --git a/include/rtdm/rtdm_driver.h b/include/rtdm/rtdm_driver.h
> index 3026aff..0340de8 100644
> --- a/include/rtdm/rtdm_driver.h
> +++ b/include/rtdm/rtdm_driver.h
> @@ -1168,7 +1168,7 @@ int rtdm_mmap_to_user(rtdm_user_info_t *user_info,
>  		      struct vm_operations_struct *vm_ops,
>  		      void *vm_private_data);
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data);
> diff --git a/ksrc/skins/rtdm/drvlib.c b/ksrc/skins/rtdm/drvlib.c
> index 65c630f..8922689 100644
> --- a/ksrc/skins/rtdm/drvlib.c
> +++ b/ksrc/skins/rtdm/drvlib.c
> @@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
>  #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
>  struct rtdm_mmap_data {
>  	void *src_vaddr;
> -	unsigned long src_paddr;
> +	phys_addr_t src_paddr;
>  	struct vm_operations_struct *vm_ops;
>  	void *vm_private_data;
>  };
> @@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
>  static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
> *vma)
>  {
>  	struct rtdm_mmap_data *mmap_data = filp->private_data;
> -	unsigned long vaddr, paddr, maddr, size;
> +	unsigned long vaddr, maddr, size;
> +	phys_addr_t paddr;
>  	int ret;
>  
>  	vma->vm_ops = mmap_data->vm_ops;
>  	vma->vm_private_data = mmap_data->vm_private_data;
>  
>  	vaddr = (unsigned long)mmap_data->src_vaddr;
> -	paddr = (unsigned long)mmap_data->src_paddr;
> +	paddr = mmap_data->src_paddr;
>  	if (!paddr)
>  		/* kmalloc memory */
>  		paddr = virt_to_phys((void *)vaddr);
> @@ -1982,7 +1983,7 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
>   * Rescheduling: possible.
>   */
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data)
> ---



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 257 bytes --]

Re: [Xenomai-core] [PATCH] rtdm: Extend rtdm_iomap_to_user to map phys addr > 4G

[Herrera-Bendezu, Luis]

Jan,

Thanks for your feedback and help.

Luis
>-----Original Message-----
>From: jan.kiszka@domain.hid [mailto:jan.kiszka@domain.hid
>Sent: Saturday, November 21, 2009 3:43 AM
>To: Herrera-Bendezu, Luis
>Cc: xenomai-core
>Subject: Re: [PATCH] rtdm: Extend rtdm_iomap_to_user to map 
>phys addr > 4G
>
>Herrera-Bendezu, Luis wrote:
>> rtdm_iomap_to_user does not handle I/O memory mapping of
>> physical I/O address grater than 4 GB.
>> 
>> This patch changes the src_addr argument and underlying
>> code to handle this case.
>> 
>> Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
>                                                ^^^^^^^^^^^
>Something made your mail address unreadable. This is pointless (your
>address is already archived on this list). Moreover, we need a proper
>signature as a declaration that you are authorized to contribute this
>patch. One may argue that the patch is trivial and not "copyrightable",
>but we better avoid being sloppy even in that case.
>
>Besides this, the patch is unfortunately line wrap. Make sure that
>wrapping is switched off or use a different mailer.
>
>Thanks,
>Jan


rtdm_iomap_to_user does not handle I/O memory mapping of
physical I/O address grater than 4 GB.

This patch changes the src_addr argument and underlying
code to handle this case.

Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
---
diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h
index 020e763..f2a9424 100644
--- a/include/asm-generic/system.h
+++ b/include/asm-generic/system.h
@@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
vm_area_struct *vma,
 static inline int xnarch_remap_io_page_range(struct file *filp,
 					     struct vm_area_struct *vma,
 					     unsigned long from,
-					     unsigned long to,
+					     phys_addr_t to,
 					     unsigned long size,
 					     pgprot_t prot)
 {
diff --git a/include/asm-generic/wrappers.h
b/include/asm-generic/wrappers.h
index 943ed34..239eb93 100644
--- a/include/asm-generic/wrappers.h
+++ b/include/asm-generic/wrappers.h
@@ -400,4 +400,8 @@ static inline int wrap_raise_cap(int cap)
 }
 #endif /* LINUX_VERSION_CODE >= 2.6.29 */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
+typedef unsigned long phys_addr_t;
+#endif
+
 #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
diff --git a/include/rtdm/rtdm_driver.h b/include/rtdm/rtdm_driver.h
index 3026aff..0340de8 100644
--- a/include/rtdm/rtdm_driver.h
+++ b/include/rtdm/rtdm_driver.h
@@ -1168,7 +1168,7 @@ int rtdm_mmap_to_user(rtdm_user_info_t *user_info,
 		      struct vm_operations_struct *vm_ops,
 		      void *vm_private_data);
 int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
-		       unsigned long src_addr, size_t len,
+		       phys_addr_t src_addr, size_t len,
 		       int prot, void **pptr,
 		       struct vm_operations_struct *vm_ops,
 		       void *vm_private_data);
diff --git a/ksrc/skins/rtdm/drvlib.c b/ksrc/skins/rtdm/drvlib.c
index 65c630f..8922689 100644
--- a/ksrc/skins/rtdm/drvlib.c
+++ b/ksrc/skins/rtdm/drvlib.c
@@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
 #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
 struct rtdm_mmap_data {
 	void *src_vaddr;
-	unsigned long src_paddr;
+	phys_addr_t src_paddr;
 	struct vm_operations_struct *vm_ops;
 	void *vm_private_data;
 };
@@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
 static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
*vma)
 {
 	struct rtdm_mmap_data *mmap_data = filp->private_data;
-	unsigned long vaddr, paddr, maddr, size;
+	unsigned long vaddr, maddr, size;
+	phys_addr_t paddr;
 	int ret;
 
 	vma->vm_ops = mmap_data->vm_ops;
 	vma->vm_private_data = mmap_data->vm_private_data;
 
 	vaddr = (unsigned long)mmap_data->src_vaddr;
-	paddr = (unsigned long)mmap_data->src_paddr;
+	paddr = mmap_data->src_paddr;
 	if (!paddr)
 		/* kmalloc memory */
 		paddr = virt_to_phys((void *)vaddr);
@@ -1982,7 +1983,7 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
  * Rescheduling: possible.
  */
 int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
-		       unsigned long src_addr, size_t len,
+		       phys_addr_t src_addr, size_t len,
 		       int prot, void **pptr,
 		       struct vm_operations_struct *vm_ops,
 		       void *vm_private_data)
---

Re: [Xenomai-core] [PATCH] rtdm: Extend rtdm_iomap_to_user to map phys addr > 4G

[Jan Kiszka]

[-- Attachment #1: Type: text/plain, Size: 4887 bytes --]

Herrera-Bendezu, Luis wrote:
> Jan,
> 
> Thanks for your feedback and help.

Merged your patch (and sent out a pull request), though the line
wrapping issue persisted (manually fixed up).

Your next patch to an open source project probably deserves the use of a
better mail client.

Jan

>> -----Original Message-----
>> From: jan.kiszka@domain.hid [mailto:jan.kiszka@domain.hid
>> Sent: Saturday, November 21, 2009 3:43 AM
>> To: Herrera-Bendezu, Luis
>> Cc: xenomai-core
>> Subject: Re: [PATCH] rtdm: Extend rtdm_iomap_to_user to map 
>> phys addr > 4G
>>
>> Herrera-Bendezu, Luis wrote:
>>> rtdm_iomap_to_user does not handle I/O memory mapping of
>>> physical I/O address grater than 4 GB.
>>>
>>> This patch changes the src_addr argument and underlying
>>> code to handle this case.
>>>
>>> Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
>>                                                ^^^^^^^^^^^
>> Something made your mail address unreadable. This is pointless (your
>> address is already archived on this list). Moreover, we need a proper
>> signature as a declaration that you are authorized to contribute this
>> patch. One may argue that the patch is trivial and not "copyrightable",
>> but we better avoid being sloppy even in that case.
>>
>> Besides this, the patch is unfortunately line wrap. Make sure that
>> wrapping is switched off or use a different mailer.
>>
>> Thanks,
>> Jan
> 
> 
> rtdm_iomap_to_user does not handle I/O memory mapping of
> physical I/O address grater than 4 GB.
> 
> This patch changes the src_addr argument and underlying
> code to handle this case.
> 
> Signed-off-by: Luis Herrera-Bendezu <lherrera@domain.hid>
> ---
> diff --git a/include/asm-generic/system.h b/include/asm-generic/system.h
> index 020e763..f2a9424 100644
> --- a/include/asm-generic/system.h
> +++ b/include/asm-generic/system.h
> @@ -417,7 +417,7 @@ static inline int xnarch_remap_vm_page(struct
> vm_area_struct *vma,
>  static inline int xnarch_remap_io_page_range(struct file *filp,
>  					     struct vm_area_struct *vma,
>  					     unsigned long from,
> -					     unsigned long to,
> +					     phys_addr_t to,
>  					     unsigned long size,
>  					     pgprot_t prot)
>  {
> diff --git a/include/asm-generic/wrappers.h
> b/include/asm-generic/wrappers.h
> index 943ed34..239eb93 100644
> --- a/include/asm-generic/wrappers.h
> +++ b/include/asm-generic/wrappers.h
> @@ -400,4 +400,8 @@ static inline int wrap_raise_cap(int cap)
>  }
>  #endif /* LINUX_VERSION_CODE >= 2.6.29 */
>  
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
> +typedef unsigned long phys_addr_t;
> +#endif
> +
>  #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */
> diff --git a/include/rtdm/rtdm_driver.h b/include/rtdm/rtdm_driver.h
> index 3026aff..0340de8 100644
> --- a/include/rtdm/rtdm_driver.h
> +++ b/include/rtdm/rtdm_driver.h
> @@ -1168,7 +1168,7 @@ int rtdm_mmap_to_user(rtdm_user_info_t *user_info,
>  		      struct vm_operations_struct *vm_ops,
>  		      void *vm_private_data);
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data);
> diff --git a/ksrc/skins/rtdm/drvlib.c b/ksrc/skins/rtdm/drvlib.c
> index 65c630f..8922689 100644
> --- a/ksrc/skins/rtdm/drvlib.c
> +++ b/ksrc/skins/rtdm/drvlib.c
> @@ -1765,7 +1765,7 @@ void rtdm_nrtsig_pend(rtdm_nrtsig_t *nrt_sig);
>  #if defined(CONFIG_XENO_OPT_PERVASIVE) || defined(DOXYGEN_CPP)
>  struct rtdm_mmap_data {
>  	void *src_vaddr;
> -	unsigned long src_paddr;
> +	phys_addr_t src_paddr;
>  	struct vm_operations_struct *vm_ops;
>  	void *vm_private_data;
>  };
> @@ -1773,14 +1773,15 @@ struct rtdm_mmap_data {
>  static int rtdm_mmap_buffer(struct file *filp, struct vm_area_struct
> *vma)
>  {
>  	struct rtdm_mmap_data *mmap_data = filp->private_data;
> -	unsigned long vaddr, paddr, maddr, size;
> +	unsigned long vaddr, maddr, size;
> +	phys_addr_t paddr;
>  	int ret;
>  
>  	vma->vm_ops = mmap_data->vm_ops;
>  	vma->vm_private_data = mmap_data->vm_private_data;
>  
>  	vaddr = (unsigned long)mmap_data->src_vaddr;
> -	paddr = (unsigned long)mmap_data->src_paddr;
> +	paddr = mmap_data->src_paddr;
>  	if (!paddr)
>  		/* kmalloc memory */
>  		paddr = virt_to_phys((void *)vaddr);
> @@ -1982,7 +1983,7 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
>   * Rescheduling: possible.
>   */
>  int rtdm_iomap_to_user(rtdm_user_info_t *user_info,
> -		       unsigned long src_addr, size_t len,
> +		       phys_addr_t src_addr, size_t len,
>  		       int prot, void **pptr,
>  		       struct vm_operations_struct *vm_ops,
>  		       void *vm_private_data)
> ---


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