[EMAIL PROTECTED] wrote:
> Hello Alexis, hello Philippe,
>
> thanks for your suggestions - the protection bits did the trick! Adding them
> to xnarch_remap_io_page_range(...) in rtdm_mmap_buffer() solved the problem.
> We already tried this few months ago using
>
> pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE | _PAGE_GUARDED | PAGE_SHARED;
>
> but missed the fact that xnarch_remap_io_page_range only takes PAGE_SHARED
> instead of use vma->vm_page_prot as its 5th parameter. I am not sure wether
> this extension will have side effects on other architectures. Maybe there is
> a better place for this fix. What do you think?
>
Not all archs will have the same requirements, unfortunately. Could you try the
attached patch? It also makes sure that prefetchable PCI memory won't be
accessed as page guarded in 2.6. TIA,
> Thanks again!
>
> Thomas
>
>
>
>
>> -----Ursprüngliche Nachricht-----
>> Von: [EMAIL PROTECTED]
>> [mailto:[EMAIL PROTECTED] Im Auftrag von Philippe Gerum
>> Gesendet: Sonntag, 19. Oktober 2008 20:11
>> An: Gilles Chanteperdrix
>> Cc: [email protected]
>> Betreff: Re: [Xenomai-help] rtdm_iomap_to_user on PPC
>>
>> Gilles Chanteperdrix wrote:
>>> Philippe Gerum wrote:
>>>> Gilles Chanteperdrix wrote:
>>>>> Alexis Berlemont wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On Friday 17 October 2008 06:46,
>> [EMAIL PROTECTED] wrote:
>>>>>>> No comments or ideas? Providing this feature is
>> essential for our
>>>>>>> CPCI drivers. We have to port some Linux applications
>> to Xenomai
>>>>>>> which use that mmap stuff intensely.
>>>>>>>
>>>>>>> Thanks again!
>>>>>>>
>>>>>>> Thomas
>>>>>>>
>>>>>>>> -----Ursprüngliche Nachricht-----
>>>>>>>> Von: [EMAIL PROTECTED]
>>>>>>>> [mailto:[EMAIL PROTECTED] Im Auftrag von
>>>>>>>> [EMAIL PROTECTED]
>>>>>>>> Gesendet: Mittwoch, 8. Oktober 2008 11:49
>>>>>>>> An: [email protected]
>>>>>>>> Betreff: [Xenomai-help] rtdm_iomap_to_user on PPC
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> in the following thread I was asking for a solution to use
>>>>>>>> rtdm_iomap_to_user() on PPC (MPC5200, Denx 2.4.25)
>>>>>> In 2.4 kernel, rtdm_iomap_to_user() is based on the function
>>>>>> remap_page_range (with vma->vm_flags |= VM_RESERVED).
>>>>>>
>>>>>> Once, I had to develop a classical Linux driver (for PPC) which
>>>>>> provided mmap functionalites so as to let a user
>> application mmap a
>>>>>> buffer allocated thanks to __get_free_pages().
>>>>>>
>>>>>> On a 2.6 kernel, I used remap_pfn_range() and it works
>> great but on
>>>>>> 2.4 kernel the function remap_page_range() did not work as I
>>>>>> expected. I had a quick look on its implementation and I
>> found that
>>>>>> instead of mapping my buffer it mapped newly allocated
>> zeroed pages (if my memories are correct).
>>>>>> If I remember well, these pages were allocated in lazy
>> mode. That
>>>>>> could explain the freeze of your whole system: in case a RT
>>>>>> application in primary mode tries to access the mmapped buffer.
>>>>> Well, normally, the fault should cause the RT application
>> to switch
>>>>> to secondary mode and be handled gracefully from there,
>> unless there
>>>>> is a bug hidden in Xenomai or I-pipe. Besides, RT applications
>>>>> usually use "mlockall", so the kernel should make all the pages
>>>>> present and not rely on further faults (at least, is it
>> how it works on 2.6).
>>>> powerpc may still trigger minor faults upon TLB misses
>> though. That
>>>> arch has a software-assisted MMU.
>>> Ok, and can these faults cause lockups when they happen in
>> primary mode?
>> Unless I messed up things in the I-pipe patch, no. Depending
>> on the MMU management code, some of them will reach the Linux
>> fault handler and trigger the mode switch via the Xenomai
>> fault handler, others will be processed directly from the
>> low-level exception code when it is possible to fix up the
>> mapping from there.
>>
>> As I mentioned a long time ago, the issue is more likely
>> related to the protection bits used with PCI memory
>> resources, which do require additional fixup on powerpc
>> (_PAGE_GUARDED and _PAGE_NO_CACHE come to mind here).
>>
>> --
>> Philippe.
>>
>> _______________________________________________
>> Xenomai-help mailing list
>> [email protected]
>> https://mail.gna.org/listinfo/xenomai-help
>>
>
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> Vorstand: Gerd Finkbeiner (Vorsitzender), Dr. Ingo Koch, Dr. Markus Rall,
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--
Philippe.
Index: include/asm-generic/system.h
===================================================================
--- include/asm-generic/system.h (revision 4270)
+++ include/asm-generic/system.h (working copy)
@@ -409,13 +409,16 @@
return wrap_remap_vm_page(vma,from,to);
}
-static inline int xnarch_remap_io_page_range(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,
unsigned long size,
pgprot_t prot)
{
- return wrap_remap_io_page_range(vma,from,to,size,prot);
+ return wrap_remap_io_page_range(vma,from,to,size,
+ wrap_phys_mem_prot(filp, (to) >> PAGE_SHIFT,
+ size, prot));
}
static inline int xnarch_remap_kmem_page_range(struct vm_area_struct *vma,
Index: include/asm-powerpc/wrappers.h
===================================================================
--- include/asm-powerpc/wrappers.h (revision 4270)
+++ include/asm-powerpc/wrappers.h (working copy)
@@ -31,6 +31,9 @@
#define CONFIG_MMU 1
+#define wrap_phys_mem_prot(filp,pfn,size,prot) \
+ __pgprot(pgprot_val(prot) | _PAGE_NO_CACHE | _PAGE_GUARDED)
+
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
#define show_stack(p,sp) print_backtrace(sp) /* Only works for current. */
@@ -51,6 +54,9 @@
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0) */
+#define wrap_phys_mem_prot(filp,pfn,size,prot) \
+ phys_mem_access_prot(filp, pfn, size, prot)
+
#ifdef CONFIG_PPC64
#define wrap_range_ok(task,addr,size) \
__access_ok(((__force unsigned long)(addr)),(size),(task->thread.fs))
Index: ksrc/skins/rtdm/drvlib.c
===================================================================
--- ksrc/skins/rtdm/drvlib.c (revision 4270)
+++ ksrc/skins/rtdm/drvlib.c (working copy)
@@ -1807,7 +1807,7 @@
} else
#endif /* CONFIG_MMU */
if (mmap_data->src_paddr)
- return xnarch_remap_io_page_range(vma, maddr, paddr,
+ return xnarch_remap_io_page_range(filp, vma, maddr, paddr,
size, PAGE_SHARED);
else
return xnarch_remap_kmem_page_range(vma, maddr, paddr,
Index: ksrc/nucleus/heap.c
===================================================================
--- ksrc/nucleus/heap.c (revision 4270)
+++ ksrc/nucleus/heap.c (working copy)
@@ -1053,7 +1053,7 @@
vaddr += PAGE_SIZE;
size -= PAGE_SIZE;
}
- } else if (xnarch_remap_io_page_range(vma,
+ } else if (xnarch_remap_io_page_range(file,vma,
vma->vm_start,
virt_to_phys((void *)vaddr),
size, PAGE_SHARED))
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