Messages in this thread | | | Date | Tue, 3 Mar 2009 12:22:18 +0100 | Subject | memory allocation over 4gb under x86_64 | From | protagora27 protagora27 <> |
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Hello folks,
I have a 64 bit dma that I have to program with 64 bit physical address beyond 4 gb because I have to test dma with memory allocation beyond 4 gb. I 'm using linux x86_64 2.6.24 and I have 8 gb ram. How can I allocate physical dma memory beyond 4gb ? In x86_64 can I use __pa to have physical address ? I have used kmalloc giving virtual address : ffff810225d10340 and using __pa i have: 225d10340 that is over 8 gb . Does it mean that kmalloc return address is not linear mapped with phys ram ?
I would like to find a function that returns a physical adddres beyond 4gb and then i write phys address in dma register .
Thanks.
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