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Altera_Forum's avatar
Altera_Forum
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16 years ago

Linux with MMU on NEEK

Hi, all. I'm testing Linux MMU version, on my NEEK. http://www.nioswiki.com/linux It works fine and I can use "bash" shell. This is the evident proof that we are using the true 'fo...
Altera_Forum's avatar
Altera_Forum
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15 years ago

Hi,

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Just to clarify -- these are kernel virtual addresses (e.g. from kmalloc()) if given an address from vmalloc() this would not work, right?

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Yes, it's right. For the difference of the 'kmalloc()' and 'vmalloc()', please refer the next site.

http://book.chinaunix.net/special/ebook/linux_kernel_development/0672327201/ch11lev1sec5.html

Of course, the kernel can access the address area from vmalloc(), but must use MMU and page tables, so the 'pure' hardware like DMA can't access those without complicated address conversions, while kmalloc() uses simple straight mapping like 0xC0000000 to 0x00000000.

Kazu