Re: syscall __NR_mmap2

Richard B. Johnson (root@chaos.analogic.com)
Tue, 8 Jul 2003 07:54:26 -0400 (EDT)


On Tue, 8 Jul 2003, Jamie Lokier wrote:

> Richard B. Johnson wrote:
> > mmap2(0xb8000, 8192, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 3, 0xb8000) = 0xb8000
>
> You meant to write:
>
> mmap2(0xb8000, 8192, PROT_READ|PROT_WRITE,
> MAP_SHARED|MAP_FIXED, 3, 0xb8000 >> 12);
>
> The offset argument to mmap2 is divided by PAGE_SIZE.
> That is the whole point of mmap2 :)
>
> -- Jamie

Okay. Do you know where that's documented? Nothing in linux/Documentation,
and nothing in any headers. Do you have to read the code to find out?

So, the address is now the offset in PAGES, not bytes. Seems logical,
but there is no clue in any documentation.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.

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