* mapping of pages out of upper 128MB into kernel address space
@ 2006-11-22 18:05 pledr
2006-11-22 18:29 ` Alan
0 siblings, 1 reply; 2+ messages in thread
From: pledr @ 2006-11-22 18:05 UTC (permalink / raw)
To: linux-kernel
Hi,
in a kernel module I have to translate user addresses into kernel addresses. The user uses shared memory allocated with shm_open / ftruncate. This shared memory is allocated somewhere in the upmost 128MB of physical memory that is NOT permanently mapped into the kernel ( found in swapper_pg_dir ). How can I "smp_save" map this memory into the kernel address space ?
Kind regards
Peter Lezoch
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* Re: mapping of pages out of upper 128MB into kernel address space
2006-11-22 18:05 mapping of pages out of upper 128MB into kernel address space pledr
@ 2006-11-22 18:29 ` Alan
0 siblings, 0 replies; 2+ messages in thread
From: Alan @ 2006-11-22 18:29 UTC (permalink / raw)
To: pledr; +Cc: linux-kernel
On 22 Nov 2006 18:05 GMT
<pledr@t-online.de> wrote:
> Hi,
> in a kernel module I have to translate user addresses into kernel addresses. The user uses shared memory allocated with shm_open / ftruncate. This shared memory is allocated somewhere in the upmost 128MB of physical memory that is NOT permanently mapped into the kernel ( found in swapper_pg_dir ). How can I "smp_save" map this memory into the kernel address space ?
See how copy_highpage and friends are used by copy_to/from_user. The
kmaps are a limited resource so you can only really use them to briefly
map objects in this way.
Alan
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2006-11-22 18:05 mapping of pages out of upper 128MB into kernel address space pledr
2006-11-22 18:29 ` Alan
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