Section: Misc. Reference Manual Pages (AUGUST 1995)
Updated: Linux 1.3.15
Index
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NAME
vremap
- remap an arbitrary physical address space into the kernel virtual
address space.
SYNOPSIS
void * vremap(unsigned long offset, unsigned long size);
DESCRIPTION
vremap()
remaps size bytes from the physical memory starting at offset to the
kernel space. offset has to be page aligned and size
becomes page aligned.
Needed when the kernel wants to access high addresses
directly.
The physical memory is 1:1 mapped to the kernel space.
Some IO cards use memory frames with addresses
behind the physical memory or even use
addresses higher than the size of the kernel space ( 1GB on i386 ).
In this case vremap() can be used.
RETURN VALUE
vremap()
returns a void pointer to the virtual address of the mapped memory, and
NULL
on failure. vremap() will fail if no area is available in the
virtual address space of the kernel, if the address wraps around the end of the
physical address space, if offset is not page_aligned,
and if offset
is lower than the end of physical RAM , because this is already mapped to
kernel space.
SOURCES
linux/mm/vmalloc.c
BUGS/LIMITAIONS
vremap() is only available in kernel 1.3.10 or newer.
There is no include file with a declaration of this function, and it is not
exported for use in modules.
AUTHOR
Linus Torvalds
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- SOURCES
-
- BUGS/LIMITAIONS
-
- AUTHOR
-
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