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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() 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 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


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