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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __UM_FIXMAP_H
#define __UM_FIXMAP_H
#include <asm/processor.h>
#include <asm/archparam.h>
#include <asm/page.h>
#include <linux/threads.h>
/*
* Here we define all the compile-time 'special' virtual
* addresses. The point is to have a constant address at
* compile time, but to set the physical address only
* in the boot process. We allocate these special addresses
* from the end of virtual memory (0xfffff000) backwards.
* Also this lets us do fail-safe vmalloc(), we
* can guarantee that these special addresses and
* vmalloc()-ed addresses never overlap.
*
* these 'compile-time allocated' memory buffers are
* fixed-size 4k pages. (or larger if used with an increment
* highger than 1) use fixmap_set(idx,phys) to associate
* physical memory with fixmap indices.
*
* TLB entries of such buffers will not be flushed across
* task switches.
*/
/*
* on UP currently we will have no trace of the fixmap mechanizm,
* no page table allocations, etc. This might change in the
* future, say framebuffers for the console driver(s) could be
* fix-mapped?
*/
enum fixed_addresses {
__end_of_fixed_addresses
};
extern void __set_fixmap (enum fixed_addresses idx,
unsigned long phys, pgprot_t flags);
/*
* used by vmalloc.c.
*
* Leave one empty page between vmalloc'ed areas and
* the start of the fixmap, and leave one page empty
* at the top of mem..
*/
#define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE)
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
#include <asm-generic/fixmap.h>
#endif
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