From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/um/include/asm/fixmap.h | 56 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 arch/um/include/asm/fixmap.h (limited to 'arch/um/include/asm/fixmap.h') diff --git a/arch/um/include/asm/fixmap.h b/arch/um/include/asm/fixmap.h new file mode 100644 index 000000000..2efac5827 --- /dev/null +++ b/arch/um/include/asm/fixmap.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __UM_FIXMAP_H +#define __UM_FIXMAP_H + +#include +#include +#include +#include + +/* + * 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 + +#endif -- cgit v1.2.3