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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/mips/include/asm/fixmap.h
parentInitial commit. (diff)
downloadlinux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz
linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/mips/include/asm/fixmap.h')
-rw-r--r--arch/mips/include/asm/fixmap.h82
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
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+++ b/arch/mips/include/asm/fixmap.h
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+/*
+ * fixmap.h: compile-time virtual memory allocation
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Ingo Molnar
+ *
+ * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
+ */
+
+#ifndef _ASM_FIXMAP_H
+#define _ASM_FIXMAP_H
+
+#include <asm/page.h>
+#include <spaces.h>
+#ifdef CONFIG_HIGHMEM
+#include <linux/threads.h>
+#include <asm/kmap_types.h>
+#endif
+
+/*
+ * 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 {
+#define FIX_N_COLOURS 8
+ FIX_CMAP_BEGIN,
+ FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
+#ifdef CONFIG_HIGHMEM
+ /* reserved pte's for temporary kernel mappings */
+ FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
+ FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
+#endif
+ __end_of_fixed_addresses
+};
+
+/*
+ * 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_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+
+#include <asm-generic/fixmap.h>
+
+#define kmap_get_fixmap_pte(vaddr) \
+ pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
+
+/*
+ * Called from pgtable_init()
+ */
+extern void fixrange_init(unsigned long start, unsigned long end,
+ pgd_t *pgd_base);
+
+
+#endif