1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * highmem.c: virtual kernel memory mappings for high memory
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * PowerPC version, stolen from the i386 version.
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Used in CONFIG_HIGHMEM systems for memory pages which
8*4882a593Smuzhiyun * are not addressable by direct kernel virtual addresses.
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Copyright (C) 1999 Gerhard Wichert, Siemens AG
11*4882a593Smuzhiyun * Gerhard.Wichert@pdb.siemens.de
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun *
14*4882a593Smuzhiyun * Redesigned the x86 32-bit VM architecture to deal with
15*4882a593Smuzhiyun * up to 16 Terrabyte physical memory. With current x86 CPUs
16*4882a593Smuzhiyun * we now support up to 64 Gigabytes physical RAM.
17*4882a593Smuzhiyun *
18*4882a593Smuzhiyun * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
19*4882a593Smuzhiyun *
20*4882a593Smuzhiyun * Reworked for PowerPC by various contributors. Moved from
21*4882a593Smuzhiyun * highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
22*4882a593Smuzhiyun */
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun #include <linux/highmem.h>
25*4882a593Smuzhiyun #include <linux/module.h>
26*4882a593Smuzhiyun
kmap_atomic_high_prot(struct page * page,pgprot_t prot)27*4882a593Smuzhiyun void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun unsigned long vaddr;
30*4882a593Smuzhiyun int idx, type;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun type = kmap_atomic_idx_push();
33*4882a593Smuzhiyun idx = type + KM_TYPE_NR*smp_processor_id();
34*4882a593Smuzhiyun vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
35*4882a593Smuzhiyun WARN_ON(IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !pte_none(*(kmap_pte - idx)));
36*4882a593Smuzhiyun __set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot), 1);
37*4882a593Smuzhiyun local_flush_tlb_page(NULL, vaddr);
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun return (void*) vaddr;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun EXPORT_SYMBOL(kmap_atomic_high_prot);
42*4882a593Smuzhiyun
kunmap_atomic_high(void * kvaddr)43*4882a593Smuzhiyun void kunmap_atomic_high(void *kvaddr)
44*4882a593Smuzhiyun {
45*4882a593Smuzhiyun unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun if (vaddr < __fix_to_virt(FIX_KMAP_END))
48*4882a593Smuzhiyun return;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM)) {
51*4882a593Smuzhiyun int type = kmap_atomic_idx();
52*4882a593Smuzhiyun unsigned int idx;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun idx = type + KM_TYPE_NR * smp_processor_id();
55*4882a593Smuzhiyun WARN_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun /*
58*4882a593Smuzhiyun * force other mappings to Oops if they'll try to access
59*4882a593Smuzhiyun * this pte without first remap it
60*4882a593Smuzhiyun */
61*4882a593Smuzhiyun pte_clear(&init_mm, vaddr, kmap_pte-idx);
62*4882a593Smuzhiyun local_flush_tlb_page(NULL, vaddr);
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun kmap_atomic_idx_pop();
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun EXPORT_SYMBOL(kunmap_atomic_high);
68