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