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1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
14 #include <linux/vmalloc.h>
16 #include <asm/pgalloc.h>
17 #include <asm/kmap_types.h>
18 #include <asm/fixmap.h>
20 #include <linux/pgtable.h>
21 #include <linux/sched.h>
22 #include <asm/tlbflush.h>
24 extern int mem_init_done
;
26 static unsigned int fixmaps_used __initdata
;
29 * Remap an arbitrary physical address space into the kernel virtual
30 * address space. Needed when the kernel wants to access high addresses
33 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
34 * have to convert them into an offset in a page-aligned mapping, but the
35 * caller shouldn't need to know that small detail.
37 void __iomem
*__ref
ioremap(phys_addr_t addr
, unsigned long size
)
41 unsigned long offset
, last_addr
;
42 struct vm_struct
*area
= NULL
;
44 /* Don't allow wraparound or zero size */
45 last_addr
= addr
+ size
- 1;
46 if (!size
|| last_addr
< addr
)
50 * Mappings have to be page-aligned
52 offset
= addr
& ~PAGE_MASK
;
54 size
= PAGE_ALIGN(last_addr
+ 1) - p
;
56 if (likely(mem_init_done
)) {
57 area
= get_vm_area(size
, VM_IOREMAP
);
60 v
= (unsigned long)area
->addr
;
62 if ((fixmaps_used
+ (size
>> PAGE_SHIFT
)) > FIX_N_IOREMAPS
)
64 v
= fix_to_virt(FIX_IOREMAP_BEGIN
+ fixmaps_used
);
65 fixmaps_used
+= (size
>> PAGE_SHIFT
);
68 if (ioremap_page_range(v
, v
+ size
, p
,
69 __pgprot(pgprot_val(PAGE_KERNEL
) | _PAGE_CI
))) {
70 if (likely(mem_init_done
))
73 fixmaps_used
-= (size
>> PAGE_SHIFT
);
77 return (void __iomem
*)(offset
+ (char *)v
);
79 EXPORT_SYMBOL(ioremap
);
81 void iounmap(void *addr
)
83 /* If the page is from the fixmap pool then we just clear out
86 if (unlikely((unsigned long)addr
> FIXADDR_START
)) {
87 /* This is a bit broken... we don't really know
88 * how big the area is so it's difficult to know
89 * how many fixed pages to invalidate...
90 * just flush tlb and hope for the best...
91 * consider this a FIXME
93 * Really we should be clearing out one or more page
94 * table entries for these virtual addresses so that
95 * future references cause a page fault... for now, we
97 * i) this code never gets called on known boards
98 * ii) invalid accesses to the freed areas aren't made
104 return vfree((void *)(PAGE_MASK
& (unsigned long)addr
));
106 EXPORT_SYMBOL(iounmap
);
109 * OK, this one's a bit tricky... ioremap can get called before memory is
110 * initialized (early serial console does this) and will want to alloc a page
111 * for its mapping. No userspace pages will ever get allocated before memory
112 * is initialized so this applies only to kernel pages. In the event that
113 * this is called before memory is initialized we allocate the page using
114 * the memblock infrastructure.
117 pte_t __ref
*pte_alloc_one_kernel(struct mm_struct
*mm
)
121 if (likely(mem_init_done
)) {
122 pte
= (pte_t
*)get_zeroed_page(GFP_KERNEL
);
124 pte
= memblock_alloc(PAGE_SIZE
, PAGE_SIZE
);
126 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
127 __func__
, PAGE_SIZE
, PAGE_SIZE
);