1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/efi.h>
4 #include <linux/memblock.h>
5 #include <linux/spinlock.h>
6 #include <asm/unaccepted_memory.h>
7 
8 /* Protects unaccepted memory bitmap */
9 static DEFINE_SPINLOCK(unaccepted_memory_lock);
10 
11 /*
12  * accept_memory() -- Consult bitmap and accept the memory if needed.
13  *
14  * Only memory that is explicitly marked as unaccepted in the bitmap requires
15  * an action. All the remaining memory is implicitly accepted and doesn't need
16  * acceptance.
17  *
18  * No need to accept:
19  *  - anything if the system has no unaccepted table;
20  *  - memory that is below phys_base;
21  *  - memory that is above the memory that addressable by the bitmap;
22  */
23 void accept_memory(phys_addr_t start, phys_addr_t end)
24 {
25 	struct efi_unaccepted_memory *unaccepted;
26 	unsigned long range_start, range_end;
27 	unsigned long flags;
28 	u64 unit_size;
29 
30 	unaccepted = efi_get_unaccepted_table();
31 	if (!unaccepted)
32 		return;
33 
34 	unit_size = unaccepted->unit_size;
35 
36 	/*
37 	 * Only care for the part of the range that is represented
38 	 * in the bitmap.
39 	 */
40 	if (start < unaccepted->phys_base)
41 		start = unaccepted->phys_base;
42 	if (end < unaccepted->phys_base)
43 		return;
44 
45 	/* Translate to offsets from the beginning of the bitmap */
46 	start -= unaccepted->phys_base;
47 	end -= unaccepted->phys_base;
48 
49 	/* Make sure not to overrun the bitmap */
50 	if (end > unaccepted->size * unit_size * BITS_PER_BYTE)
51 		end = unaccepted->size * unit_size * BITS_PER_BYTE;
52 
53 	range_start = start / unit_size;
54 
55 	spin_lock_irqsave(&unaccepted_memory_lock, flags);
56 	for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap,
57 				   DIV_ROUND_UP(end, unit_size)) {
58 		unsigned long phys_start, phys_end;
59 		unsigned long len = range_end - range_start;
60 
61 		phys_start = range_start * unit_size + unaccepted->phys_base;
62 		phys_end = range_end * unit_size + unaccepted->phys_base;
63 
64 		arch_accept_memory(phys_start, phys_end);
65 		bitmap_clear(unaccepted->bitmap, range_start, len);
66 	}
67 	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
68 }
69 
70 bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end)
71 {
72 	struct efi_unaccepted_memory *unaccepted;
73 	unsigned long flags;
74 	bool ret = false;
75 	u64 unit_size;
76 
77 	unaccepted = efi_get_unaccepted_table();
78 	if (!unaccepted)
79 		return false;
80 
81 	unit_size = unaccepted->unit_size;
82 
83 	/*
84 	 * Only care for the part of the range that is represented
85 	 * in the bitmap.
86 	 */
87 	if (start < unaccepted->phys_base)
88 		start = unaccepted->phys_base;
89 	if (end < unaccepted->phys_base)
90 		return false;
91 
92 	/* Translate to offsets from the beginning of the bitmap */
93 	start -= unaccepted->phys_base;
94 	end -= unaccepted->phys_base;
95 
96 	/* Make sure not to overrun the bitmap */
97 	if (end > unaccepted->size * unit_size * BITS_PER_BYTE)
98 		end = unaccepted->size * unit_size * BITS_PER_BYTE;
99 
100 	spin_lock_irqsave(&unaccepted_memory_lock, flags);
101 	while (start < end) {
102 		if (test_bit(start / unit_size, unaccepted->bitmap)) {
103 			ret = true;
104 			break;
105 		}
106 
107 		start += unit_size;
108 	}
109 	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
110 
111 	return ret;
112 }
113