1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Common EFI memory map functions.
4  */
5 
6 #define pr_fmt(fmt) "efi: " fmt
7 
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/efi.h>
11 #include <linux/io.h>
12 #include <asm/early_ioremap.h>
13 #include <asm/efi.h>
14 #include <linux/memblock.h>
15 #include <linux/slab.h>
16 
__efi_memmap_alloc_early(unsigned long size)17 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
18 {
19 	return memblock_phys_alloc(size, SMP_CACHE_BYTES);
20 }
21 
__efi_memmap_alloc_late(unsigned long size)22 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
23 {
24 	unsigned int order = get_order(size);
25 	struct page *p = alloc_pages(GFP_KERNEL, order);
26 
27 	if (!p)
28 		return 0;
29 
30 	return PFN_PHYS(page_to_pfn(p));
31 }
32 
__efi_memmap_free(u64 phys,unsigned long size,unsigned long flags)33 void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
34 {
35 	if (flags & EFI_MEMMAP_MEMBLOCK) {
36 		if (slab_is_available())
37 			memblock_free_late(phys, size);
38 		else
39 			memblock_phys_free(phys, size);
40 	} else if (flags & EFI_MEMMAP_SLAB) {
41 		struct page *p = pfn_to_page(PHYS_PFN(phys));
42 		unsigned int order = get_order(size);
43 
44 		free_pages((unsigned long) page_address(p), order);
45 	}
46 }
47 
48 /**
49  * efi_memmap_alloc - Allocate memory for the EFI memory map
50  * @num_entries: Number of entries in the allocated map.
51  * @data: efi memmap installation parameters
52  *
53  * Depending on whether mm_init() has already been invoked or not,
54  * either memblock or "normal" page allocation is used.
55  *
56  * Returns zero on success, a negative error code on failure.
57  */
efi_memmap_alloc(unsigned int num_entries,struct efi_memory_map_data * data)58 int __init efi_memmap_alloc(unsigned int num_entries,
59 		struct efi_memory_map_data *data)
60 {
61 	/* Expect allocation parameters are zero initialized */
62 	WARN_ON(data->phys_map || data->size);
63 
64 	data->size = num_entries * efi.memmap.desc_size;
65 	data->desc_version = efi.memmap.desc_version;
66 	data->desc_size = efi.memmap.desc_size;
67 	data->flags &= ~(EFI_MEMMAP_SLAB | EFI_MEMMAP_MEMBLOCK);
68 	data->flags |= efi.memmap.flags & EFI_MEMMAP_LATE;
69 
70 	if (slab_is_available()) {
71 		data->flags |= EFI_MEMMAP_SLAB;
72 		data->phys_map = __efi_memmap_alloc_late(data->size);
73 	} else {
74 		data->flags |= EFI_MEMMAP_MEMBLOCK;
75 		data->phys_map = __efi_memmap_alloc_early(data->size);
76 	}
77 
78 	if (!data->phys_map)
79 		return -ENOMEM;
80 	return 0;
81 }
82 
83 /**
84  * efi_memmap_install - Install a new EFI memory map in efi.memmap
85  * @data: efi memmap installation parameters
86  *
87  * Unlike efi_memmap_init_*(), this function does not allow the caller
88  * to switch from early to late mappings. It simply uses the existing
89  * mapping function and installs the new memmap.
90  *
91  * Returns zero on success, a negative error code on failure.
92  */
efi_memmap_install(struct efi_memory_map_data * data)93 int __init efi_memmap_install(struct efi_memory_map_data *data)
94 {
95 	efi_memmap_unmap();
96 
97 	if (efi_enabled(EFI_PARAVIRT))
98 		return 0;
99 
100 	return __efi_memmap_init(data);
101 }
102 
103 /**
104  * efi_memmap_split_count - Count number of additional EFI memmap entries
105  * @md: EFI memory descriptor to split
106  * @range: Address range (start, end) to split around
107  *
108  * Returns the number of additional EFI memmap entries required to
109  * accommodate @range.
110  */
efi_memmap_split_count(efi_memory_desc_t * md,struct range * range)111 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
112 {
113 	u64 m_start, m_end;
114 	u64 start, end;
115 	int count = 0;
116 
117 	start = md->phys_addr;
118 	end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
119 
120 	/* modifying range */
121 	m_start = range->start;
122 	m_end = range->end;
123 
124 	if (m_start <= start) {
125 		/* split into 2 parts */
126 		if (start < m_end && m_end < end)
127 			count++;
128 	}
129 
130 	if (start < m_start && m_start < end) {
131 		/* split into 3 parts */
132 		if (m_end < end)
133 			count += 2;
134 		/* split into 2 parts */
135 		if (end <= m_end)
136 			count++;
137 	}
138 
139 	return count;
140 }
141 
142 /**
143  * efi_memmap_insert - Insert a memory region in an EFI memmap
144  * @old_memmap: The existing EFI memory map structure
145  * @buf: Address of buffer to store new map
146  * @mem: Memory map entry to insert
147  *
148  * It is suggested that you call efi_memmap_split_count() first
149  * to see how large @buf needs to be.
150  */
efi_memmap_insert(struct efi_memory_map * old_memmap,void * buf,struct efi_mem_range * mem)151 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
152 			      struct efi_mem_range *mem)
153 {
154 	u64 m_start, m_end, m_attr;
155 	efi_memory_desc_t *md;
156 	u64 start, end;
157 	void *old, *new;
158 
159 	/* modifying range */
160 	m_start = mem->range.start;
161 	m_end = mem->range.end;
162 	m_attr = mem->attribute;
163 
164 	/*
165 	 * The EFI memory map deals with regions in EFI_PAGE_SIZE
166 	 * units. Ensure that the region described by 'mem' is aligned
167 	 * correctly.
168 	 */
169 	if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
170 	    !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
171 		WARN_ON(1);
172 		return;
173 	}
174 
175 	for (old = old_memmap->map, new = buf;
176 	     old < old_memmap->map_end;
177 	     old += old_memmap->desc_size, new += old_memmap->desc_size) {
178 
179 		/* copy original EFI memory descriptor */
180 		memcpy(new, old, old_memmap->desc_size);
181 		md = new;
182 		start = md->phys_addr;
183 		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
184 
185 		if (m_start <= start && end <= m_end)
186 			md->attribute |= m_attr;
187 
188 		if (m_start <= start &&
189 		    (start < m_end && m_end < end)) {
190 			/* first part */
191 			md->attribute |= m_attr;
192 			md->num_pages = (m_end - md->phys_addr + 1) >>
193 				EFI_PAGE_SHIFT;
194 			/* latter part */
195 			new += old_memmap->desc_size;
196 			memcpy(new, old, old_memmap->desc_size);
197 			md = new;
198 			md->phys_addr = m_end + 1;
199 			md->num_pages = (end - md->phys_addr + 1) >>
200 				EFI_PAGE_SHIFT;
201 		}
202 
203 		if ((start < m_start && m_start < end) && m_end < end) {
204 			/* first part */
205 			md->num_pages = (m_start - md->phys_addr) >>
206 				EFI_PAGE_SHIFT;
207 			/* middle part */
208 			new += old_memmap->desc_size;
209 			memcpy(new, old, old_memmap->desc_size);
210 			md = new;
211 			md->attribute |= m_attr;
212 			md->phys_addr = m_start;
213 			md->num_pages = (m_end - m_start + 1) >>
214 				EFI_PAGE_SHIFT;
215 			/* last part */
216 			new += old_memmap->desc_size;
217 			memcpy(new, old, old_memmap->desc_size);
218 			md = new;
219 			md->phys_addr = m_end + 1;
220 			md->num_pages = (end - m_end) >>
221 				EFI_PAGE_SHIFT;
222 		}
223 
224 		if ((start < m_start && m_start < end) &&
225 		    (end <= m_end)) {
226 			/* first part */
227 			md->num_pages = (m_start - md->phys_addr) >>
228 				EFI_PAGE_SHIFT;
229 			/* latter part */
230 			new += old_memmap->desc_size;
231 			memcpy(new, old, old_memmap->desc_size);
232 			md = new;
233 			md->phys_addr = m_start;
234 			md->num_pages = (end - md->phys_addr + 1) >>
235 				EFI_PAGE_SHIFT;
236 			md->attribute |= m_attr;
237 		}
238 	}
239 }
240