memmap.c

  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
 17static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
 18{
 19	return memblock_phys_alloc(size, SMP_CACHE_BYTES);
 20}
 21
 22static 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
 33static
 34void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
 35{
 36	if (flags & EFI_MEMMAP_MEMBLOCK) {
 37		if (slab_is_available())
 38			memblock_free_late(phys, size);
 39		else
 40			memblock_phys_free(phys, size);
 41	} else if (flags & EFI_MEMMAP_SLAB) {
 42		struct page *p = pfn_to_page(PHYS_PFN(phys));
 43		unsigned int order = get_order(size);
 44
 45		__free_pages(p, order);
 46	}
 47}
 48
 49/**
 50 * efi_memmap_alloc - Allocate memory for the EFI memory map
 51 * @num_entries: Number of entries in the allocated map.
 52 * @data: efi memmap installation parameters
 53 *
 54 * Depending on whether mm_init() has already been invoked or not,
 55 * either memblock or "normal" page allocation is used.
 56 *
 57 * Returns zero on success, a negative error code on failure.
 58 */
 59int __init efi_memmap_alloc(unsigned int num_entries,
 60		struct efi_memory_map_data *data)
 61{
 62	/* Expect allocation parameters are zero initialized */
 63	WARN_ON(data->phys_map || data->size);
 64
 65	data->size = num_entries * efi.memmap.desc_size;
 66	data->desc_version = efi.memmap.desc_version;
 67	data->desc_size = efi.memmap.desc_size;
 68	data->flags &= ~(EFI_MEMMAP_SLAB | EFI_MEMMAP_MEMBLOCK);
 69	data->flags |= efi.memmap.flags & EFI_MEMMAP_LATE;
 70
 71	if (slab_is_available()) {
 72		data->flags |= EFI_MEMMAP_SLAB;
 73		data->phys_map = __efi_memmap_alloc_late(data->size);
 74	} else {
 75		data->flags |= EFI_MEMMAP_MEMBLOCK;
 76		data->phys_map = __efi_memmap_alloc_early(data->size);
 77	}
 78
 79	if (!data->phys_map)
 80		return -ENOMEM;
 81	return 0;
 82}
 83
 84/**
 85 * efi_memmap_install - Install a new EFI memory map in efi.memmap
 86 * @data: efi memmap installation parameters
 87 *
 88 * Unlike efi_memmap_init_*(), this function does not allow the caller
 89 * to switch from early to late mappings. It simply uses the existing
 90 * mapping function and installs the new memmap.
 91 *
 92 * Returns zero on success, a negative error code on failure.
 93 */
 94int __init efi_memmap_install(struct efi_memory_map_data *data)
 95{
 96	unsigned long size = efi.memmap.desc_size * efi.memmap.nr_map;
 97	unsigned long flags = efi.memmap.flags;
 98	u64 phys = efi.memmap.phys_map;
 99	int ret;
100
101	efi_memmap_unmap();
102
103	if (efi_enabled(EFI_PARAVIRT))
104		return 0;
105
106	ret = __efi_memmap_init(data);
107	if (ret)
108		return ret;
109
110	__efi_memmap_free(phys, size, flags);
111	return 0;
112}
113
114/**
115 * efi_memmap_split_count - Count number of additional EFI memmap entries
116 * @md: EFI memory descriptor to split
117 * @range: Address range (start, end) to split around
118 *
119 * Returns the number of additional EFI memmap entries required to
120 * accommodate @range.
121 */
122int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
123{
124	u64 m_start, m_end;
125	u64 start, end;
126	int count = 0;
127
128	start = md->phys_addr;
129	end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
130
131	/* modifying range */
132	m_start = range->start;
133	m_end = range->end;
134
135	if (m_start <= start) {
136		/* split into 2 parts */
137		if (start < m_end && m_end < end)
138			count++;
139	}
140
141	if (start < m_start && m_start < end) {
142		/* split into 3 parts */
143		if (m_end < end)
144			count += 2;
145		/* split into 2 parts */
146		if (end <= m_end)
147			count++;
148	}
149
150	return count;
151}
152
153/**
154 * efi_memmap_insert - Insert a memory region in an EFI memmap
155 * @old_memmap: The existing EFI memory map structure
156 * @buf: Address of buffer to store new map
157 * @mem: Memory map entry to insert
158 *
159 * It is suggested that you call efi_memmap_split_count() first
160 * to see how large @buf needs to be.
161 */
162void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
163			      struct efi_mem_range *mem)
164{
165	u64 m_start, m_end, m_attr;
166	efi_memory_desc_t *md;
167	u64 start, end;
168	void *old, *new;
169
170	/* modifying range */
171	m_start = mem->range.start;
172	m_end = mem->range.end;
173	m_attr = mem->attribute;
174
175	/*
176	 * The EFI memory map deals with regions in EFI_PAGE_SIZE
177	 * units. Ensure that the region described by 'mem' is aligned
178	 * correctly.
179	 */
180	if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
181	    !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
182		WARN_ON(1);
183		return;
184	}
185
186	for (old = old_memmap->map, new = buf;
187	     old < old_memmap->map_end;
188	     old += old_memmap->desc_size, new += old_memmap->desc_size) {
189
190		/* copy original EFI memory descriptor */
191		memcpy(new, old, old_memmap->desc_size);
192		md = new;
193		start = md->phys_addr;
194		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
195
196		if (m_start <= start && end <= m_end)
197			md->attribute |= m_attr;
198
199		if (m_start <= start &&
200		    (start < m_end && m_end < end)) {
201			/* first part */
202			md->attribute |= m_attr;
203			md->num_pages = (m_end - md->phys_addr + 1) >>
204				EFI_PAGE_SHIFT;
205			/* latter part */
206			new += old_memmap->desc_size;
207			memcpy(new, old, old_memmap->desc_size);
208			md = new;
209			md->phys_addr = m_end + 1;
210			md->num_pages = (end - md->phys_addr + 1) >>
211				EFI_PAGE_SHIFT;
212		}
213
214		if ((start < m_start && m_start < end) && m_end < end) {
215			/* first part */
216			md->num_pages = (m_start - md->phys_addr) >>
217				EFI_PAGE_SHIFT;
218			/* middle part */
219			new += old_memmap->desc_size;
220			memcpy(new, old, old_memmap->desc_size);
221			md = new;
222			md->attribute |= m_attr;
223			md->phys_addr = m_start;
224			md->num_pages = (m_end - m_start + 1) >>
225				EFI_PAGE_SHIFT;
226			/* last part */
227			new += old_memmap->desc_size;
228			memcpy(new, old, old_memmap->desc_size);
229			md = new;
230			md->phys_addr = m_end + 1;
231			md->num_pages = (end - m_end) >>
232				EFI_PAGE_SHIFT;
233		}
234
235		if ((start < m_start && m_start < end) &&
236		    (end <= m_end)) {
237			/* first part */
238			md->num_pages = (m_start - md->phys_addr) >>
239				EFI_PAGE_SHIFT;
240			/* latter part */
241			new += old_memmap->desc_size;
242			memcpy(new, old, old_memmap->desc_size);
243			md = new;
244			md->phys_addr = m_start;
245			md->num_pages = (end - md->phys_addr + 1) >>
246				EFI_PAGE_SHIFT;
247			md->attribute |= m_attr;
248		}
249	}
250}