1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Memory subsystem initialization for Hexagon
4 *
5 * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
6 */
7
8#include <linux/init.h>
9#include <linux/mm.h>
10#include <linux/memblock.h>
11#include <asm/atomic.h>
12#include <linux/highmem.h>
13#include <asm/tlb.h>
14#include <asm/sections.h>
15#include <asm/setup.h>
16#include <asm/vm_mmu.h>
17
18/*
19 * Define a startpg just past the end of the kernel image and a lastpg
20 * that corresponds to the end of real or simulated platform memory.
21 */
22#define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
23
24unsigned long bootmem_lastpg; /* Should be set by platform code */
25unsigned long __phys_offset; /* physical kernel offset >> 12 */
26
27/* Set as variable to limit PMD copies */
28int max_kernel_seg = 0x303;
29
30/* indicate pfn's of high memory */
31unsigned long highstart_pfn, highend_pfn;
32
33/* Default cache attribute for newly created page tables */
34unsigned long _dflt_cache_att = CACHEDEF;
35
36/*
37 * The current "generation" of kernel map, which should not roll
38 * over until Hell freezes over. Actual bound in years needs to be
39 * calculated to confirm.
40 */
41DEFINE_SPINLOCK(kmap_gen_lock);
42
43/* checkpatch says don't init this to 0. */
44unsigned long long kmap_generation;
45
46void sync_icache_dcache(pte_t pte)
47{
48 unsigned long addr;
49 struct page *page;
50
51 page = pte_page(pte);
52 addr = (unsigned long) page_address(page);
53
54 __vmcache_idsync(addr, PAGE_SIZE);
55}
56
57/*
58 * In order to set up page allocator "nodes",
59 * somebody has to call free_area_init() for UMA.
60 *
61 * In this mode, we only have one pg_data_t
62 * structure: contig_mem_data.
63 */
64static void __init paging_init(void)
65{
66 unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, };
67
68 /*
69 * This is not particularly well documented anywhere, but
70 * give ZONE_NORMAL all the memory, including the big holes
71 * left by the kernel+bootmem_map which are already left as reserved
72 * in the bootmem_map; free_area_init should see those bits and
73 * adjust accordingly.
74 */
75
76 max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
77
78 free_area_init(max_zone_pfn); /* sets up the zonelists and mem_map */
79
80 /*
81 * Set the init_mm descriptors "context" value to point to the
82 * initial kernel segment table's physical address.
83 */
84 init_mm.context.ptbase = __pa(init_mm.pgd);
85}
86
87#ifndef DMA_RESERVE
88#define DMA_RESERVE (4)
89#endif
90
91#define DMA_CHUNKSIZE (1<<22)
92#define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
93
94/*
95 * Pick out the memory size. We look for mem=size,
96 * where size is "size[KkMm]"
97 */
98static int __init early_mem(char *p)
99{
100 unsigned long size;
101 char *endp;
102
103 size = memparse(ptr: p, retptr: &endp);
104
105 bootmem_lastpg = PFN_DOWN(size);
106
107 return 0;
108}
109early_param("mem", early_mem);
110
111size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
112
113void __init setup_arch_memory(void)
114{
115 /* XXX Todo: this probably should be cleaned up */
116 u32 *segtable = (u32 *) &swapper_pg_dir[0];
117 u32 *segtable_end;
118
119 /*
120 * Set up boot memory allocator
121 *
122 * The Gorman book also talks about these functions.
123 * This needs to change for highmem setups.
124 */
125
126 /* Prior to this, bootmem_lastpg is actually mem size */
127 bootmem_lastpg += ARCH_PFN_OFFSET;
128
129 /* Memory size needs to be a multiple of 16M */
130 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
131 ~((BIG_KERNEL_PAGE_SIZE) - 1));
132
133 memblock_add(PHYS_OFFSET,
134 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
135
136 /* Reserve kernel text/data/bss */
137 memblock_reserve(PHYS_OFFSET,
138 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
139 /*
140 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
141 * memory allocation
142 */
143 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
144 min_low_pfn = ARCH_PFN_OFFSET;
145 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
146
147 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
148 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
149 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn);
150 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);
151
152 /*
153 * The default VM page tables (will be) populated with
154 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
155 * higher than what we have memory for.
156 */
157
158 /* this is pointer arithmetic; each entry covers 4MB */
159 segtable = segtable + (PAGE_OFFSET >> 22);
160
161 /* this actually only goes to the end of the first gig */
162 segtable_end = segtable + (1<<(30-22));
163
164 /*
165 * Move forward to the start of empty pages; take into account
166 * phys_offset shift.
167 */
168
169 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
170 {
171 int i;
172
173 for (i = 1 ; i <= DMA_RESERVE ; i++)
174 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
175 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
176 | __HEXAGON_C_UNC << 6
177 | __HVM_PDE_S_4MB);
178 }
179
180 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
181 segtable_end);
182 while (segtable < (segtable_end-8))
183 *(segtable++) = __HVM_PDE_S_INVALID;
184 /* stop the pointer at the device I/O 4MB page */
185
186 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
187 segtable);
188
189#if 0
190 /* Other half of the early device table from vm_init_segtable. */
191 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
192 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
193 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
194 __HVM_PDE_S_4KB;
195 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
196#endif
197
198 /*
199 * The bootmem allocator seemingly just lives to feed memory
200 * to the paging system
201 */
202 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
203 paging_init(); /* See Gorman Book, 2.3 */
204
205 /*
206 * At this point, the page allocator is kind of initialized, but
207 * apparently no pages are available (just like with the bootmem
208 * allocator), and need to be freed themselves via mem_init(),
209 * which is called by start_kernel() later on in the process
210 */
211}
212
213static const pgprot_t protection_map[16] = {
214 [VM_NONE] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
215 CACHEDEF),
216 [VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
217 _PAGE_READ | CACHEDEF),
218 [VM_WRITE] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
219 CACHEDEF),
220 [VM_WRITE | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
221 _PAGE_READ | CACHEDEF),
222 [VM_EXEC] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
223 _PAGE_EXECUTE | CACHEDEF),
224 [VM_EXEC | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
225 _PAGE_EXECUTE | _PAGE_READ |
226 CACHEDEF),
227 [VM_EXEC | VM_WRITE] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
228 _PAGE_EXECUTE | CACHEDEF),
229 [VM_EXEC | VM_WRITE | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
230 _PAGE_EXECUTE | _PAGE_READ |
231 CACHEDEF),
232 [VM_SHARED] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
233 CACHEDEF),
234 [VM_SHARED | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
235 _PAGE_READ | CACHEDEF),
236 [VM_SHARED | VM_WRITE] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
237 _PAGE_WRITE | CACHEDEF),
238 [VM_SHARED | VM_WRITE | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
239 _PAGE_READ | _PAGE_WRITE |
240 CACHEDEF),
241 [VM_SHARED | VM_EXEC] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
242 _PAGE_EXECUTE | CACHEDEF),
243 [VM_SHARED | VM_EXEC | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
244 _PAGE_EXECUTE | _PAGE_READ |
245 CACHEDEF),
246 [VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
247 _PAGE_EXECUTE | _PAGE_WRITE |
248 CACHEDEF),
249 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(_PAGE_PRESENT | _PAGE_USER |
250 _PAGE_READ | _PAGE_EXECUTE |
251 _PAGE_WRITE | CACHEDEF)
252};
253DECLARE_VM_GET_PAGE_PROT
254

source code of linux/arch/hexagon/mm/init.c