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