xref: /freebsd/sys/kern/subr_physmem.c (revision a521f2116473fbd8c09db395518f060a27d02334)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2014 Ian Lepore <ian@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_acpi.h"
33 #include "opt_ddb.h"
34 
35 /*
36  * Routines for describing and initializing anything related to physical memory.
37  */
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/physmem.h>
42 #include <vm/vm.h>
43 #include <vm/vm_param.h>
44 #include <vm/vm_page.h>
45 #include <vm/vm_phys.h>
46 #include <vm/vm_dumpset.h>
47 #include <machine/md_var.h>
48 
49 /*
50  * These structures are used internally to keep track of regions of physical
51  * ram, and regions within the physical ram that need to be excluded.  An
52  * exclusion region can be excluded from crash dumps, from the vm pool of pages
53  * that can be allocated, or both, depending on the exclusion flags associated
54  * with the region.
55  */
56 #ifdef DEV_ACPI
57 #define	MAX_HWCNT	32	/* ACPI needs more regions */
58 #define	MAX_EXCNT	32
59 #else
60 #define	MAX_HWCNT	16
61 #define	MAX_EXCNT	16
62 #endif
63 
64 #if defined(__arm__)
65 #define	MAX_PHYS_ADDR	0xFFFFFFFFull
66 #elif defined(__aarch64__) || defined(__riscv)
67 #define	MAX_PHYS_ADDR	0xFFFFFFFFFFFFFFFFull
68 #endif
69 
70 struct region {
71 	vm_paddr_t	addr;
72 	vm_size_t	size;
73 	uint32_t	flags;
74 };
75 
76 static struct region hwregions[MAX_HWCNT];
77 static struct region exregions[MAX_EXCNT];
78 
79 static size_t hwcnt;
80 static size_t excnt;
81 
82 /*
83  * realmem is the total number of hardware pages, excluded or not.
84  * Maxmem is one greater than the last physical page number.
85  */
86 long realmem;
87 long Maxmem;
88 
89 /*
90  * Print the contents of the physical and excluded region tables using the
91  * provided printf-like output function (which will be either printf or
92  * db_printf).
93  */
94 static void
95 physmem_dump_tables(int (*prfunc)(const char *, ...))
96 {
97 	int flags, i;
98 	uintmax_t addr, size;
99 	const unsigned int mbyte = 1024 * 1024;
100 
101 	prfunc("Physical memory chunk(s):\n");
102 	for (i = 0; i < hwcnt; ++i) {
103 		addr = hwregions[i].addr;
104 		size = hwregions[i].size;
105 		prfunc("  0x%08jx - 0x%08jx, %5ju MB (%7ju pages)\n", addr,
106 		    addr + size - 1, size / mbyte, size / PAGE_SIZE);
107 	}
108 
109 	prfunc("Excluded memory regions:\n");
110 	for (i = 0; i < excnt; ++i) {
111 		addr  = exregions[i].addr;
112 		size  = exregions[i].size;
113 		flags = exregions[i].flags;
114 		prfunc("  0x%08jx - 0x%08jx, %5ju MB (%7ju pages) %s %s\n",
115 		    addr, addr + size - 1, size / mbyte, size / PAGE_SIZE,
116 		    (flags & EXFLAG_NOALLOC) ? "NoAlloc" : "",
117 		    (flags & EXFLAG_NODUMP)  ? "NoDump" : "");
118 	}
119 
120 #ifdef DEBUG
121 	prfunc("Avail lists:\n");
122 	for (i = 0; phys_avail[i] != 0; ++i) {
123 		prfunc("  phys_avail[%d] 0x%08x\n", i, phys_avail[i]);
124 	}
125 	for (i = 0; dump_avail[i] != 0; ++i) {
126 		prfunc("  dump_avail[%d] 0x%08x\n", i, dump_avail[i]);
127 	}
128 #endif
129 }
130 
131 /*
132  * Print the contents of the static mapping table.  Used for bootverbose.
133  */
134 void
135 physmem_print_tables(void)
136 {
137 
138 	physmem_dump_tables(printf);
139 }
140 
141 /*
142  * Walk the list of hardware regions, processing it against the list of
143  * exclusions that contain the given exflags, and generating an "avail list".
144  *
145  * Updates the value at *pavail with the sum of all pages in all hw regions.
146  *
147  * Returns the number of pages of non-excluded memory added to the avail list.
148  */
149 static size_t
150 regions_to_avail(vm_paddr_t *avail, uint32_t exflags, size_t maxavail,
151     long *pavail, long *prealmem)
152 {
153 	size_t acnt, exi, hwi;
154 	uint64_t end, start, xend, xstart;
155 	long availmem, totalmem;
156 	const struct region *exp, *hwp;
157 
158 	totalmem = 0;
159 	availmem = 0;
160 	acnt = 0;
161 	for (hwi = 0, hwp = hwregions; hwi < hwcnt; ++hwi, ++hwp) {
162 		start = hwp->addr;
163 		end   = hwp->size + start;
164 		totalmem += atop((vm_offset_t)(end - start));
165 		for (exi = 0, exp = exregions; exi < excnt; ++exi, ++exp) {
166 			/*
167 			 * If the excluded region does not match given flags,
168 			 * continue checking with the next excluded region.
169 			 */
170 			if ((exp->flags & exflags) == 0)
171 				continue;
172 			xstart = exp->addr;
173 			xend   = exp->size + xstart;
174 			/*
175 			 * If the excluded region ends before this hw region,
176 			 * continue checking with the next excluded region.
177 			 */
178 			if (xend <= start)
179 				continue;
180 			/*
181 			 * If the excluded region begins after this hw region
182 			 * we're done because both lists are sorted.
183 			 */
184 			if (xstart >= end)
185 				break;
186 			/*
187 			 * If the excluded region completely covers this hw
188 			 * region, shrink this hw region to zero size.
189 			 */
190 			if ((start >= xstart) && (end <= xend)) {
191 				start = xend;
192 				end = xend;
193 				break;
194 			}
195 			/*
196 			 * If the excluded region falls wholly within this hw
197 			 * region without abutting or overlapping the beginning
198 			 * or end, create an available entry from the leading
199 			 * fragment, then adjust the start of this hw region to
200 			 * the end of the excluded region, and continue checking
201 			 * the next excluded region because another exclusion
202 			 * could affect the remainder of this hw region.
203 			 */
204 			if ((xstart > start) && (xend < end)) {
205 				if (acnt > 0 &&
206 				    avail[acnt - 1] == (vm_paddr_t)start) {
207 					avail[acnt - 1] = (vm_paddr_t)xstart;
208 				} else {
209 					avail[acnt++] = (vm_paddr_t)start;
210 					avail[acnt++] = (vm_paddr_t)xstart;
211 				}
212 				availmem += atop((vm_offset_t)(xstart - start));
213 				start = xend;
214 				continue;
215 			}
216 			/*
217 			 * We know the excluded region overlaps either the start
218 			 * or end of this hardware region (but not both), trim
219 			 * the excluded portion off the appropriate end.
220 			 */
221 			if (xstart <= start)
222 				start = xend;
223 			else
224 				end = xstart;
225 		}
226 		/*
227 		 * If the trimming actions above left a non-zero size, create an
228 		 * available entry for it.
229 		 */
230 		if (end > start) {
231 			if (acnt > 0 && avail[acnt - 1] == (vm_paddr_t)start) {
232 				avail[acnt - 1] = (vm_paddr_t)end;
233 			} else {
234 				avail[acnt++] = (vm_paddr_t)start;
235 				avail[acnt++] = (vm_paddr_t)end;
236 			}
237 			availmem += atop((vm_offset_t)(end - start));
238 		}
239 		if (acnt >= maxavail)
240 			panic("Not enough space in the dump/phys_avail arrays");
241 	}
242 
243 	if (pavail != NULL)
244 		*pavail = availmem;
245 	if (prealmem != NULL)
246 		*prealmem = totalmem;
247 	return (acnt);
248 }
249 
250 /*
251  * Insertion-sort a new entry into a regions list; sorted by start address.
252  */
253 static size_t
254 insert_region(struct region *regions, size_t rcnt, vm_paddr_t addr,
255     vm_size_t size, uint32_t flags)
256 {
257 	size_t i;
258 	struct region *ep, *rp;
259 
260 	ep = regions + rcnt;
261 	for (i = 0, rp = regions; i < rcnt; ++i, ++rp) {
262 		if (rp->addr == addr && rp->size == size) /* Pure dup. */
263 			return (rcnt);
264 		if (flags == rp->flags) {
265 			if (addr + size == rp->addr) {
266 				rp->addr = addr;
267 				rp->size += size;
268 				return (rcnt);
269 			} else if (rp->addr + rp->size == addr) {
270 				rp->size += size;
271 				return (rcnt);
272 			}
273 		}
274 		if (addr < rp->addr) {
275 			bcopy(rp, rp + 1, (ep - rp) * sizeof(*rp));
276 			break;
277 		}
278 	}
279 	rp->addr  = addr;
280 	rp->size  = size;
281 	rp->flags = flags;
282 	rcnt++;
283 
284 	return (rcnt);
285 }
286 
287 /*
288  * Add a hardware memory region.
289  */
290 void
291 physmem_hardware_region(uint64_t pa, uint64_t sz)
292 {
293 	vm_offset_t adj;
294 
295 	/*
296 	 * Filter out the page at PA 0x00000000.  The VM can't handle it, as
297 	 * pmap_extract() == 0 means failure.
298 	 */
299 	if (pa == 0) {
300 		if (sz <= PAGE_SIZE)
301 			return;
302 		pa  = PAGE_SIZE;
303 		sz -= PAGE_SIZE;
304 	} else if (pa > MAX_PHYS_ADDR) {
305 		/* This range is past usable memory, ignore it */
306 		return;
307 	}
308 
309 	/*
310 	 * Also filter out the page at the end of the physical address space --
311 	 * if addr is non-zero and addr+size is zero we wrapped to the next byte
312 	 * beyond what vm_paddr_t can express.  That leads to a NULL pointer
313 	 * deref early in startup; work around it by leaving the last page out.
314 	 *
315 	 * XXX This just in:  subtract out a whole megabyte, not just 1 page.
316 	 * Reducing the size by anything less than 1MB results in the NULL
317 	 * pointer deref in _vm_map_lock_read().  Better to give up a megabyte
318 	 * than leave some folks with an unusable system while we investigate.
319 	 */
320 	if ((pa + sz) > (MAX_PHYS_ADDR - 1024 * 1024)) {
321 		sz = MAX_PHYS_ADDR - pa + 1;
322 		if (sz <= 1024 * 1024)
323 			return;
324 		sz -= 1024 * 1024;
325 	}
326 
327 	/*
328 	 * Round the starting address up to a page boundary, and truncate the
329 	 * ending page down to a page boundary.
330 	 */
331 	adj = round_page(pa) - pa;
332 	pa  = round_page(pa);
333 	sz  = trunc_page(sz - adj);
334 
335 	if (sz > 0 && hwcnt < nitems(hwregions))
336 		hwcnt = insert_region(hwregions, hwcnt, pa, sz, 0);
337 }
338 
339 /*
340  * Add an exclusion region.
341  */
342 void
343 physmem_exclude_region(vm_paddr_t pa, vm_size_t sz, uint32_t exflags)
344 {
345 	vm_offset_t adj;
346 
347 	/*
348 	 * Truncate the starting address down to a page boundary, and round the
349 	 * ending page up to a page boundary.
350 	 */
351 	adj = pa - trunc_page(pa);
352 	pa  = trunc_page(pa);
353 	sz  = round_page(sz + adj);
354 
355 	if (excnt >= nitems(exregions))
356 		panic("failed to exclude region %#jx-%#jx", (uintmax_t)pa,
357 		    (uintmax_t)(pa + sz));
358 	excnt = insert_region(exregions, excnt, pa, sz, exflags);
359 }
360 
361 size_t
362 physmem_avail(vm_paddr_t *avail, size_t maxavail)
363 {
364 
365 	return (regions_to_avail(avail, EXFLAG_NOALLOC, maxavail, NULL, NULL));
366 }
367 
368 /*
369  * Process all the regions added earlier into the global avail lists.
370  *
371  * Updates the kernel global 'physmem' with the number of physical pages
372  * available for use (all pages not in any exclusion region).
373  *
374  * Updates the kernel global 'Maxmem' with the page number one greater then the
375  * last page of physical memory in the system.
376  */
377 void
378 physmem_init_kernel_globals(void)
379 {
380 	size_t nextidx;
381 
382 	regions_to_avail(dump_avail, EXFLAG_NODUMP, PHYS_AVAIL_ENTRIES, NULL,
383 	    NULL);
384 	nextidx = regions_to_avail(phys_avail, EXFLAG_NOALLOC,
385 	    PHYS_AVAIL_ENTRIES, &physmem, &realmem);
386 	if (nextidx == 0)
387 		panic("No memory entries in phys_avail");
388 	Maxmem = atop(phys_avail[nextidx - 1]);
389 }
390 
391 #ifdef DDB
392 #include <ddb/ddb.h>
393 
394 DB_SHOW_COMMAND(physmem, db_show_physmem)
395 {
396 
397 	physmem_dump_tables(db_printf);
398 }
399 
400 #endif /* DDB */
401