Root/kernel/early_res.c

1/*
2 * early_res, could be used to replace bootmem
3 */
4#include <linux/kernel.h>
5#include <linux/types.h>
6#include <linux/init.h>
7#include <linux/bootmem.h>
8#include <linux/mm.h>
9#include <linux/early_res.h>
10
11/*
12 * Early reserved memory areas.
13 */
14/*
15 * need to make sure this one is bigger enough before
16 * find_fw_memmap_area could be used
17 */
18#define MAX_EARLY_RES_X 32
19
20struct early_res {
21    u64 start, end;
22    char name[15];
23    char overlap_ok;
24};
25static struct early_res early_res_x[MAX_EARLY_RES_X] __initdata;
26
27static int max_early_res __initdata = MAX_EARLY_RES_X;
28static struct early_res *early_res __initdata = &early_res_x[0];
29static int early_res_count __initdata;
30
31static int __init find_overlapped_early(u64 start, u64 end)
32{
33    int i;
34    struct early_res *r;
35
36    for (i = 0; i < max_early_res && early_res[i].end; i++) {
37        r = &early_res[i];
38        if (end > r->start && start < r->end)
39            break;
40    }
41
42    return i;
43}
44
45/*
46 * Drop the i-th range from the early reservation map,
47 * by copying any higher ranges down one over it, and
48 * clearing what had been the last slot.
49 */
50static void __init drop_range(int i)
51{
52    int j;
53
54    for (j = i + 1; j < max_early_res && early_res[j].end; j++)
55        ;
56
57    memmove(&early_res[i], &early_res[i + 1],
58           (j - 1 - i) * sizeof(struct early_res));
59
60    early_res[j - 1].end = 0;
61    early_res_count--;
62}
63
64static void __init drop_range_partial(int i, u64 start, u64 end)
65{
66    u64 common_start, common_end;
67    u64 old_start, old_end;
68
69    old_start = early_res[i].start;
70    old_end = early_res[i].end;
71    common_start = max(old_start, start);
72    common_end = min(old_end, end);
73
74    /* no overlap ? */
75    if (common_start >= common_end)
76        return;
77
78    if (old_start < common_start) {
79        /* make head segment */
80        early_res[i].end = common_start;
81        if (old_end > common_end) {
82            char name[15];
83
84            /*
85             * Save a local copy of the name, since the
86             * early_res array could get resized inside
87             * reserve_early_without_check() ->
88             * __check_and_double_early_res(), which would
89             * make the current name pointer invalid.
90             */
91            strncpy(name, early_res[i].name,
92                     sizeof(early_res[i].name) - 1);
93            /* add another for left over on tail */
94            reserve_early_without_check(common_end, old_end, name);
95        }
96        return;
97    } else {
98        if (old_end > common_end) {
99            /* reuse the entry for tail left */
100            early_res[i].start = common_end;
101            return;
102        }
103        /* all covered */
104        drop_range(i);
105    }
106}
107
108/*
109 * Split any existing ranges that:
110 * 1) are marked 'overlap_ok', and
111 * 2) overlap with the stated range [start, end)
112 * into whatever portion (if any) of the existing range is entirely
113 * below or entirely above the stated range. Drop the portion
114 * of the existing range that overlaps with the stated range,
115 * which will allow the caller of this routine to then add that
116 * stated range without conflicting with any existing range.
117 */
118static void __init drop_overlaps_that_are_ok(u64 start, u64 end)
119{
120    int i;
121    struct early_res *r;
122    u64 lower_start, lower_end;
123    u64 upper_start, upper_end;
124    char name[15];
125
126    for (i = 0; i < max_early_res && early_res[i].end; i++) {
127        r = &early_res[i];
128
129        /* Continue past non-overlapping ranges */
130        if (end <= r->start || start >= r->end)
131            continue;
132
133        /*
134         * Leave non-ok overlaps as is; let caller
135         * panic "Overlapping early reservations"
136         * when it hits this overlap.
137         */
138        if (!r->overlap_ok)
139            return;
140
141        /*
142         * We have an ok overlap. We will drop it from the early
143         * reservation map, and add back in any non-overlapping
144         * portions (lower or upper) as separate, overlap_ok,
145         * non-overlapping ranges.
146         */
147
148        /* 1. Note any non-overlapping (lower or upper) ranges. */
149        strncpy(name, r->name, sizeof(name) - 1);
150
151        lower_start = lower_end = 0;
152        upper_start = upper_end = 0;
153        if (r->start < start) {
154            lower_start = r->start;
155            lower_end = start;
156        }
157        if (r->end > end) {
158            upper_start = end;
159            upper_end = r->end;
160        }
161
162        /* 2. Drop the original ok overlapping range */
163        drop_range(i);
164
165        i--; /* resume for-loop on copied down entry */
166
167        /* 3. Add back in any non-overlapping ranges. */
168        if (lower_end)
169            reserve_early_overlap_ok(lower_start, lower_end, name);
170        if (upper_end)
171            reserve_early_overlap_ok(upper_start, upper_end, name);
172    }
173}
174
175static void __init __reserve_early(u64 start, u64 end, char *name,
176                        int overlap_ok)
177{
178    int i;
179    struct early_res *r;
180
181    i = find_overlapped_early(start, end);
182    if (i >= max_early_res)
183        panic("Too many early reservations");
184    r = &early_res[i];
185    if (r->end)
186        panic("Overlapping early reservations "
187              "%llx-%llx %s to %llx-%llx %s\n",
188              start, end - 1, name ? name : "", r->start,
189              r->end - 1, r->name);
190    r->start = start;
191    r->end = end;
192    r->overlap_ok = overlap_ok;
193    if (name)
194        strncpy(r->name, name, sizeof(r->name) - 1);
195    early_res_count++;
196}
197
198/*
199 * A few early reservtations come here.
200 *
201 * The 'overlap_ok' in the name of this routine does -not- mean it
202 * is ok for these reservations to overlap an earlier reservation.
203 * Rather it means that it is ok for subsequent reservations to
204 * overlap this one.
205 *
206 * Use this entry point to reserve early ranges when you are doing
207 * so out of "Paranoia", reserving perhaps more memory than you need,
208 * just in case, and don't mind a subsequent overlapping reservation
209 * that is known to be needed.
210 *
211 * The drop_overlaps_that_are_ok() call here isn't really needed.
212 * It would be needed if we had two colliding 'overlap_ok'
213 * reservations, so that the second such would not panic on the
214 * overlap with the first. We don't have any such as of this
215 * writing, but might as well tolerate such if it happens in
216 * the future.
217 */
218void __init reserve_early_overlap_ok(u64 start, u64 end, char *name)
219{
220    drop_overlaps_that_are_ok(start, end);
221    __reserve_early(start, end, name, 1);
222}
223
224static void __init __check_and_double_early_res(u64 ex_start, u64 ex_end)
225{
226    u64 start, end, size, mem;
227    struct early_res *new;
228
229    /* do we have enough slots left ? */
230    if ((max_early_res - early_res_count) > max(max_early_res/8, 2))
231        return;
232
233    /* double it */
234    mem = -1ULL;
235    size = sizeof(struct early_res) * max_early_res * 2;
236    if (early_res == early_res_x)
237        start = 0;
238    else
239        start = early_res[0].end;
240    end = ex_start;
241    if (start + size < end)
242        mem = find_fw_memmap_area(start, end, size,
243                     sizeof(struct early_res));
244    if (mem == -1ULL) {
245        start = ex_end;
246        end = get_max_mapped();
247        if (start + size < end)
248            mem = find_fw_memmap_area(start, end, size,
249                         sizeof(struct early_res));
250    }
251    if (mem == -1ULL)
252        panic("can not find more space for early_res array");
253
254    new = __va(mem);
255    /* save the first one for own */
256    new[0].start = mem;
257    new[0].end = mem + size;
258    new[0].overlap_ok = 0;
259    /* copy old to new */
260    if (early_res == early_res_x) {
261        memcpy(&new[1], &early_res[0],
262             sizeof(struct early_res) * max_early_res);
263        memset(&new[max_early_res+1], 0,
264             sizeof(struct early_res) * (max_early_res - 1));
265        early_res_count++;
266    } else {
267        memcpy(&new[1], &early_res[1],
268             sizeof(struct early_res) * (max_early_res - 1));
269        memset(&new[max_early_res], 0,
270             sizeof(struct early_res) * max_early_res);
271    }
272    memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
273    early_res = new;
274    max_early_res *= 2;
275    printk(KERN_DEBUG "early_res array is doubled to %d at [%llx - %llx]\n",
276        max_early_res, mem, mem + size - 1);
277}
278
279/*
280 * Most early reservations come here.
281 *
282 * We first have drop_overlaps_that_are_ok() drop any pre-existing
283 * 'overlap_ok' ranges, so that we can then reserve this memory
284 * range without risk of panic'ing on an overlapping overlap_ok
285 * early reservation.
286 */
287void __init reserve_early(u64 start, u64 end, char *name)
288{
289    if (start >= end)
290        return;
291
292    __check_and_double_early_res(start, end);
293
294    drop_overlaps_that_are_ok(start, end);
295    __reserve_early(start, end, name, 0);
296}
297
298void __init reserve_early_without_check(u64 start, u64 end, char *name)
299{
300    struct early_res *r;
301
302    if (start >= end)
303        return;
304
305    __check_and_double_early_res(start, end);
306
307    r = &early_res[early_res_count];
308
309    r->start = start;
310    r->end = end;
311    r->overlap_ok = 0;
312    if (name)
313        strncpy(r->name, name, sizeof(r->name) - 1);
314    early_res_count++;
315}
316
317void __init free_early(u64 start, u64 end)
318{
319    struct early_res *r;
320    int i;
321
322    i = find_overlapped_early(start, end);
323    r = &early_res[i];
324    if (i >= max_early_res || r->end != end || r->start != start)
325        panic("free_early on not reserved area: %llx-%llx!",
326             start, end - 1);
327
328    drop_range(i);
329}
330
331void __init free_early_partial(u64 start, u64 end)
332{
333    struct early_res *r;
334    int i;
335
336    if (start == end)
337        return;
338
339    if (WARN_ONCE(start > end, " wrong range [%#llx, %#llx]\n", start, end))
340        return;
341
342try_next:
343    i = find_overlapped_early(start, end);
344    if (i >= max_early_res)
345        return;
346
347    r = &early_res[i];
348    /* hole ? */
349    if (r->end >= end && r->start <= start) {
350        drop_range_partial(i, start, end);
351        return;
352    }
353
354    drop_range_partial(i, start, end);
355    goto try_next;
356}
357
358#ifdef CONFIG_NO_BOOTMEM
359static void __init subtract_early_res(struct range *range, int az)
360{
361    int i, count;
362    u64 final_start, final_end;
363    int idx = 0;
364
365    count = 0;
366    for (i = 0; i < max_early_res && early_res[i].end; i++)
367        count++;
368
369    /* need to skip first one ?*/
370    if (early_res != early_res_x)
371        idx = 1;
372
373#define DEBUG_PRINT_EARLY_RES 1
374
375#if DEBUG_PRINT_EARLY_RES
376    printk(KERN_INFO "Subtract (%d early reservations)\n", count);
377#endif
378    for (i = idx; i < count; i++) {
379        struct early_res *r = &early_res[i];
380#if DEBUG_PRINT_EARLY_RES
381        printk(KERN_INFO " #%d [%010llx - %010llx] %15s\n", i,
382            r->start, r->end, r->name);
383#endif
384        final_start = PFN_DOWN(r->start);
385        final_end = PFN_UP(r->end);
386        if (final_start >= final_end)
387            continue;
388        subtract_range(range, az, final_start, final_end);
389    }
390
391}
392
393int __init get_free_all_memory_range(struct range **rangep, int nodeid)
394{
395    int i, count;
396    u64 start = 0, end;
397    u64 size;
398    u64 mem;
399    struct range *range;
400    int nr_range;
401
402    count = 0;
403    for (i = 0; i < max_early_res && early_res[i].end; i++)
404        count++;
405
406    count *= 2;
407
408    size = sizeof(struct range) * count;
409    end = get_max_mapped();
410#ifdef MAX_DMA32_PFN
411    if (end > (MAX_DMA32_PFN << PAGE_SHIFT))
412        start = MAX_DMA32_PFN << PAGE_SHIFT;
413#endif
414    mem = find_fw_memmap_area(start, end, size, sizeof(struct range));
415    if (mem == -1ULL)
416        panic("can not find more space for range free");
417
418    range = __va(mem);
419    /* use early_node_map[] and early_res to get range array at first */
420    memset(range, 0, size);
421    nr_range = 0;
422
423    /* need to go over early_node_map to find out good range for node */
424    nr_range = add_from_early_node_map(range, count, nr_range, nodeid);
425#ifdef CONFIG_X86_32
426    subtract_range(range, count, max_low_pfn, -1ULL);
427#endif
428    subtract_early_res(range, count);
429    nr_range = clean_sort_range(range, count);
430
431    /* need to clear it ? */
432    if (nodeid == MAX_NUMNODES) {
433        memset(&early_res[0], 0,
434             sizeof(struct early_res) * max_early_res);
435        early_res = NULL;
436        max_early_res = 0;
437    }
438
439    *rangep = range;
440    return nr_range;
441}
442#else
443void __init early_res_to_bootmem(u64 start, u64 end)
444{
445    int i, count;
446    u64 final_start, final_end;
447    int idx = 0;
448
449    count = 0;
450    for (i = 0; i < max_early_res && early_res[i].end; i++)
451        count++;
452
453    /* need to skip first one ?*/
454    if (early_res != early_res_x)
455        idx = 1;
456
457    printk(KERN_INFO "(%d/%d early reservations) ==> bootmem [%010llx - %010llx]\n",
458             count - idx, max_early_res, start, end);
459    for (i = idx; i < count; i++) {
460        struct early_res *r = &early_res[i];
461        printk(KERN_INFO " #%d [%010llx - %010llx] %16s", i,
462            r->start, r->end, r->name);
463        final_start = max(start, r->start);
464        final_end = min(end, r->end);
465        if (final_start >= final_end) {
466            printk(KERN_CONT "\n");
467            continue;
468        }
469        printk(KERN_CONT " ==> [%010llx - %010llx]\n",
470            final_start, final_end);
471        reserve_bootmem_generic(final_start, final_end - final_start,
472                BOOTMEM_DEFAULT);
473    }
474    /* clear them */
475    memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
476    early_res = NULL;
477    max_early_res = 0;
478    early_res_count = 0;
479}
480#endif
481
482/* Check for already reserved areas */
483static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
484{
485    int i;
486    u64 addr = *addrp;
487    int changed = 0;
488    struct early_res *r;
489again:
490    i = find_overlapped_early(addr, addr + size);
491    r = &early_res[i];
492    if (i < max_early_res && r->end) {
493        *addrp = addr = round_up(r->end, align);
494        changed = 1;
495        goto again;
496    }
497    return changed;
498}
499
500/* Check for already reserved areas */
501static inline int __init bad_addr_size(u64 *addrp, u64 *sizep, u64 align)
502{
503    int i;
504    u64 addr = *addrp, last;
505    u64 size = *sizep;
506    int changed = 0;
507again:
508    last = addr + size;
509    for (i = 0; i < max_early_res && early_res[i].end; i++) {
510        struct early_res *r = &early_res[i];
511        if (last > r->start && addr < r->start) {
512            size = r->start - addr;
513            changed = 1;
514            goto again;
515        }
516        if (last > r->end && addr < r->end) {
517            addr = round_up(r->end, align);
518            size = last - addr;
519            changed = 1;
520            goto again;
521        }
522        if (last <= r->end && addr >= r->start) {
523            (*sizep)++;
524            return 0;
525        }
526    }
527    if (changed) {
528        *addrp = addr;
529        *sizep = size;
530    }
531    return changed;
532}
533
534/*
535 * Find a free area with specified alignment in a specific range.
536 * only with the area.between start to end is active range from early_node_map
537 * so they are good as RAM
538 */
539u64 __init find_early_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
540             u64 size, u64 align)
541{
542    u64 addr, last;
543
544    addr = round_up(ei_start, align);
545    if (addr < start)
546        addr = round_up(start, align);
547    if (addr >= ei_last)
548        goto out;
549    while (bad_addr(&addr, size, align) && addr+size <= ei_last)
550        ;
551    last = addr + size;
552    if (last > ei_last)
553        goto out;
554    if (last > end)
555        goto out;
556
557    return addr;
558
559out:
560    return -1ULL;
561}
562
563u64 __init find_early_area_size(u64 ei_start, u64 ei_last, u64 start,
564             u64 *sizep, u64 align)
565{
566    u64 addr, last;
567
568    addr = round_up(ei_start, align);
569    if (addr < start)
570        addr = round_up(start, align);
571    if (addr >= ei_last)
572        goto out;
573    *sizep = ei_last - addr;
574    while (bad_addr_size(&addr, sizep, align) && addr + *sizep <= ei_last)
575        ;
576    last = addr + *sizep;
577    if (last > ei_last)
578        goto out;
579
580    return addr;
581
582out:
583    return -1ULL;
584}
585

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