| 1 | #include <stdint.h> |
| 2 | #include <stddef.h> |
| 3 | #include <stdbool.h> |
| 4 | #include <lib/elsewhere.h> |
| 5 | #include <lib/misc.h> |
| 6 | #include <mm/pmm.h> |
| 7 | |
| 8 | static bool elsewhere_overlap_check(uint64_t base1, uint64_t top1, |
| 9 | uint64_t base2, uint64_t top2) { |
| 10 | return (base1 < top2 && base2 < top1); |
| 11 | } |
| 12 | |
| 13 | bool elsewhere_append( |
| 14 | bool flexible_target, |
| 15 | struct elsewhere_range *ranges, uint64_t *ranges_count, |
| 16 | uint64_t ranges_max, |
| 17 | void *elsewhere, uint64_t *target, size_t t_length) { |
| 18 | // original target of -1 means "allocate after top of all ranges" |
| 19 | // flexible target is ignored |
| 20 | flexible_target = true; |
| 21 | if (*target == (uint64_t)-1) { |
| 22 | uint64_t top = 0; |
| 23 | |
| 24 | for (size_t i = 0; i < *ranges_count; i++) { |
| 25 | uint64_t r_top = CHECKED_ADD(ranges[i].target, ranges[i].length, continue); |
| 26 | |
| 27 | if (top < r_top) { |
| 28 | top = r_top; |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | *target = ALIGN_UP(top, 4096, return false); |
| 33 | } |
| 34 | |
| 35 | uint64_t max_retries = 0x10000; |
| 36 | |
| 37 | retry: |
| 38 | if (max_retries-- == 0) { |
| 39 | return false; |
| 40 | } |
| 41 | |
| 42 | for (size_t i = 0; i < *ranges_count; i++) { |
| 43 | uint64_t t_top = CHECKED_ADD(*target, t_length, return false); |
| 44 | |
| 45 | // Ensure allocation stays within 32-bit address space. |
| 46 | if (t_top > 0x100000000) { |
| 47 | return false; |
| 48 | } |
| 49 | |
| 50 | // Does it overlap with other elsewhere ranges targets? |
| 51 | { |
| 52 | uint64_t base = ranges[i].target; |
| 53 | uint64_t length = ranges[i].length; |
| 54 | uint64_t top = CHECKED_ADD(base, length, continue); |
| 55 | |
| 56 | if (elsewhere_overlap_check(base, top, *target, t_top)) { |
| 57 | if (!flexible_target) { |
| 58 | return false; |
| 59 | } |
| 60 | *target = ALIGN_UP(top, 4096, return false); |
| 61 | goto retry; |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | // Does it overlap with other elsewhere ranges sources? |
| 66 | { |
| 67 | uint64_t base = ranges[i].elsewhere; |
| 68 | uint64_t length = ranges[i].length; |
| 69 | uint64_t top = CHECKED_ADD(base, length, continue); |
| 70 | |
| 71 | if (elsewhere_overlap_check(base, top, *target, t_top)) { |
| 72 | if (!flexible_target) { |
| 73 | return false; |
| 74 | } |
| 75 | *target = ALIGN_UP(top, 4096, return false); |
| 76 | goto retry; |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | // Make sure it is memory that actually exists. |
| 81 | if (!memmap_alloc_range(*target, t_length, MEMMAP_BOOTLOADER_RECLAIMABLE, |
| 82 | MEMMAP_USABLE, false, true, false)) { |
| 83 | if (!memmap_alloc_range(*target, t_length, MEMMAP_BOOTLOADER_RECLAIMABLE, |
| 84 | MEMMAP_BOOTLOADER_RECLAIMABLE, false, true, false)) { |
| 85 | if (!flexible_target) { |
| 86 | return false; |
| 87 | } |
| 88 | *target += 0x1000; |
| 89 | goto retry; |
| 90 | } |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | // Add the elsewhere range |
| 95 | if (*ranges_count >= ranges_max) { |
| 96 | panic(false, "elsewhere: ranges array overflow"); |
| 97 | } |
| 98 | ranges[*ranges_count].elsewhere = (uintptr_t)elsewhere; |
| 99 | ranges[*ranges_count].target = *target; |
| 100 | ranges[*ranges_count].length = t_length; |
| 101 | *ranges_count += 1; |
| 102 | |
| 103 | return true; |
| 104 | } |
