1 /* 2 * Copyright 2004-2006, Axel Dörfler, axeld@pinc-software.de. All rights reserved. 3 * Copyright 2002/03, Thomas Kurschel. All rights reserved. 4 * 5 * Distributed under the terms of the MIT License. 6 */ 7 8 /* 9 VM helper functions. 10 11 Important assumption: get_memory_map must combine adjacent 12 physical pages, so contignous memory always leads to a S/G 13 list of length one. 14 */ 15 16 #include "KernelExport_ext.h" 17 #include "wrapper.h" 18 19 #include <string.h> 20 21 #include <algorithm> 22 23 24 /** get sg list of iovec 25 * TBD: this should be moved to somewhere in kernel 26 */ 27 28 status_t 29 get_iovec_memory_map(iovec *vec, size_t vec_count, size_t vec_offset, size_t len, 30 physical_entry *map, uint32 max_entries, uint32 *num_entries, size_t *mapped_len) 31 { 32 uint32 cur_idx; 33 size_t left_len; 34 35 SHOW_FLOW(3, "vec_count=%" B_PRIuSIZE ", vec_offset=%" B_PRIuSIZE ", len=%" 36 B_PRIuSIZE ", max_entries=%" B_PRIu32, vec_count, vec_offset, len, 37 max_entries); 38 39 // skip iovec blocks if needed 40 while (vec_count > 0 && vec_offset > vec->iov_len) { 41 vec_offset -= vec->iov_len; 42 --vec_count; 43 ++vec; 44 } 45 46 for (left_len = len, cur_idx = 0; left_len > 0 && vec_count > 0 47 && cur_idx < max_entries;) { 48 char *range_start; 49 size_t range_len; 50 status_t res; 51 uint32 cur_num_entries, cur_mapped_len; 52 uint32 tmp_idx; 53 54 SHOW_FLOW( 3, "left_len=%d, vec_count=%d, cur_idx=%" B_PRIu32, 55 (int)left_len, (int)vec_count, cur_idx ); 56 57 // map one iovec 58 range_start = (char *)vec->iov_base + vec_offset; 59 range_len = std::min(vec->iov_len - vec_offset, left_len); 60 61 SHOW_FLOW( 3, "range_start=%" B_PRIxADDR ", range_len=%" B_PRIxSIZE, 62 (addr_t)range_start, range_len ); 63 64 vec_offset = 0; 65 66 cur_num_entries = max_entries - cur_idx; 67 if ((res = get_memory_map_etc(B_CURRENT_TEAM, range_start, range_len, 68 &map[cur_idx], &cur_num_entries)) != B_OK) { 69 // according to docu, no error is ever reported - argh! 70 SHOW_ERROR(1, "invalid io_vec passed (%s)", strerror(res)); 71 return res; 72 } 73 74 cur_mapped_len = 0; 75 76 for (tmp_idx = cur_idx; tmp_idx < cur_idx + cur_num_entries; ++tmp_idx) 77 cur_mapped_len += map[tmp_idx].size; 78 79 if (cur_mapped_len == 0) { 80 panic("get_memory_map() returned empty list; left_len=%d, idx=%" 81 B_PRIu32 "/%" B_PRIu32, (int)left_len, cur_idx, max_entries); 82 SHOW_ERROR(2, "get_memory_map() returned empty list; left_len=%d, " 83 "idx=%" B_PRIu32 "/%" B_PRIu32, (int)left_len, cur_idx, 84 max_entries); 85 return B_ERROR; 86 } 87 88 SHOW_FLOW( 3, "cur_num_entries=%" B_PRIu32 ", cur_mapped_len=%x", 89 cur_num_entries, (int)cur_mapped_len ); 90 91 // try to combine with previous sg block 92 if (cur_num_entries > 0 && cur_idx > 0 93 && map[cur_idx].address 94 == map[cur_idx - 1].address + map[cur_idx - 1].size) { 95 SHOW_FLOW0( 3, "combine with previous chunk" ); 96 map[cur_idx - 1].size += map[cur_idx].size; 97 memcpy(&map[cur_idx], &map[cur_idx + 1], 98 (cur_num_entries - 1) * sizeof(map[0])); 99 --cur_num_entries; 100 } 101 102 cur_idx += cur_num_entries; 103 left_len -= cur_mapped_len; 104 105 // advance iovec if current one is described completely 106 if (cur_mapped_len == range_len) { 107 ++vec; 108 --vec_count; 109 } 110 } 111 112 *num_entries = cur_idx; 113 *mapped_len = len - left_len; 114 115 SHOW_FLOW( 3, "num_entries=%" B_PRIu32 ", mapped_len=%" B_PRIxSIZE, 116 *num_entries, *mapped_len); 117 118 return B_OK; 119 } 120 121