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authorJohannes Weiner <hannes@saeurebad.de>2008-08-20 17:09:15 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-20 18:40:31 -0400
commit481ebd0d76b501c5772f702ae31e55350c0858a3 (patch)
tree37f13727a66bf2cb10e4d8be7a608edf9cd5009e /mm/bootmem.c
parenta09f48551273ee89d4e9ae37474807dc2da1d757 (diff)
bootmem: fix aligning of node-relative indexes and offsets
Absolute alignment requirements may never be applied to node-relative offsets. Andreas Herrmann spotted this flaw when a bootmem allocation on an unaligned node was itself not aligned because the combination of an unaligned node with an aligned offset into that node is not garuanteed to be aligned itself. This patch introduces two helper functions that align a node-relative index or offset with respect to the node's starting address so that the absolute PFN or virtual address that results from combining the two satisfies the requested alignment. Then all the broken ALIGN()s in alloc_bootmem_core() are replaced by these helpers. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Reported-by: Andreas Herrmann <andreas.herrmann3@amd.com> Debugged-by: Andreas Herrmann <andreas.herrmann3@amd.com> Reviewed-by: Andreas Herrmann <andreas.herrmann3@amd.com> Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/bootmem.c')
-rw-r--r--mm/bootmem.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c
index e023c68b0255..ad8eec6e44a8 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -405,6 +405,29 @@ int __init reserve_bootmem(unsigned long addr, unsigned long size,
405} 405}
406#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */ 406#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
407 407
408static unsigned long align_idx(struct bootmem_data *bdata, unsigned long idx,
409 unsigned long step)
410{
411 unsigned long base = bdata->node_min_pfn;
412
413 /*
414 * Align the index with respect to the node start so that the
415 * combination of both satisfies the requested alignment.
416 */
417
418 return ALIGN(base + idx, step) - base;
419}
420
421static unsigned long align_off(struct bootmem_data *bdata, unsigned long off,
422 unsigned long align)
423{
424 unsigned long base = PFN_PHYS(bdata->node_min_pfn);
425
426 /* Same as align_idx for byte offsets */
427
428 return ALIGN(base + off, align) - base;
429}
430
408static void * __init alloc_bootmem_core(struct bootmem_data *bdata, 431static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
409 unsigned long size, unsigned long align, 432 unsigned long size, unsigned long align,
410 unsigned long goal, unsigned long limit) 433 unsigned long goal, unsigned long limit)
@@ -441,7 +464,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
441 else 464 else
442 start = ALIGN(min, step); 465 start = ALIGN(min, step);
443 466
444 sidx = start - bdata->node_min_pfn;; 467 sidx = start - bdata->node_min_pfn;
445 midx = max - bdata->node_min_pfn; 468 midx = max - bdata->node_min_pfn;
446 469
447 if (bdata->hint_idx > sidx) { 470 if (bdata->hint_idx > sidx) {
@@ -450,7 +473,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
450 * catch the fallback below. 473 * catch the fallback below.
451 */ 474 */
452 fallback = sidx + 1; 475 fallback = sidx + 1;
453 sidx = ALIGN(bdata->hint_idx, step); 476 sidx = align_idx(bdata, bdata->hint_idx, step);
454 } 477 }
455 478
456 while (1) { 479 while (1) {
@@ -459,7 +482,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
459 unsigned long eidx, i, start_off, end_off; 482 unsigned long eidx, i, start_off, end_off;
460find_block: 483find_block:
461 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx); 484 sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
462 sidx = ALIGN(sidx, step); 485 sidx = align_idx(bdata, sidx, step);
463 eidx = sidx + PFN_UP(size); 486 eidx = sidx + PFN_UP(size);
464 487
465 if (sidx >= midx || eidx > midx) 488 if (sidx >= midx || eidx > midx)
@@ -467,7 +490,7 @@ find_block:
467 490
468 for (i = sidx; i < eidx; i++) 491 for (i = sidx; i < eidx; i++)
469 if (test_bit(i, bdata->node_bootmem_map)) { 492 if (test_bit(i, bdata->node_bootmem_map)) {
470 sidx = ALIGN(i, step); 493 sidx = align_idx(bdata, i, step);
471 if (sidx == i) 494 if (sidx == i)
472 sidx += step; 495 sidx += step;
473 goto find_block; 496 goto find_block;
@@ -475,7 +498,7 @@ find_block:
475 498
476 if (bdata->last_end_off & (PAGE_SIZE - 1) && 499 if (bdata->last_end_off & (PAGE_SIZE - 1) &&
477 PFN_DOWN(bdata->last_end_off) + 1 == sidx) 500 PFN_DOWN(bdata->last_end_off) + 1 == sidx)
478 start_off = ALIGN(bdata->last_end_off, align); 501 start_off = align_off(bdata, bdata->last_end_off, align);
479 else 502 else
480 start_off = PFN_PHYS(sidx); 503 start_off = PFN_PHYS(sidx);
481 504
@@ -499,7 +522,7 @@ find_block:
499 } 522 }
500 523
501 if (fallback) { 524 if (fallback) {
502 sidx = ALIGN(fallback - 1, step); 525 sidx = align_idx(bdata, fallback - 1, step);
503 fallback = 0; 526 fallback = 0;
504 goto find_block; 527 goto find_block;
505 } 528 }