diff options
Diffstat (limited to 'src/lib/memrange.c')
| -rw-r--r-- | src/lib/memrange.c | 36 |
1 files changed, 23 insertions, 13 deletions
diff --git a/src/lib/memrange.c b/src/lib/memrange.c index 39f502caa6..b68b86e2f8 100644 --- a/src/lib/memrange.c +++ b/src/lib/memrange.c @@ -378,11 +378,11 @@ struct range_entry *memranges_next_entry(struct memranges *ranges, /* Find a range entry that satisfies the given constraints to fit a hole that matches the * required alignment, is big enough, does not exceed the limit and has a matching tag. */ -static const struct range_entry *memranges_find_entry(struct memranges *ranges, - resource_t limit, resource_t size, - unsigned char align, unsigned long tag) +static const struct range_entry * +memranges_find_entry(struct memranges *ranges, resource_t limit, resource_t size, + unsigned char align, unsigned long tag, bool last) { - const struct range_entry *r; + const struct range_entry *r, *last_entry = NULL; resource_t base, end; if (size == 0) @@ -407,25 +407,35 @@ static const struct range_entry *memranges_find_entry(struct memranges *ranges, if (end > limit) break; - return r; + if (!last) + return r; + + last_entry = r; } - return NULL; + return last_entry; } bool memranges_steal(struct memranges *ranges, resource_t limit, resource_t size, - unsigned char align, unsigned long tag, resource_t *stolen_base) + unsigned char align, unsigned long tag, resource_t *stolen_base, + bool from_top) { - resource_t base; - const struct range_entry *r = memranges_find_entry(ranges, limit, size, align, tag); + const struct range_entry *r; + r = memranges_find_entry(ranges, limit, size, align, tag, from_top); if (r == NULL) return false; - base = ALIGN_UP(r->begin, POWER_OF_2(align)); - - memranges_create_hole(ranges, base, size); - *stolen_base = base; + if (from_top) { + /* Ensure we're within the range, even aligned down. + Proof is simple: If ALIGN_UP(r->begin) would be + higher, the stolen range wouldn't fit.*/ + assert(r->begin <= ALIGN_DOWN(range_entry_end(r) - size, POWER_OF_2(align))); + *stolen_base = ALIGN_DOWN(range_entry_end(r) - size, POWER_OF_2(align)); + } else { + *stolen_base = ALIGN_UP(r->begin, POWER_OF_2(align)); + } + memranges_create_hole(ranges, *stolen_base, size); return true; } |