From 9c6274cd8fb1c9ee0eb674ce5945a05f818cb32e Mon Sep 17 00:00:00 2001 From: Furquan Shaikh Date: Wed, 11 Mar 2020 19:06:24 -0700 Subject: memrange: Add support for stealing required memory from given ranges This change adds memranges_steal() which allows the user to steal memory from the list of available ranges by providing a set of constraints (limit, size, alignment, tag). It tries to find the first big enough range that can satisfy the constraints, creates a hole as per the request and returns base of the stolen memory. BUG=b:149186922 Signed-off-by: Furquan Shaikh Change-Id: Ibe9cfae18fc6101ab2e7e27233e45324c8117708 Reviewed-on: https://review.coreboot.org/c/coreboot/+/39484 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/lib/memrange.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'src/lib') diff --git a/src/lib/memrange.c b/src/lib/memrange.c index 21fff003a1..b9c09e8782 100644 --- a/src/lib/memrange.c +++ b/src/lib/memrange.c @@ -391,3 +391,58 @@ struct range_entry *memranges_next_entry(struct memranges *ranges, { return r->next; } + +/* 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, + size_t align, unsigned long tag) +{ + const struct range_entry *r; + resource_t base, end; + + if (size == 0) + return NULL; + + if (!IS_POWER_OF_2(align)) + return NULL; + + if (!IS_ALIGNED(align, ranges->align)) + return NULL; + + memranges_each_entry(r, ranges) { + + if (r->tag != tag) + continue; + + base = ALIGN_UP(r->begin, align); + end = base + size - 1; + + if (end > r->end) + continue; + + if (end > limit) + continue; + + return r; + } + + return NULL; +} + +bool memranges_steal(struct memranges *ranges, resource_t limit, resource_t size, size_t align, + unsigned long tag, resource_t *stolen_base) +{ + resource_t base; + const struct range_entry *r = memranges_find_entry(ranges, limit, size, align, tag); + + if (r == NULL) + return false; + + base = ALIGN_UP(r->begin, align); + + memranges_create_hole(ranges, base, size); + *stolen_base = base; + + return true; +} -- cgit v1.2.3