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memrange: Honor limit in the last step of top-down stealing

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We only checked that the resource fits below the given `limit` in
memranges_find_entry(), but then accidentally placed it at the top
of the found memrange. As most resources have only a coarse limit,
e.g. the 4G barrier of 32-bit space, this became only visible when
artificially setting an unusual, lower limit on a resource.

So, for the final placement, use `MIN(limit, range end)` instead
of the range's end alone.

Change-Id: I3cc62ac3d427683c00ba0ac9f991fca62e99ce44
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76480
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin L Roth <gaumless@gmail.com>
This commit is contained in:
Nico Huber 2023-07-15 01:47:04 +02:00 committed by Martin L Roth
parent 8a58483072
commit b2893e22e6
1 changed files with 3 additions and 2 deletions
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5
src/lib/memrange.c
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@ -427,11 +427,12 @@ bool memranges_steal(struct memranges *ranges, resource_t limit, resource_t size
return false;
if (from_top) {
limit = MIN(limit, r->end);
/* 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));
assert(r->begin <= ALIGN_DOWN(limit - size + 1, POWER_OF_2(align)));
*stolen_base = ALIGN_DOWN(limit - size + 1, POWER_OF_2(align));
} else {
*stolen_base = ALIGN_UP(r->begin, POWER_OF_2(align));
}