allocator_v4: Introduce RESOURCE_ALLOCATION_TOP_DOWN
Add option to resource allocator v4 that restores the top-down
allocation approach at the domain level.
This makes it easier to handle 64-bit resources natively. With
the top-down approach, resources that can be placed either above
or below 4G would be placed above, to save precious space below
the 4G boundary.
Change-Id: Iaf463d3e6b37d52e46761d8e210034fded58a8a4
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41957
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
diff --git a/src/device/Kconfig b/src/device/Kconfig
index 6f4a24e..af9beb3 100644
--- a/src/device/Kconfig
+++ b/src/device/Kconfig
@@ -933,6 +933,11 @@
ranges for allocating resources. This allows allocation of resources
above 4G boundary as well.
+config RESOURCE_ALLOCATION_TOP_DOWN
+ bool "Allocate resources from top down"
+ default y
+ depends on RESOURCE_ALLOCATOR_V4
+
config XHCI_UTILS
def_bool n
help
diff --git a/src/device/resource_allocator_v4.c b/src/device/resource_allocator_v4.c
index 2b62fc8..222f1e9 100644
--- a/src/device/resource_allocator_v4.c
+++ b/src/device/resource_allocator_v4.c
@@ -372,6 +372,9 @@
static void allocate_child_resources(struct bus *bus, struct memranges *ranges,
unsigned long type_mask, unsigned long type_match)
{
+ const bool allocate_top_down =
+ bus->dev->path.type == DEVICE_PATH_DOMAIN &&
+ CONFIG(RESOURCE_ALLOCATION_TOP_DOWN);
struct resource *resource = NULL;
const struct device *dev;
@@ -381,7 +384,7 @@
continue;
if (memranges_steal(ranges, resource->limit, resource->size, resource->align,
- type_match, &resource->base) == false) {
+ type_match, &resource->base, allocate_top_down) == false) {
printk(BIOS_ERR, " ERROR: Resource didn't fit!!! ");
printk(BIOS_DEBUG, " %s %02lx * size: 0x%llx limit: %llx %s\n",
dev_path(dev), resource->index,
diff --git a/src/include/memrange.h b/src/include/memrange.h
index a8a8de9..f7c5bfc 100644
--- a/src/include/memrange.h
+++ b/src/include/memrange.h
@@ -161,15 +161,17 @@
const struct range_entry *r);
/* Steals memory from the available list in given ranges as per the constraints:
- * limit = Upper bound for the memory range to steal (Inclusive).
- * size = Requested size for the stolen memory.
- * align = Required alignment(log 2) for the starting address of the stolen memory.
- * tag = Use a range that matches the given tag.
+ * limit = Upper bound for the memory range to steal (Inclusive).
+ * size = Requested size for the stolen memory.
+ * align = Required alignment(log 2) for the starting address of the stolen memory.
+ * tag = Use a range that matches the given tag.
+ * from_top = Steal the highest possible range.
*
* If the constraints can be satisfied, this function creates a hole in the memrange,
* writes the base address of that hole to stolen_base and returns true. Otherwise it returns
* false. */
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);
#endif /* MEMRANGE_H_ */
diff --git a/src/lib/memrange.c b/src/lib/memrange.c
index 39f502c..b68b86e 100644
--- a/src/lib/memrange.c
+++ b/src/lib/memrange.c
@@ -378,11 +378,11 @@
/* 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 @@
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;
}