src/flashrom: allow nested regions

src/flashrom/0002-layout.c-allow-nested-regions.patch

@@ -0,0 +1,45 @@
+From 5af5c5418f5335ab1c843f8ab6eb148d413d32a6 Mon Sep 17 00:00:00 2001
+From: Adam Joseph <adam@westernsemico.com>
+Date: Tue, 18 Oct 2022 15:47:41 -0700
+Subject: [PATCH 2/2] layout.c: allow nested regions
+
+Many BIOSes have nested regions.  For example, AGESA for KGPE-D16
+expects a BIOS region covering essentially the whole chip, which is
+used by SMM to protect the critical parts of the flash chip.  This
+means that `flashrom --fmap` won't work with those images.
+
+Let's adjust the overlapping-regions check to allow nested regions,
+where one region completely contains another region.
+---
+ layout.c | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/layout.c b/layout.c
+index e688f79..072ab5f 100644
+--- a/layout.c
++++ b/layout.c
+@@ -245,7 +245,7 @@ int process_include_args(struct flashrom_layout *l, const struct layout_include_
+ 	return 0;
+ }
+ 
+-/* returns boolean 1 if any regions overlap, 0 otherwise */
++/* returns boolean 1 if any regions overlap and neither fully contains the other, 0 otherwise */
+ int included_regions_overlap(const struct flashrom_layout *const l)
+ {
+ 	const struct romentry *lhs = NULL;
+@@ -266,6 +266,12 @@ int included_regions_overlap(const struct flashrom_layout *const l)
+ 			if (lhs->end < rhs->start)
+ 				continue;
+ 
++			if (lhs->start <= rhs->start && lhs->end >= rhs->end)
++				continue;
++
++			if (rhs->start <= lhs->start && rhs->end >= lhs->end)
++				continue;
++
+ 			msg_gdbg("Regions %s [0x%08x-0x%08x] and %s [0x%08x-0x%08x] overlap\n",
+ 				 lhs->name, lhs->start, lhs->end, rhs->name, rhs->start, rhs->end);
+ 			overlap_detected = 1;
+-- 
+2.37.2
+

src/flashrom/default.nix

@@ -25,6 +25,7 @@ stdenv.mkDerivation {
 
   patches = [
     ./0001-implement-wp-enable-disable-for-gigadevice-flash-chi.patch
+    ./0002-layout.c-allow-nested-regions.patch
   ];
 
   makeFlags = [ "PREFIX=$(out)" "libinstall" ];