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Peter Marheine has uploaded this change for review.

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Correct get_flash_region() to use inclusive upper bounds

get_flash_region() emits a struct flash_region, which uses chipoff_t for
the start and end addresses of a region. chipoff_t is defined as a valid
flash address, so it was wrong to be setting the end address to start +
len; this is clearly wrong in the case where there is a single region
because setting end to the flash size generates an address that is
beyond the end of the chip (due to zero-indexing).

This changes the one actual implementation of .get_region in ichspi.c to
use inclusive upper bounds, and corrects all callers of
get_flash_region() to treat the upper bounds as inclusive. Overall this
reduces complexity slightly by removing more downward adjustments by 1
than it needs to add upward adjustments.

Change-Id: Ia0ca867aef33b598c2697fc264807fa5e29683ec
---
M erasure_layout.c
M flashrom.c
M ichspi.c
3 files changed, 20 insertions(+), 20 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/96/82496/1

diff --git a/erasure_layout.c b/erasure_layout.c
index 1dd6b60..ef7987a 100644
--- a/erasure_layout.c
+++ b/erasure_layout.c
@@ -316,13 +316,13 @@
 				struct flash_region region;
 				get_flash_region(flashctx, addr, &region);
 
-				len = min(start_addr + block_len, region.end) - addr;
+				len = min(start_addr + block_len, region.end + 1) - addr;
 
 				if (region.write_prot) {
 					msg_gdbg("%s: cannot erase inside %s "
 						"region (%#08"PRIx32"..%#08"PRIx32"), skipping range (%#08x..%#08x).\n",
 						 __func__, region.name,
-						 region.start, region.end - 1,
+						 region.start, region.end,
 						 addr, addr + len - 1);
 					free(region.name);
 					continue;
@@ -331,7 +331,7 @@
 				msg_gdbg("%s: %s region (%#08"PRIx32"..%#08"PRIx32") is "
 					"writable, erasing range (%#08x..%#08x).\n",
 					 __func__, region.name,
-					 region.start, region.end - 1,
+					 region.start, region.end,
 					 addr, addr + len - 1);
 				free(region.name);
 
diff --git a/flashrom.c b/flashrom.c
index a056929..a8ad3f0 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -379,7 +379,7 @@
 	} else {
 		region->name = strdup("");
 		region->start = 0;
-		region->end = flashrom_flash_getsize(flash);
+		region->end = flashrom_flash_getsize(flash) - 1;
 		region->read_prot = false;
 		region->write_prot = false;
 	}
@@ -388,12 +388,12 @@
 int check_for_unwritable_regions(const struct flashctx *flash, unsigned int start, unsigned int len)
 {
 	struct flash_region region;
-	for (unsigned int addr = start; addr < start + len; addr = region.end) {
+	for (unsigned int addr = start; addr < start + len; addr = region.end + 1) {
 		get_flash_region(flash, addr, &region);
 
 		if (region.write_prot) {
 			msg_gerr("%s: cannot write/erase inside %s region (%#08"PRIx32"..%#08"PRIx32").\n",
-				 __func__, region.name, region.start, region.end - 1);
+				 __func__, region.name, region.start, region.end);
 			free(region.name);
 			return -1;
 		}
@@ -596,14 +596,14 @@
 		struct flash_region region;
 		get_flash_region(flash, addr, &region);
 
-		read_len = min(start + len, region.end) - addr;
+		read_len = min(start + len, region.end + 1) - addr;
 		uint8_t *rbuf = buf + addr - start;
 
 		if (region.read_prot) {
 			if (flash->flags.skip_unreadable_regions) {
 				msg_gdbg("%s: cannot read inside %s region (%#08"PRIx32"..%#08"PRIx32"), "
 					 "filling (%#08x..%#08x) with erased value instead.\n",
-					 __func__, region.name, region.start, region.end - 1,
+					 __func__, region.name, region.start, region.end,
 					 addr, addr + read_len - 1);
 				free(region.name);
 
@@ -612,12 +612,12 @@
 			}
 
 			msg_gerr("%s: cannot read inside %s region (%#08"PRIx32"..%#08"PRIx32").\n",
-				 __func__, region.name, region.start, region.end - 1);
+				 __func__, region.name, region.start, region.end);
 			free(region.name);
 			return -1;
 		}
 		msg_gdbg("%s: %s region (%#08"PRIx32"..%#08"PRIx32") is readable, reading range (%#08x..%#08x).\n",
-			 __func__, region.name, region.start, region.end - 1, addr, addr + read_len - 1);
+			 __func__, region.name, region.start, region.end, addr, addr + read_len - 1);
 		free(region.name);
 
 		read_func_t *read_func = lookup_read_func_ptr(flash->chip);
@@ -665,25 +665,25 @@
 	for (size_t addr = start; addr < start + len; addr += read_len) {
 		struct flash_region region;
 		get_flash_region(flash, addr, &region);
-		read_len = min(start + len, region.end) - addr;
+		read_len = min(start + len, region.end + 1) - addr;
 
 		if ((region.write_prot && flash->flags.skip_unwritable_regions) ||
 		    (region.read_prot  && flash->flags.skip_unreadable_regions)) {
 			msg_gdbg("%s: Skipping verification of %s region (%#08"PRIx32"..%#08"PRIx32")\n",
-				 __func__, region.name, region.start, region.end - 1);
+				 __func__, region.name, region.start, region.end);
 			free(region.name);
 			continue;
 		}
 
 		if (region.read_prot) {
 			msg_gerr("%s: Verification imposible because %s region (%#08"PRIx32"..%#08"PRIx32") is unreadable.\n",
-				 __func__, region.name, region.start, region.end - 1);
+				 __func__, region.name, region.start, region.end);
 			free(region.name);
 			goto out_free;
 		}
 
 		msg_gdbg("%s: Verifying %s region (%#08"PRIx32"..%#08"PRIx32")\n",
-			 __func__, region.name, region.start, region.end - 1);
+			 __func__, region.name, region.start, region.end);
 		free(region.name);
 
 		ret = read_flash(flash, readbuf, addr, read_len);
@@ -1046,18 +1046,18 @@
 		struct flash_region region;
 		get_flash_region(flash, addr, &region);
 
-		write_len = min(start + len, region.end) - addr;
+		write_len = min(start + len, region.end + 1) - addr;
 		const uint8_t *rbuf = buf + addr - start;
 
 		if (region.write_prot) {
 			msg_gdbg("%s: cannot write inside %s region (%#08"PRIx32"..%#08"PRIx32"), skipping (%#08x..%#08x).\n",
-				 __func__, region.name, region.start, region.end - 1, addr, addr + write_len - 1);
+				 __func__, region.name, region.start, region.end, addr, addr + write_len - 1);
 			free(region.name);
 			continue;
 		}
 
 		msg_gdbg("%s: %s region (%#08"PRIx32"..%#08"PRIx32") is writable, writing range (%#08x..%#08x).\n",
-			 __func__, region.name, region.start, region.end - 1, addr, addr + write_len - 1);
+			 __func__, region.name, region.start, region.end, addr, addr + write_len - 1);
 
 		write_func_t *write_func = lookup_write_func_ptr(flash->chip);
 		int ret = write_func(flash, rbuf, addr, write_len);
@@ -1511,7 +1511,7 @@
 		struct flash_region region;
 		get_flash_region(flashctx, addr, &region);
 
-		len = min(info->erase_start + erase_len, region.end) - addr;
+		len = min(info->erase_start + erase_len, region.end + 1) - addr;
 
 		if (region.write_prot) {
 			msg_gdbg("%s: cannot erase inside %s region (%#08"PRIx32"..%#08"PRIx32"), skipping range (%#08x..%#08x).\n",
diff --git a/ichspi.c b/ichspi.c
index bee5ec9..249e966 100644
--- a/ichspi.c
+++ b/ichspi.c
@@ -1451,12 +1451,12 @@
 			 * fd_regions[i] ends before addr, constrain
 			 * region->start so that it does not overlap.
 			 */
-			region->start = max(region->start, limit + 1);
+			region->start = max(region->start, limit);
 		} else {
 			/* fd_regions[i] contains addr, copy to *region. */
 			name = fd_regions[i].name;
 			region->start = base;
-			region->end = limit + 1;
+			region->end = limit;
 			region->read_prot  = (level == LOCKED) || (level == READ_PROT);
 			region->write_prot = (level == LOCKED) || (level == WRITE_PROT);
 			break;

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