Attention is currently required from: Aarya, Nikolai Artemiev.

Peter Marheine would like Nikolai Artemiev to review this change.

View Change

erasure_layout: Fix get_flash_region bug

When flash regions are protected, erase could incorrectly erase regions
which were meant to be protected by requesting the correct size but
using an erase opcode with coarser granularity than desired (for
instance using a 16-byte erase command while attempting to erase only 8
bytes).

This fixes that by exchanging the nesting of the loops over erase blocks
and flash regions.

Old:
 - Select erasefns
 - Loop over blocks to erase for each selected erasefn
  - Loop over programmer flash regions within erase block
    - Erase regions (may fail since selected erasefn will be
      too big if flash region is smaller than erase block)

New:
 - Loop over programmer flash regions within erase block
   - Select erasefns within programer flash region
     - Loop over blocks to erase for each selected erasefn
     - Erase regions

Eraser selection and erasing has also been factored out into a helper
function to manage nesting depth.

TEST=builds, tests pass
BUG=https://ticket.coreboot.org/issues/525

Change-Id: Ic5bf9d0f0e4a94c48d6f6e74e3cb9cccdc7adec9
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Signed-off-by: Peter Marheine <pmarheine@chromium.org>
---
M erasure_layout.c
1 file changed, 102 insertions(+), 92 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/93/82393/1

diff --git a/erasure_layout.c b/erasure_layout.c
index 1dd6b60..cf955e5 100644
--- a/erasure_layout.c
+++ b/erasure_layout.c
@@ -238,6 +238,80 @@
 	}
 }
 
+static int erase_write_helper(struct flashctx *const flashctx, chipoff_t region_start, chipoff_t region_end,
+		uint8_t *curcontents, uint8_t *newcontents,
+		struct erase_layout *erase_layout, bool *all_skipped)
+{
+	const size_t erasefn_count = count_usable_erasers(flashctx);
+
+	// select erase functions
+	for (size_t i = 0; i < erase_layout[erasefn_count - 1].block_count; i++) {
+		if (erase_layout[erasefn_count - 1].layout_list[i].start_addr <= region_end &&
+			region_start <= erase_layout[erasefn_count - 1].layout_list[i].end_addr)
+			select_erase_functions(flashctx, erase_layout,
+						erasefn_count - 1, i,
+						curcontents, newcontents,
+						region_start, region_end);
+	}
+
+	// erase
+	for (size_t i = 0; i < erasefn_count; i++) {
+		for (size_t j = 0; j < erase_layout[i].block_count; j++) {
+			if (!erase_layout[i].layout_list[j].selected)
+				continue;
+
+			chipoff_t start_addr = erase_layout[i].layout_list[j].start_addr;
+			unsigned int block_len = erase_layout[i].layout_list[j].end_addr - start_addr + 1;
+			const uint8_t erased_value = ERASED_VALUE(flashctx);
+			// execute erase
+			erasefunc_t *erasefn = lookup_erase_func_ptr(erase_layout[i].eraser);
+
+
+			if (erasefn(flashctx, start_addr, block_len)) {
+				return -1;
+			}
+			if (check_erased_range(flashctx, start_addr, block_len)) {
+				return -1;
+				msg_cerr("ERASE FAILED!\n");
+			}
+
+			// adjust curcontents
+			memset(curcontents+start_addr, erased_value, block_len);
+			// after erase make it unselected again
+			erase_layout[i].layout_list[j].selected = false;
+			msg_cdbg("E(%"PRIx32":%"PRIx32")", start_addr, start_addr + block_len - 1);
+
+			*all_skipped = false;
+		}
+	}
+
+	// write
+	unsigned int start_here = 0, len_here = 0, erase_len = region_end - region_start + 1;
+	while ((len_here = get_next_write(curcontents + region_start + start_here,
+					newcontents + region_start + start_here,
+					erase_len - start_here, &start_here,
+					flashctx->chip->gran))) {
+		// execute write
+		int ret = write_flash(flashctx,
+				newcontents + region_start + start_here,
+				region_start + start_here, len_here);
+		if (ret) {
+			msg_cerr("Write failed at %#x, Abort.\n", region_start + start_here);
+			return -1;
+		}
+
+		// adjust curcontents
+		memcpy(curcontents + region_start + start_here,
+			newcontents + region_start + start_here, len_here);
+		msg_cdbg("W(%"PRIx32":%"PRIx32")", region_start + start_here, region_start + start_here + len_here - 1);
+
+		*all_skipped = false;
+	}
+
+	return 0;
+}
+
+
 /*
  * @brief	wrapper to use the erase algorithm
  *
@@ -253,12 +327,15 @@
 		uint8_t *curcontents, uint8_t *newcontents,
 		struct erase_layout *erase_layout, bool *all_skipped)
 {
-	const size_t erasefn_count = count_usable_erasers(flashctx);
 	int ret = 0;
-	size_t i;
 	chipoff_t old_start = region_start, old_end = region_end;
 	align_region(erase_layout, flashctx, &region_start, &region_end);
 
+	if (!flashctx->flags.skip_unwritable_regions) {
+		if (check_for_unwritable_regions(flashctx, region_start, region_end - region_start))
+			return -1;
+	}
+
 	uint8_t *old_start_buf = NULL, *old_end_buf = NULL;
 	old_start_buf = (uint8_t *)malloc(old_start - region_start);
 	if (!old_start_buf) {
@@ -285,101 +362,34 @@
 		memcpy(newcontents + end_offset, curcontents + end_offset, region_end - old_end);
 	}
 
-	// select erase functions
-	for (i = 0; i < erase_layout[erasefn_count - 1].block_count; i++) {
-		if (erase_layout[erasefn_count - 1].layout_list[i].start_addr <= region_end &&
-			region_start <= erase_layout[erasefn_count - 1].layout_list[i].end_addr)
-			select_erase_functions(flashctx, erase_layout,
-						erasefn_count - 1, i,
-						curcontents, newcontents,
-						region_start, region_end);
-	}
+	unsigned int len;
+	for (unsigned int addr = region_start; addr <= region_end; addr += len) {
+		struct flash_region region;
+		get_flash_region(flashctx, addr, &region);
+		len = min(region_end, region.end - 1) - addr + 1;
 
-	for (i = 0; i < erasefn_count; i++) {
-		for (size_t j = 0; j < erase_layout[i].block_count; j++) {
-			if (!erase_layout[i].layout_list[j].selected)	continue;
-
-			// erase
-			chipoff_t start_addr = erase_layout[i].layout_list[j].start_addr;
-			unsigned int block_len = erase_layout[i].layout_list[j].end_addr - start_addr + 1;
-			const uint8_t erased_value = ERASED_VALUE(flashctx);
-			// execute erase
-			erasefunc_t *erasefn = lookup_erase_func_ptr(erase_layout[i].eraser);
-
-			if (!flashctx->flags.skip_unwritable_regions) {
-				if (check_for_unwritable_regions(flashctx, start_addr, block_len))
-					goto _end;
-			}
-
-			unsigned int len;
-			for (unsigned int addr = start_addr; addr < start_addr + block_len; addr += len) {
-				struct flash_region region;
-				get_flash_region(flashctx, addr, &region);
-
-				len = min(start_addr + block_len, region.end) - 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,
-						 addr, addr + len - 1);
-					free(region.name);
-					continue;
-				}
-
-				msg_gdbg("%s: %s region (%#08"PRIx32"..%#08"PRIx32") is "
-					"writable, erasing range (%#08x..%#08x).\n",
-					 __func__, region.name,
-					 region.start, region.end - 1,
-					 addr, addr + len - 1);
-				free(region.name);
-
-				if (erasefn(flashctx, addr, len)) {
-					ret = -1;
-					goto _end;
-				}
-				if (check_erased_range(flashctx, addr, len)) {
-					ret = - 1;
-					msg_cerr("ERASE FAILED!\n");
-					goto _end;
-				}
-			}
-
-			// adjust curcontents
-			memset(curcontents+start_addr, erased_value, block_len);
-			// after erase make it unselected again
-			erase_layout[i].layout_list[j].selected = false;
-			msg_cdbg("E(%"PRIx32":%"PRIx32")", start_addr, start_addr + block_len - 1);
-
-			*all_skipped = false;
+		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,
+				 addr, addr + len - 1);
+			free(region.name);
+			continue;
 		}
-	}
 
-	// write
-	unsigned int start_here = 0, len_here = 0, erase_len = region_end - region_start + 1;
-	while ((len_here = get_next_write(curcontents + region_start + start_here,
-					newcontents + region_start + start_here,
-					erase_len - start_here, &start_here,
-					flashctx->chip->gran))) {
-		// execute write
-		ret = write_flash(flashctx,
-				newcontents + region_start + start_here,
-				region_start + start_here, len_here);
-		if (ret) {
-			msg_cerr("Write failed at %#zx, Abort.\n", i);
-			ret = -1;
+		msg_gdbg("%s: %s region (%#08"PRIx32"..%#08"PRIx32") is "
+			"writable, erasing range (%#08x..%#08x).\n",
+			 __func__, region.name,
+			 region.start, region.end - 1,
+			 addr, addr + len - 1);
+		free(region.name);
+
+
+		ret = erase_write_helper(flashctx, addr, addr + len - 1, curcontents, newcontents, erase_layout, all_skipped);
+		if (ret)
 			goto _end;
-		}
-
-		// adjust curcontents
-		memcpy(curcontents + region_start + start_here,
-			newcontents + region_start + start_here, len_here);
-		msg_cdbg("W(%"PRIx32":%"PRIx32")", region_start + start_here, region_start + start_here + len_here - 1);
-
-		*all_skipped = false;
 	}
-
 _end:
 	memcpy(newcontents + region_start, old_start_buf, old_start - region_start);
 	memcpy(newcontents + old_end, old_end_buf, region_end - old_end);

To view, visit change 82393. To unsubscribe, or for help writing mail filters, visit settings.