[PATCH v2 11/18] bloblist: Reduce blob-header size

Raymond Mao raymond.mao at linaro.org
Mon Nov 27 20:50:22 CET 2023


From: Simon Glass <sjg at chromium.org>

The v0.9 spec provides for an 8-byte header for each blob, with fewer
fields.
The blob start address should be aligned to the alignment specified
by the bloblist header.
Update the implementation to match this.

Signed-off-by: Simon Glass <sjg at chromium.org>
Co-developed-by: Raymond Mao <raymond.mao at linaro.org>
Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
---
Changes in v2
- Update the blob start address to align to the alignment required by
  the bloblist header.
- Define the macros of bloblist header size and bloblist record header
  size as the size of their structures.  

 common/bloblist.c  | 17 +++++++++--------
 include/bloblist.h | 33 ++++++++++++++++++++++-----------
 test/bloblist.c    | 16 ++++++++--------
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/common/bloblist.c b/common/bloblist.c
index 59a092d4cd..55a7e1f591 100644
--- a/common/bloblist.c
+++ b/common/bloblist.c
@@ -85,12 +85,14 @@ static struct bloblist_rec *bloblist_first_blob(struct bloblist_hdr *hdr)
 
 static inline uint rec_hdr_size(struct bloblist_rec *rec)
 {
-	return rec->hdr_size;
+	return (rec->tag_and_hdr_size & BLOBLISTR_HDR_SIZE_MASK) >>
+		BLOBLISTR_HDR_SIZE_SHIFT;
 }
 
 static inline uint rec_tag(struct bloblist_rec *rec)
 {
-	return rec->tag;
+	return (rec->tag_and_hdr_size & BLOBLISTR_TAG_MASK) >>
+		BLOBLISTR_TAG_SHIFT;
 }
 
 static ulong bloblist_blob_end_ofs(struct bloblist_hdr *hdr,
@@ -99,7 +101,7 @@ static ulong bloblist_blob_end_ofs(struct bloblist_hdr *hdr,
 	ulong offset;
 
 	offset = (void *)rec - (void *)hdr;
-	offset += rec_hdr_size(rec) + ALIGN(rec->size, BLOBLIST_ALIGN);
+	offset += rec_hdr_size(rec) + ALIGN(rec->size, 1 << hdr->align_log2);
 
 	return offset;
 }
@@ -143,7 +145,7 @@ static int bloblist_addrec(uint tag, int size, int align_log2,
 	int data_start, aligned_start, new_alloced;
 
 	if (!align_log2)
-		align_log2 = BLOBLIST_ALIGN_LOG2;
+		align_log2 = BLOBLIST_BLOB_ALIGN_LOG2;
 
 	/* Figure out where the new data will start */
 	data_start = map_to_sysmem(hdr) + hdr->alloced + sizeof(*rec);
@@ -176,8 +178,7 @@ static int bloblist_addrec(uint tag, int size, int align_log2,
 	}
 	rec = (void *)hdr + hdr->alloced;
 
-	rec->tag = tag;
-	rec->hdr_size = sizeof(struct bloblist_rec);
+	rec->tag_and_hdr_size = tag | sizeof(*rec) << BLOBLISTR_HDR_SIZE_SHIFT;
 	rec->size = size;
 
 	/* Zero the record data */
@@ -281,8 +282,8 @@ static int bloblist_resize_rec(struct bloblist_hdr *hdr,
 	int new_alloced;	/* New value for @hdr->alloced */
 	ulong next_ofs;	/* Offset of the record after @rec */
 
-	expand_by = ALIGN(new_size - rec->size, BLOBLIST_ALIGN);
-	new_alloced = ALIGN(hdr->alloced + expand_by, BLOBLIST_ALIGN);
+	expand_by = ALIGN(new_size - rec->size, BLOBLIST_BLOB_ALIGN);
+	new_alloced = ALIGN(hdr->alloced + expand_by, BLOBLIST_BLOB_ALIGN);
 	if (new_size < 0) {
 		log_debug("Attempt to shrink blob size below 0 (%x)\n",
 			  new_size);
diff --git a/include/bloblist.h b/include/bloblist.h
index ab7a7fc299..745bcdd227 100644
--- a/include/bloblist.h
+++ b/include/bloblist.h
@@ -24,11 +24,11 @@
  * which would add to code size. For Thumb-2 the code size needed in SPL is
  * approximately 940 bytes (e.g. for chromebook_bob).
  *
- * 5. Bloblist uses 16-byte alignment internally and is designed to start on a
- * 16-byte boundary. Its headers are multiples of 16 bytes. This makes it easier
- * to deal with data structures which need this level of alignment, such as ACPI
- * tables. For use in SPL and TPL the alignment can be relaxed, since it can be
- * relocated to an aligned address in U-Boot proper.
+ * 5. Bloblist uses 8-byte alignment internally and is designed to start on a
+ * 8-byte boundary. Its headers are 8 bytes long. It is possible to achieve
+ * larger alignment (e.g. 16 bytes) by adding a dummy header, For use in SPL and
+ * TPL the alignment can be relaxed, since it can be relocated to an aligned
+ * address in U-Boot proper.
  *
  * 6. Bloblist is designed to be passed to Linux as reserved memory. While linux
  * doesn't understand the bloblist header, it can be passed the indivdual blobs.
@@ -77,6 +77,9 @@ enum {
 	BLOBLIST_VERSION	= 1,
 	BLOBLIST_MAGIC		= 0x6ed0ff,
 
+	BLOBLIST_BLOB_ALIGN_LOG2 = 3,
+	BLOBLIST_BLOB_ALIGN	 = 1 << BLOBLIST_BLOB_ALIGN_LOG2,
+
 	BLOBLIST_ALIGN_LOG2	= 3,
 	BLOBLIST_ALIGN		= 1 << BLOBLIST_ALIGN_LOG2,
 };
@@ -195,17 +198,25 @@ struct bloblist_hdr {
  *
  * NOTE: Only exported for testing purposes. Do not use this struct.
  *
- * @tag: Tag indicating what the record contains
- * @hdr_size: Size of this header, normally sizeof(struct bloblist_rec). The
- *	record's data starts at this offset from the start of the record
+ * @tag_and_hdr_size: Tag indicating what the record contains (bottom 24 bits), and
+ *	size of this header (top 8 bits), normally sizeof(struct bloblist_rec).
+ *	The record's data starts at this offset from the start of the record
  * @size: Size of record in bytes, excluding the header size. This does not
  *	need to be aligned (e.g. 3 is OK).
  */
 struct bloblist_rec {
-	u32 tag;
-	u32 hdr_size;
+	u32 tag_and_hdr_size;
 	u32 size;
-	u32 _spare;
+};
+
+enum {
+	BLOBLISTR_TAG_SHIFT		= 0,
+	BLOBLISTR_TAG_MASK		= 0xffffffU << BLOBLISTR_TAG_SHIFT,
+	BLOBLISTR_HDR_SIZE_SHIFT	= 24,
+	BLOBLISTR_HDR_SIZE_MASK		= 0xffU << BLOBLISTR_HDR_SIZE_SHIFT,
+
+	BLOBLIST_HDR_SIZE		= sizeof(struct bloblist_hdr),
+	BLOBLIST_REC_HDR_SIZE		= sizeof(struct bloblist_rec),
 };
 
 /**
diff --git a/test/bloblist.c b/test/bloblist.c
index 32256be772..7e65f30518 100644
--- a/test/bloblist.c
+++ b/test/bloblist.c
@@ -261,8 +261,8 @@ static int bloblist_test_cmd_info(struct unit_test_state *uts)
 	run_command("bloblist info", 0);
 	ut_assert_nextline("base:     %lx", (ulong)map_to_sysmem(hdr));
 	ut_assert_nextline("size:     400    1 KiB");
-	ut_assert_nextline("alloced:  70     112 Bytes");
-	ut_assert_nextline("free:     390    912 Bytes");
+	ut_assert_nextline("alloced:  58     88 Bytes");
+	ut_assert_nextline("free:     3a8    936 Bytes");
 	ut_assert_console_end();
 	ut_unsilence_console(uts);
 
@@ -320,12 +320,12 @@ static int bloblist_test_align(struct unit_test_state *uts)
 		data = bloblist_add(i, size, 0);
 		ut_assertnonnull(data);
 		addr = map_to_sysmem(data);
-		ut_asserteq(0, addr & (BLOBLIST_ALIGN - 1));
+		ut_asserteq(0, addr & (BLOBLIST_BLOB_ALIGN - 1));
 
 		/* Only the bytes in the blob data should be zeroed */
 		for (j = 0; j < size; j++)
 			ut_asserteq(0, data[j]);
-		for (; j < BLOBLIST_ALIGN; j++)
+		for (; j < BLOBLIST_BLOB_ALIGN; j++)
 			ut_asserteq(ERASE_BYTE, data[j]);
 	}
 
@@ -340,7 +340,7 @@ static int bloblist_test_align(struct unit_test_state *uts)
 	}
 
 	/* Check alignment with an bloblist starting on a smaller alignment */
-	hdr = map_sysmem(TEST_ADDR + BLOBLIST_ALIGN, TEST_BLOBLIST_SIZE);
+	hdr = map_sysmem(TEST_ADDR + BLOBLIST_BLOB_ALIGN, TEST_BLOBLIST_SIZE);
 	memset(hdr, ERASE_BYTE, TEST_BLOBLIST_SIZE);
 	memset(hdr, '\0', sizeof(*hdr));
 	ut_assertok(bloblist_new(TEST_ADDR + BLOBLIST_ALIGN,
@@ -349,7 +349,7 @@ static int bloblist_test_align(struct unit_test_state *uts)
 	data = bloblist_add(1, 5, BLOBLIST_ALIGN_LOG2 + 1);
 	ut_assertnonnull(data);
 	addr = map_to_sysmem(data);
-	ut_asserteq(0, addr & (BLOBLIST_ALIGN * 2 - 1));
+	ut_asserteq(0, addr & (BLOBLIST_BLOB_ALIGN * 2 - 1));
 
 	return 0;
 }
@@ -437,7 +437,7 @@ static int bloblist_test_grow(struct unit_test_state *uts)
 	hdr = ptr;
 	ut_asserteq(sizeof(struct bloblist_hdr) +
 		    sizeof(struct bloblist_rec) * 2 + small_size * 2 +
-		    BLOBLIST_ALIGN,
+		    BLOBLIST_BLOB_ALIGN,
 		    hdr->alloced);
 
 	return 0;
@@ -572,7 +572,7 @@ static int bloblist_test_resize_last(struct unit_test_state *uts)
 	ut_asserteq((u8)ERASE_BYTE, *((u8 *)hdr + alloced_val + 4));
 
 	/* Check that the new top of the allocated blobs has not been touched */
-	alloced_val += BLOBLIST_ALIGN;
+	alloced_val += BLOBLIST_BLOB_ALIGN;
 	ut_asserteq(alloced_val, hdr->alloced);
 	ut_asserteq((u8)ERASE_BYTE, *((u8 *)hdr + hdr->alloced));
 
-- 
2.25.1



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