[PATCH v5 04/12] smbios: Use SMBIOS 3.0 to support an address above 4GB

[Simon Glass]

When the SMBIOS table is written to an address above 4GB a 32-bit table
address is not large enough.

Use an SMBIOS3 table in that case.

Note that we cannot use efi_allocate_pages() since this function has
nothing to do with EFI. There is no equivalent function to allocate
memory below 4GB in U-Boot. One solution would be to create a separate
malloc() pool, or just always put the malloc() pool below 4GB.

- Use log_debug() for warning
- Rebase on Heinrich's smbios.h patch
- Set the checksum for SMBIOS3

Signed-off-by: Simon Glass <sjg at chromium.org>
---

(no changes since v4)

Changes in v4:
- Check the start of the table rather than the end

Changes in v2:
- Check the end of the table rather than the start.

 include/smbios.h |  6 +++++-
 lib/smbios.c     | 30 +++++++++++++++++++++++++-----
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/include/smbios.h b/include/smbios.h
index e601283d293..77be58887a2 100644
--- a/include/smbios.h
+++ b/include/smbios.h
@@ -12,7 +12,7 @@
 
 /* SMBIOS spec version implemented */
 #define SMBIOS_MAJOR_VER	3
-#define SMBIOS_MINOR_VER	0
+#define SMBIOS_MINOR_VER	7
 
 enum {
 	SMBIOS_STR_MAX	= 64,	/* Maximum length allowed for a string */
@@ -80,6 +80,10 @@ struct __packed smbios3_entry {
 	u64 struct_table_address;
 };
 
+/* These two structures should use the same amount of 16-byte-aligned space */
+static_assert(ALIGN(16, sizeof(struct smbios_entry)) ==
+	      ALIGN(16, sizeof(struct smbios3_entry)));
+
 /* BIOS characteristics */
 #define BIOS_CHARACTERISTICS_PCI_SUPPORTED	(1 << 7)
 #define BIOS_CHARACTERISTICS_UPGRADEABLE	(1 << 11)
diff --git a/lib/smbios.c b/lib/smbios.c
index eea72670bd9..7f79d969c92 100644
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -567,7 +567,11 @@ ulong write_smbios_table(ulong addr)
 	addr = ALIGN(addr, 16);
 	start_addr = addr;
 
-	addr += sizeof(struct smbios_entry);
+	/*
+	 * So far we don't know which struct will be used, but they both end
+	 * up using the same amount of 16-bit-aligned space
+	 */
+	addr += max(sizeof(struct smbios_entry), sizeof(struct smbios3_entry));
 	addr = ALIGN(addr, 16);
 	tables = addr;
 
@@ -590,16 +594,32 @@ ulong write_smbios_table(ulong addr)
 	 * We must use a pointer here so things work correctly on sandbox. The
 	 * user of this table is not aware of the mapping of addresses to
 	 * sandbox's DRAM buffer.
+	 *
+	 * Check the address of the end of the tables. If it is above 4GB then
+	 * it is sensible to use SMBIOS3 even if the start of the table is below
+	 * 4GB (this case is very unlikely to happen in practice)
 	 */
 	table_addr = (ulong)map_sysmem(tables, 0);
-	if (sizeof(table_addr) > sizeof(u32) && table_addr > (ulong)UINT_MAX) {
+	if (sizeof(table_addr) > sizeof(u32) && addr >= (ulong)UINT_MAX) {
+		struct smbios3_entry *se;
 		/*
 		 * We need to put this >32-bit pointer into the table but the
 		 * field is only 32 bits wide.
 		 */
-		printf("WARNING: SMBIOS table_address overflow %llx\n",
-		       (unsigned long long)table_addr);
-		addr = 0;
+		log_debug("WARNING: Using SMBIOS3.0 due to table-address overflow %lx\n",
+			  table_addr);
+		se = map_sysmem(start_addr, sizeof(struct smbios_entry));
+		memset(se, '\0', sizeof(struct smbios_entry));
+		memcpy(se->anchor, "_SM3_", 5);
+		se->length = sizeof(struct smbios3_entry);
+		se->major_ver = SMBIOS_MAJOR_VER;
+		se->minor_ver = SMBIOS_MINOR_VER;
+		se->doc_rev = 0;
+		se->entry_point_rev = 1;
+		se->max_struct_size = len;
+		se->struct_table_address = table_addr;
+		se->checksum = table_compute_checksum(se,
+						sizeof(struct smbios3_entry));
 	} else {
 		struct smbios_entry *se;
 
-- 
2.34.1