[S] Change in coreboot[master]: lib/smbios: Add 32 bit entry point if below 4G

[Maximilian Brune (Code Review)]

Maximilian Brune has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/76911?usp=email )

Change subject: lib/smbios: Add 32 bit entry point if below 4G
......................................................................

lib/smbios: Add 32 bit entry point if below 4G

If the smbios table is not below 4G there is no need to have a 32 bit
entry point. Even worse it could cause the payload to try to use the
entry point.

Signed-off-by: Maximilian Brune 
Change-Id: I4cb426bb0c45282ed03ff4c65d15004b7f985dab
---
M src/lib/smbios.c
1 file changed, 22 insertions(+), 17 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/11/76911/1

diff --git a/src/lib/smbios.c b/src/lib/smbios.c
index deee193b..f03d743 100644
--- a/src/lib/smbios.c
+++ b/src/lib/smbios.c
@@ -1201,7 +1201,7 @@

unsigned long smbios_write_tables(unsigned long current)
 {
-	struct smbios_entry *se;
+	struct smbios_entry *se = NULL;
    struct smbios_entry30 *se3;
    unsigned long tables;
    int len = 0;
@@ -1211,9 +1211,12 @@
    current = ALIGN_UP(current, 16);
    printk(BIOS_DEBUG, "%s: %08lx\n", __func__, current);

-	se = (struct smbios_entry *)current;
-	current += sizeof(*se);
-	current = ALIGN_UP(current, 16);
+	// only add a 32 bit entry point if SMBIOS table is below 4G
+	if (current < UINT32_MAX) {
+		se = (struct smbios_entry *)current;
+		current += sizeof(*se);
+		current = ALIGN_UP(current, 16);
+	}

se3 = (struct smbios_entry30 *)current;
    current += sizeof(*se3);
@@ -1251,21 +1254,23 @@

update_max(len, max_struct_size, smbios_write_type127(&current, handle++));

-	/* Install SMBIOS 2.1 entry point */
-	memset(se, 0, sizeof(*se));
-	memcpy(se->anchor, "_SM_", 4);
-	se->length = sizeof(*se);
-	se->major_version = 3;
-	se->minor_version = 0;
-	se->max_struct_size = max_struct_size;
-	se->struct_count = handle;
-	memcpy(se->intermediate_anchor_string, "_DMI_", 5);
+	if (se) {
+		/* Install SMBIOS 2.1 entry point */
+		memset(se, 0, sizeof(*se));
+		memcpy(se->anchor, "_SM_", 4);
+		se->length = sizeof(*se);
+		se->major_version = 3;
+		se->minor_version = 0;
+		se->max_struct_size = max_struct_size;
+		se->struct_count = handle;
+		memcpy(se->intermediate_anchor_string, "_DMI_", 5);

-	se->struct_table_address = (u32)tables;
-	se->struct_table_length = len;
+		se->struct_table_address = (u32)tables;
+		se->struct_table_length = len;

-	se->intermediate_checksum = smbios_checksum((u8 *)se + 0x10, sizeof(*se) - 0x10);
-	se->checksum = smbios_checksum((u8 *)se, sizeof(*se));
+		se->intermediate_checksum = smbios_checksum((u8 *)se + 0x10, sizeof(*se) - 0x10);
+		se->checksum = smbios_checksum((u8 *)se, sizeof(*se));
+	}

/* Install SMBIOS 3.0 entry point */
    memset(se3, 0, sizeof(*se3));