firmware: dmi_scan: Fix ordering of product_uuid

[ Upstream commit 5c1ac56b51b9d222ab202dec1ac2f4215346129d ]

In function dmi_present(), dmi_walk_early() calls dmi_table(), which
calls dmi_decode(), which ultimately calls dmi_save_uuid(). This last
function makes a decision based on the value of global variable
dmi_ver. The problem is that this variable is set right _after_
dmi_walk_early() returns. So dmi_save_uuid() always sees dmi_ver == 0
regardless of the actual version implemented.

This causes /sys/class/dmi/id/product_uuid to always use the old
ordering even on systems implementing DMI/SMBIOS 2.6 or later, which
should use the new ordering.

This is broken since kernel v3.8 for legacy DMI implementations and
since kernel v3.10 for SMBIOS 2 implementations. SMBIOS 3
implementations with the 64-bit entry point are not affected.

The first breakage does not matter much as in practice legacy DMI
implementations are always for versions older than 2.6, which is when
the UUID ordering changed. The second breakage is more problematic as
it affects the vast majority of x86 systems manufactured since 2009.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: 9f9c9cbb6057 ("drivers/firmware/dmi_scan.c: fetch dmi version from SMBIOS if it exists")
Fixes: 79bae42d51a5 ("dmi_scan: refactor dmi_scan_machine(), {smbios,dmi}_present()")
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Artem Savkov <artem.savkov@gmail.com>
Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: stable@vger.kernel.org [v3.10+]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 17afc51f3054402c22a2a8d2fd50c1c809edd160..35286fe52823e4e916c7524cf31fce0005136682 100644 (file)
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -489,6 +489,10 @@ static int __init dmi_present(const u8 *buf)
        buf += 16;
 
        if (memcmp(buf, "_DMI_", 5) == 0 && dmi_checksum(buf, 15)) {
+               if (smbios_ver)
+                       dmi_ver = smbios_ver;
+               else
+                       dmi_ver = (buf[14] & 0xF0) << 4 | (buf[14] & 0x0F);
                dmi_num = (buf[13] << 8) | buf[12];
                dmi_len = (buf[7] << 8) | buf[6];
                dmi_base = (buf[11] << 24) | (buf[10] << 16) |
@@ -496,12 +500,9 @@ static int __init dmi_present(const u8 *buf)
 
                if (dmi_walk_early(dmi_decode) == 0) {
                        if (smbios_ver) {
-                               dmi_ver = smbios_ver;
                                pr_info("SMBIOS %d.%d present.\n",
                                       dmi_ver >> 8, dmi_ver & 0xFF);
                        } else {
-                               dmi_ver = (buf[14] & 0xF0) << 4 |
-                                          (buf[14] & 0x0F);
                                pr_info("Legacy DMI %d.%d present.\n",
                                       dmi_ver >> 8, dmi_ver & 0xFF);
                        }