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firmware: dmi_scan: Fix ordering of product_uuid

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commit 5c1ac56b51 upstream.

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: 9f9c9cbb60 ("drivers/firmware/dmi_scan.c: fetch dmi version from SMBIOS if it exists")
Fixes: 79bae42d51 ("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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Jean Delvare
2015-05-14 14:40:50 +02:00
committed by Ben Hutchings
parent 5c64725826
commit b7314518be
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/firmware/dmi_scan.c
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@ -438,6 +438,10 @@ 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) |
@ -445,12 +449,9 @@ 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);
}