From: Jean Delvare jdelvare@suse.de
[ Upstream commit c9aba14362a6eec583819ec8f4b872c1816f5cbe ]
Since version 3.0.0 of the SMBIOS specification, there can be multiple entry points in memory, pointing to one or two DMI tables. If both a 32-bit ("_SM_") entry point and a 64-bit ("_SM3_") entry point are present, the specification requires that the latter points to a table which is a super-set of the table pointed to by the former. Therefore we should give preference to the 64-bit ("_SM3_") entry point.
However, currently the code is picking the first valid entry point it finds. Per specification, we should look for a 64-bit ("_SM3_") entry point first, and if we can't find any, look for a 32-bit ("_SM_" or "_DMI_") entry point. Modify the code to do that.
Signed-off-by: Jean Delvare jdelvare@suse.de Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/firmware/dmi_scan.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c index 88bebe1968b7..8590f94de9dc 100644 --- a/drivers/firmware/dmi_scan.c +++ b/drivers/firmware/dmi_scan.c @@ -648,6 +648,21 @@ void __init dmi_scan_machine(void) if (p == NULL) goto error;
+ /* + * Same logic as above, look for a 64-bit entry point + * first, and if not found, fall back to 32-bit entry point. + */ + memcpy_fromio(buf, p, 16); + for (q = p + 16; q < p + 0x10000; q += 16) { + memcpy_fromio(buf + 16, q, 16); + if (!dmi_smbios3_present(buf)) { + dmi_available = 1; + dmi_early_unmap(p, 0x10000); + goto out; + } + memcpy(buf, buf + 16, 16); + } + /* * Iterate over all possible DMI header addresses q. * Maintain the 32 bytes around q in buf. On the @@ -658,7 +673,7 @@ void __init dmi_scan_machine(void) memset(buf, 0, 16); for (q = p; q < p + 0x10000; q += 16) { memcpy_fromio(buf + 16, q, 16); - if (!dmi_smbios3_present(buf) || !dmi_present(buf)) { + if (!dmi_present(buf)) { dmi_available = 1; dmi_early_unmap(p, 0x10000); goto out;