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path: root/drivers/firmware/dmi_scan.c
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Diffstat (limited to 'drivers/firmware/dmi_scan.c')
-rw-r--r--drivers/firmware/dmi_scan.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index eb760a2..232fa8f 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -419,6 +419,13 @@ static void __init dmi_format_ids(char *buf, size_t len)
dmi_get_system_info(DMI_BIOS_DATE));
}
+/*
+ * Check for DMI/SMBIOS headers in the system firmware image. Any
+ * SMBIOS header must start 16 bytes before the DMI header, so take a
+ * 32 byte buffer and check for DMI at offset 16 and SMBIOS at offset
+ * 0. If the DMI header is present, set dmi_ver accordingly (SMBIOS
+ * takes precedence) and return 0. Otherwise return 1.
+ */
static int __init dmi_present(const u8 *buf)
{
int smbios_ver;
@@ -506,6 +513,13 @@ void __init dmi_scan_machine(void)
if (p == NULL)
goto error;
+ /*
+ * Iterate over all possible DMI header addresses q.
+ * Maintain the 32 bytes around q in buf. On the
+ * first iteration, substitute zero for the
+ * out-of-range bytes so there is no chance of falsely
+ * detecting an SMBIOS header.
+ */
memset(buf, 0, 16);
for (q = p; q < p + 0x10000; q += 16) {
memcpy_fromio(buf + 16, q, 16);
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