[PATCH] firmware/dmi: Print product serial number if any

[Erwan Velu <erwanaliasr1@gmail.com>]

During the boot sequence, the kernel prints a string to identify the
running host. This is pretty handy to estimate the underlying hardware
in case of early crash.

This patch add the product serial number in this reporting if any got found,
or keep the current string. In a large fleet of servers, this
information could be useful to identify the host that generated a given trace.

Test ran with the following command : qemu-system-x86_64 -kernel arch/x86/boot/bzImage --enable-kvm -m 512  -serial stdio  -append 'console=ttyS0' -smbios type=1,serial=R90YT7WC

Prior the patch:
[    0.000000] DMI: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014

With the patch:
[    0.000000] DMI: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014, SN: R90YT7WC

Signed-off-by: Erwan Velu <e.velu@criteo.com>
---
 drivers/firmware/dmi_scan.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 0eb6b617f709..601e003c67f4 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -536,6 +536,7 @@ static void __init dmi_format_ids(char *buf, size_t len)
 {
 	int c = 0;
 	const char *board;	/* Board Name is optional */
+	const char *product_serial; /* Product serial is optional */
 
 	c += print_filtered(buf + c, len - c,
 			    dmi_get_system_info(DMI_SYS_VENDOR));
@@ -554,6 +555,14 @@ static void __init dmi_format_ids(char *buf, size_t len)
 	c += scnprintf(buf + c, len - c, " ");
 	c += print_filtered(buf + c, len - c,
 			    dmi_get_system_info(DMI_BIOS_DATE));
+
+	product_serial = dmi_get_system_info(DMI_PRODUCT_SERIAL);
+	if (product_serial) {
+		if (strlen(product_serial)) {
+			c += scnprintf(buf + c, len - c, ", SN: ");
+			c += print_filtered(buf + c, len - c, product_serial);
+		}
+	}
 }
 
 /*
-- 
2.37.3