diff mbox series

efi: Use standard format for printing the EFI revision

Message ID 20230131131043.1707904-1-ardb@kernel.org
State New
Headers show
Series efi: Use standard format for printing the EFI revision | expand

Commit Message

Ard Biesheuvel Jan. 31, 2023, 1:10 p.m. UTC
The UEFI spec section 4.2.1 describes the way the human readable EFI
revision should be constructed from the 32-bit revision field in the
system table:

  The upper 16 bits of this field contain the major revision value,
  and the lower 16 bits contain the minor revision value. The minor
  revision values are binary coded decimals and are limited to the
  range of 00..99.

  When printed or displayed UEFI spec revision is referred as (Major
  revision).(Minor revision upper decimal).(Minor revision lower
  decimal) or (Major revision).(Minor revision upper decimal) in case
  Minor revision lower decimal is set to 0.

Let's adhere to this when logging the EFI revision to the kernel log.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/efi.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 14797a0332c60bed..6bbc8cc6dc0d4d45 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -806,6 +806,7 @@  void __init efi_systab_report_header(const efi_table_hdr_t *systab_hdr,
 	char vendor[100] = "unknown";
 	const efi_char16_t *c16;
 	size_t i;
+	int rev;
 
 	c16 = map_fw_vendor(fw_vendor, sizeof(vendor) * sizeof(efi_char16_t));
 	if (c16) {
@@ -816,10 +817,12 @@  void __init efi_systab_report_header(const efi_table_hdr_t *systab_hdr,
 		unmap_fw_vendor(c16, sizeof(vendor) * sizeof(efi_char16_t));
 	}
 
-	pr_info("EFI v%u.%.02u by %s\n",
-		systab_hdr->revision >> 16,
-		systab_hdr->revision & 0xffff,
-		vendor);
+	pr_info("EFI v%u.%u", systab_hdr->revision >> 16,
+		(systab_hdr->revision & 0xffff) / 10);
+	rev = (systab_hdr->revision & 0xffff) % 10;
+	if (rev)
+		pr_cont(".%u", rev);
+	pr_cont(" by %s\n", vendor);
 
 	if (IS_ENABLED(CONFIG_X86_64) &&
 	    systab_hdr->revision > EFI_1_10_SYSTEM_TABLE_REVISION &&