x86/boot: Drop redundant code setting the root device

The root device defaults to 0,0 and is no longer configurable at build
time [0], so there is no need for the build tool to ever write to this
field.

[0] 079f85e624189292 ("x86, build: Do not set the root_dev field in bzImage")

This change has no impact on the resulting bzImage binary.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230912090051.4014114-23-ardb@google.com

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index a87d9133384b0986124cfa154be3081d2a707bcf..6059f87b159d0e14d64f61875570a9dd1730e0d6 100644 (file)
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -236,7 +236,7 @@ root_flags: .word ROOT_RDONLY
 syssize:       .long 0                 /* Filled in by build.c */
 ram_size:      .word 0                 /* Obsolete */
 vid_mode:      .word SVGA_MODE
-root_dev:      .word 0                 /* Filled in by build.c */
+root_dev:      .word 0                 /* Default to major/minor 0/0 */
 boot_flag:     .word 0xAA55
 
        # offset 512, entry point

diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 0354c223e35492b61e0a0c8c1c18dd5385eba421..efa4e9c7d7135ba7f3292dba74d2ba3f8f10e19f 100644 (file)
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -40,10 +40,6 @@ typedef unsigned char  u8;
 typedef unsigned short u16;
 typedef unsigned int   u32;
 
-#define DEFAULT_MAJOR_ROOT 0
-#define DEFAULT_MINOR_ROOT 0
-#define DEFAULT_ROOT_DEV (DEFAULT_MAJOR_ROOT << 8 | DEFAULT_MINOR_ROOT)
-
 /* Minimal number of setup sectors */
 #define SETUP_SECT_MIN 5
 #define SETUP_SECT_MAX 64
@@ -399,9 +395,6 @@ int main(int argc, char ** argv)
 
        update_pecoff_setup_and_reloc(i);
 
-       /* Set the default root device */
-       put_unaligned_le16(DEFAULT_ROOT_DEV, &buf[508]);
-
        /* Open and stat the kernel file */
        fd = open(argv[2], O_RDONLY);
        if (fd < 0)