[v2,17/23] x86/boot: Reduce size of the DOS stub

Commit Message

Evgeniy Baskov Oct. 25, 2022, 2:12 p.m. UTC

This is required to fit more sections in PE section tables,
since its size is restricted by zero page located at specific offset
after the PE header.

Signed-off-by: Evgeniy Baskov <[e-mail]>
---
 arch/x86/boot/header.S | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

Patch

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index f912d7770130..e4de831b2f64 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -59,17 +59,16 @@  start2:
 	cld
 
 	movw	$bugger_off_msg, %si
+	movw	$bugger_off_msg_size, %cx
 
 msg_loop:
 	lodsb
-	andb	%al, %al
-	jz	bs_die
 	movb	$0xe, %ah
 	movw	$7, %bx
 	int	$0x10
-	jmp	msg_loop
+	decw	%cx
+	jnz	msg_loop
 
-bs_die:
 	# Allow the user to press a key, then reboot
 	xorw	%ax, %ax
 	int	$0x16
@@ -89,10 +88,9 @@  bs_die:
 
 	.section ".bsdata", "a"
 bugger_off_msg:
-	.ascii	"Use a boot loader.\r\n"
-	.ascii	"\n"
-	.ascii	"Remove disk and press any key to reboot...\r\n"
-	.byte	0
+	.ascii	"Use a boot loader. "
+	.ascii	"Press a key to reboot"
+	.set	bugger_off_msg_size, . - bugger_off_msg
 
 #ifdef CONFIG_EFI_STUB
 pe_header: