misc/59151: efiboot hangs on new motherboard

[stix%stix.id.au@localhost]

>Number:         59151
>Category:       misc
>Synopsis:       efiboot hangs on new motherboard
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 07 05:00:00 +0000 2025
>Originator:     Paul Ripke
>Release:        NetBSD 10.1_STABLE
>Organization:
Paul Ripke
"Great minds discuss ideas, average minds discuss events, small minds
 discuss people."
-- Disputed: Often attributed to Eleanor Roosevelt. 1948.
>Environment:
System: NetBSD slave 10.1_STABLE NetBSD 10.1_STABLE (SLAVE) #13: Sun Jan 26 21:19:05 AEDT 2025 stix@slave:/home/netbsd/netbsd-10/obj.amd64/home/netbsd/netbsd-10/src/sys/arch/amd64/compile/SLAVE amd64
Architecture: x86_64
Machine: amd64
>Description:
Booting live image, install image, etc, from USB hangs apparently after
loading efiboot, leaving a blank screen with a text-mode cursor in the top
left.
This is on a new Gigabyte B650M DS3H motherboard with latest BIOS/firmware.

>How-To-Repeat:
Try booting one of these motherboards.
>Fix:
I suspect that this firmware implements memory protection on the efiboot
image. I also assume that the variables written to as defined in the asm
are read-only, generating an exception, resulting in a silent hang.

This patch fixes it for me:

diff --git a/sys/arch/i386/stand/efiboot/bootx64/efibootx64.c b/sys/arch/i386/stand/efiboot/bootx64/efibootx64.c
index feb51595eda2..b34505461bc4 100644
--- a/sys/arch/i386/stand/efiboot/bootx64/efibootx64.c
+++ b/sys/arch/i386/stand/efiboot/bootx64/efibootx64.c
@@ -30,14 +30,14 @@
 
 #include <sys/bootblock.h>
 
-void startprog64_start(physaddr_t, physaddr_t, physaddr_t, u_long,
+extern void startprog64_start(physaddr_t, physaddr_t, physaddr_t, u_long,
     void *, physaddr_t);
-extern void (*startprog64)(physaddr_t, physaddr_t, physaddr_t, u_long,
+void (*startprog64)(physaddr_t, physaddr_t, physaddr_t, u_long,
     void *, physaddr_t);
 extern u_int startprog64_size;
 
-void multiboot64_start(physaddr_t, physaddr_t, uint32_t);
-extern void (*multiboot64)(physaddr_t, physaddr_t, uint32_t);
+extern void multiboot64_start(physaddr_t, physaddr_t, uint32_t);
+void (*multiboot64)(physaddr_t, physaddr_t, uint32_t);
 extern u_int multiboot64_size;
 
 void
diff --git a/sys/arch/i386/stand/efiboot/bootx64/multiboot64.S b/sys/arch/i386/stand/efiboot/bootx64/multiboot64.S
index 96757aeccc03..cb040d27b86a 100644
--- a/sys/arch/i386/stand/efiboot/bootx64/multiboot64.S
+++ b/sys/arch/i386/stand/efiboot/bootx64/multiboot64.S
@@ -6,10 +6,6 @@
 #define DATA_SEGMENT    0x10
 
 	.align	16
-	.globl _C_LABEL(multiboot64)
-_C_LABEL(multiboot64):
-	.quad 0
-
 	.globl _C_LABEL(multiboot64_size)
 _C_LABEL(multiboot64_size):
 	.long multiboot64_end - _C_LABEL(multiboot64_start)
diff --git a/sys/arch/i386/stand/efiboot/bootx64/startprog64.S b/sys/arch/i386/stand/efiboot/bootx64/startprog64.S
index 050e3068a243..0c2643a7254d 100644
--- a/sys/arch/i386/stand/efiboot/bootx64/startprog64.S
+++ b/sys/arch/i386/stand/efiboot/bootx64/startprog64.S
@@ -66,10 +66,6 @@ WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #define	DATA_SEGMENT	0x10
 
 	.align	16
-	.globl _C_LABEL(startprog64)
-_C_LABEL(startprog64):
-	.quad 0
-
 	.globl _C_LABEL(startprog64_size)
 _C_LABEL(startprog64_size):
 	.long startprog64_end - _C_LABEL(startprog64_start)