> From: Ted Bullock <tbullock@comlore.com>
> Date: Tue, 03 Nov 2026 23:19:04 -0600

This will have to be tested on a wider range of real hardware.

> Hi David and tech@
> 
> Ok, so the OpenBSD kernel and bootloader have a defect according to the
> open firmware specification that stops openbsd from booting with sparc on
> qemu with its bundled firmware. We’re requesting zero return values and leaving
> no space for the catch result and ending up clobbered with overwritten memory.
> 
> The openboot firmware is more graceful for our request than openbios
> which is why we don't see this on physical sun machines.
> 
> Anyway, this shows up a few times for the call-method firmware operation,
> it's supposed to be able to return the extra value and we are getting
> hit by that.
> 
> The following patch fixes the kernel and the bootloader so they follow
> the Open Firmware Client Interface Developer’s Guide.
> 
> Page 26 has the rule:
> The arguments N_args and N_returns specify the number of calling arguments
> and return values; they must agree with the number of arguments and
> return values expected by the particular service.
> 
> and Page 30 describes "call-method"
> OUT: catch-result, stack-result1, ... , stack-resultQ
> 
> Pops the result returned by catch into catch-result.
> 
> If that result is zero, pops up to N_returns-1 items from the Forth data
> stack into the returned values portion of the argument array, with
> stack_result1 corresponding to the top of the stack.
> 
> Anyway, my Sun Blade boots without this patch. With the patch, QEMU boots
> with its shipped BIOS.
> 
> --- a/sys/arch/sparc64/sparc64/ofw_machdep.c
> +++ b/sys/arch/sparc64/sparc64/ofw_machdep.c
> @@ -260,6 +260,7 @@
>  		cell_t ihandle;
>  		cell_t len;
>  		cell_t vaddr;
> +		cell_t status;
>  	} args;
>  
>  	if (mmuh == -1 && ((mmuh = get_mmu_handle()) == -1)) {
> @@ -268,7 +269,7 @@
>  	}
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 4;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("release");
>  	args.ihandle = HDL2CELL(mmuh);
>  	args.vaddr = ADR2CELL(vaddr);
> @@ -293,6 +294,7 @@
>  		cell_t ihandle;
>  		cell_t len;
>  		cell_t vaddr;
> +		cell_t status;
>  	} args;
>  
>  	if (mmuh == -1 && ((mmuh = get_mmu_handle()) == -1)) {
> @@ -301,7 +303,7 @@
>  	}
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 4;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("unmap");
>  	args.ihandle = HDL2CELL(mmuh);
>  	args.vaddr = ADR2CELL(vaddr);
> @@ -328,6 +330,7 @@
>  		cell_t vaddr;
>  		cell_t phys_hi;
>  		cell_t phys_lo;
> +		cell_t status;
>  	} args;
>  
>  	if (mmuh == -1 && ((mmuh = get_mmu_handle()) == -1)) {
> @@ -336,7 +339,7 @@
>  	}
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 7;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("map");
>  	args.ihandle = HDL2CELL(mmuh);
>  	args.mode = mode;
> @@ -443,6 +446,7 @@
>  		cell_t len;
>  		cell_t phys_hi;
>  		cell_t phys_lo;
> +		cell_t status;
>  	} args;
>  
>  	if (memh == -1 && ((memh = get_memory_handle()) == -1)) {
> @@ -451,7 +455,7 @@
>  	}
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 5;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("release");
>  	args.ihandle = HDL2CELL(memh);
>  	args.len = len;
> 
> --- a/sys/arch/sparc64/stand/ofwboot/Locore.c
> +++ b/sys/arch/sparc64/stand/ofwboot/Locore.c
> @@ -420,11 +420,12 @@
>  		cell_t ihandle;
>  		cell_t len;
>  		cell_t vaddr;
> +		cell_t status;
>  	} args;
>  
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 4;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("release");
>  	args.ihandle = HDL2CELL(mmuh);
>  	args.vaddr = ADR2CELL(vaddr);
> @@ -452,11 +453,12 @@
>  		cell_t vaddr;
>  		cell_t paddr_hi;
>  		cell_t paddr_lo;
> +		cell_t status;
>  	} args;
>  
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 7;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("map");
>  	args.ihandle = HDL2CELL(mmuh);
>  	args.mode = mode;
> @@ -519,11 +521,12 @@
>  		cell_t len;
>  		cell_t phys_hi;
>  		cell_t phys_lo;
> +		cell_t status;
>  	} args;
>  
>  	args.name = ADR2CELL("call-method");
>  	args.nargs = 5;
> -	args.nreturns = 0;
> +	args.nreturns = 1;
>  	args.method = ADR2CELL("release");
>  	args.ihandle = HDL2CELL(memh);
>  	args.len = len;
> 
>