Re: [PATCH] m68k: virt: correctly set the initial PC

[Philippe Mathieu-Daudé]

On 5/4/21 3:18 PM, Laurent Vivier wrote:
> Set initial PC to the entry of the loaded kernel.
> 
> This fixes kernel reboot with "-kernel" parameter.
> 
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  hw/m68k/virt.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c
> index e9a5d4c69b97..4fb3a7ebf0f2 100644
> --- a/hw/m68k/virt.c
> +++ b/hw/m68k/virt.c
> @@ -88,14 +88,21 @@
>  #define VIRT_VIRTIO_MMIO_BASE 0xff010000     /* MMIO: 0xff010000 - 
> 0xff01ffff */
>  #define VIRT_VIRTIO_IRQ_BASE  PIC_IRQ(2, 1)  /* PIC: 2, 3, 4, 5, IRQ: ALL */
>  
> +typedef struct {
> +    M68kCPU *cpu;
> +    hwaddr initial_pc;
> +    hwaddr initial_stack;
> +} ResetInfo;
> +
>  static void main_cpu_reset(void *opaque)
>  {
> -    M68kCPU *cpu = opaque;
> +    ResetInfo *reset_info = opaque;
> +    M68kCPU *cpu = reset_info->cpu;
>      CPUState *cs = CPU(cpu);
>  
>      cpu_reset(cs);
> -    cpu->env.aregs[7] = ldl_phys(cs->as, 0);
> -    cpu->env.pc = ldl_phys(cs->as, 4);
> +    cpu->env.aregs[7] = reset_info->initial_stack;
> +    cpu->env.pc = reset_info->initial_pc;
>  }
>  
>  static void virt_init(MachineState *machine)
> @@ -116,6 +123,7 @@ static void virt_init(MachineState *machine)
>      SysBusDevice *sysbus;
>      hwaddr io_base;
>      int i;
> +    ResetInfo *reset_info;
>  
>      if (ram_size > 3399672 * KiB) {
>          /*
> @@ -127,9 +135,13 @@ static void virt_init(MachineState *machine)
>          exit(1);
>      }
>  
> +    reset_info = g_malloc0(sizeof(ResetInfo));
> +
>      /* init CPUs */
>      cpu = M68K_CPU(cpu_create(machine->cpu_type));
> -    qemu_register_reset(main_cpu_reset, cpu);
> +
> +    reset_info->cpu = cpu;
> +    qemu_register_reset(main_cpu_reset, reset_info);
>  
>      /* RAM */
>      memory_region_add_subregion(get_system_memory(), 0, machine->ram);
> @@ -209,7 +221,7 @@ static void virt_init(MachineState *machine)
>              error_report("could not load kernel '%s'", kernel_filename);
>              exit(1);
>          }
> -        stl_phys(cs->as, 4, elf_entry); /* reset initial PC */
> +        reset_info->initial_pc = elf_entry;

Missing the stack?

           reset_info->initial_stack = ldl_phys(cs->as, 0);

>          parameters_base = (high + 1) & ~1;
>  
>          BOOTINFO1(cs->as, parameters_base, BI_MACHTYPE, MACH_VIRT);
>