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Re: [PATCH] m68k: virt: correctly set the initial PC
From: |
Laurent Vivier |
Subject: |
Re: [PATCH] m68k: virt: correctly set the initial PC |
Date: |
Tue, 4 May 2021 16:20:47 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 |
Le 04/05/2021 à 16:13, Philippe Mathieu-Daudé a écrit :
> 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);
No, as it's a g_malloc0(), initial_stack is set to 0, so aregs[7] (SP) will be
reset to 0 on reboot.
We could also set it to ram_size if we want something usable, but it's not
needed for the kernel
entry point.
Thanks,
Laurent