Re: [Xen-devel] [PATCH 08/14] xen: arm: support dumping 64-bit guest stack

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 12 Mar 2013, Ian Campbell wrote:
> From: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

it would be nice to support more guest modes but this is undoubtedly an 
improvement.

Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


>  xen/arch/arm/traps.c |   80 
> +++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 76 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index 2f4e157..2671eba 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -523,9 +523,81 @@ void vcpu_show_registers(const struct vcpu *v)
>      _show_registers(&v->arch.cpu_info->guest_cpu_user_regs, &ctxt, 1, v);
>  }
>  
> -static void show_guest_stack(struct cpu_user_regs *regs)
> +static void show_guest_stack(struct vcpu *v, struct cpu_user_regs *regs)
>  {
> -    printk("GUEST STACK GOES HERE\n");
> +    int i;
> +    vaddr_t sp;
> +    paddr_t stack_phys;
> +    void *mapped;
> +    unsigned long *stack, addr;
> +
> +    switch ( regs->cpsr & PSR_MODE_MASK )
> +    {
> +    case PSR_MODE_USR:
> +    case PSR_MODE_SYS:
> +#ifdef CONFIG_ARM_64
> +    case PSR_MODE_EL0t:
> +#endif
> +        printk("No stack trace for guest user-mode\n");
> +        return;
> +
> +    case PSR_MODE_FIQ:
> +    case PSR_MODE_IRQ:
> +    case PSR_MODE_SVC:
> +    case PSR_MODE_ABT:
> +    case PSR_MODE_UND:
> +        printk("No stack trace for 32-bit guest kernel-mode\n");
> +        return;
> +
> +#ifdef CONFIG_ARM_64
> +    case PSR_MODE_EL1t:
> +        sp = regs->sp_el0;
> +        break;
> +    case PSR_MODE_EL1h:
> +        sp = regs->sp_el1;
> +        break;
> +#endif
> +
> +    case PSR_MODE_HYP:
> +    case PSR_MODE_MON:
> +#ifdef CONFIG_ARM_64
> +    case PSR_MODE_EL3h:
> +    case PSR_MODE_EL3t:
> +    case PSR_MODE_EL2h:
> +    case PSR_MODE_EL2t:
> +#endif
> +    default:
> +        BUG();
> +        return;
> +    }
> +
> +    printk("Guest stack trace from sp=%"PRIvaddr":\n  ", sp);
> +
> +    if ( gvirt_to_maddr(sp, &stack_phys) )
> +    {
> +        printk("Failed to convert stack to physical address\n");
> +        return;
> +    }
> +
> +    mapped = map_domain_page(stack_phys >> PAGE_SHIFT);
> +
> +    stack = mapped + (sp & ~PAGE_MASK);
> +
> +    for ( i = 0; i < (debug_stack_lines*stack_words_per_line); i++ )
> +    {
> +        if ( (((long)stack - 1) ^ ((long)(stack + 1) - 1)) & PAGE_SIZE )
> +            break;
> +        addr = *stack;
> +        if ( (i != 0) && ((i % stack_words_per_line) == 0) )
> +            printk("\n  ");
> +        printk(" %p", _p(addr));
> +        stack++;
> +    }
> +    if ( i == 0 )
> +        printk("Stack empty.");
> +    printk("\n");
> +    unmap_domain_page(mapped);
> +
>  }
>  
>  #define STACK_BEFORE_EXCEPTION(regs) ((register_t*)(regs)->sp)
> @@ -589,7 +661,7 @@ void show_stack(struct cpu_user_regs *regs)
>      int i;
>  
>      if ( guest_mode(regs) )
> -        return show_guest_stack(regs);
> +        return show_guest_stack(current, regs);
>  
>      printk("Xen stack trace from sp=%p:\n  ", stack);
>  
> @@ -631,7 +703,7 @@ void vcpu_show_execution_state(struct vcpu *v)
>  
>      vcpu_show_registers(v);
>      if ( !usr_mode(&v->arch.cpu_info->guest_cpu_user_regs) )
> -        show_guest_stack(&v->arch.cpu_info->guest_cpu_user_regs);
> +        show_guest_stack(v, &v->arch.cpu_info->guest_cpu_user_regs);
>  
>      vcpu_unpause(v);
>  }
> -- 
> 1.7.10.4
> 

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