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

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-04-08 at 18:29 +0100, Stefano Stabellini wrote:
> 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.

I implemented the one I needed to debug the issue I was facing at the
time ;-) Hopefully others will do the same...
> 
> 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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