Re: [Xen-devel] [PATCH 06/38] arm: enable interrupts while handling traps

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 1 Jun 2012, Ian Campbell wrote:
> For most traps we can do this as soon as we have saved the necessary state.
> For IRQs and FIQs we must wait until we have acked the interrupt with the GIC.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>


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

>  xen/arch/arm/entry.S |   17 ++++++++++++++---
>  xen/arch/arm/gic.c   |    2 ++
>  xen/arch/arm/traps.c |    1 -
>  3 files changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/arm/entry.S b/xen/arch/arm/entry.S
> index 7a22e2d..5bc3906 100644
> --- a/xen/arch/arm/entry.S
> +++ b/xen/arch/arm/entry.S
> @@ -46,6 +46,17 @@ save_guest_regs:
>       ALIGN;                                                                  
>                         \
>  trap_##trap:                                                                 
>                         \
>       SAVE_ALL;                                                               
>                         \
> +     cpsie i;        /* local_irq_enable */                                  
>                         \
> +     adr lr, return_from_trap;                                               
>                         \
> +     mov r0, sp;                                                             
>                         \
> +     mov r11, sp;                                                            
>                         \
> +     bic sp, #7; /* Align the stack pointer (noop on guest trap) */          
>                         \
> +     b do_trap_##trap
> +
> +#define DEFINE_TRAP_ENTRY_NOIRQ(trap)                                        
>                                 \
> +     ALIGN;                                                                  
>                         \
> +trap_##trap:                                                                 
>                         \
> +     SAVE_ALL;                                                               
>                         \
>       adr lr, return_from_trap;                                               
>                         \
>       mov r0, sp;                                                             
>                         \
>       mov r11, sp;                                                            
>                         \
> @@ -69,8 +80,8 @@ DEFINE_TRAP_ENTRY(supervisor_call)
>  DEFINE_TRAP_ENTRY(prefetch_abort)
>  DEFINE_TRAP_ENTRY(data_abort)
>  DEFINE_TRAP_ENTRY(hypervisor)
> -DEFINE_TRAP_ENTRY(irq)
> -DEFINE_TRAP_ENTRY(fiq)
> +DEFINE_TRAP_ENTRY_NOIRQ(irq)
> +DEFINE_TRAP_ENTRY_NOIRQ(fiq)
>  
>  return_from_trap:
>       mov sp, r11
> @@ -83,7 +94,7 @@ ENTRY(return_to_new_vcpu)
>  ENTRY(return_to_guest)
>       mov r11, sp
>       bic sp, #7 /* Align the stack pointer */
> -     bl leave_hypervisor_tail
> +     bl leave_hypervisor_tail /* Disables interrupts on return */
>       mov sp, r11
>       RESTORE_ONE_BANKED(SP_usr)
>       /* LR_usr is the same physical register as lr and is restored below */
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index cc9d37b..1a2b95f 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -509,6 +509,8 @@ void gic_interrupt(struct cpu_user_regs *regs, int is_fiq)
>      uint32_t intack = GICC[GICC_IAR];
>      unsigned int irq = intack & GICC_IA_IRQ;
>  
> +    local_irq_enable();
> +
>      if ( irq == 1023 )
>          /* Spurious interrupt */
>          return;
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index abc26a3..5ed754f 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -412,7 +412,6 @@ static void do_debug_trap(struct cpu_user_regs *regs, 
> unsigned int code)
>  static void do_trap_hypercall(struct cpu_user_regs *regs, unsigned long iss)
>  {
>      arm_hypercall_t *call = NULL;
> -    local_irq_enable();
>  
>      if ( iss != XEN_HYPERCALL_TAG )
>      {
> -- 
> 1.7.9.1
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
> 

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