Re: [Qemu-devel] ARM: BKPT instructions should raise prefetch aborts with IFSR type 00010

[Alex Zuepke <azuepke@sysgo.com>]

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Hi,

Peter Maydell schrieb:
> On 25 March 2011 10:54, Alex Zuepke <azuepke@sysgo.com> wrote:
>> while digging through some problems with BKPT exceptions on ARM, I
>> discovered that QEMU does not update IFSR on prefetch aborts. This
>> should be done since ARMv6 according to ARM docs. Please include.
> 
> This patch is the wrong approach to fixing this bug -- the
> updating of the IFSR needs to be done when the exception
> is taken, not when we translate the breakpoint instruction.
> 
> I'll put this on my todo list. If you happen to have a convenient
> test case demonstrating the problem, that would make a fix happen
> faster ;-)
> 
> -- PMM

I tried to fix it, new patch attached.
But I'm not sure if it is required for semihosting as well.

On ARMv7-M bkpt works differently, and debug registers aren't
implemented yet, so I didn't touch it.

Best Regards,
Alex

-- 
Alexander Zuepke                                azuepke@sysgo.com
SYSGO AG ~ Am Pfaffenstein 14 ~ 55270 Klein-Winternheim ~ Germany

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 target-arm: BKPT instructions should raise prefetch aborts with IFSR type 00010
 diff against qemu 0.14.1
 Signed-off-by: Alex Zuepke <azuepke@sysgo.com>
diff --git a/target-arm/helper.c b/target-arm/helper.c
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -847,6 +849,7 @@ void do_interrupt(CPUARMState *env)
                 return;
             }
         }
+        env->cp15.c5_insn = 2;
         /* Fall through to prefetch abort.  */
     case EXCP_PREFETCH_ABORT:
         new_mode = ARM_CPU_MODE_ABT;