Re: [Qemu-ppc] [PATCH 2/2] PPC: Fix GDB read on code area for PPC6xx

[Alexander Graf]

On 18.06.2013, at 16:53, Fabien Chouteau wrote:

> On PPC 6xx, data and code have separated TLBs. Until now QEMU was only
> looking at data TLBs, which is not good when GDB wants to read code.
> 
> This patch adds a second call to get_physical_address() with an
> ACCESS_CODE type of access when the first call with ACCESS_INT fails.
> 
> Signed-off-by: Fabien Chouteau <address@hidden>
> ---
> target-ppc/mmu_helper.c |   10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/target-ppc/mmu_helper.c b/target-ppc/mmu_helper.c
> index 910e022..19f0b8c 100644
> --- a/target-ppc/mmu_helper.c
> +++ b/target-ppc/mmu_helper.c
> @@ -1378,7 +1378,15 @@ hwaddr cpu_get_phys_page_debug(CPUPPCState *env, 
> target_ulong addr)
>     }
> 
>     if (unlikely(get_physical_address(env, &ctx, addr, 0, ACCESS_INT) != 0)) {
> -        return -1;
> +
> +        /* Some MMUs have separate TLBs for code and data. If we only try an
> +         * ACCESS_INT, we may not be able to read instructions mapped by code
> +         * TLBs, so we also try a ACCESS_CODE.

This is pretty ugly, but I don't see any other way to conveniently give gdb the 
information it needs. Let's ask Jan whether he has an idea. Maybe a monitor 
command to switch memory access modes?


Alex

> +         */
> +        if (unlikely(get_physical_address(env, &ctx, addr, 0,
> +                                          ACCESS_CODE) != 0)) {
> +            return -1;
> +        }
>     }
> 
>     return ctx.raddr & TARGET_PAGE_MASK;
> -- 
> 1.7.9.5
>