Re: [Qemu-devel] [PATCH RESEND v1 3/5] target-microblaze: Allow the stack protection to be disabled

[Peter Crosthwaite]

On Mon, May 18, 2015 at 4:13 PM, Alistair Francis
<address@hidden> wrote:
> Microblaze stack protection is configurable and isn't always enabled.
> This patch allows the stack protection to be disabled from the CPU
> properties.
>
> Signed-off-by: Alistair Francis <address@hidden>
> ---
> Changes since RFC:
>  - Move the cfg.stackproc check into translate.c
>  - Set the PVR register
>
>  target-microblaze/cpu-qom.h   |    5 +++++
>  target-microblaze/cpu.c       |    5 +++++
>  target-microblaze/cpu.h       |    1 +
>  target-microblaze/translate.c |    2 +-
>  4 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/target-microblaze/cpu-qom.h b/target-microblaze/cpu-qom.h
> index e3e0701..7bc5b81 100644
> --- a/target-microblaze/cpu-qom.h
> +++ b/target-microblaze/cpu-qom.h
> @@ -59,6 +59,11 @@ typedef struct MicroBlazeCPU {
>      uint32_t base_vectors;
>      /*< public >*/
>
> +    /* Microblaze Configuration Settings */
> +    struct {
> +        bool stackproc;

stackprot? Although should we just verbatim match to the TRMs name for
these variables (dropping the redundant leading C_)? That would make
this "use_stack_protection" and match to QOM property name exactly.

> +    } cfg;
> +
>      CPUMBState env;
>  } MicroBlazeCPU;
>
> diff --git a/target-microblaze/cpu.c b/target-microblaze/cpu.c
> index 555bc4c..4deb256 100644
> --- a/target-microblaze/cpu.c
> +++ b/target-microblaze/cpu.c
> @@ -117,6 +117,9 @@ static void mb_cpu_realizefn(DeviceState *dev, Error 
> **errp)
>                          | PVR2_USE_FPU2_MASK \
>                          | PVR2_FPU_EXC_MASK \
>                          | 0;
> +
> +    env->pvr.regs[0] |= (cpu->cfg.stackproc ? PVR0_SPROT_MASK : 0);
> +

Parentheses not needed.

>      env->pvr.regs[10] = 0x0c000000; /* Default to spartan 3a dsp family.  */
>      env->pvr.regs[11] = PVR11_USE_MMU | (16 << 17);
>
> @@ -159,6 +162,8 @@ static const VMStateDescription vmstate_mb_cpu = {
>
>  static Property mb_properties[] = {
>      DEFINE_PROP_UINT32("xlnx.base-vectors", MicroBlazeCPU, base_vectors, 0),
> +    DEFINE_PROP_BOOL("use-stack-protection", MicroBlazeCPU, cfg.stackproc,
> +                     true),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> diff --git a/target-microblaze/cpu.h b/target-microblaze/cpu.h
> index e4c1cde..481f463 100644
> --- a/target-microblaze/cpu.h
> +++ b/target-microblaze/cpu.h
> @@ -128,6 +128,7 @@ typedef struct CPUMBState CPUMBState;
>  #define PVR0_FAULT                     0x00100000
>  #define PVR0_VERSION_MASK               0x0000FF00
>  #define PVR0_USER1_MASK                 0x000000FF
> +#define PVR0_SPROT_MASK                 0x00000001
>
>  /* User 2 PVR mask */
>  #define PVR1_USER2_MASK                 0xFFFFFFFF
> diff --git a/target-microblaze/translate.c b/target-microblaze/translate.c
> index 4068946..19faf40 100644
> --- a/target-microblaze/translate.c
> +++ b/target-microblaze/translate.c
> @@ -862,7 +862,7 @@ static inline TCGv *compute_ldst_addr(DisasContext *dc, 
> TCGv *t)
>      int stackprot = 0;
>
>      /* All load/stores use ra.  */
> -    if (dc->ra == 1) {
> +    if (dc->ra == 1 && dc->cpu->cfg.stackproc) {

There is a similar logic below for dc->rb:

        if (dc->rb == 1) {
            stackprot = 1;
        }

Should it have the same guard?

Regards,
Peter

>          stackprot = 1;
>      }
>
> --
> 1.7.1
>
>