Re: [Qemu-devel] [PATCH] booke_206_tlbwe: Discard invalid bits in MAS2

[Fabien Chouteau <chouteau@adacore.com>]

Any comment?

On 05/09/2012 03:28 PM, Fabien Chouteau wrote:
> The size of EPN field in MAS2 depends on page size. This patch adds a
> mask to discard invalid bits in EPN field.
> 
> Definition of EPN field from e500v2 RM:
> EPN Effective page number: Depending on page size, only the bits
> associated with a page boundary are valid. Bits that represent offsets
> within a page are ignored and should be cleared.
> 
> There is a similar (but more complicated) definition in PowerISA V2.06.
> 
> Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
> ---
>  target-ppc/op_helper.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index 4ef2332..6bc64ad 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -4227,6 +4227,8 @@ void helper_booke206_tlbwe(void)
>      uint32_t tlbncfg, tlbn;
>      ppcmas_tlb_t *tlb;
>      uint32_t size_tlb, size_ps;
> +    target_ulong mask;
> +
>  
>      switch (env->spr[SPR_BOOKE_MAS0] & MAS0_WQ_MASK) {
>      case MAS0_WQ_ALWAYS:
> @@ -4289,8 +4291,12 @@ void helper_booke206_tlbwe(void)
>          tlb->mas1 |= (tlbncfg & TLBnCFG_MINSIZE) >> 12;
>      }
>  
> -    /* XXX needs to change when supporting 64-bit e500 */
> -    tlb->mas2 = env->spr[SPR_BOOKE_MAS2] & 0xffffffff;
> +    /* Make a mask from TLB size to discard invalid bits in EPN field */
> +    mask = ~(booke206_tlb_to_page_size(env, tlb) - 1);
> +    /* Add a mask for page attributes */
> +    mask |= MAS2_ACM | MAS2_VLE | MAS2_W | MAS2_I | MAS2_M | MAS2_G | MAS2_E;
> +
> +    tlb->mas2 = env->spr[SPR_BOOKE_MAS2] & mask;
>  
>      if (!(tlbncfg & TLBnCFG_IPROT)) {
>          /* no IPROT supported by TLB */


-- 
Fabien Chouteau