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Re: [Qemu-devel] [PATCH v1 1/1] target-arm: helper.c: RAZ REVIDR cp regi
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v1 1/1] target-arm: helper.c: RAZ REVIDR cp register |
Date: |
Tue, 23 Apr 2013 11:55:17 +0100 |
On 23 April 2013 03:08, <address@hidden> wrote:
> From: Peter Crosthwaite <address@hidden>
>
> Guests should be able to read REVIDR without suffering an abort. Just
> RAZ the REVIDR register.
>
> Signed-off-by: Peter Crosthwaite <address@hidden>
> ---
>
> target-arm/helper.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index fd055e8..e655c74 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -1187,6 +1187,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
> { .name = "TLBTR",
> .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 3,
> .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
> + /* RAZ the REVIDR register */
> + { .name = "REVIDR",
> + .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 6,
> + .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
> /* crn = 0 op1 = 0 crm = 3..7 : currently unassigned; we RAZ. */
> { .name = "DUMMY",
> .cp = 15, .crn = 0, .crm = 3, .opc1 = 0, .opc2 = CP_ANY,
REVIDR is v7 only, so I don't think this is the right place to define it.
(It's also IMPDEF whether it exists or whether it's an alias for MIDR;
A7, A9 and A15 have a REVIDR, A5 and A8 don't.)
I suggest doing what we do for the MPIDR: define a feature bit
and a one-entry cp_reginfo for it.
(We don't implement the documented behaviour that unallocated
entries in c0,c0,0,X should read the MIDR, so I wouldn't worry
about that.)
thanks
-- PMM