Re: [Qemu-arm] [PATCH 05/10] target/arm: Implement AArch32 HCR and HCR2

[Luc Michel]

On 8/14/18 2:42 PM, Peter Maydell wrote:
> The AArch32 HCR and HCR2 registers alias HCR_EL2
> bits [31:0] and [63:32]; implement them.
> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target/arm/helper.c | 39 +++++++++++++++++++++++++++++++++++----
>  1 file changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index b6412fe9d1f..9701e413859 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -3754,11 +3754,15 @@ static const ARMCPRegInfo el3_no_el2_cp_reginfo[] = {
>        .opc0 = 3, .opc1 = 4, .crn = 12, .crm = 0, .opc2 = 0,
>        .access = PL2_RW,
>        .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore },
> -    { .name = "HCR_EL2", .state = ARM_CP_STATE_AA64,
> +    { .name = "HCR_EL2", .state = ARM_CP_STATE_BOTH,
>        .type = ARM_CP_NO_RAW,
>        .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 0,
>        .access = PL2_RW,
> -      .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore },
> +      .type = ARM_CP_CONST, .resetvalue = 0 },
> +    { .name = "HCR2", .state = ARM_CP_STATE_AA32,
> +      .cp = 15, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 4,
> +      .access = PL2_RW,
> +      .type = ARM_CP_CONST, .resetvalue = 0 },
As for HACTLR2, shouldn't we avoid defining HCR2 for ARMv7?

>      { .name = "CPTR_EL2", .state = ARM_CP_STATE_BOTH,
>        .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 2,
>        .access = PL2_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
> @@ -3872,10 +3876,26 @@ static void hcr_write(CPUARMState *env, const 
> ARMCPRegInfo *ri, uint64_t value)
>       * HCR_PTW forbids certain page-table setups
>       * HCR_DC Disables stage1 and enables stage2 translation
>       */
> -    if ((raw_read(env, ri) ^ value) & (HCR_VM | HCR_PTW | HCR_DC)) {
> +    if ((env->cp15.hcr_el2 ^ value) & (HCR_VM | HCR_PTW | HCR_DC)) {
>          tlb_flush(CPU(cpu));
>      }
> -    raw_write(env, ri, value);
> +    env->cp15.hcr_el2 = value;
> +}
> +
> +static void hcr_writehigh(CPUARMState *env, const ARMCPRegInfo *ri,
> +                          uint64_t value)
> +{
> +    /* Handle HCR2 write, i.e. write to high half of HCR_EL2 */
> +    value = deposit64(env->cp15.hcr_el2, 32, 32, value);
> +    hcr_write(env, NULL, value);
> +}
> +
> +static void hcr_writelow(CPUARMState *env, const ARMCPRegInfo *ri,
> +                         uint64_t value)
> +{
> +    /* Handle HCR write, i.e. write to low half of HCR_EL2 */
> +    value = deposit64(env->cp15.hcr_el2, 0, 32, value);
> +    hcr_write(env, NULL, value);
>  }
>  
>  static const ARMCPRegInfo el2_cp_reginfo[] = {
> @@ -3883,6 +3903,17 @@ static const ARMCPRegInfo el2_cp_reginfo[] = {
>        .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 0,
>        .access = PL2_RW, .fieldoffset = offsetof(CPUARMState, cp15.hcr_el2),
>        .writefn = hcr_write },
> +    { .name = "HCR", .state = ARM_CP_STATE_AA32,
> +      .type = ARM_CP_ALIAS,
> +      .cp = 15, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 0,
> +      .access = PL2_RW, .fieldoffset = offsetof(CPUARMState, cp15.hcr_el2),
> +      .writefn = hcr_writelow },
> +    { .name = "HCR2", .state = ARM_CP_STATE_AA32,
> +      .type = ARM_CP_ALIAS,
> +      .cp = 15, .opc1 = 4, .crn = 1, .crm = 1, .opc2 = 4,
> +      .access = PL2_RW,
> +      .fieldoffset = offsetofhigh32(CPUARMState, cp15.hcr_el2),
> +      .writefn = hcr_writehigh },
Also here. This one could actually be problematic as it allows ARMv7 to
write the upper 32-bits of HCR, since HCR_MASK in hcr_write() is greater
than UINT32_MAX.

-- 
Luc

>      { .name = "ELR_EL2", .state = ARM_CP_STATE_AA64,
>        .type = ARM_CP_ALIAS,
>        .opc0 = 3, .opc1 = 4, .crn = 4, .crm = 0, .opc2 = 1,
>

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