Re: [RFC PATCH v2 03/22] target/arm: Add PSTATE.ALLINT

[Richard Henderson]

On 2/21/24 03:08, Jinjie Ruan via wrote:
> The ALLINT bit in PSTATE is used to mask all IRQ or FIQ interrupts.
>
> Place this in its own field within ENV, as that will
> make it easier to reset from within TCG generated code.
>
> With the change to pstate_read/write, exception entry
> and return are automatically handled.
>
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>   target/arm/cpu.c | 3 +++
>   target/arm/cpu.h | 9 +++++++--
>   2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 5fa86bc8d5..5e5978c302 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -1104,6 +1104,9 @@ static void aarch64_cpu_dump_state(CPUState *cs, FILE *f, 
> int flags)
>       if (cpu_isar_feature(aa64_bti, cpu)) {
>           qemu_fprintf(f, "  BTYPE=%d", (psr & PSTATE_BTYPE) >> 10);
>       }
> +    if (cpu_isar_feature(aa64_nmi, cpu)) {
> +        qemu_fprintf(f, "  ALLINT=%d", (psr & PSTATE_ALLINT) >> 13);
> +    }

This is one bit -- !!(psr & ALLINT) is better

We don't individually print DAIF either; why is this bit more special?

> @@ -224,6 +224,7 @@ typedef struct CPUArchState {
>        *    semantics as for AArch32, as described in the comments on each 
> field)
>        *  nRW (also known as M[4]) is kept, inverted, in env->aarch64
>        *  DAIF (exception masks) are kept in env->daif
> +     *  ALLINT (all IRQ or FIQ interrupts masks) are kept in env->allint
>        *  BTYPE is kept in env->btype
>        *  SM and ZA are kept in env->svcr
>        *  all other bits are stored in their correct places in env->pstate
> @@ -261,6 +262,7 @@ typedef struct CPUArchState {
>       uint32_t btype;  /* BTI branch type.  spsr[11:10].  */
>       uint64_t daif; /* exception masks, in the bits they are in PSTATE */
>       uint64_t svcr; /* PSTATE.{SM,ZA} in the bits they are in SVCR */
> +    uint64_t allint; /* All IRQ or FIQ interrupt mask, in the bit in PSTATE */

Why is this split out from env->pstate?

The allint bit matches the documentation for SPSR_EL1, which is how env->pstate is 
documented.  The other exclusions have some performance imperative which I don't see for 
allint.


r~