target/arm: Add PSTATE.ALLINT

When PSTATE.ALLINT is set, an IRQ or FIQ interrupt that is targeted to
ELx, with or without superpriority is masked. As Richard suggested, place
ALLINT bit in PSTATE in env->pstate.

In the pseudocode, AArch64.ExceptionReturn() calls SetPSTATEFromPSR(), which
treats PSTATE.ALLINT as one of the bits which are reinstated from SPSR to
PSTATE regardless of whether this is an illegal exception return or not. So
handle PSTATE.ALLINT the same way as PSTATE.DAIF in the illegal_return exit
path of the exception_return helper. With the change, exception entry and
return are automatically handled.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240407081733.3231820-3-ruanjinjie@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/cpu.h

@@ -1430,6 +1430,7 @@ void pmu_init(ARMCPU *cpu);
 #define PSTATE_D (1U << 9)
 #define PSTATE_BTYPE (3U << 10)
 #define PSTATE_SSBS (1U << 12)
+#define PSTATE_ALLINT (1U << 13)
 #define PSTATE_IL (1U << 20)
 #define PSTATE_SS (1U << 21)
 #define PSTATE_PAN (1U << 22)

target/arm/tcg/helper-a64.c

@@ -892,8 +892,8 @@ void HELPER(exception_return)(CPUARMState *env, uint64_t new_pc)
      */
     env->pstate |= PSTATE_IL;
     env->pc = new_pc;
-    spsr &= PSTATE_NZCV | PSTATE_DAIF;
-    spsr |= pstate_read(env) & ~(PSTATE_NZCV | PSTATE_DAIF);
+    spsr &= PSTATE_NZCV | PSTATE_DAIF | PSTATE_ALLINT;
+    spsr |= pstate_read(env) & ~(PSTATE_NZCV | PSTATE_DAIF | PSTATE_ALLINT);
     pstate_write(env, spsr);
     if (!arm_singlestep_active(env)) {
         env->pstate &= ~PSTATE_SS;