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target/openrisc: Fix delay slot exception flag to match spec 

The delay slot exception flag is only set on the SR register during
exception.  Previously it was being set on both the ESR and SR this
caused QEMU to differ from the spec.  The was apparent as the linux
kernel had a bug where it could boot on QEMU but not on real hardware.

The fixed logic now matches hardware.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
This commit is contained in:
Stafford Horne 2018-07-01 14:02:11 +09:00
parent 4151e53019
commit 9f6e8afad7
1 changed files with 12 additions and 7 deletions
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19
target/openrisc/interrupt.c
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@ -35,13 +35,6 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
int exception = cs->exception_index;
env->epcr = env->pc;
if (env->dflag) {
env->dflag = 0;
env->sr |= SR_DSX;
env->epcr -= 4;
} else {
env->sr &= ~SR_DSX;
}
if (exception == EXCP_SYSCALL) {
env->epcr += 4;
}
@ -51,7 +44,10 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
env->eear = env->pc;
}
/* During exceptions esr is populared with the pre-exception sr. */
env->esr = cpu_get_sr(env);
/* In parallel sr is updated to disable mmu, interrupts, timers and
set the delay slot exception flag. */
env->sr &= ~SR_DME;
env->sr &= ~SR_IME;
env->sr |= SR_SM;
@ -61,6 +57,15 @@ void openrisc_cpu_do_interrupt(CPUState *cs)
env->pmr &= ~PMR_SME;
env->lock_addr = -1;
/* Set/clear dsx to indicate if we are in a delay slot exception. */
if (env->dflag) {
env->dflag = 0;
env->sr |= SR_DSX;
env->epcr -= 4;
} else {
env->sr &= ~SR_DSX;
}
if (exception > 0 && exception < EXCP_NR) {
static const char * const int_name[EXCP_NR] = {
[EXCP_RESET] = "RESET",