diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2018-08-20 11:24:32 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2018-08-20 11:24:32 +0100 |
| commit | aec4dd09f172ee64c19222b78269d5952fd9c1dc (patch) | |
| tree | ca949782d84fcbed0980f521f2771d3fcf60c36f | |
| parent | 68e78e332cb1c3f8b0317a0443acb2b5e190f0dd (diff) | |
target/arm: Permit accesses to ELR_Hyp from Hyp mode via MSR/MRS (banked)
The MSR (banked) and MRS (banked) instructions allow accesses to ELR_Hyp
from either Monitor or Hyp mode. Our translate time check
was overly strict and only permitted access from Monitor mode.
The runtime check we do in msr_mrs_banked_exc_checks() had the
correct code in it, but never got there because of the earlier
"currmode == tgtmode" check. Special case ELR_Hyp.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Message-id: 20180814124254.5229-9-peter.maydell@linaro.org
| -rw-r--r-- | target/arm/op_helper.c | 22 | ||||
| -rw-r--r-- | target/arm/translate.c | 10 |
2 files changed, 18 insertions, 14 deletions
diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index d550978b5b..952b8d122b 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -611,6 +611,14 @@ static void msr_mrs_banked_exc_checks(CPUARMState *env, uint32_t tgtmode, */ int curmode = env->uncached_cpsr & CPSR_M; + if (regno == 17) { + /* ELR_Hyp: a special case because access from tgtmode is OK */ + if (curmode != ARM_CPU_MODE_HYP && curmode != ARM_CPU_MODE_MON) { + goto undef; + } + return; + } + if (curmode == tgtmode) { goto undef; } @@ -638,17 +646,9 @@ static void msr_mrs_banked_exc_checks(CPUARMState *env, uint32_t tgtmode, } if (tgtmode == ARM_CPU_MODE_HYP) { - switch (regno) { - case 17: /* ELR_Hyp */ - if (curmode != ARM_CPU_MODE_HYP && curmode != ARM_CPU_MODE_MON) { - goto undef; - } - break; - default: - if (curmode != ARM_CPU_MODE_MON) { - goto undef; - } - break; + /* SPSR_Hyp, r13_hyp: accessible from Monitor mode only */ + if (curmode != ARM_CPU_MODE_MON) { + goto undef; } } diff --git a/target/arm/translate.c b/target/arm/translate.c index 14aa2cd3cd..8405c08fd1 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -4506,10 +4506,14 @@ static bool msr_banked_access_decode(DisasContext *s, int r, int sysm, int rn, } break; case ARM_CPU_MODE_HYP: - /* Note that we can forbid accesses from EL2 here because they - * must be from Hyp mode itself + /* + * SPSR_hyp and r13_hyp can only be accessed from Monitor mode + * (and so we can forbid accesses from EL2 or below). elr_hyp + * can be accessed also from Hyp mode, so forbid accesses from + * EL0 or EL1. */ - if (!arm_dc_feature(s, ARM_FEATURE_EL2) || s->current_el < 3) { + if (!arm_dc_feature(s, ARM_FEATURE_EL2) || s->current_el < 2 || + (s->current_el < 3 && *regno != 17)) { goto undef; } break; |