The LDRT/STRT "unprivileged load/store" instructions behave like
normal ones if executed at EL0. We handle this correctly for
the load/store semantics, but get the MTE checking wrong.
We always look at s->mte_active[is_unpriv] to see whether we should
be doing MTE checks, but in hflags.c when we set the TB flags that
will be used to fill the mte_active[] array we only set the
MTE0_ACTIVE bit if UNPRIV is true (i.e. we are not at EL0).
This means that a LDRT at EL0 will see s->mte_active[1] as 0,
and will not do MTE checks even when MTE is enabled.
To avoid the translate-time code having to do an explicit check on
s->unpriv to see if it is OK to index into the mte_active[] array,
duplicate MTE_ACTIVE into MTE0_ACTIVE when UNPRIV is false.
(This isn't a very serious bug because generally nobody executes
LDRT/STRT at EL0, because they have no use there.)
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230912140434.1333369-2-peter.maydell@linaro.org
---
target/arm/tcg/hflags.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c
index 616c5fa7237..ea642384f5a 100644
--- a/target/arm/tcg/hflags.c
+++ b/target/arm/tcg/hflags.c
@@ -306,6 +306,15 @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
&& !(env->pstate & PSTATE_TCO)
&& (sctlr & (el == 0 ? SCTLR_TCF0 : SCTLR_TCF))) {
DP_TBFLAG_A64(flags, MTE_ACTIVE, 1);
+ if (!EX_TBFLAG_A64(flags, UNPRIV)) {
+ /*
+ * In non-unpriv contexts (eg EL0), unpriv load/stores
+ * act like normal ones; duplicate the MTE info to
+ * avoid translate-a64.c having to check UNPRIV to see
+ * whether it is OK to index into MTE_ACTIVE[].
+ */
+ DP_TBFLAG_A64(flags, MTE0_ACTIVE, 1);
+ }
}
}
/* And again for unprivileged accesses, if required. */
--
2.34.1