On 4/17/22 19:44, Richard Henderson wrote:
There is no branch prediction in TCG, therefore there is no
need to actually include the context number into the predictor.
Therefore all we need to do is add the state for SCXTNUM_ELx. >
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
v2: Update emulation.rst; clear CSV2_FRAC; use decimal; tidy access_scxtnum.
v3: Rely on EL3-no-EL2 squashing during registration.
---
docs/system/arm/emulation.rst | 3 ++
target/arm/cpu.h | 16 +++++++++
target/arm/cpu64.c | 3 +-
target/arm/helper.c | 66 ++++++++++++++++++++++++++++++++++-
4 files changed, 86 insertions(+), 2 deletions(-)
diff --git a/target/arm/helper.c b/target/arm/helper.c
@@ -7233,7 +7243,57 @@ static const ARMCPRegInfo mte_el0_cacheop_reginfo[] = {
},
};
Hi Richard,
I tried to compare with the pseudocode from arm doc and I've a few
interrogations. It seems to me there are missing cases in the access
checks, but I lack the background to know if these are not checked
somewhere else or guaranteed to never happen.
-#endif > +static CPAccessResult access_scxtnum(CPUARMState *env, const
ARMCPRegInfo *ri,
+ bool isread)
+{
The following checks are missing:
+ for HFG[W/R]TR_EL2.SCXTNUM_EL0/1
+ HCR_EL2.<NV2,NV1,NV> when accessing SCXTNUM_EL1, but maybe these
are always guaranteed to fail because we don't support the features ?
+ HCR_EL2.NV when accessing SCXTNUM_EL2
+ int el = arm_current_el(env);
+
+ if (el == 0) {
+ uint64_t hcr = arm_hcr_el2_eff(env);
+ if ((hcr & (HCR_TGE | HCR_E2H)) != (HCR_TGE | HCR_E2H)) {
+ if (env->cp15.sctlr_el[1] & SCTLR_TSCXT) {
+ if (hcr & HCR_TGE) {
+ return CP_ACCESS_TRAP_EL2;
+ }
+ return CP_ACCESS_TRAP;
+ }
+ if (arm_is_el2_enabled(env) && !(hcr & HCR_ENSCXT)) {
This case is also present when accessing SCXTNUM_EL0 from el1 (but
without "(hcr & (HCR_TGE | HCR_E2H)) != (HCR_TGE | HCR_E2H)" precondition)
+ return CP_ACCESS_TRAP_EL2;
+ }
+ goto no_sctlr_el2;
+ }
+ }
+ if (el < 2 && (env->cp15.sctlr_el[2] & SCTLR_TSCXT)) {
+ return CP_ACCESS_TRAP_EL2;
+ }
+ no_sctlr_el2:
+ if (el < 3
+ && arm_feature(env, ARM_FEATURE_EL3)
+ && !(env->cp15.scr_el3 & SCR_ENSCXT)) {
+ return CP_ACCESS_TRAP_EL3;
+ }
+ return CP_ACCESS_OK;
+}
Regards,
--
Damien
