| Message ID | 1454690704-16233-2-git-send-email-peter.maydell@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05.02.2016 19:44, Peter Maydell wrote: > Correct some corner cases we were getting wrong for > CNTFRQ access rights: > * should UNDEF from 32-bit Secure EL1 > * only writable from the highest implemented exception level, > which might not be EL1 now > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > target-arm/helper.c | 31 ++++++++++++++++++++++++++++--- > 1 file changed, 28 insertions(+), 3 deletions(-) > > diff --git a/target-arm/helper.c b/target-arm/helper.c > index 7a8881a..082701a 100644 > --- a/target-arm/helper.c > +++ b/target-arm/helper.c > @@ -1217,9 +1217,34 @@ static const ARMCPRegInfo v6k_cp_reginfo[] = { > static CPAccessResult gt_cntfrq_access(CPUARMState *env, const ARMCPRegInfo *ri, > bool isread) > { > - /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero */ > - if (arm_current_el(env) == 0 && !extract32(env->cp15.c14_cntkctl, 0, 2)) { > - return CP_ACCESS_TRAP; > + /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero. > + * Writable only at the highest implemented exception level. > + */ > + switch (arm_current_el(env)) { > + case 0: > + if (!extract32(env->cp15.c14_cntkctl, 0, 2)) { > + return CP_ACCESS_TRAP; > + } > + /* EL0 reads are forbidden by the .access fields */ s/reads/writes/ ? > + break; > + case 1: > + if (!isread && (arm_feature(env, ARM_FEATURE_EL2) > + || arm_feature(env, ARM_FEATURE_EL3))) { > + return CP_ACCESS_TRAP_UNCATEGORIZED; > + } > + if (!isread && ri->state == ARM_CP_STATE_AA32 && > + arm_is_secure_below_el3(env)) { > + /* Accesses from 32-bit Secure EL1 UNDEF (*not* trap to EL3!) */ > + return CP_ACCESS_TRAP_UNCATEGORIZED; > + } > + break; > + case 2: > + if (!isread && arm_feature(env, ARM_FEATURE_EL3)) { > + return CP_ACCESS_TRAP_UNCATEGORIZED; > + } > + break; > + case 3: > + break; > } > return CP_ACCESS_OK; > } Maybe calculating "the highest implemented exception level" could simplify reading of the code a bit? E.g.: int highest_el = arm_feature(env, ARM_FEATURE_EL3) ? 3 : arm_feature(env, ARM_FEATURE_EL2) ? 2 : 1; We would probably want to have a dedicated static inline function for this similar to HighestEL() from ARMv8 ARM pseudocode. Kind regards, Sergey
On 8 February 2016 at 15:25, Sergey Fedorov <serge.fdrv@gmail.com> wrote: > On 05.02.2016 19:44, Peter Maydell wrote: >> Correct some corner cases we were getting wrong for >> CNTFRQ access rights: >> * should UNDEF from 32-bit Secure EL1 >> * only writable from the highest implemented exception level, >> which might not be EL1 now >> + switch (arm_current_el(env)) { >> + case 0: >> + if (!extract32(env->cp15.c14_cntkctl, 0, 2)) { >> + return CP_ACCESS_TRAP; >> + } >> + /* EL0 reads are forbidden by the .access fields */ > > s/reads/writes/ ? Yes. >> + break; >> + case 1: >> + if (!isread && (arm_feature(env, ARM_FEATURE_EL2) >> + || arm_feature(env, ARM_FEATURE_EL3))) { >> + return CP_ACCESS_TRAP_UNCATEGORIZED; >> + } >> + if (!isread && ri->state == ARM_CP_STATE_AA32 && >> + arm_is_secure_below_el3(env)) { >> + /* Accesses from 32-bit Secure EL1 UNDEF (*not* trap to EL3!) */ >> + return CP_ACCESS_TRAP_UNCATEGORIZED; >> + } >> + break; >> + case 2: >> + if (!isread && arm_feature(env, ARM_FEATURE_EL3)) { >> + return CP_ACCESS_TRAP_UNCATEGORIZED; >> + } >> + break; >> + case 3: >> + break; >> } >> return CP_ACCESS_OK; >> } > > Maybe calculating "the highest implemented exception level" could > simplify reading of the code a bit? E.g.: > > int highest_el = arm_feature(env, ARM_FEATURE_EL3) ? 3 : > arm_feature(env, ARM_FEATURE_EL2) ? 2 : 1; > > We would probably want to have a dedicated static inline function for > this similar to HighestEL() from ARMv8 ARM pseudocode. Mmm, that might look neater. I'll have a play with the code. thanks -- PMM
diff --git a/target-arm/helper.c b/target-arm/helper.c index 7a8881a..082701a 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -1217,9 +1217,34 @@ static const ARMCPRegInfo v6k_cp_reginfo[] = { static CPAccessResult gt_cntfrq_access(CPUARMState *env, const ARMCPRegInfo *ri, bool isread) { - /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero */ - if (arm_current_el(env) == 0 && !extract32(env->cp15.c14_cntkctl, 0, 2)) { - return CP_ACCESS_TRAP; + /* CNTFRQ: not visible from PL0 if both PL0PCTEN and PL0VCTEN are zero. + * Writable only at the highest implemented exception level. + */ + switch (arm_current_el(env)) { + case 0: + if (!extract32(env->cp15.c14_cntkctl, 0, 2)) { + return CP_ACCESS_TRAP; + } + /* EL0 reads are forbidden by the .access fields */ + break; + case 1: + if (!isread && (arm_feature(env, ARM_FEATURE_EL2) + || arm_feature(env, ARM_FEATURE_EL3))) { + return CP_ACCESS_TRAP_UNCATEGORIZED; + } + if (!isread && ri->state == ARM_CP_STATE_AA32 && + arm_is_secure_below_el3(env)) { + /* Accesses from 32-bit Secure EL1 UNDEF (*not* trap to EL3!) */ + return CP_ACCESS_TRAP_UNCATEGORIZED; + } + break; + case 2: + if (!isread && arm_feature(env, ARM_FEATURE_EL3)) { + return CP_ACCESS_TRAP_UNCATEGORIZED; + } + break; + case 3: + break; } return CP_ACCESS_OK; }
Correct some corner cases we were getting wrong for CNTFRQ access rights: * should UNDEF from 32-bit Secure EL1 * only writable from the highest implemented exception level, which might not be EL1 now Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- target-arm/helper.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)