| Message ID | 20181108163329.19940-7-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | KVM Guest Debug fixes (plus TCG EL2 debug tweaks) | expand |
On 11/8/18 5:33 PM, Alex Bennée wrote: > The test was incomplete and incorrectly caused debug exceptions to be > generated when returning to EL2 after a failed attempt to single-step > an EL1 instruction. Fix this while cleaning up the function a little. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > target/arm/cpu.h | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/target/arm/cpu.h b/target/arm/cpu.h > index 1efff21a18..a6d8eb14f6 100644 > --- a/target/arm/cpu.h > +++ b/target/arm/cpu.h > @@ -2764,23 +2764,33 @@ static inline bool arm_v7m_csselr_razwi(ARMCPU *cpu) > return (cpu->clidr & R_V7M_CLIDR_CTYPE_ALL_MASK) != 0; > } > > +/* See AArch64.GenerateDebugExceptionsFrom() in ARM ARM pseudocode */ > static inline bool aa64_generate_debug_exceptions(CPUARMState *env) > { > + int cur_el = arm_current_el(env); > + int debug_el; > + > if (arm_is_secure(env)) { > /* MDCR_EL3.SDD disables debug events from Secure state */ > if (extract32(env->cp15.mdcr_el3, 16, 1) != 0 > - || arm_current_el(env) == 3) { > + || cur_el == 3) { Hmm. Perhaps better as if (cur_el == 3) { return false; } /* MDCR_EL3.SDD disables... */ if (arm_is_secure_below_el3(env) && extract32(env->cp15.mdcr_el3, 16, 1)) { return false; } and of course more symbols would be nice, but it's not wrong as-is. r~
diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 1efff21a18..a6d8eb14f6 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -2764,23 +2764,33 @@ static inline bool arm_v7m_csselr_razwi(ARMCPU *cpu) return (cpu->clidr & R_V7M_CLIDR_CTYPE_ALL_MASK) != 0; } +/* See AArch64.GenerateDebugExceptionsFrom() in ARM ARM pseudocode */ static inline bool aa64_generate_debug_exceptions(CPUARMState *env) { + int cur_el = arm_current_el(env); + int debug_el; + if (arm_is_secure(env)) { /* MDCR_EL3.SDD disables debug events from Secure state */ if (extract32(env->cp15.mdcr_el3, 16, 1) != 0 - || arm_current_el(env) == 3) { + || cur_el == 3) { return false; } } - if (arm_current_el(env) == arm_debug_target_el(env)) { - if ((extract32(env->cp15.mdscr_el1, 13, 1) == 0) - || (env->daif & PSTATE_D)) { - return false; - } + /* + * Same EL to same EL debug exceptions need MDSCR_KDE enabled + * while not masking the (D)ebug bit in DAIF. + */ + debug_el = arm_debug_target_el(env); + + if (cur_el == debug_el) { + return extract32(env->cp15.mdscr_el1, 13, 1) + && !(env->daif & PSTATE_D); } - return true; + + /* Otherwise the debug target needs to be a higher EL */ + return debug_el > cur_el; } static inline bool aa32_generate_debug_exceptions(CPUARMState *env) @@ -2833,9 +2843,6 @@ static inline bool aa32_generate_debug_exceptions(CPUARMState *env) * since the pseudocode has it at all callsites except for the one in * CheckSoftwareStep(), where it is elided because both branches would * always return the same value. - * - * Parts of the pseudocode relating to EL2 and EL3 are omitted because we - * don't yet implement those exception levels or their associated trap bits. */ static inline bool arm_generate_debug_exceptions(CPUARMState *env) {
The test was incomplete and incorrectly caused debug exceptions to be generated when returning to EL2 after a failed attempt to single-step an EL1 instruction. Fix this while cleaning up the function a little. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- target/arm/cpu.h | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) -- 2.17.1