From 5b4c46eeabe79a1a22554653eecdd4f7f6c628ad Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Fri, 16 Nov 2018 21:43:39 -0500 Subject: [PATCH] arm: fix aa64_generate_debug_exceptions to work with EL2 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. Backports commit 22af90255ec2100a44cbbb7f0460ba15eed79538 from qemu --- qemu/target/arm/cpu.h | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/qemu/target/arm/cpu.h b/qemu/target/arm/cpu.h index a8a7d211..c8a9d502 100644 --- a/qemu/target/arm/cpu.h +++ b/qemu/target/arm/cpu.h @@ -2713,23 +2713,35 @@ 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) { - 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) { - return false; - } + int cur_el = arm_current_el(env); + int debug_el; + + if (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; - } + /* MDCR_EL3.SDD disables debug events from Secure state */ + if (arm_is_secure_below_el3(env) + && extract32(env->cp15.mdcr_el3, 16, 1)) { + return false; } - return true; + + /* + * 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); + } + + /* Otherwise the debug target needs to be a higher EL */ + return debug_el > cur_el; } static inline bool aa32_generate_debug_exceptions(CPUARMState *env)