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authorZhuojia Shen <chaosdefinition@hotmail.com>2023-06-06 10:19:40 +0100
committerPeter Maydell <peter.maydell@linaro.org>2023-06-06 10:19:40 +0100
commitf9ac778898cb28307e0f91421aba34d43c34b679 (patch)
treebb19b404245559a155a6269198417c6dd633250b /target/arm/debug_helper.c
parentc81e4ab370e858550852b052f689a0a721b879d4 (diff)
downloadfocaccia-qemu-f9ac778898cb28307e0f91421aba34d43c34b679.tar.gz
focaccia-qemu-f9ac778898cb28307e0f91421aba34d43c34b679.zip
target/arm: trap DCC access in user mode emulation
Accessing EL0-accessible Debug Communication Channel (DCC) registers in
user mode emulation is currently enabled.  However, it does not match
Linux behavior as Linux sets MDSCR_EL1.TDCC on startup to disable EL0
access to DCC (see __cpu_setup() in arch/arm64/mm/proc.S).

This patch fixes access_tdcc() to check MDSCR_EL1.TDCC for EL0 and sets
MDSCR_EL1.TDCC for user mode emulation to match Linux.

Signed-off-by: Zhuojia Shen <chaosdefinition@hotmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: DS7PR12MB630905198DD8E69F6817544CAC4EA@DS7PR12MB6309.namprd12.prod.outlook.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'target/arm/debug_helper.c')
-rw-r--r--target/arm/debug_helper.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/target/arm/debug_helper.c b/target/arm/debug_helper.c
index d41cc643b1..8362462a07 100644
--- a/target/arm/debug_helper.c
+++ b/target/arm/debug_helper.c
@@ -842,12 +842,14 @@ static CPAccessResult access_tda(CPUARMState *env, const ARMCPRegInfo *ri,
  * is implemented then these are controlled by MDCR_EL2.TDCC for
  * EL2 and MDCR_EL3.TDCC for EL3. They are also controlled by
  * the general debug access trap bits MDCR_EL2.TDA and MDCR_EL3.TDA.
+ * For EL0, they are also controlled by MDSCR_EL1.TDCC.
  */
 static CPAccessResult access_tdcc(CPUARMState *env, const ARMCPRegInfo *ri,
                                   bool isread)
 {
     int el = arm_current_el(env);
     uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
+    bool mdscr_el1_tdcc = extract32(env->cp15.mdscr_el1, 12, 1);
     bool mdcr_el2_tda = (mdcr_el2 & MDCR_TDA) || (mdcr_el2 & MDCR_TDE) ||
         (arm_hcr_el2_eff(env) & HCR_TGE);
     bool mdcr_el2_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
@@ -855,6 +857,9 @@ static CPAccessResult access_tdcc(CPUARMState *env, const ARMCPRegInfo *ri,
     bool mdcr_el3_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
                                           (env->cp15.mdcr_el3 & MDCR_TDCC);
 
+    if (el < 1 && mdscr_el1_tdcc) {
+        return CP_ACCESS_TRAP;
+    }
     if (el < 2 && (mdcr_el2_tda || mdcr_el2_tdcc)) {
         return CP_ACCESS_TRAP_EL2;
     }