target/arm: Update MSR access for PAN

For aarch64, there's a dedicated msr (imm, reg) insn.
For aarch32, this is done via msr to cpsr.  Writes from el0
are ignored, which is already handled by the CPSR_USER mask.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200208125816.14954-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index e4f17c7e83..058fb23959 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -4163,6 +4163,24 @@ static void aa64_daif_write(CPUARMState *env, const ARMCPRegInfo *ri,
     env->daif = value & PSTATE_DAIF;
 }
 
+static uint64_t aa64_pan_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    return env->pstate & PSTATE_PAN;
+}
+
+static void aa64_pan_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                           uint64_t value)
+{
+    env->pstate = (env->pstate & ~PSTATE_PAN) | (value & PSTATE_PAN);
+}
+
+static const ARMCPRegInfo pan_reginfo = {
+    .name = "PAN", .state = ARM_CP_STATE_AA64,
+    .opc0 = 3, .opc1 = 0, .crn = 4, .crm = 2, .opc2 = 3,
+    .type = ARM_CP_NO_RAW, .access = PL1_RW,
+    .readfn = aa64_pan_read, .writefn = aa64_pan_write
+};
+
 static CPAccessResult aa64_cacheop_access(CPUARMState *env,
                                           const ARMCPRegInfo *ri,
                                           bool isread)
@@ -7599,6 +7617,9 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     if (cpu_isar_feature(aa64_lor, cpu)) {
         define_arm_cp_regs(cpu, lor_reginfo);
     }
+    if (cpu_isar_feature(aa64_pan, cpu)) {
+        define_one_arm_cp_reg(cpu, &pan_reginfo);
+    }
 
     if (arm_feature(env, ARM_FEATURE_EL2) && cpu_isar_feature(aa64_vh, cpu)) {
         define_arm_cp_regs(cpu, vhe_reginfo);