[Qemu-devel] [PATCH v2 19/35] target-arm: A64: Make cache ID registers visible to AArch64

[Peter Maydell <peter.maydell@linaro.org>]

Make the cache ID system registers (CLIDR, CCSELR, CCSIDR, CTR)
visible to AArch64. These are mostly simple 64-bit extensions of the
existing 32 bit system registers and so can share reginfo definitions.
CTR needs to have a split definition, but we can clean up the
temporary user-mode implementation in favour of using the CPU-specified
reset value, and implement the system-mode-required semantics of
restricting its EL0 accessibility if SCTLR.UCT is not set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target-arm/cpu.c    |  2 ++
 target-arm/cpu.h    |  2 +-
 target-arm/cpu64.c  |  1 +
 target-arm/helper.c | 31 +++++++++++++++++++++----------
 4 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index fe18b65..8fed098 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -91,6 +91,8 @@ static void arm_cpu_reset(CPUState *s)
         env->aarch64 = 1;
 #if defined(CONFIG_USER_ONLY)
         env->pstate = PSTATE_MODE_EL0t;
+        /* Userspace expects access to CTL_EL0 */
+        env->cp15.c1_sys |= SCTLR_UCT;
 #else
         env->pstate = PSTATE_D | PSTATE_A | PSTATE_I | PSTATE_F
             | PSTATE_MODE_EL1h;
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index d1ed423..f5b706e 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -166,7 +166,7 @@ typedef struct CPUARMState {
     /* System control coprocessor (cp15) */
     struct {
         uint32_t c0_cpuid;
-        uint32_t c0_cssel; /* Cache size selection.  */
+        uint64_t c0_cssel; /* Cache size selection.  */
         uint32_t c1_sys; /* System control register.  */
         uint32_t c1_coproc; /* Coprocessor access register.  */
         uint32_t c1_xscaleauxcr; /* XScale auxiliary control register.  */
diff --git a/target-arm/cpu64.c b/target-arm/cpu64.c
index a639c2e..8426bf1 100644
--- a/target-arm/cpu64.c
+++ b/target-arm/cpu64.c
@@ -45,6 +45,7 @@ static void aarch64_any_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_ARM_DIV);
     set_feature(&cpu->env, ARM_FEATURE_V7MP);
     set_feature(&cpu->env, ARM_FEATURE_AARCH64);
+    cpu->ctr = 0x80030003; /* 32 byte I and D cacheline size, VIPT icache */
 }
 #endif
 
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 06331dd..f46dd0f 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -629,9 +629,11 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
     { .name = "SCR", .cp = 15, .crn = 1, .crm = 1, .opc1 = 0, .opc2 = 0,
       .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c1_scr),
       .resetvalue = 0, },
-    { .name = "CCSIDR", .cp = 15, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 0,
+    { .name = "CCSIDR", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 0,
       .access = PL1_R, .readfn = ccsidr_read, .type = ARM_CP_NO_MIGRATE },
-    { .name = "CSSELR", .cp = 15, .crn = 0, .crm = 0, .opc1 = 2, .opc2 = 0,
+    { .name = "CSSELR", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 2, .opc2 = 0,
       .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c0_cssel),
       .writefn = csselr_write, .resetvalue = 0 },
     /* Auxiliary ID register: this actually has an IMPDEF value but for now
@@ -1524,13 +1526,6 @@ static const ARMCPRegInfo v8_cp_reginfo[] = {
     { .name = "FPSR", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 4, .crm = 4,
       .access = PL0_RW, .readfn = aa64_fpsr_read, .writefn = aa64_fpsr_write },
-    /* This claims a 32 byte cacheline size for icache and dcache, VIPT icache.
-     * It will eventually need to have a CPU-specified reset value.
-     */
-    { .name = "CTR_EL0", .state = ARM_CP_STATE_AA64,
-      .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 0, .crm = 0,
-      .access = PL0_R, .type = ARM_CP_CONST,
-      .resetvalue = 0x80030003 },
     /* Prohibit use of DC ZVA. OPTME: implement DC ZVA and allow its use.
      * For system mode the DZP bit here will need to be computed, not constant.
      */
@@ -1550,6 +1545,17 @@ static void sctlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
     tlb_flush(env, 1);
 }
 
+static CPAccessResult ctr_el0_access(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    /* Only accessible in EL0 if SCTLR.UCT is set (and only in AArch64,
+     * but the AArch32 CTR has its own reginfo struct)
+     */
+    if (arm_current_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UCT)) {
+        return CP_ACCESS_TRAP;
+    }
+    return CP_ACCESS_OK;
+}
+
 void register_cp_regs_for_features(ARMCPU *cpu)
 {
     /* Register all the coprocessor registers based on feature bits */
@@ -1634,7 +1640,8 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             .raw_writefn = raw_write,
         };
         ARMCPRegInfo clidr = {
-            .name = "CLIDR", .cp = 15, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 1,
+            .name = "CLIDR", .state = ARM_CP_STATE_BOTH,
+            .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 1,
             .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->clidr
         };
         define_one_arm_cp_reg(cpu, &pmcr);
@@ -1713,6 +1720,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             { .name = "CTR",
               .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 1,
               .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
+            { .name = "CTR_EL0", .state = ARM_CP_STATE_AA64,
+              .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 0, .crm = 0,
+              .access = PL0_R, .accessfn = ctr_el0_access,
+              .type = ARM_CP_CONST, .resetvalue = cpu->ctr },
             { .name = "TCMTR",
               .cp = 15, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 2,
               .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
-- 
1.8.5