[Qemu-devel] [PATCH 4/4] target-arm: refactor cp15.c13 register access

[Riku Voipio <riku.voipio@iki.fi>]

From: Riku Voipio <riku.voipio@nokia.com>

Access the cp15.c13 TLS registers directly with TCG ops instead of with
a slow helper. If the the cp15 read/write was not TLS register access,
fall back to the cp15 helper.

This makes accessing __thread variables in linux-user when apps are compiled
with -mtp=cp15 possible. legal cp15 register to acces from linux-user are
already checked in cp15_user_ok.

While at it, make the cp15.c13 Thread ID registers available only on
ARMv6K and newer.

Signed-off-by: Riku Voipio <riku.voipio@nokia.com>
---
 target-arm/helper.c    |   16 --------------
 target-arm/translate.c |   55 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index b3aec99..27001e8 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -511,7 +511,6 @@ void HELPER(set_cp15)(CPUState *env, uint32_t insn, uint32_t val)
 uint32_t HELPER(get_cp15)(CPUState *env, uint32_t insn)
 {
     cpu_abort(env, "cp15 insn %08x\n", insn);
-    return 0;
 }
 
 /* These should probably raise undefined insn exceptions.  */
@@ -1491,15 +1490,6 @@ void HELPER(set_cp15)(CPUState *env, uint32_t insn, uint32_t val)
               tlb_flush(env, 0);
             env->cp15.c13_context = val;
             break;
-        case 2:
-            env->cp15.c13_tls1 = val;
-            break;
-        case 3:
-            env->cp15.c13_tls2 = val;
-            break;
-        case 4:
-            env->cp15.c13_tls3 = val;
-            break;
         default:
             goto bad_reg;
         }
@@ -1779,12 +1769,6 @@ uint32_t HELPER(get_cp15)(CPUState *env, uint32_t insn)
             return env->cp15.c13_fcse;
         case 1:
             return env->cp15.c13_context;
-        case 2:
-            return env->cp15.c13_tls1;
-        case 3:
-            return env->cp15.c13_tls2;
-        case 4:
-            return env->cp15.c13_tls3;
         default:
             goto bad_reg;
         }
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 5cf3e06..786c329 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -2455,6 +2455,57 @@ static int cp15_user_ok(uint32_t insn)
     return 0;
 }
 
+static int cp15_tls_load_store(CPUState *env, DisasContext *s, uint32_t insn, uint32_t rd)
+{
+    TCGv tmp;
+    int cpn = (insn >> 16) & 0xf;
+    int cpm = insn & 0xf;
+    int op = ((insn >> 5) & 7) | ((insn >> 18) & 0x38);
+
+    if (!arm_feature(env, ARM_FEATURE_V6K))
+        return 0;
+
+    if (!(cpn == 13 && cpm == 0))
+        return 0;
+
+    if (insn & ARM_CP_RW_BIT) {
+        tmp = new_tmp();
+        switch (op) {
+        case 2:
+            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls1));
+            break;
+        case 3:
+            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls2));
+            break;
+        case 4:
+            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls3));
+            break;
+        default:
+            dead_tmp(tmp);
+            return 0;
+        }
+        store_reg(s, rd, tmp);
+
+    } else {
+        tmp = load_reg(s, rd);
+        switch (op) {
+        case 2:
+            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls1));
+            break;
+        case 3:
+            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls2));
+            break;
+        case 4:
+            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls3));
+            break;
+        default:
+            return 0;
+        }
+        dead_tmp(tmp);
+    }
+    return 1;
+}
+
 /* Disassemble system coprocessor (cp15) instruction.  Return nonzero if
    instruction is not defined.  */
 static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn)
@@ -2489,6 +2540,10 @@ static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn)
         return 0;
     }
     rd = (insn >> 12) & 0xf;
+
+    if (cp15_tls_load_store(env, s, insn, rd))
+        return 0;
+
     tmp2 = tcg_const_i32(insn);
     if (insn & ARM_CP_RW_BIT) {
         tmp = new_tmp();
-- 
1.6.5