target/arm: Recover 4 bits from TBFLAGs

We had completely run out of TBFLAG bits.
Split A- and M-profile bits into two overlapping buckets.
This results in 4 free bits.

We used to initialize all of the a32 and m32 fields in DisasContext
by assignment, in arm_tr_init_disas_context.  Now we only initialize
either the a32 or m32 by assignment, because the bits overlap in
tbflags.  So zero the entire structure in gen_intermediate_code.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200206105448.4726-16-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 7 insertions, 10 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 7ee4197456..5609bb18e8 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11353,11 +11353,8 @@ static uint32_t rebuild_hflags_m32(CPUARMState *env, int fp_el,
 {
     uint32_t flags = 0;
 
-    /* v8M always enables the fpu.  */
-    flags = FIELD_DP32(flags, TBFLAG_A32, VFPEN, 1);
-
     if (arm_v7m_is_handler_mode(env)) {
-        flags = FIELD_DP32(flags, TBFLAG_A32, HANDLER, 1);
+        flags = FIELD_DP32(flags, TBFLAG_M32, HANDLER, 1);
     }
 
     /*
@@ -11368,7 +11365,7 @@ static uint32_t rebuild_hflags_m32(CPUARMState *env, int fp_el,
     if (arm_feature(env, ARM_FEATURE_V8) &&
         !((mmu_idx & ARM_MMU_IDX_M_NEGPRI) &&
           (env->v7m.ccr[env->v7m.secure] & R_V7M_CCR_STKOFHFNMIGN_MASK))) {
-        flags = FIELD_DP32(flags, TBFLAG_A32, STACKCHECK, 1);
+        flags = FIELD_DP32(flags, TBFLAG_M32, STACKCHECK, 1);
     }
 
     return rebuild_hflags_common_32(env, fp_el, mmu_idx, flags);
@@ -11561,7 +11558,7 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
             if (arm_feature(env, ARM_FEATURE_M_SECURITY) &&
                 FIELD_EX32(env->v7m.fpccr[M_REG_S], V7M_FPCCR, S)
                 != env->v7m.secure) {
-                flags = FIELD_DP32(flags, TBFLAG_A32, FPCCR_S_WRONG, 1);
+                flags = FIELD_DP32(flags, TBFLAG_M32, FPCCR_S_WRONG, 1);
             }
 
             if ((env->v7m.fpccr[env->v7m.secure] & R_V7M_FPCCR_ASPEN_MASK) &&
@@ -11573,12 +11570,12 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
                  * active FP context; we must create a new FP context before
                  * executing any FP insn.
                  */
-                flags = FIELD_DP32(flags, TBFLAG_A32, NEW_FP_CTXT_NEEDED, 1);
+                flags = FIELD_DP32(flags, TBFLAG_M32, NEW_FP_CTXT_NEEDED, 1);
             }
 
             bool is_secure = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_S_MASK;
             if (env->v7m.fpccr[is_secure] & R_V7M_FPCCR_LSPACT_MASK) {
-                flags = FIELD_DP32(flags, TBFLAG_A32, LSPACT, 1);
+                flags = FIELD_DP32(flags, TBFLAG_M32, LSPACT, 1);
             }
         } else {
             /*
@@ -11599,8 +11596,8 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
             }
         }
 
-        flags = FIELD_DP32(flags, TBFLAG_A32, THUMB, env->thumb);
-        flags = FIELD_DP32(flags, TBFLAG_A32, CONDEXEC, env->condexec_bits);
+        flags = FIELD_DP32(flags, TBFLAG_AM32, THUMB, env->thumb);
+        flags = FIELD_DP32(flags, TBFLAG_AM32, CONDEXEC, env->condexec_bits);
         pstate_for_ss = env->uncached_cpsr;
     }