target/arm: Split out rebuild_hflags_common

Create a function to compute the values of the TBFLAG_ANY bits
that will be cached.  For now, the env->hflags variable is not
used, and the results are fed back to cpu_get_tb_cpu_state.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191023150057.25731-2-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/cpu.h

@@ -231,6 +231,9 @@ typedef struct CPUARMState {
     uint32_t pstate;
     uint32_t aarch64; /* 1 if CPU is in aarch64 state; inverse of PSTATE.nRW */
 
+    /* Cached TBFLAGS state.  See below for which bits are included.  */
+    uint32_t hflags;
+
     /* Frequently accessed CPSR bits are stored separately for efficiency.
        This contains all the other bits.  Use cpsr_{read,write} to access
        the whole CPSR.  */
@@ -3140,15 +3143,18 @@ typedef ARMCPU ArchCPU;
 
 #include "exec/cpu-all.h"
 
-/* Bit usage in the TB flags field: bit 31 indicates whether we are
+/*
+ * Bit usage in the TB flags field: bit 31 indicates whether we are
  * in 32 or 64 bit mode. The meaning of the other bits depends on that.
  * We put flags which are shared between 32 and 64 bit mode at the top
  * of the word, and flags which apply to only one mode at the bottom.
+ *
+ * Unless otherwise noted, these bits are cached in env->hflags.
  */
 FIELD(TBFLAG_ANY, AARCH64_STATE, 31, 1)
 FIELD(TBFLAG_ANY, MMUIDX, 28, 3)
 FIELD(TBFLAG_ANY, SS_ACTIVE, 27, 1)
-FIELD(TBFLAG_ANY, PSTATE_SS, 26, 1)
+FIELD(TBFLAG_ANY, PSTATE_SS, 26, 1)     /* Not cached. */
 /* Target EL if we take a floating-point-disabled exception */
 FIELD(TBFLAG_ANY, FPEXC_EL, 24, 2)
 FIELD(TBFLAG_ANY, BE_DATA, 23, 1)
@@ -3159,13 +3165,14 @@ FIELD(TBFLAG_ANY, BE_DATA, 23, 1)
 FIELD(TBFLAG_ANY, DEBUG_TARGET_EL, 21, 2)
 
 /* Bit usage when in AArch32 state: */
-FIELD(TBFLAG_A32, THUMB, 0, 1)
+FIELD(TBFLAG_A32, THUMB, 0, 1)          /* Not cached. */
-FIELD(TBFLAG_A32, VECLEN, 1, 3)
+FIELD(TBFLAG_A32, VECLEN, 1, 3)         /* Not cached. */
-FIELD(TBFLAG_A32, VECSTRIDE, 4, 2)
+FIELD(TBFLAG_A32, VECSTRIDE, 4, 2)      /* Not cached. */
 /*
  * We store the bottom two bits of the CPAR as TB flags and handle
  * checks on the other bits at runtime. This shares the same bits as
  * VECSTRIDE, which is OK as no XScale CPU has VFP.
+ * Not cached, because VECLEN+VECSTRIDE are not cached.
  */
 FIELD(TBFLAG_A32, XSCALE_CPAR, 4, 2)
 /*
@@ -3174,15 +3181,15 @@ FIELD(TBFLAG_A32, XSCALE_CPAR, 4, 2)
  * the same thing as the current security state of the processor!
  */
 FIELD(TBFLAG_A32, NS, 6, 1)
-FIELD(TBFLAG_A32, VFPEN, 7, 1)
+FIELD(TBFLAG_A32, VFPEN, 7, 1)          /* Not cached. */
-FIELD(TBFLAG_A32, CONDEXEC, 8, 8)
+FIELD(TBFLAG_A32, CONDEXEC, 8, 8)       /* Not cached. */
 FIELD(TBFLAG_A32, SCTLR_B, 16, 1)
 /* For M profile only, set if FPCCR.LSPACT is set */
-FIELD(TBFLAG_A32, LSPACT, 18, 1)
+FIELD(TBFLAG_A32, LSPACT, 18, 1)        /* Not cached. */
 /* For M profile only, set if we must create a new FP context */
-FIELD(TBFLAG_A32, NEW_FP_CTXT_NEEDED, 19, 1)
+FIELD(TBFLAG_A32, NEW_FP_CTXT_NEEDED, 19, 1) /* Not cached. */
 /* For M profile only, set if FPCCR.S does not match current security state */
-FIELD(TBFLAG_A32, FPCCR_S_WRONG, 20, 1)
+FIELD(TBFLAG_A32, FPCCR_S_WRONG, 20, 1) /* Not cached. */
 /* For M profile only, Handler (ie not Thread) mode */
 FIELD(TBFLAG_A32, HANDLER, 21, 1)
 /* For M profile only, whether we should generate stack-limit checks */
@@ -3194,7 +3201,7 @@ FIELD(TBFLAG_A64, SVEEXC_EL, 2, 2)
 FIELD(TBFLAG_A64, ZCR_LEN, 4, 4)
 FIELD(TBFLAG_A64, PAUTH_ACTIVE, 8, 1)
 FIELD(TBFLAG_A64, BT, 9, 1)
-FIELD(TBFLAG_A64, BTYPE, 10, 2)
+FIELD(TBFLAG_A64, BTYPE, 10, 2)         /* Not cached. */
 FIELD(TBFLAG_A64, TBID, 12, 2)
 
 static inline bool bswap_code(bool sctlr_b)

target/arm/helper.c

@@ -11054,6 +11054,22 @@ ARMMMUIdx arm_stage1_mmu_idx(CPUARMState *env)
 }
 #endif
 
+static uint32_t rebuild_hflags_common(CPUARMState *env, int fp_el,
+                                      ARMMMUIdx mmu_idx, uint32_t flags)
+{
+    flags = FIELD_DP32(flags, TBFLAG_ANY, FPEXC_EL, fp_el);
+    flags = FIELD_DP32(flags, TBFLAG_ANY, MMUIDX,
+                       arm_to_core_mmu_idx(mmu_idx));
+
+    if (arm_cpu_data_is_big_endian(env)) {
+        flags = FIELD_DP32(flags, TBFLAG_ANY, BE_DATA, 1);
+    }
+    if (arm_singlestep_active(env)) {
+        flags = FIELD_DP32(flags, TBFLAG_ANY, SS_ACTIVE, 1);
+    }
+    return flags;
+}
+
 void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
                           target_ulong *cs_base, uint32_t *pflags)
 {
@@ -11145,7 +11161,7 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
         }
     }
 
-    flags = FIELD_DP32(flags, TBFLAG_ANY, MMUIDX, arm_to_core_mmu_idx(mmu_idx));
+    flags = rebuild_hflags_common(env, fp_el, mmu_idx, flags);
 
     /* The SS_ACTIVE and PSTATE_SS bits correspond to the state machine
      * states defined in the ARM ARM for software singlestep:
@@ -11153,9 +11169,9 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
      *     0            x       Inactive (the TB flag for SS is always 0)
      *     1            0       Active-pending
      *     1            1       Active-not-pending
+     * SS_ACTIVE is set in hflags; PSTATE_SS is computed every TB.
      */
-    if (arm_singlestep_active(env)) {
+    if (FIELD_EX32(flags, TBFLAG_ANY, SS_ACTIVE)) {
-        flags = FIELD_DP32(flags, TBFLAG_ANY, SS_ACTIVE, 1);
         if (is_a64(env)) {
             if (env->pstate & PSTATE_SS) {
                 flags = FIELD_DP32(flags, TBFLAG_ANY, PSTATE_SS, 1);
@@ -11166,10 +11182,6 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
             }
         }
     }
-    if (arm_cpu_data_is_big_endian(env)) {
-        flags = FIELD_DP32(flags, TBFLAG_ANY, BE_DATA, 1);
-    }
-    flags = FIELD_DP32(flags, TBFLAG_ANY, FPEXC_EL, fp_el);
 
     if (arm_v7m_is_handler_mode(env)) {
         flags = FIELD_DP32(flags, TBFLAG_A32, HANDLER, 1);