target/i386: Assert SS32 for x86_64 user-only

For user-only, SS32 == !VM86, because we are never in
real-mode.  Since we cannot enter vm86 mode for x86_64
user-only, SS32 is always set.

Since we're adding an accessor macro, pull the value
directly out of flags otherwise.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210514151342.384376-12-richard.henderson@linaro.org>

target/i386/tcg/translate.c

@@ -107,7 +107,6 @@ typedef struct DisasContext {
 #endif
     int vex_l;  /* vex vector length */
     int vex_v;  /* vex vvvv register, without 1's complement.  */
-    int ss32;   /* 32 bit stack segment */
     CCOp cc_op;  /* current CC operation */
     bool cc_op_dirty;
 #ifdef TARGET_X86_64
@@ -160,9 +159,11 @@ typedef struct DisasContext {
 #if defined(CONFIG_USER_ONLY) && defined(TARGET_X86_64)
 #define VM86(S)   false
 #define CODE32(S) true
+#define SS32(S)   true
 #else
 #define VM86(S)   (((S)->flags & HF_VM_MASK) != 0)
 #define CODE32(S) (((S)->flags & HF_CS32_MASK) != 0)
+#define SS32(S)   (((S)->flags & HF_SS32_MASK) != 0)
 #endif
 
 static void gen_eob(DisasContext *s);
@@ -352,7 +353,7 @@ static inline MemOp mo_pushpop(DisasContext *s, MemOp ot)
 /* Select the size of the stack pointer.  */
 static inline MemOp mo_stacksize(DisasContext *s)
 {
-    return CODE64(s) ? MO_64 : s->ss32 ? MO_32 : MO_16;
+    return CODE64(s) ? MO_64 : SS32(s) ? MO_32 : MO_16;
 }
 
 /* Select only size 64 else 32.  Used for SSE operand sizes.  */
@@ -2451,12 +2452,12 @@ static inline void gen_pop_update(DisasContext *s, MemOp ot)
 
 static inline void gen_stack_A0(DisasContext *s)
 {
-    gen_lea_v_seg(s, s->ss32 ? MO_32 : MO_16, cpu_regs[R_ESP], R_SS, -1);
+    gen_lea_v_seg(s, SS32(s) ? MO_32 : MO_16, cpu_regs[R_ESP], R_SS, -1);
 }
 
 static void gen_pusha(DisasContext *s)
 {
-    MemOp s_ot = s->ss32 ? MO_32 : MO_16;
+    MemOp s_ot = SS32(s) ? MO_32 : MO_16;
     MemOp d_ot = s->dflag;
     int size = 1 << d_ot;
     int i;
@@ -2472,7 +2473,7 @@ static void gen_pusha(DisasContext *s)
 
 static void gen_popa(DisasContext *s)
 {
-    MemOp s_ot = s->ss32 ? MO_32 : MO_16;
+    MemOp s_ot = SS32(s) ? MO_32 : MO_16;
     MemOp d_ot = s->dflag;
     int size = 1 << d_ot;
     int i;
@@ -2494,7 +2495,7 @@ static void gen_popa(DisasContext *s)
 static void gen_enter(DisasContext *s, int esp_addend, int level)
 {
     MemOp d_ot = mo_pushpop(s, s->dflag);
-    MemOp a_ot = CODE64(s) ? MO_64 : s->ss32 ? MO_32 : MO_16;
+    MemOp a_ot = CODE64(s) ? MO_64 : SS32(s) ? MO_32 : MO_16;
     int size = 1 << d_ot;
 
     /* Push BP; compute FrameTemp into T1.  */
@@ -8496,8 +8497,8 @@ static void i386_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cpu)
     g_assert(IOPL(dc) == iopl);
     g_assert(VM86(dc) == ((flags & HF_VM_MASK) != 0));
     g_assert(CODE32(dc) == ((flags & HF_CS32_MASK) != 0));
+    g_assert(SS32(dc) == ((flags & HF_SS32_MASK) != 0));
 
-    dc->ss32 = (flags >> HF_SS32_SHIFT) & 1;
     dc->addseg = (flags >> HF_ADDSEG_SHIFT) & 1;
     dc->f_st = 0;
     dc->tf = (flags >> TF_SHIFT) & 1;