tcg: Move TLB_FLAGS_MASK check out of get_alignment_bits

The replacement isn't ideal, as the raw count of bits
is not easily synced with exec/cpu-all.h, but it does
remove from tcg.h the target dependency on TARGET_PAGE_BITS_MIN
which is built into TLB_FLAGS_MASK.

Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/exec/cpu-all.h

@@ -314,6 +314,9 @@ CPUArchState *cpu_copy(CPUArchState *env);
  *
  * Use TARGET_PAGE_BITS_MIN so that these bits are constant
  * when TARGET_PAGE_BITS_VARY is in effect.
+ *
+ * The count, if not the placement of these bits is known
+ * to tcg/tcg-op-ldst.c, check_max_alignment().
  */
 /* Zero if TLB entry is valid.  */
 #define TLB_INVALID_MASK    (1 << (TARGET_PAGE_BITS_MIN - 1))

include/tcg/tcg.h

@@ -305,10 +305,6 @@ static inline unsigned get_alignment_bits(MemOp memop)
         /* A specific alignment requirement.  */
         a = a >> MO_ASHIFT;
     }
-#if defined(CONFIG_SOFTMMU)
-    /* The requested alignment cannot overlap the TLB flags.  */
-    tcg_debug_assert((TLB_FLAGS_MASK & ((1 << a) - 1)) == 0);
-#endif
     return a;
 }
 

tcg/tcg-op-ldst.c

@@ -32,11 +32,23 @@
 #include "tcg-internal.h"
 
 
-static inline MemOp tcg_canonicalize_memop(MemOp op, bool is64, bool st)
+static void check_max_alignment(unsigned a_bits)
+{
+#if defined(CONFIG_SOFTMMU)
+    /*
+     * The requested alignment cannot overlap the TLB flags.
+     * FIXME: Must keep the count up-to-date with "exec/cpu-all.h".
+     */
+    tcg_debug_assert(a_bits + 6 <= tcg_ctx->page_bits);
+#endif
+}
+
+static MemOp tcg_canonicalize_memop(MemOp op, bool is64, bool st)
 {
-    /* Trigger the asserts within as early as possible.  */
     unsigned a_bits = get_alignment_bits(op);
 
+    check_max_alignment(a_bits);
+
     /* Prefer MO_ALIGN+MO_XX over MO_ALIGN_XX+MO_XX */
     if (a_bits == (op & MO_SIZE)) {
         op = (op & ~MO_AMASK) | MO_ALIGN;
@@ -491,6 +503,7 @@ static void tcg_gen_qemu_ld_i128_int(TCGv_i128 val, TCGTemp *addr,
     TCGv_i64 ext_addr = NULL;
     TCGOpcode opc;
 
+    check_max_alignment(get_alignment_bits(memop));
     tcg_gen_req_mo(TCG_MO_LD_LD | TCG_MO_ST_LD);
 
     /* TODO: For now, force 32-bit hosts to use the helper. */
@@ -599,6 +612,7 @@ static void tcg_gen_qemu_st_i128_int(TCGv_i128 val, TCGTemp *addr,
     TCGv_i64 ext_addr = NULL;
     TCGOpcode opc;
 
+    check_max_alignment(get_alignment_bits(memop));
     tcg_gen_req_mo(TCG_MO_ST_LD | TCG_MO_ST_ST);
 
     /* TODO: For now, force 32-bit hosts to use the helper. */