target/hppa: Adjust priv for B,GATE at runtime

Do not compile in the priv change based on the first translation;
look up the PTE at execution time.  This is required for CF_PCREL,
where a page may be mapped multiple times with different attributes.

Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/hppa/cpu.h

@@ -380,7 +380,6 @@ void hppa_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
 extern const MemoryRegionOps hppa_io_eir_ops;
 extern const VMStateDescription vmstate_hppa_cpu;
 void hppa_cpu_alarm_timer(void *);
-int hppa_artype_for_page(CPUHPPAState *env, target_ulong vaddr);
 #endif
 G_NORETURN void hppa_dynamic_excp(CPUHPPAState *env, int excp, uintptr_t ra);
 

target/hppa/helper.h

@@ -86,6 +86,7 @@ DEF_HELPER_1(halt, noreturn, env)
 DEF_HELPER_1(reset, noreturn, env)
 DEF_HELPER_1(rfi, void, env)
 DEF_HELPER_1(rfi_r, void, env)
+DEF_HELPER_FLAGS_2(b_gate_priv, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_2(write_interval_timer, TCG_CALL_NO_RWG, void, env, tl)
 DEF_HELPER_FLAGS_2(write_eirr, TCG_CALL_NO_RWG, void, env, tl)
 DEF_HELPER_FLAGS_2(swap_system_mask, TCG_CALL_NO_RWG, tl, env, tl)

target/hppa/mem_helper.c

@@ -691,13 +691,6 @@ target_ulong HELPER(lpa)(CPUHPPAState *env, target_ulong addr)
     return phys;
 }
 
-/* Return the ar_type of the TLB at VADDR, or -1.  */
-int hppa_artype_for_page(CPUHPPAState *env, target_ulong vaddr)
-{
-    HPPATLBEntry *ent = hppa_find_tlb(env, vaddr);
-    return ent ? ent->ar_type : -1;
-}
-
 /*
  * diag_btlb() emulates the PDC PDC_BLOCK_TLB firmware call to
  * allow operating systems to modify the Block TLB (BTLB) entries.
@@ -793,3 +786,30 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
         break;
     }
 }
+
+uint64_t HELPER(b_gate_priv)(CPUHPPAState *env, uint64_t iaoq_f)
+{
+    uint64_t gva = hppa_form_gva(env, env->iasq_f, iaoq_f);
+    HPPATLBEntry *ent = hppa_find_tlb(env, gva);
+
+    if (ent == NULL) {
+        raise_exception_with_ior(env, EXCP_ITLB_MISS, GETPC(), gva, false);
+    }
+
+    /*
+     * There should be no need to check page permissions, as that will
+     * already have been done by tb_lookup via get_page_addr_code.
+     * All we need at this point is to check the ar_type.
+     *
+     * No change for non-gateway pages or for priv decrease.
+     */
+    if (ent->ar_type & 4) {
+        int old_priv = iaoq_f & 3;
+        int new_priv = ent->ar_type & 3;
+
+        if (new_priv < old_priv) {
+            iaoq_f = (iaoq_f & -4) | new_priv;
+        }
+    }
+    return iaoq_f;
+}

target/hppa/translate.c

@@ -3961,6 +3961,7 @@ static bool trans_bl(DisasContext *ctx, arg_bl *a)
 static bool trans_b_gate(DisasContext *ctx, arg_b_gate *a)
 {
     int64_t disp = a->disp;
+    bool indirect = false;
 
     /* Trap if PSW[B] is set. */
     if (ctx->psw_xb & PSW_B) {
@@ -3970,24 +3971,22 @@ static bool trans_b_gate(DisasContext *ctx, arg_b_gate *a)
     nullify_over(ctx);
 
 #ifndef CONFIG_USER_ONLY
-    if (ctx->tb_flags & PSW_C) {
-        int type = hppa_artype_for_page(cpu_env(ctx->cs), ctx->base.pc_next);
-        /* If we could not find a TLB entry, then we need to generate an
-           ITLB miss exception so the kernel will provide it.
-           The resulting TLB fill operation will invalidate this TB and
-           we will re-translate, at which point we *will* be able to find
-           the TLB entry and determine if this is in fact a gateway page.  */
-        if (type < 0) {
-            gen_excp(ctx, EXCP_ITLB_MISS);
-            return true;
-        }
-        /* No change for non-gateway pages or for priv decrease.  */
-        if (type >= 4 && type - 4 < ctx->privilege) {
-            disp -= ctx->privilege;
-            disp += type - 4;
-        }
+    if (ctx->privilege == 0) {
+        /* Privilege cannot decrease. */
+    } else if (!(ctx->tb_flags & PSW_C)) {
+        /* With paging disabled, priv becomes 0. */
+        disp -= ctx->privilege;
     } else {
-        disp -= ctx->privilege;  /* priv = 0 */
+        /* Adjust the dest offset for the privilege change from the PTE. */
+        TCGv_i64 off = tcg_temp_new_i64();
+
+        gen_helper_b_gate_priv(off, tcg_env,
+                               tcg_constant_i64(ctx->iaoq_first
+                                                + ctx->iaq_f.disp));
+
+        ctx->iaq_j.base = off;
+        ctx->iaq_j.disp = disp + 8;
+        indirect = true;
     }
 #endif
 
@@ -4000,6 +3999,9 @@ static bool trans_b_gate(DisasContext *ctx, arg_b_gate *a)
         save_gpr(ctx, a->l, tmp);
     }
 
+    if (indirect) {
+        return do_ibranch(ctx, 0, false, a->n);
+    }
     return do_dbranch(ctx, disp, 0, a->n);
 }