target/nios2: Implement rdprs, wrprs

Implement these out of line, so that tcg global temps
(aka the architectural registers) are synced back to
tcg storage as required.  This makes sure that we get
the proper results when status.PRS == status.CRS.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-55-richard.henderson@linaro.org>

diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index f6efaa79b398dee701e280bd7e0350cf201bd54a..cca821cf807044c866cc44161606d0b99688dcbe 100644 (file)
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -220,6 +220,7 @@ struct ArchCPU {
 
     bool diverr_present;
     bool mmu_present;
+    bool eic_present;
 
     uint32_t pid_num_bits;
     uint32_t tlb_num_ways;

diff --git a/target/nios2/helper.h b/target/nios2/helper.h
index 6f5ec60b0d7c6921adf4605069b0cd2705e529f7..1648d76adea7a4d25b8d28d62a84b9ae2656fae0 100644 (file)
--- a/target/nios2/helper.h
+++ b/target/nios2/helper.h
@@ -24,6 +24,8 @@ DEF_HELPER_FLAGS_3(divu, TCG_CALL_NO_WG, i32, env, i32, i32)
 
 #if !defined(CONFIG_USER_ONLY)
 DEF_HELPER_3(eret, noreturn, env, i32, i32)
+DEF_HELPER_FLAGS_2(rdprs, TCG_CALL_NO_WG, i32, env, i32)
+DEF_HELPER_3(wrprs, void, env, i32, i32)
 DEF_HELPER_2(mmu_write_tlbacc, void, env, i32)
 DEF_HELPER_2(mmu_write_tlbmisc, void, env, i32)
 DEF_HELPER_2(mmu_write_pteaddr, void, env, i32)

diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c
index 38a71a1f2d5351f15f9de6b0651da57446971346..a3164f5356f78394dff23b2ccb9be5304eed3d50 100644 (file)
--- a/target/nios2/op_helper.c
+++ b/target/nios2/op_helper.c
@@ -83,4 +83,20 @@ void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc)
     env->pc = new_pc;
     cpu_loop_exit(cs);
 }
+
+/*
+ * RDPRS and WRPRS are implemented out of line so that if PRS == CRS,
+ * all of the tcg global temporaries are synced back to ENV.
+ */
+uint32_t helper_rdprs(CPUNios2State *env, uint32_t regno)
+{
+    unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
+    return env->shadow_regs[prs][regno];
+}
+
+void helper_wrprs(CPUNios2State *env, uint32_t regno, uint32_t val)
+{
+    unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
+    env->shadow_regs[prs][regno] = val;
+}
 #endif /* !CONFIG_USER_ONLY */

diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index 363f2ea3cab2feb0f87951f4af77b9b13022a7b2..e566175db58695750aaa5d3e6bfbe82ac0983b6a 100644 (file)
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -130,6 +130,7 @@ typedef struct DisasContext {
     uint32_t          tb_flags;
     TCGv              sink;
     const ControlRegState *cr_state;
+    bool              eic_present;
 } DisasContext;
 
 static TCGv cpu_R[NUM_GP_REGS];
@@ -387,6 +388,27 @@ gen_i_math_logic(andhi, andi, 0, imm_shifted)
 gen_i_math_logic(orhi , ori,  1, imm_shifted)
 gen_i_math_logic(xorhi, xori, 1, imm_shifted)
 
+/* rB <- prs.rA + sigma(IMM16) */
+static void rdprs(DisasContext *dc, uint32_t code, uint32_t flags)
+{
+    if (!dc->eic_present) {
+        t_gen_helper_raise_exception(dc, EXCP_ILLEGAL);
+        return;
+    }
+    if (!gen_check_supervisor(dc)) {
+        return;
+    }
+
+#ifdef CONFIG_USER_ONLY
+    g_assert_not_reached();
+#else
+    I_TYPE(instr, code);
+    TCGv dest = dest_gpr(dc, instr.b);
+    gen_helper_rdprs(dest, cpu_env, tcg_constant_i32(instr.a));
+    tcg_gen_addi_tl(dest, dest, instr.imm16.s);
+#endif
+}
+
 /* Prototype only, defined below */
 static void handle_r_type_instr(DisasContext *dc, uint32_t code,
                                 uint32_t flags);
@@ -448,7 +470,7 @@ static const Nios2Instruction i_type_instructions[] = {
     INSTRUCTION_FLG(gen_stx, MO_SL),                  /* stwio */
     INSTRUCTION_FLG(gen_bxx, TCG_COND_LTU),           /* bltu */
     INSTRUCTION_FLG(gen_ldx, MO_UL),                  /* ldwio */
-    INSTRUCTION_UNIMPLEMENTED(),                      /* rdprs */
+    INSTRUCTION(rdprs),                               /* rdprs */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION_FLG(handle_r_type_instr, 0),          /* R-Type */
     INSTRUCTION_NOP(),                                /* flushd */
@@ -648,6 +670,36 @@ static void wrctl(DisasContext *dc, uint32_t code, uint32_t flags)
 #endif
 }
 
+/* prs.rC <- rA */
+static void wrprs(DisasContext *dc, uint32_t code, uint32_t flags)
+{
+    if (!dc->eic_present) {
+        t_gen_helper_raise_exception(dc, EXCP_ILLEGAL);
+        return;
+    }
+    if (!gen_check_supervisor(dc)) {
+        return;
+    }
+
+#ifdef CONFIG_USER_ONLY
+    g_assert_not_reached();
+#else
+    R_TYPE(instr, code);
+    gen_helper_wrprs(cpu_env, tcg_constant_i32(instr.c),
+                     load_gpr(dc, instr.a));
+    /*
+     * The expected write to PRS[r0] is 0, from CRS[r0].
+     * If not, and CRS == PRS (which we cannot tell from here),
+     * we may now have a non-zero value in our current r0.
+     * By ending the TB, we re-evaluate tb_flags and find out.
+     */
+    if (instr.c == 0
+        && (instr.a != 0 || !FIELD_EX32(dc->tb_flags, TBFLAGS, R0_0))) {
+        dc->base.is_jmp = DISAS_UPDATE;
+    }
+#endif
+}
+
 /* Comparison instructions */
 static void gen_cmpxx(DisasContext *dc, uint32_t code, uint32_t flags)
 {
@@ -793,7 +845,7 @@ static const Nios2Instruction r_type_instructions[] = {
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION(slli),                                /* slli */
     INSTRUCTION(sll),                                 /* sll */
-    INSTRUCTION_UNIMPLEMENTED(),                      /* wrprs */
+    INSTRUCTION(wrprs),                               /* wrprs */
     INSTRUCTION_ILLEGAL(),
     INSTRUCTION(or),                                  /* or */
     INSTRUCTION(mulxsu),                              /* mulxsu */
@@ -895,6 +947,7 @@ static void nios2_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     dc->mem_idx = cpu_mmu_index(env, false);
     dc->cr_state = cpu->cr_state;
     dc->tb_flags = dc->base.tb->flags;
+    dc->eic_present = cpu->eic_present;
 
     /* Bound the number of insns to execute to those left on the page.  */
     page_insns = -(dc->base.pc_first | TARGET_PAGE_MASK) / 4;