[Qemu-devel] [PATCH v2 16/31] target-xtensa: add PS register and access control

[Max Filippov <jcmvbkbc@gmail.com>]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 target-xtensa/cpu.h       |   53 ++++++++++++++++++++++++++++++++++++++++++++-
 target-xtensa/helper.c    |    1 +
 target-xtensa/translate.c |   29 ++++++++++++++++++++----
 3 files changed, 77 insertions(+), 6 deletions(-)

diff --git a/target-xtensa/cpu.h b/target-xtensa/cpu.h
index 5a3b40e..a5f62b2 100644
--- a/target-xtensa/cpu.h
+++ b/target-xtensa/cpu.h
@@ -108,8 +108,27 @@ enum {
 enum {
     SAR = 3,
     SCOMPARE1 = 12,
+    PS = 230,
 };
 
+#define PS_INTLEVEL 0xf
+#define PS_INTLEVEL_SHIFT 0
+
+#define PS_EXCM 0x10
+#define PS_UM 0x20
+
+#define PS_RING 0xc0
+#define PS_RING_SHIFT 6
+
+#define PS_OWB 0xf00
+#define PS_OWB_SHIFT 8
+
+#define PS_CALLINC 0x30000
+#define PS_CALLINC_SHIFT 16
+#define PS_CALLINC_LEN 2
+
+#define PS_WOE 0x40000
+
 typedef struct XtensaConfig {
     const char *name;
     uint64_t options;
@@ -145,17 +164,49 @@ static inline bool xtensa_option_enabled(const XtensaConfig *config, int opt)
     return (config->options & XTENSA_OPTION_BIT(opt)) != 0;
 }
 
+static inline int xtensa_get_ring(const CPUState *env)
+{
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_MMU)) {
+        return (env->sregs[PS] & PS_RING) >> PS_RING_SHIFT;
+    } else {
+        return 0;
+    }
+}
+
+static inline int xtensa_get_cring(const CPUState *env)
+{
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_MMU) &&
+            (env->sregs[PS] & PS_EXCM) == 0) {
+        return (env->sregs[PS] & PS_RING) >> PS_RING_SHIFT;
+    } else {
+        return 0;
+    }
+}
+
+/* MMU modes definitions */
+#define MMU_MODE0_SUFFIX _ring0
+#define MMU_MODE1_SUFFIX _ring1
+#define MMU_MODE2_SUFFIX _ring2
+#define MMU_MODE3_SUFFIX _ring3
+
 static inline int cpu_mmu_index(CPUState *env)
 {
-    return 0;
+    return xtensa_get_cring(env);
 }
 
+#define XTENSA_TBFLAG_RING_MASK 0x3
+#define XTENSA_TBFLAG_EXCM 0x4
+
 static inline void cpu_get_tb_cpu_state(CPUState *env, target_ulong *pc,
         target_ulong *cs_base, int *flags)
 {
     *pc = env->pc;
     *cs_base = 0;
     *flags = 0;
+    *flags |= xtensa_get_ring(env);
+    if (env->sregs[PS] & PS_EXCM) {
+        *flags |= XTENSA_TBFLAG_EXCM;
+    }
 }
 
 #include "cpu-all.h"
diff --git a/target-xtensa/helper.c b/target-xtensa/helper.c
index c6ffcc9..bc186af 100644
--- a/target-xtensa/helper.c
+++ b/target-xtensa/helper.c
@@ -37,6 +37,7 @@
 void cpu_reset(CPUXtensaState *env)
 {
     env->pc = 0;
+    env->sregs[PS] = 0x1f;
 }
 
 static const XtensaConfig core_config[] = {
diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index 83ac611..729002b 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -45,6 +45,8 @@ typedef struct DisasContext {
     TranslationBlock *tb;
     uint32_t pc;
     uint32_t next_pc;
+    int cring;
+    int ring;
     int is_jmp;
     int singlestep_enabled;
 
@@ -65,6 +67,7 @@ static TCGv_i32 cpu_UR[256];
 static const char * const sregnames[256] = {
     [SAR] = "SAR",
     [SCOMPARE1] = "SCOMPARE1",
+    [PS] = "PS",
 };
 
 static const char * const uregnames[256] = {
@@ -239,11 +242,25 @@ static void gen_wsr_sar(DisasContext *dc, uint32_t sr, TCGv_i32 s)
     dc->sar_m32_5bit = false;
 }
 
+static void gen_wsr_ps(DisasContext *dc, uint32_t sr, TCGv_i32 v)
+{
+    uint32_t mask = PS_WOE | PS_CALLINC | PS_OWB |
+        PS_UM | PS_EXCM | PS_INTLEVEL;
+
+    if (option_enabled(dc, XTENSA_OPTION_MMU)) {
+        mask |= PS_RING;
+    }
+    tcg_gen_andi_i32(cpu_SR[sr], v, mask);
+    /* This can change mmu index, so exit tb */
+    gen_jumpi(dc, dc->next_pc, -1);
+}
+
 static void gen_wsr(DisasContext *dc, uint32_t sr, TCGv_i32 s)
 {
     static void (* const wsr_handler[256])(DisasContext *dc,
             uint32_t sr, TCGv_i32 v) = {
         [SAR] = gen_wsr_sar,
+        [PS] = gen_wsr_ps,
     };
 
     if (sregnames[sr]) {
@@ -973,7 +990,7 @@ static void disas_xtensa_insn(DisasContext *dc)
 
             /* no ext L32R */
 
-            tcg_gen_qemu_ld32u(cpu_R[RRR_T], tmp, 0);
+            tcg_gen_qemu_ld32u(cpu_R[RRR_T], tmp, dc->cring);
             tcg_temp_free(tmp);
         }
         break;
@@ -982,7 +999,7 @@ static void disas_xtensa_insn(DisasContext *dc)
 #define gen_load_store(type, shift) do { \
             TCGv_i32 addr = tcg_temp_new_i32(); \
             tcg_gen_addi_i32(addr, cpu_R[RRI8_S], RRI8_IMM8 << shift); \
-            tcg_gen_qemu_##type(cpu_R[RRI8_T], addr, 0); \
+            tcg_gen_qemu_##type(cpu_R[RRI8_T], addr, dc->cring); \
             tcg_temp_free(addr); \
         } while (0)
 
@@ -1140,11 +1157,11 @@ static void disas_xtensa_insn(DisasContext *dc)
 
                 tcg_gen_mov_i32(tmp, cpu_R[RRI8_T]);
                 tcg_gen_addi_i32(addr, cpu_R[RRI8_S], RRI8_IMM8 << 2);
-                tcg_gen_qemu_ld32u(cpu_R[RRI8_T], addr, 0);
+                tcg_gen_qemu_ld32u(cpu_R[RRI8_T], addr, dc->cring);
                 tcg_gen_brcond_i32(TCG_COND_NE, cpu_R[RRI8_T],
                         cpu_SR[SCOMPARE1], label);
 
-                tcg_gen_qemu_st32(tmp, addr, 0);
+                tcg_gen_qemu_st32(tmp, addr, dc->cring);
 
                 gen_set_label(label);
                 tcg_temp_free(addr);
@@ -1345,7 +1362,7 @@ static void disas_xtensa_insn(DisasContext *dc)
 #define gen_narrow_load_store(type) do { \
             TCGv_i32 addr = tcg_temp_new_i32(); \
             tcg_gen_addi_i32(addr, cpu_R[RRRN_S], RRRN_R << 2); \
-            tcg_gen_qemu_##type(cpu_R[RRRN_T], addr, 0); \
+            tcg_gen_qemu_##type(cpu_R[RRRN_T], addr, dc->cring); \
             tcg_temp_free(addr); \
         } while (0)
 
@@ -1468,6 +1485,8 @@ static void gen_intermediate_code_internal(
     dc.singlestep_enabled = env->singlestep_enabled;
     dc.tb = tb;
     dc.pc = pc_start;
+    dc.ring = tb->flags & XTENSA_TBFLAG_RING_MASK;
+    dc.cring = (tb->flags & XTENSA_TBFLAG_EXCM) ? 0 : dc.ring;
     dc.is_jmp = DISAS_NEXT;
 
     init_sar_tracker(&dc);
-- 
1.7.3.4