target/xtensa: fix access to the INTERRUPT SR

INTERRUPT special register may be changed both by the core (by writing
to INTSET and INTCLEAR registers) and by external events (by triggering
and clearing HW IRQs). In MTTCG this state must be protected from
concurrent access, otherwise interrupts may be lost or spurious
interrupts may be detected.

Use atomic operations to change INTSET SR.
Fix wsr.intset so that it soesn't clear any bits.
Fix wsr.intclear so that it doesn't clear bit that corresponds to NMI.

Signed-off-by: Max Filippov <[email protected]>

diff --git a/hw/xtensa/pic_cpu.c b/hw/xtensa/pic_cpu.c
index 0e812d7f061c3639283eacd5b3c2ea055031c2c0..7e4c65e5ec30a6cbe1a5efcf07a0655478e9ba4d 100644 (file)
--- a/hw/xtensa/pic_cpu.c
+++ b/hw/xtensa/pic_cpu.c
@@ -68,9 +68,9 @@ static void xtensa_set_irq(void *opaque, int irq, int active)
         uint32_t irq_bit = 1 << irq;
 
         if (active) {
-            env->sregs[INTSET] |= irq_bit;
+            atomic_or(&env->sregs[INTSET], irq_bit);
         } else if (env->config->interrupt[irq].inttype == INTTYPE_LEVEL) {
-            env->sregs[INTSET] &= ~irq_bit;
+            atomic_and(&env->sregs[INTSET], ~irq_bit);
         }
 
         check_interrupts(env);

diff --git a/target/xtensa/exc_helper.c b/target/xtensa/exc_helper.c
index 371a32ba5ad9a6a07fe06e2198ef64a706b47d73..4a1f7aef5dcf3b594f8e95ebba2a0d76f02fda2e 100644 (file)
--- a/target/xtensa/exc_helper.c
+++ b/target/xtensa/exc_helper.c
@@ -127,6 +127,19 @@ void HELPER(check_interrupts)(CPUXtensaState *env)
     qemu_mutex_unlock_iothread();
 }
 
+void HELPER(intset)(CPUXtensaState *env, uint32_t v)
+{
+    atomic_or(&env->sregs[INTSET],
+              v & env->config->inttype_mask[INTTYPE_SOFTWARE]);
+}
+
+void HELPER(intclear)(CPUXtensaState *env, uint32_t v)
+{
+    atomic_and(&env->sregs[INTSET],
+               ~(v & (env->config->inttype_mask[INTTYPE_SOFTWARE] |
+                      env->config->inttype_mask[INTTYPE_EDGE])));
+}
+
 static uint32_t relocated_vector(CPUXtensaState *env, uint32_t vector)
 {
     if (xtensa_option_enabled(env->config,

diff --git a/target/xtensa/helper.h b/target/xtensa/helper.h
index 89eb97e265146e66535fcf2e3e2e3a209b9fd6b3..2a7db35874fe9369de3338b1fa9d17f51c1bc6f3 100644 (file)
--- a/target/xtensa/helper.h
+++ b/target/xtensa/helper.h
@@ -22,6 +22,8 @@ DEF_HELPER_1(update_ccount, void, env)
 DEF_HELPER_2(wsr_ccount, void, env, i32)
 DEF_HELPER_2(update_ccompare, void, env, i32)
 DEF_HELPER_1(check_interrupts, void, env)
+DEF_HELPER_2(intset, void, env, i32)
+DEF_HELPER_2(intclear, void, env, i32)
 DEF_HELPER_3(check_atomctl, void, env, i32, i32)
 DEF_HELPER_2(wsr_memctl, void, env, i32)
 

diff --git a/target/xtensa/op_helper.c b/target/xtensa/op_helper.c
index 1865f46c4b5f04e5ae3db3cad86e8e40762fa7a0..04971b044fac7a0409dbc050bd3ee1eee89d3efa 100644 (file)
--- a/target/xtensa/op_helper.c
+++ b/target/xtensa/op_helper.c
@@ -62,6 +62,8 @@ void HELPER(update_ccompare)(CPUXtensaState *env, uint32_t i)
 {
     uint64_t dcc;
 
+    atomic_and(&env->sregs[INTSET],
+               ~(1u << env->config->timerint[i]));
     HELPER(update_ccount)(env);
     dcc = (uint64_t)(env->sregs[CCOMPARE + i] - env->sregs[CCOUNT] - 1) + 1;
     timer_mod(env->ccompare[i].timer,

diff --git a/target/xtensa/translate.c b/target/xtensa/translate.c
index a435d9c36cf174e1a481307038e5110e135c6197..d1e9f59b31bd89c0f76ed7d6f0b8be99b1a7a96d 100644 (file)
--- a/target/xtensa/translate.c
+++ b/target/xtensa/translate.c
@@ -646,20 +646,12 @@ static void gen_check_interrupts(DisasContext *dc)
 
 static void gen_wsr_intset(DisasContext *dc, uint32_t sr, TCGv_i32 v)
 {
-    tcg_gen_andi_i32(cpu_SR[sr], v,
-            dc->config->inttype_mask[INTTYPE_SOFTWARE]);
+    gen_helper_intset(cpu_env, v);
 }
 
 static void gen_wsr_intclear(DisasContext *dc, uint32_t sr, TCGv_i32 v)
 {
-    TCGv_i32 tmp = tcg_temp_new_i32();
-
-    tcg_gen_andi_i32(tmp, v,
-            dc->config->inttype_mask[INTTYPE_EDGE] |
-            dc->config->inttype_mask[INTTYPE_NMI] |
-            dc->config->inttype_mask[INTTYPE_SOFTWARE]);
-    tcg_gen_andc_i32(cpu_SR[INTSET], cpu_SR[INTSET], tmp);
-    tcg_temp_free(tmp);
+    gen_helper_intclear(cpu_env, v);
 }
 
 static void gen_wsr_intenable(DisasContext *dc, uint32_t sr, TCGv_i32 v)
@@ -706,12 +698,10 @@ static void gen_wsr_icountlevel(DisasContext *dc, uint32_t sr, TCGv_i32 v)
 static void gen_wsr_ccompare(DisasContext *dc, uint32_t sr, TCGv_i32 v)
 {
     uint32_t id = sr - CCOMPARE;
-    uint32_t int_bit = 1 << dc->config->timerint[id];
     TCGv_i32 tmp = tcg_const_i32(id);
 
     assert(id < dc->config->nccompare);
     tcg_gen_mov_i32(cpu_SR[sr], v);
-    tcg_gen_andi_i32(cpu_SR[INTSET], cpu_SR[INTSET], ~int_bit);
     if (tb_cflags(dc->base.tb) & CF_USE_ICOUNT) {
         gen_io_start();
     }