target-xtensa: fix guest hang on masked CCOMPARE interrupt

QEMU timer is used to post CCOMPARE interrupt when the core is halted.
If that CCOMPARE interrupt is masked off then the timer must be rearmed
in the callback, otherwise it will be rearmed next time the core goes to
halt by the waiti instruction.

Add test case into timer testsuite.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

diff --git a/hw/xtensa_pic.c b/hw/xtensa_pic.c
index 3033ae214a0b55a527213ef1a65fa8e4caea70e9..e5085ea9e75ee0fe9fbc7666ac4bed1f30f27a70 100644 (file)
--- a/hw/xtensa_pic.c
+++ b/hw/xtensa_pic.c
@@ -116,10 +116,35 @@ void xtensa_timer_irq(CPUState *env, uint32_t id, uint32_t active)
     qemu_set_irq(env->irq_inputs[env->config->timerint[id]], active);
 }
 
+void xtensa_rearm_ccompare_timer(CPUState *env)
+{
+    int i;
+    uint32_t wake_ccount = env->sregs[CCOUNT] - 1;
+
+    for (i = 0; i < env->config->nccompare; ++i) {
+        if (env->sregs[CCOMPARE + i] - env->sregs[CCOUNT] <
+                wake_ccount - env->sregs[CCOUNT]) {
+            wake_ccount = env->sregs[CCOMPARE + i];
+        }
+    }
+    env->wake_ccount = wake_ccount;
+    qemu_mod_timer(env->ccompare_timer, env->halt_clock +
+            muldiv64(wake_ccount - env->sregs[CCOUNT],
+                1000000, env->config->clock_freq_khz));
+}
+
 static void xtensa_ccompare_cb(void *opaque)
 {
     CPUState *env = opaque;
-    xtensa_advance_ccount(env, env->wake_ccount - env->sregs[CCOUNT]);
+
+    if (env->halted) {
+        env->halt_clock = qemu_get_clock_ns(vm_clock);
+        xtensa_advance_ccount(env, env->wake_ccount - env->sregs[CCOUNT]);
+        if (!cpu_has_work(env)) {
+            env->sregs[CCOUNT] = env->wake_ccount + 1;
+            xtensa_rearm_ccompare_timer(env);
+        }
+    }
 }
 
 void xtensa_irq_init(CPUState *env)

diff --git a/target-xtensa/cpu.h b/target-xtensa/cpu.h
index 339075dda1db6844498849485d2abdf9287389a9..966f5152494440ac520df545f0613ee38dfd9de8 100644 (file)
--- a/target-xtensa/cpu.h
+++ b/target-xtensa/cpu.h
@@ -313,6 +313,7 @@ void check_interrupts(CPUXtensaState *s);
 void xtensa_irq_init(CPUState *env);
 void xtensa_advance_ccount(CPUState *env, uint32_t d);
 void xtensa_timer_irq(CPUState *env, uint32_t id, uint32_t active);
+void xtensa_rearm_ccompare_timer(CPUState *env);
 int cpu_xtensa_signal_handler(int host_signum, void *pinfo, void *puc);
 void xtensa_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 void xtensa_sync_window_from_phys(CPUState *env);

diff --git a/target-xtensa/op_helper.c b/target-xtensa/op_helper.c
index 64847fc8e62bcce2a8a839809f243bb23594fe6e..060561103109f645962369e462b7760341adbbf6 100644 (file)
--- a/target-xtensa/op_helper.c
+++ b/target-xtensa/op_helper.c
@@ -370,23 +370,11 @@ void HELPER(waiti)(uint32_t pc, uint32_t intlevel)
         return;
     }
 
-    if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT)) {
-        int i;
-        uint32_t wake_ccount = env->sregs[CCOUNT] - 1;
-
-        for (i = 0; i < env->config->nccompare; ++i) {
-            if (env->sregs[CCOMPARE + i] - env->sregs[CCOUNT] <
-                    wake_ccount - env->sregs[CCOUNT]) {
-                wake_ccount = env->sregs[CCOMPARE + i];
-            }
-        }
-        env->wake_ccount = wake_ccount;
-        qemu_mod_timer(env->ccompare_timer, qemu_get_clock_ns(vm_clock) +
-                muldiv64(wake_ccount - env->sregs[CCOUNT],
-                    1000000, env->config->clock_freq_khz));
-    }
     env->halt_clock = qemu_get_clock_ns(vm_clock);
     env->halted = 1;
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT)) {
+        xtensa_rearm_ccompare_timer(env);
+    }
     HELPER(exception)(EXCP_HLT);
 }
 

diff --git a/tests/xtensa/test_timer.S b/tests/xtensa/test_timer.S
index ede63955cc9e38edf19078f0322d2626a802a211..1041cc6658719a6119d49b8ec2922691428325d5 100644 (file)
--- a/tests/xtensa/test_timer.S
+++ b/tests/xtensa/test_timer.S
@@ -14,6 +14,7 @@ test ccompare
     wsr     a2, intenable
     rsr     a2, interrupt
     wsr     a2, intclear
+    movi    a2, 0
     wsr     a2, ccompare1
     wsr     a2, ccompare2
 
@@ -37,6 +38,7 @@ test ccompare0_interrupt
     wsr     a2, intenable
     rsr     a2, interrupt
     wsr     a2, intclear
+    movi    a2, 0
     wsr     a2, ccompare1
     wsr     a2, ccompare2
 
@@ -66,6 +68,7 @@ test ccompare1_interrupt
     wsr     a2, intenable
     rsr     a2, interrupt
     wsr     a2, intclear
+    movi    a2, 0
     wsr     a2, ccompare0
     wsr     a2, ccompare2
 
@@ -92,6 +95,7 @@ test ccompare2_interrupt
     wsr     a2, intenable
     rsr     a2, interrupt
     wsr     a2, intclear
+    movi    a2, 0
     wsr     a2, ccompare0
     wsr     a2, ccompare1
 
@@ -112,4 +116,63 @@ test ccompare2_interrupt
 2:
 test_end
 
+test ccompare_interrupt_masked
+    set_vector kernel, 2f
+    movi    a2, 0
+    wsr     a2, intenable
+    rsr     a2, interrupt
+    wsr     a2, intclear
+    movi    a2, 0
+    wsr     a2, ccompare2
+
+    movi    a3, 40
+    rsr     a2, ccount
+    addi    a2, a2, 20
+    wsr     a2, ccompare1
+    addi    a2, a2, 20
+    wsr     a2, ccompare0
+    rsync
+    rsr     a2, interrupt
+    assert  eqi, a2, 0
+
+    movi    a2, 0x40
+    wsr     a2, intenable
+    rsil    a2, 0
+    loop    a3, 1f
+    nop
+1:
+    test_fail
+2:
+    rsr     a2, exccause
+    assert  eqi, a2, 4 /* LEVEL1_INTERRUPT_CAUSE */
+test_end
+
+test ccompare_interrupt_masked_waiti
+    set_vector kernel, 2f
+    movi    a2, 0
+    wsr     a2, intenable
+    rsr     a2, interrupt
+    wsr     a2, intclear
+    movi    a2, 0
+    wsr     a2, ccompare2
+
+    movi    a3, 40
+    rsr     a2, ccount
+    addi    a2, a2, 20
+    wsr     a2, ccompare1
+    addi    a2, a2, 20
+    wsr     a2, ccompare0
+    rsync
+    rsr     a2, interrupt
+    assert  eqi, a2, 0
+
+    movi    a2, 0x40
+    wsr     a2, intenable
+    waiti   0
+    test_fail
+2:
+    rsr     a2, exccause
+    assert  eqi, a2, 4 /* LEVEL1_INTERRUPT_CAUSE */
+test_end
+
 test_suite_end