RISC-V: Change local interrupts from edge to level

This effectively changes riscv_cpu_update_mip
from edge to level. i.e. cpu_interrupt or
cpu_reset_interrupt are called regardless of
the current interrupt level.

Fixes WFI doesn't return when a IPI is issued:

- https://github.com/riscv/riscv-qemu/issues/132

To test:

1) Apply RISC-V Linux CPU hotplug patch:

- http://lists.infradead.org/pipermail/linux-riscv/2018-May/000603.html

2) Enable CONFIG_CPU_HOTPLUG in linux .config

3) Try to offline and online cpus:

  echo 1 > /sys/devices/system/cpu/cpu2/online
  echo 0 > /sys/devices/system/cpu/cpu2/online
  echo 1 > /sys/devices/system/cpu/cpu2/online

Reported-by: Atish Patra <atishp04@gmail.com>
Cc: Atish Patra <atishp04@gmail.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 555756d40c..073bdcfe74 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -95,9 +95,9 @@ uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
         cmp = atomic_cmpxchg(&env->mip, old, new);
     } while (old != cmp);
 
-    if (new && !old) {
+    if (new) {
         cpu_interrupt(CPU(cpu), CPU_INTERRUPT_HARD);
-    } else if (!new && old) {
+    } else {
         cpu_reset_interrupt(CPU(cpu), CPU_INTERRUPT_HARD);
     }