[PATCH v2] target/riscv/cpu_helper: Fix linking problem with semihosting disabled

[Thomas Huth <thuth@redhat.com>]

If QEMU has been configured with "--without-default-devices", the build
is currently failing with:

 /usr/bin/ld: libqemu-riscv32-softmmu.a.p/target_riscv_cpu_helper.c.o:
  in function `riscv_cpu_do_interrupt':
 .../qemu/target/riscv/cpu_helper.c:1678:(.text+0x2214): undefined
  reference to `do_common_semihosting'

We always want semihosting to be enabled if TCG is available, so change
the "imply" statements in the Kconfig file to "select", and make sure to
avoid calling into do_common_semihosting() if TCG is not available.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 v2: Use "select" in the Kconfig file, and "CONFIG_TCG" in the #ifdef

 target/riscv/cpu_helper.c | 2 ++
 target/riscv/Kconfig      | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 395a1d9140..dc147181a3 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -1674,10 +1674,12 @@ void riscv_cpu_do_interrupt(CPUState *cs)
     if (!async) {
         /* set tval to badaddr for traps with address information */
         switch (cause) {
+#ifdef CONFIG_TCG
         case RISCV_EXCP_SEMIHOST:
             do_common_semihosting(cs);
             env->pc += 4;
             return;
+#endif
         case RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT:
         case RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT:
         case RISCV_EXCP_LOAD_ADDR_MIS:
diff --git a/target/riscv/Kconfig b/target/riscv/Kconfig
index c332616d36..11bc09b414 100644
--- a/target/riscv/Kconfig
+++ b/target/riscv/Kconfig
@@ -1,9 +1,9 @@
 config RISCV32
     bool
-    imply ARM_COMPATIBLE_SEMIHOSTING if TCG
+    select ARM_COMPATIBLE_SEMIHOSTING if TCG
     select DEVICE_TREE # needed by boot.c
 
 config RISCV64
     bool
-    imply ARM_COMPATIBLE_SEMIHOSTING if TCG
+    select ARM_COMPATIBLE_SEMIHOSTING if TCG
     select DEVICE_TREE # needed by boot.c
-- 
2.46.0