target/arm: Set arm_v7m_tcg_ops cpu_exec_halt to arm_cpu_exec_halt()

In commit a96edb687e we set the cpu_exec_halt field of the
TCGCPUOps arm_tcg_ops to arm_cpu_exec_halt(), but we left the
arm_v7m_tcg_ops struct unchanged.  That isn't wrong, because for
M-profile FEAT_WFxT doesn't exist and the default handling for "no
cpu_exec_halt method" is correct, but it's perhaps a little
confusing.  We would also like to make setting the cpu_exec_halt
method mandatory.

Initialize arm_v7m_tcg_ops cpu_exec_halt to the same function we use
for A-profile.  (On M-profile we never set up the wfxt timer so there
is no change in behaviour here.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

target/arm/cpu.c

@@ -1133,7 +1133,7 @@ static bool arm_cpu_virtio_is_big_endian(CPUState *cs)
 }
 
 #ifdef CONFIG_TCG
-static bool arm_cpu_exec_halt(CPUState *cs)
+bool arm_cpu_exec_halt(CPUState *cs)
 {
     bool leave_halt = cpu_has_work(cs);
 

target/arm/internals.h

@@ -368,6 +368,9 @@ void arm_restore_state_to_opc(CPUState *cs,
 
 #ifdef CONFIG_TCG
 void arm_cpu_synchronize_from_tb(CPUState *cs, const TranslationBlock *tb);
+
+/* Our implementation of TCGCPUOps::cpu_exec_halt */
+bool arm_cpu_exec_halt(CPUState *cs);
 #endif /* CONFIG_TCG */
 
 typedef enum ARMFPRounding {

target/arm/tcg/cpu-v7m.c

@@ -244,6 +244,7 @@ static const TCGCPUOps arm_v7m_tcg_ops = {
 #else
     .tlb_fill = arm_cpu_tlb_fill,
     .cpu_exec_interrupt = arm_v7m_cpu_exec_interrupt,
+    .cpu_exec_halt = arm_cpu_exec_halt,
     .do_interrupt = arm_v7m_cpu_do_interrupt,
     .do_transaction_failed = arm_cpu_do_transaction_failed,
     .do_unaligned_access = arm_cpu_do_unaligned_access,