target/s390x: Implement s390x_cpu_record_sigbus

For s390x, the only unaligned accesses that are signaled are atomic,
and we don't actually want to raise SIGBUS for those, but instead
raise a SPECIFICATION error, which the kernel will report as SIGILL.

Split out a do_unaligned_access function to share between the user-only
s390x_cpu_record_sigbus and the sysemu s390x_do_unaligned_access.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

3 files changed, 26 insertions, 10 deletions

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 593dda75c4..ccdbaf84d5 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -269,6 +269,7 @@ static const struct TCGCPUOps s390_tcg_ops = {
 
 #ifdef CONFIG_USER_ONLY
     .record_sigsegv = s390_cpu_record_sigsegv,
+    .record_sigbus = s390_cpu_record_sigbus,
 #else
     .tlb_fill = s390_cpu_tlb_fill,
     .cpu_exec_interrupt = s390_cpu_exec_interrupt,
diff --git a/target/s390x/s390x-internal.h b/target/s390x/s390x-internal.h
index 163aa4f94a..1a178aed41 100644
--- a/target/s390x/s390x-internal.h
+++ b/target/s390x/s390x-internal.h
@@ -270,18 +270,20 @@ ObjectClass *s390_cpu_class_by_name(const char *name);
 void s390x_cpu_debug_excp_handler(CPUState *cs);
 void s390_cpu_do_interrupt(CPUState *cpu);
 bool s390_cpu_exec_interrupt(CPUState *cpu, int int_req);
-void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
-                                   MMUAccessType access_type, int mmu_idx,
-                                   uintptr_t retaddr) QEMU_NORETURN;
 
 #ifdef CONFIG_USER_ONLY
 void s390_cpu_record_sigsegv(CPUState *cs, vaddr address,
                              MMUAccessType access_type,
                              bool maperr, uintptr_t retaddr);
+void s390_cpu_record_sigbus(CPUState *cs, vaddr address,
+                            MMUAccessType access_type, uintptr_t retaddr);
 #else
 bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                        MMUAccessType access_type, int mmu_idx,
                        bool probe, uintptr_t retaddr);
+void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
+                                   MMUAccessType access_type, int mmu_idx,
+                                   uintptr_t retaddr) QEMU_NORETURN;
 #endif
 
 
diff --git a/target/s390x/tcg/excp_helper.c b/target/s390x/tcg/excp_helper.c
index b923d080fc..4e7648f301 100644
--- a/target/s390x/tcg/excp_helper.c
+++ b/target/s390x/tcg/excp_helper.c
@@ -82,6 +82,19 @@ void HELPER(data_exception)(CPUS390XState *env, uint32_t dxc)
     tcg_s390_data_exception(env, dxc, GETPC());
 }
 
+/*
+ * Unaligned accesses are only diagnosed with MO_ALIGN.  At the moment,
+ * this is only for the atomic operations, for which we want to raise a
+ * specification exception.
+ */
+static void QEMU_NORETURN do_unaligned_access(CPUState *cs, uintptr_t retaddr)
+{
+    S390CPU *cpu = S390_CPU(cs);
+    CPUS390XState *env = &cpu->env;
+
+    tcg_s390_program_interrupt(env, PGM_SPECIFICATION, retaddr);
+}
+
 #if defined(CONFIG_USER_ONLY)
 
 void s390_cpu_do_interrupt(CPUState *cs)
@@ -106,6 +119,12 @@ void s390_cpu_record_sigsegv(CPUState *cs, vaddr address,
     cpu_loop_exit_restore(cs, retaddr);
 }
 
+void s390_cpu_record_sigbus(CPUState *cs, vaddr address,
+                            MMUAccessType access_type, uintptr_t retaddr)
+{
+    do_unaligned_access(cs, retaddr);
+}
+
 #else /* !CONFIG_USER_ONLY */
 
 static inline uint64_t cpu_mmu_idx_to_asc(int mmu_idx)
@@ -593,17 +612,11 @@ void s390x_cpu_debug_excp_handler(CPUState *cs)
     }
 }
 
-/* Unaligned accesses are only diagnosed with MO_ALIGN.  At the moment,
-   this is only for the atomic operations, for which we want to raise a
-   specification exception.  */
 void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
                                    MMUAccessType access_type,
                                    int mmu_idx, uintptr_t retaddr)
 {
-    S390CPU *cpu = S390_CPU(cs);
-    CPUS390XState *env = &cpu->env;
-
-    tcg_s390_program_interrupt(env, PGM_SPECIFICATION, retaddr);
+    do_unaligned_access(cs, retaddr);
 }
 
 static void QEMU_NORETURN monitor_event(CPUS390XState *env,