PPC: Activate UBSAN in testing

Also enable -fno-sanitize=alignment like x86 since support for unaligned
accesses is guaranteed by the ISA and the existing OPAL setup code
relies on it.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Shawn Anastasio <sanastasio@raptorengineering.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>
(cherry picked from commit 7cf163879c)

automation/gitlab-ci/build.yaml

@@ -352,6 +352,9 @@ debian-12-ppc64le-gcc-debug:
     CONTAINER: debian:12-ppc64le
     KBUILD_DEFCONFIG: ppc64_defconfig
     HYPERVISOR_ONLY: y
+    EXTRA_XEN_CONFIG: |
+      CONFIG_UBSAN=y
+      CONFIG_UBSAN_FATAL=y
 
 debian-12-riscv64-gcc-debug:
   extends: .gcc-riscv64-cross-build-debug

xen/arch/ppc/Kconfig

@@ -2,6 +2,7 @@ config PPC
 	def_bool y
 	select FUNCTION_ALIGNMENT_4B
 	select HAS_DEVICE_TREE
+	select HAS_UBSAN
 	select HAS_VMAP
 
 config PPC64

xen/arch/ppc/arch.mk

@@ -7,3 +7,9 @@ CFLAGS += -m64 -mlittle-endian -mcpu=$(ppc-march-y)
 CFLAGS += -mstrict-align -mcmodel=medium -mabi=elfv2 -fPIC -mno-altivec -mno-vsx -msoft-float
 
 LDFLAGS += -m elf64lppc
+
+ifeq ($(CONFIG_UBSAN),y)
+# Don't enable alignment sanitisation since Power ISA guarantees hardware
+# support for unaligned accesses.
+$(call cc-option-add,CFLAGS_UBSAN,CC,-fno-sanitize=alignment)
+endif

xen/arch/ppc/include/asm/processor.h

@@ -219,6 +219,8 @@ static inline void noreturn die(void)
  */
 #define cpu_relax() asm volatile ( "or %r1, %r1, %r1; or %r2, %r2, %r2" )
 
+#define dump_execution_state() run_in_exception_handler(show_execution_state)
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_PPC_PROCESSOR_H */

xen/arch/ppc/stubs.c

@@ -47,7 +47,7 @@ void send_timer_event(struct vcpu *v)
 
 void show_execution_state(const struct cpu_user_regs *regs)
 {
-    BUG_ON("unimplemented");
+    printk("TODO: Implement show_execution_state(regs)\n");
 }
 
 void arch_hypercall_tasklet_result(struct vcpu *v, long res)