build: convert frame_pointer to Kconfig

Converts the frame_pointer option to a Kconfig option.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>

INSTALL

@@ -230,7 +230,6 @@ hypervisor build.
 perfc=y
 perfc_arrays=y
 lock_profile=y
-frame_pointer=y
 lto=y
 
 During tools build external repos will be cloned into the source tree.

xen/Kconfig.debug

@@ -20,6 +20,14 @@ config CRASH_DEBUG
 	  If you want to attach gdb to Xen to debug Xen if it crashes
 	  then say Y.
 
+config FRAME_POINTER
+	bool "Compile Xen with frame pointers"
+	default DEBUG
+	---help---
+	  If you say Y here the resulting Xen will be slightly larger and
+	  maybe slower, but it gives very useful debugging information
+	  in case of any Xen bugs.
+
 config VERBOSE_DEBUG
 	bool "Verbose debug messages"
 	default DEBUG

xen/Rules.mk

@@ -6,7 +6,6 @@
 perfc         ?= n
 perfc_arrays  ?= n
 lock_profile  ?= n
-frame_pointer ?= n
 lto           ?= n
 
 -include $(BASEDIR)/include/config/auto.conf
@@ -15,9 +14,6 @@ include $(XEN_ROOT)/Config.mk
 
 # Hardcoded configuration implications and dependencies.
 # Do this is a neater way if it becomes unwieldy.
-ifeq ($(debug),y)
-frame_pointer := y
-endif
 ifeq ($(perfc_arrays),y)
 perfc := y
 endif
@@ -28,6 +24,9 @@ endif
 ifeq ($(origin debug),command line)
 $(warning "You must use 'make menuconfig' to enable/disable debug now.")
 endif
+ifneq ($(origin frame_pointer),undefined)
+$(error "You must use 'make menuconfig' to enable/disable frame_pointer now.")
+endif
 ifneq ($(origin kexec),undefined)
 $(error "You must use 'make menuconfig' to enable/disable kexec now.")
 endif
@@ -64,7 +63,7 @@ endif
 CFLAGS-$(perfc)         += -DPERF_COUNTERS
 CFLAGS-$(perfc_arrays)  += -DPERF_ARRAYS
 CFLAGS-$(lock_profile)  += -DLOCK_PROFILE
-CFLAGS-$(frame_pointer) += -fno-omit-frame-pointer -DCONFIG_FRAME_POINTER
+CFLAGS-$(CONFIG_FRAME_POINTER) += -fno-omit-frame-pointer
 
 ifneq ($(max_phys_irqs),)
 CFLAGS-y                += -DMAX_PHYS_IRQS=$(max_phys_irqs)