Introduce an annotation similar to __hwdom_init and use it througout the
file. All external callers are either themselves __init or are limited to
OVERLAY_DTB=y. Adjust the Makefile accordingly to also have string
literals moved into .init.rodata.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -15,7 +15,9 @@ obj-$(CONFIG_HAS_ALTERNATIVE) += alterna
 obj-y += cpuerrata.o
 obj-y += cpufeature.o
 obj-y += decode.o
-obj-y += device.o
+device-y := device.init.o
+device-$(CONFIG_OVERLAY_DTB) := device.o
+obj-y += $(device-y)
 obj-$(CONFIG_IOREQ_SERVER) += dm.o
 obj-$(CONFIG_DOM0LESS_BOOT) += dom0less-build.init.o
 obj-y += domain.o
--- a/xen/arch/arm/device.c
+++ b/xen/arch/arm/device.c
@@ -9,6 +9,7 @@
  */
 
 #include <xen/device_tree.h>
+#include <xen/dt-overlay.h>
 #include <xen/errno.h>
 #include <xen/iocap.h>
 #include <xen/lib.h>
@@ -16,8 +17,8 @@
 #include <asm/firmware/sci.h>
 #include <asm/setup.h>
 
-int map_irq_to_domain(struct domain *d, unsigned int irq,
-                      bool need_mapping, const char *devname)
+int __overlay_init map_irq_to_domain(struct domain *d, unsigned int irq,
+                                     bool need_mapping, const char *devname)
 {
     int res;
 
@@ -49,8 +50,8 @@ int map_irq_to_domain(struct domain *d,
     return 0;
 }
 
-int map_range_to_domain(const struct dt_device_node *dev,
-                        uint64_t addr, uint64_t len, void *data)
+int __overlay_init map_range_to_domain(const struct dt_device_node *dev,
+                                       uint64_t addr, uint64_t len, void *data)
 {
     struct map_range_data *mr_data = data;
     struct domain *d = mr_data->d;
@@ -124,10 +125,10 @@ int map_range_to_domain(const struct dt_
  *   < 0 error
  *   0   success
  */
-int map_device_irqs_to_domain(struct domain *d,
-                              struct dt_device_node *dev,
-                              bool need_mapping,
-                              struct rangeset *irq_ranges)
+int __overlay_init map_device_irqs_to_domain(struct domain *d,
+                                             struct dt_device_node *dev,
+                                             bool need_mapping,
+                                             struct rangeset *irq_ranges)
 {
     unsigned int i, nirq;
     int res, irq;
@@ -180,9 +181,9 @@ int map_device_irqs_to_domain(struct dom
     return 0;
 }
 
-static int map_dt_irq_to_domain(const struct dt_device_node *dev,
-                                const struct dt_irq *dt_irq,
-                                void *data)
+static int __overlay_init map_dt_irq_to_domain(const struct dt_device_node *dev,
+                                               const struct dt_irq *dt_irq,
+                                               void *data)
 {
     struct map_range_data *mr_data = data;
     struct domain *d = mr_data->d;
@@ -219,8 +220,8 @@ static int map_dt_irq_to_domain(const st
  * then we may need to perform additional mappings in order to make
  * the child resources available to domain 0.
  */
-static int map_device_children(const struct dt_device_node *dev,
-                               struct map_range_data *mr_data)
+static int __overlay_init map_device_children(const struct dt_device_node *dev,
+                                              struct map_range_data *mr_data)
 {
     if ( dt_device_type_is_equal(dev, "pci") )
     {
@@ -250,8 +251,10 @@ static int map_device_children(const str
  *  - Assign the device to the guest if it's protected by an IOMMU
  *  - Map the IRQs and iomem regions to DOM0
  */
-int handle_device(struct domain *d, struct dt_device_node *dev, p2m_type_t p2mt,
-                  struct rangeset *iomem_ranges, struct rangeset *irq_ranges)
+int __overlay_init handle_device(struct domain *d, struct dt_device_node *dev,
+                                 p2m_type_t p2mt,
+                                 struct rangeset *iomem_ranges,
+                                 struct rangeset *irq_ranges)
 {
     unsigned int naddr;
     unsigned int i;
--- a/xen/include/xen/dt-overlay.h
+++ b/xen/include/xen/dt-overlay.h
@@ -42,10 +42,18 @@ struct xen_sysctl_dt_overlay;
 struct xen_domctl_dt_overlay;
 
 #ifdef CONFIG_OVERLAY_DTB
+
+#define __overlay_init
+
 long dt_overlay_sysctl(struct xen_sysctl_dt_overlay *op);
 long dt_overlay_domctl(struct domain *d, struct xen_domctl_dt_overlay *op);
+
 #else
+
 #include <xen/errno.h>
+
+#define __overlay_init __init
+
 static inline long dt_overlay_sysctl(struct xen_sysctl_dt_overlay *op)
 {
     return -EOPNOTSUPP;

On 26/02/2026 4:28 pm, Jan Beulich wrote:
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -15,7 +15,9 @@ obj-$(CONFIG_HAS_ALTERNATIVE) += alterna
>  obj-y += cpuerrata.o
>  obj-y += cpufeature.o
>  obj-y += decode.o
> -obj-y += device.o
> +device-y := device.init.o
> +device-$(CONFIG_OVERLAY_DTB) := device.o
> +obj-y += $(device-y)

I know we've argued over this before and not come to a conclusion, but I
still firmly believe this to be an anti-pattern we should expunge.

obj-y += $(if $(CONFIG_OVERLAY_DTB),device.o,device.init.o)

conveys the meaning more clearly and succinctly.

~Andrew

On 26.02.2026 18:14, Andrew Cooper wrote:
> On 26/02/2026 4:28 pm, Jan Beulich wrote:
>> --- a/xen/arch/arm/Makefile
>> +++ b/xen/arch/arm/Makefile
>> @@ -15,7 +15,9 @@ obj-$(CONFIG_HAS_ALTERNATIVE) += alterna
>>  obj-y += cpuerrata.o
>>  obj-y += cpufeature.o
>>  obj-y += decode.o
>> -obj-y += device.o
>> +device-y := device.init.o
>> +device-$(CONFIG_OVERLAY_DTB) := device.o
>> +obj-y += $(device-y)
> 
> I know we've argued over this before and not come to a conclusion, but I
> still firmly believe this to be an anti-pattern we should expunge.
> 
> obj-y += $(if $(CONFIG_OVERLAY_DTB),device.o,device.init.o)

Whereas I think this one (in its adjusted form to really only accept 'y')
is, firmly believing that the "lists everywhere" approach is the more
readable and, more importantly, more scalable one. The form you suggest
quickly gets to its limits when multiple CONFIG_* need dealing with.

Jan