generic: power: backport v6.15 patch to fix build with GCC15

Backports an upstream fix ([1]) for a build regression of
'drivers/power/supply' with GCC15 -Wunterminated-string-initialization.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=77f5bb150132bbbcd6bc37ffdc80c9e140e373a4

Signed-off-by: Jonas Jelonek <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18950
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/generic/backport-6.12/807-v6.15-power-supply-sysfs-remove-duplicate-nul-termination-to-fix-build-with-GCC15.patch

@@ -0,0 +1,39 @@
+From 77f5bb150132bbbcd6bc37ffdc80c9e140e373a4 Mon Sep 17 00:00:00 2001
+From: Kees Cook <[email protected]>
+Date: Wed, 16 Apr 2025 15:27:41 -0700
+Subject: [PATCH] power: supply: sysfs: Remove duplicate NUL termination
+
+GCC 15's new -Wunterminated-string-initialization notices that one of
+the sysfs attr strings would lack the implicit trailing NUL byte during
+initialization:
+
+drivers/power/supply/power_supply_sysfs.c:183:57: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (32 chars into 31 available) [-Wunterminated-string-initialization]
+  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
+      |                                                         ^
+drivers/power/supply/power_supply_sysfs.c:36:23: note: in definition of macro '_POWER_SUPPLY_ATTR'
+   36 |         .attr_name = #_name "\0",               \
+      |                       ^~~~~
+drivers/power/supply/power_supply_sysfs.c:183:9: note: in expansion of macro 'POWER_SUPPLY_ATTR'
+  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
+      |         ^~~~~~~~~~~~~~~~~
+
+However, the macro used was explicitly adding a trailing NUL byte (which
+is not needed). Remove this to avoid the GCC warning. No binary
+differences are seen after this change (there was always run for a NUL
+byte, it's just that the _second_ NUL byte was getting truncated).
+
+Signed-off-by: Kees Cook <[email protected]>
+Link: https://lore.kernel.org/r/[email protected]
+Signed-off-by: Sebastian Reichel <[email protected]>
+
+--- a/drivers/power/supply/power_supply_sysfs.c
++++ b/drivers/power/supply/power_supply_sysfs.c
+@@ -33,7 +33,7 @@ struct power_supply_attr {
+ [POWER_SUPPLY_PROP_ ## _name] =			\
+ {						\
+ 	.prop_name = #_name,			\
+-	.attr_name = #_name "\0",		\
++	.attr_name = #_name,			\
+ 	.text_values = _text,			\
+ 	.text_values_len = _len,		\
+ }

target/linux/generic/backport-6.6/807-v6.15-power-supply-sysfs-remove-duplicate-nul-termination-to-fix-build-with-GCC15.patch

@@ -0,0 +1,39 @@
+From 77f5bb150132bbbcd6bc37ffdc80c9e140e373a4 Mon Sep 17 00:00:00 2001
+From: Kees Cook <[email protected]>
+Date: Wed, 16 Apr 2025 15:27:41 -0700
+Subject: [PATCH] power: supply: sysfs: Remove duplicate NUL termination
+
+GCC 15's new -Wunterminated-string-initialization notices that one of
+the sysfs attr strings would lack the implicit trailing NUL byte during
+initialization:
+
+drivers/power/supply/power_supply_sysfs.c:183:57: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (32 chars into 31 available) [-Wunterminated-string-initialization]
+  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
+      |                                                         ^
+drivers/power/supply/power_supply_sysfs.c:36:23: note: in definition of macro '_POWER_SUPPLY_ATTR'
+   36 |         .attr_name = #_name "\0",               \
+      |                       ^~~~~
+drivers/power/supply/power_supply_sysfs.c:183:9: note: in expansion of macro 'POWER_SUPPLY_ATTR'
+  183 |         POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
+      |         ^~~~~~~~~~~~~~~~~
+
+However, the macro used was explicitly adding a trailing NUL byte (which
+is not needed). Remove this to avoid the GCC warning. No binary
+differences are seen after this change (there was always run for a NUL
+byte, it's just that the _second_ NUL byte was getting truncated).
+
+Signed-off-by: Kees Cook <[email protected]>
+Link: https://lore.kernel.org/r/[email protected]
+Signed-off-by: Sebastian Reichel <[email protected]>
+
+--- a/drivers/power/supply/power_supply_sysfs.c
++++ b/drivers/power/supply/power_supply_sysfs.c
+@@ -32,7 +32,7 @@ struct power_supply_attr {
+ [POWER_SUPPLY_PROP_ ## _name] =			\
+ {						\
+ 	.prop_name = #_name,			\
+-	.attr_name = #_name "\0",		\
++	.attr_name = #_name,			\
+ 	.text_values = _text,			\
+ 	.text_values_len = _len,		\
+ }