Host and user progs may also use __FILE__.

Make sure it shows up canonicalized, as in regular kernel code.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 130926fa592e..322b5ce9f218 100644
--- a/Makefile
+++ b/Makefile
@@ -1188,7 +1188,10 @@ export CFLAGS_GCOV
 
 # change __FILE__ to the relative path to the source directory
 ifdef building_out_of_srctree
-KBUILD_CPPFLAGS += -fmacro-prefix-map=$(srcroot)/=
+CFLAGS_PREFIX_MAP := -fmacro-prefix-map=$(srcroot)/=
+KBUILD_CPPFLAGS += $(CFLAGS_PREFIX_MAP)
+KBUILD_USERCFLAGS += $(CFLAGS_PREFIX_MAP)
+KBUILD_HOSTCFLAGS += $(CFLAGS_PREFIX_MAP)
 ifeq ($(call rustc-option-yn, --remap-path-scope=macro),y)
 KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/= --remap-path-scope=macro
 endif

---
base-commit: bd5f485f3f026225b86573e559af0b7254ef4184
change-id: 20260819-kbuild-prefix-map-5a056c1baa98

Best regards,
--  
Thomas Weißschuh <thomas.weissschuh@linutronix.de>

On Wed, 19 Aug 2026 09:53:38 +0200, Thomas Weißschuh wrote:
> kbuild: use prefix-map for host and user progs

Applied to

  https://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux.git kbuild-next-unstable

Thanks!

[1/1] kbuild: use prefix-map for host and user progs
      https://git.kernel.org/kbuild/c/7c1bcd3f127f3

Please look out for regression or issue reports or other follow up
comments, as they may result in the patch/series getting dropped or
reverted. Patches applied to an "unstable" branch are accepted pending
wider testing in -next and any post-commit review; they will generally
be moved to the main branch in a week if no issues are found.

Best regards,
-- 
Cheers,
Nathan

On Wed, Aug 19, 2026 at 09:53:38AM +0200, Thomas Weißschuh wrote:
> Host and user progs may also use __FILE__.
> 
> Make sure it shows up canonicalized, as in regular kernel code.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>  Makefile | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/Makefile b/Makefile
> index 130926fa592e..322b5ce9f218 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1188,7 +1188,10 @@ export CFLAGS_GCOV
>  
>  # change __FILE__ to the relative path to the source directory
>  ifdef building_out_of_srctree
> -KBUILD_CPPFLAGS += -fmacro-prefix-map=$(srcroot)/=
> +CFLAGS_PREFIX_MAP := -fmacro-prefix-map=$(srcroot)/=
> +KBUILD_CPPFLAGS += $(CFLAGS_PREFIX_MAP)
> +KBUILD_USERCFLAGS += $(CFLAGS_PREFIX_MAP)
> +KBUILD_HOSTCFLAGS += $(CFLAGS_PREFIX_MAP)
>  ifeq ($(call rustc-option-yn, --remap-path-scope=macro),y)
>  KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/= --remap-path-scope=macro
>  endif
> 
> ---

Thanks!

Reviewed-by: Nicolas Schier <n.schier@fritz.com>
Tested-by: Nicolas Schier <n.schier@fritz.com>