[PATCH v3 1/2] rust: uapi: add zerocopy/zerocopy_derive

[Deborah Brouwer]

Make the zerocopy and zerocopy_derive crates available for use when
building the UAPI crate and its tests. Then attempt to derive most of
the zerocopy traits for struct drm_panthor_gpu_info when generating its
binding. This will be used by the Tyr driver that needs the traits
IntoBytes and Immutable to safely copy the struct byte-for-byte to
userspace.

Signed-off-by: Deborah Brouwer <deborah.brouwer@xxxxxxxxxxxxx>
---
 rust/Makefile           | 12 +++++++++---
 rust/bindgen_parameters |  3 +++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index da1a7409d984..bf02a1efd6f3 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -365,8 +365,11 @@ rusttestlib-bindings: private rustc_target_flags = --extern ffi --extern pin_ini
 rusttestlib-bindings: $(src)/bindings/lib.rs rusttestlib-ffi rusttestlib-pin_init FORCE
 	+$(call if_changed,rustc_test_library)
 
-rusttestlib-uapi: private rustc_target_flags = --extern ffi --extern pin_init
-rusttestlib-uapi: $(src)/uapi/lib.rs rusttestlib-ffi rusttestlib-pin_init FORCE
+rusttestlib-uapi: private rustc_target_flags = --extern ffi --extern pin_init \
+	--extern zerocopy=$(objtree)/$(obj)/test/libzerocopy.rlib \
+	--extern zerocopy_derive=$(objtree)/$(obj)/test/$(libzerocopy_derive_name)
+rusttestlib-uapi: $(src)/uapi/lib.rs rusttestlib-ffi rusttestlib-pin_init \
+	rusttestlib-zerocopy rusttestlib-zerocopy_derive FORCE
 	+$(call if_changed,rustc_test_library)
 
 quiet_cmd_rustdoc_test = RUSTDOC T $<
@@ -782,11 +785,14 @@ $(obj)/bindings.o: $(src)/bindings/lib.rs \
     $(obj)/bindings/bindings_helpers_generated.rs FORCE
 	+$(call if_changed_rule,rustc_library)
 
-$(obj)/uapi.o: private rustc_target_flags = --extern ffi --extern pin_init
+$(obj)/uapi.o: private rustc_target_flags = --extern ffi --extern pin_init \
+	--extern zerocopy --extern zerocopy_derive
 $(obj)/uapi.o: private skip_gendwarfksyms = 1
 $(obj)/uapi.o: $(src)/uapi/lib.rs \
     $(obj)/ffi.o \
     $(obj)/pin_init.o \
+    $(obj)/zerocopy.o \
+    $(obj)/$(libzerocopy_derive_name) \
     $(obj)/uapi/uapi_generated.rs FORCE
 	+$(call if_changed_rule,rustc_library)
 
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
index 8402b0c93545..332bc8d6a9f7 100644
--- a/rust/bindgen_parameters
+++ b/rust/bindgen_parameters
@@ -71,3 +71,6 @@
 # Structs should implement `Zeroable` when all of their fields do.
 --with-derive-custom-struct .*=MaybeZeroable
 --with-derive-custom-union .*=MaybeZeroable
+
+# `drm_panthor_gpu_info` is copied byte-for-byte to userspace.
+--with-derive-custom-struct '^drm_panthor_gpu_info$'=zerocopy_derive::most_traits

-- 
2.55.0