Merge pull request torvalds#694 from ojeda/target

rust: generate target specification files on the fly

Author: ojeda

Documentation/kbuild/makefiles.rst

@@ -1205,6 +1205,9 @@ When kbuild executes, the following steps are followed (roughly):
 
 	Often, the KBUILD_RUSTFLAGS variable depends on the configuration.
 
+	Note that target specification file generation (for ``--target``)
+	is handled in ``scripts/generate_rust_target.rs``.
+
     KBUILD_AFLAGS_KERNEL
 	Assembler options specific for built-in
 

Makefile

@@ -551,7 +551,6 @@ KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -Werror=return-type -Wno-format-security \
 		   -std=gnu89
 KBUILD_CPPFLAGS := -D__KERNEL__
-KBUILD_RUST_TARGET := $(srctree)/arch/$(SRCARCH)/rust/target.json
 KBUILD_RUSTFLAGS := $(rust_common_flags) \
 		    -Cpanic=abort -Cembed-bitcode=n -Clto=n -Crpath=n \
 		    -Cforce-unwind-tables=n -Ccodegen-units=1 \
@@ -592,7 +591,7 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
-export KBUILD_RUST_TARGET KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
+export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
@@ -1578,7 +1577,7 @@ MRPROPER_FILES += include/config include/generated          \
 		  certs/x509.genkey \
 		  vmlinux-gdb.py \
 		  *.spec \
-		  rust/libmacros.so
+		  rust/target.json rust/libmacros.so
 
 # clean - Delete most, but leave enough to build external modules
 #

arch/arm/rust/target.json

@@ -58,7 +58,6 @@ riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei
 
 KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
 KBUILD_AFLAGS += -march=$(riscv-march-y)
-KBUILD_RUST_TARGET := $(srctree)/arch/riscv/rust/$(subst fd,,$(riscv-march-y)).json
 
 KBUILD_CFLAGS += -mno-save-restore
 KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)