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authorMiguel Ojeda <ojeda@kernel.org>2024-04-09 20:25:16 +0300
committerPalmer Dabbelt <palmer@rivosinc.com>2024-04-29 00:50:34 +0300
commit70a57b247251aabadd67795c3097c0fcc616e533 (patch)
tree67d97ccdefffbbf84a4ba3cb750739ac25cba0a5 /arch/riscv/Makefile
parent300ce44cbe2924aa83330fc5f24e035665f51b03 (diff)
downloadlinux-70a57b247251aabadd67795c3097c0fcc616e533.tar.xz
RISC-V: enable building 64-bit kernels with rust support
The rust modules work on 64-bit RISC-V, with no twiddling required. Select HAVE_RUST and provide the required flags to kbuild so that the modules can be used. The Makefile and Kconfig changes are lifted from work done by Miguel in the Rust-for-Linux tree, hence his authorship. Following the rabbit hole, the Makefile changes originated in a script, created based on config files originally added by Gary, hence his co-authorship. 32-bit is broken in core rust code, so support is limited to 64-bit: ld.lld: error: undefined symbol: __udivdi3 As 64-bit RISC-V is now supported, add it to the arch support table. Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Co-developed-by: Conor Dooley <conor.dooley@microchip.com> Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20240409-silencer-book-ce1320f06aab@spud Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/Makefile')
-rw-r--r--arch/riscv/Makefile7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index a74e70405d3f..1a2dca1e6a96 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -34,6 +34,9 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
KBUILD_AFLAGS += -mabi=lp64
KBUILD_LDFLAGS += -melf64lriscv
+
+ KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv64 --target=riscv64imac-unknown-none-elf \
+ -Cno-redzone
else
BITS := 32
UTS_MACHINE := riscv32
@@ -68,6 +71,10 @@ riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
riscv-march-$(CONFIG_RISCV_ISA_V) := $(riscv-march-y)v
+ifneq ($(CONFIG_RISCV_ISA_C),y)
+ KBUILD_RUSTFLAGS += -Ctarget-feature=-c
+endif
+
ifdef CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC
KBUILD_CFLAGS += -Wa,-misa-spec=2.2
KBUILD_AFLAGS += -Wa,-misa-spec=2.2