Initial RISC-V64 support

Author: tea

.gitmodules

@@ -1,6 +1,7 @@
 [submodule "openlibm"]
 	path = openlibm
-	url = https://gitlab.redox-os.org/redox-os/openlibm.git
+	url = https://github.com/JuliaMath/openlibm.git
+	branch = master
 [submodule "posix-regex"]
 	path = posix-regex
 	url = https://gitlab.redox-os.org/redox-os/posix-regex.git

Cargo.lock

@@ -74,3 +74,6 @@ panic = "abort"
 
 [profile.release]
 panic = "abort"
+
+[patch.crates-io]
+cc-11 = { git = "https://github.com/tea/cc-rs", branch="riscv-abi-arch-fix", package = "cc" }

Cargo.toml

@@ -1,4 +1,4 @@
-TARGET?=$(shell rustc -Z unstable-options --print target-spec-json | grep llvm-target | cut -d '"' -f4)
+export TARGET?=$(shell rustc -Z unstable-options --print target-spec-json | grep llvm-target | cut -d '"' -f4)
 
 CARGO?=cargo
 CARGO_TEST?=$(CARGO)
@@ -20,35 +20,54 @@ ifeq ($(TARGET),aarch64-unknown-linux-gnu)
 	export CC=aarch64-linux-gnu-gcc
 	export LD=aarch64-linux-gnu-ld
 	export AR=aarch64-linux-gnu-ar
+	export NM=aarch64-linux-gnu-nm
 	export OBJCOPY=aarch64-linux-gnu-objcopy
+	export CPPFLAGS=
 endif
 
 ifeq ($(TARGET),aarch64-unknown-redox)
 	export CC=aarch64-unknown-redox-gcc
 	export LD=aarch64-unknown-redox-ld
 	export AR=aarch64-unknown-redox-ar
+	export NM=aarch64-unknown-redox-nm
 	export OBJCOPY=aarch64-unknown-redox-objcopy
+	export CPPFLAGS=
 endif
 
 ifeq ($(TARGET),x86_64-unknown-linux-gnu)
 	export CC=x86_64-linux-gnu-gcc
 	export LD=x86_64-linux-gnu-ld
 	export AR=x86_64-linux-gnu-ar
+	export NM=x86_64-linux-gnu-nm
 	export OBJCOPY=x86_64-linux-gnu-objcopy
+	export CPPFLAGS=
 endif
 
 ifeq ($(TARGET),i686-unknown-redox)
 	export CC=i686-unknown-redox-gcc
 	export LD=i686-unknown-redox-ld
 	export AR=i686-unknown-redox-ar
+	export NM=i686-unknown-redox-nm
 	export OBJCOPY=i686-unknown-redox-objcopy
+	export CPPFLAGS=
 endif
 
 ifeq ($(TARGET),x86_64-unknown-redox)
 	export CC=x86_64-unknown-redox-gcc
 	export LD=x86_64-unknown-redox-ld
 	export AR=x86_64-unknown-redox-ar
+	export NM=x86_64-unknown-redox-nm
 	export OBJCOPY=x86_64-unknown-redox-objcopy
+	export CPPFLAGS=
+endif
+
+ifeq ($(TARGET),riscv64gc-unknown-redox)
+	export CC=riscv64-unknown-redox-gcc
+	export LD=riscv64-unknown-redox-ld
+	export AR=riscv64-unknown-redox-ar
+	export NM=riscv64-unknown-redox-nm
+	export OBJCOPY=riscv64-unknown-redox-objcopy
+	export CPPFLAGS=-march=rv64gc -mabi=lp64d
 endif
 
 SRC=\
@@ -158,7 +177,7 @@ $(BUILD)/debug/libc.so: $(BUILD)/debug/librelibc.a $(BUILD)/openlibm/libopenlibm
 
 $(BUILD)/debug/librelibc.a: $(SRC)
 	$(CARGO) rustc $(CARGOFLAGS) -- --emit link=$@ $(RUSTCFLAGS)
-	./renamesyms.sh $@ $(BUILD)/debug/deps/
+	./renamesyms.sh "$@" "$(BUILD)/debug/deps/"
 	touch $@
 
 $(BUILD)/debug/crt0.o: $(SRC)
@@ -198,7 +217,7 @@ $(BUILD)/release/librelibc.a: $(SRC)
 	$(CARGO) rustc --release $(CARGOFLAGS) -- --emit link=$@ $(RUSTCFLAGS)
 	# TODO: Better to only allow a certain whitelisted set of symbols? Perhaps
 	# use some cbindgen hook, specify them manually, or grep for #[no_mangle].
-	./renamesyms.sh $@ $(BUILD)/release/deps/
+	./renamesyms.sh "$@" "$(BUILD)/release/deps/"
 	touch $@
 
 $(BUILD)/release/crt0.o: $(SRC)
@@ -230,4 +249,4 @@ $(BUILD)/openlibm: openlibm
 	touch $@
 
 $(BUILD)/openlibm/libopenlibm.a: $(BUILD)/openlibm $(BUILD)/release/librelibc.a
-	$(MAKE) AR=$(AR) CC=$(CC) LD=$(LD) CPPFLAGS="-fno-stack-protector -I$(shell pwd)/include -I$(TARGET_HEADERS)" -C $< libopenlibm.a
+	$(MAKE) AR=$(AR) CC=$(CC) LD=$(LD) CPPFLAGS="$(CPPFLAGS) -fno-stack-protector -I$(shell pwd)/include -I$(TARGET_HEADERS)" -C $< libopenlibm.a

Makefile

@@ -8,6 +8,9 @@
 "target_arch=x86" = "__i386__"
 "target_arch=x86_64" = "__x86_64__"
 "target_arch=aarch64" = "__aarch64__"
+# This is not exact. It should be `defined(__riscv) && defined(__LP64__)`, or `defined(__riscv) && __riscv_xlen==64`
+# This will do however, as long as we only support riscv64 and not riscv32
+"target_arch=riscv64" = "__riscv"
 
 # XXX: silences a warning
 "feature = no_std" = "__relibc__"

cbindgen.globdefs.toml

@@ -64,6 +64,21 @@ impl<Os> GenericTcb<Os> {
         value
     }
 
+    /// Architecture specific code to read a usize from the TCB - riscv64
+    #[inline(always)]
+    #[cfg(target_arch = "riscv64")]
+    unsafe fn arch_read(offset: usize) -> usize {
+        let value;
+        asm!(
+            "ld {value}, -8(tp)", // TCB
+            "add {value}, {value}, {offset}",
+            "ld {value}, 0({value})",
+            value = out(reg) value,
+            offset = in(reg) offset,
+        );
+        value
+    }
+
     pub unsafe fn current_ptr() -> Option<*mut Self> {
         let tcb_ptr = Self::arch_read(offset_of!(Self, tcb_ptr)) as *mut Self;
         let tcb_len = Self::arch_read(offset_of!(Self, tcb_len));

generic-rt/src/lib.rs

@@ -61,6 +61,10 @@ typedef unsigned long long jmp_buf[8];
 typedef unsigned long jmp_buf[8];
 #endif
 
+#ifdef __riscv
+typedef unsigned long jmp_buf[26];
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif

include/setjmp.h

@@ -4,8 +4,10 @@
 #include <arch/x64/user.h>
 #elif defined(__aarch64__)
 #include <arch/aarch64/user.h>
+#elif defined(__riscv) && __riscv_xlen==64
+#include <arch/riscv64/user.h>
 #else
 #error "Unknown architecture"
 #endif
 
-#endif
+#endif