risc-v: add support for 64-bit RISC-V CPUs

Author: yannishuber

src/runtime/volatile/register.go

@@ -1,6 +1,6 @@
 package volatile
 
-// This file defines Register{8,16,32} types, which are convenience types for
+// This file defines Register{8,16,32,64} types, which are convenience types for
 // volatile register accesses.
 
 // Special types that causes loads/stores to be volatile (necessary for
@@ -190,3 +190,65 @@ func (r *Register32) HasBits(value uint32) bool {
 func (r *Register32) ReplaceBits(value uint32, mask uint32, pos uint8) {
 	StoreUint32(&r.Reg, LoadUint32(&r.Reg)&^(mask<<pos)|value<<pos)
 }
+
+type Register64 struct {
+	Reg uint64
+}
+
+// Get returns the value in the register. It is the volatile equivalent of:
+//
+//     *r.Reg
+//
+//go:inline
+func (r *Register64) Get() uint64 {
+	return LoadUint64(&r.Reg)
+}
+
+// Set updates the register value. It is the volatile equivalent of:
+//
+//     *r.Reg = value
+//
+//go:inline
+func (r *Register64) Set(value uint64) {
+	StoreUint64(&r.Reg, value)
+}
+
+// SetBits reads the register, sets the given bits, and writes it back. It is
+// the volatile equivalent of:
+//
+//     r.Reg |= value
+//
+//go:inline
+func (r *Register64) SetBits(value uint64) {
+	StoreUint64(&r.Reg, LoadUint64(&r.Reg)|value)
+}
+
+// ClearBits reads the register, clears the given bits, and writes it back. It
+// is the volatile equivalent of:
+//
+//     r.Reg &^= value
+//
+//go:inline
+func (r *Register64) ClearBits(value uint64) {
+	StoreUint64(&r.Reg, LoadUint64(&r.Reg)&^value)
+}
+
+// HasBits reads the register and then checks to see if the passed bits are set. It
+// is the volatile equivalent of:
+//
+//     (*r.Reg & value) > 0
+//
+//go:inline
+func (r *Register64) HasBits(value uint64) bool {
+	return (r.Get() & value) > 0
+}
+
+// ReplaceBits is a helper to simplify setting multiple bits high and/or low at
+// once. It is the volatile equivalent of:
+//
+//     r.Reg = (r.Reg & ^(mask << pos)) | value << pos
+//
+// go:inline
+func (r *Register64) ReplaceBits(value uint64, mask uint64, pos uint8) {
+	StoreUint64(&r.Reg, LoadUint64(&r.Reg)&^(mask<<pos)|value<<pos)
+}

src/runtime/volatile/volatile.go

@@ -24,6 +24,9 @@ func LoadUint16(addr *uint16) (val uint16)
 // LoadUint32 loads the volatile value *addr.
 func LoadUint32(addr *uint32) (val uint32)
 
+// LoadUint64 loads the volatile value *addr.
+func LoadUint64(addr *uint64) (val uint64)
+
 // StoreUint8 stores val to the volatile value *addr.
 func StoreUint8(addr *uint8, val uint8)
 
@@ -32,3 +35,6 @@ func StoreUint16(addr *uint16, val uint16)
 
 // StoreUint32 stores val to the volatile value *addr.
 func StoreUint32(addr *uint32, val uint32)
+
+// StoreUint64 stores val to the volatile value *addr.
+func StoreUint64(addr *uint64, val uint64)

targets/fe310.json

@@ -1,5 +1,5 @@
 {
-	"inherits": ["riscv"],
+	"inherits": ["riscv32"],
 	"features": ["+a", "+c", "+m"],
 	"build-tags": ["fe310", "sifive"]
 }

targets/riscv-qemu.json

@@ -1,5 +1,5 @@
 {
-	"inherits": ["riscv"],
+	"inherits": ["riscv32"],
 	"features": ["+a", "+c", "+m"],
 	"build-tags": ["virt", "qemu"],
 	"linkerscript": "targets/riscv-qemu.ld",

targets/riscv.json

@@ -1,5 +1,4 @@
 {
-	"llvm-target": "riscv32--none",
 	"goos": "linux",
 	"goarch": "arm",
 	"build-tags": ["tinygo.riscv", "baremetal", "linux", "arm"],
@@ -9,16 +8,12 @@
 	"rtlib": "compiler-rt",
 	"libc": "picolibc",
 	"cflags": [
-		"--target=riscv32--none",
-		"-march=rv32imac",
-		"-mabi=ilp32",
 		"-Os",
 		"-Werror",
 		"-fno-exceptions", "-fno-unwind-tables",
 		"-ffunction-sections", "-fdata-sections"
 	],
 	"ldflags": [
-		"-melf32lriscv",
 		"--gc-sections"
 	],
 	"extra-files": [

targets/riscv32.json

@@ -0,0 +1,12 @@
+{
+	"inherits": ["riscv"],
+	"llvm-target": "riscv32--none",
+	"cflags": [
+		"--target=riscv32--none",
+		"-march=rv32imac",
+		"-mabi=ilp32"
+	],
+	"ldflags": [
+		"-melf32lriscv"
+	]
+}

targets/riscv64.json

@@ -0,0 +1,13 @@
+{
+	"inherits": ["riscv"],
+	"llvm-target": "riscv64--none",
+	"build-tags": ["tinygo.riscv64"],
+	"cflags": [
+		"--target=riscv64--none",
+		"-march=rv64gc",
+		"-mabi=lp64"
+	],
+	"ldflags": [
+		"-melf64lriscv"
+	]
+}

tools/gen-device-svd/gen-device-svd.go

@@ -681,6 +681,8 @@ var (
 
 			var regType string
 			switch register.elementSize {
+			case 8:
+				regType = "volatile.Register64"
 			case 4:
 				regType = "volatile.Register32"
 			case 2:
@@ -710,6 +712,8 @@ var (
 				for _, subregister := range register.registers {
 					var subregType string
 					switch subregister.elementSize {
+					case 8:
+						subregType = "volatile.Register64"
 					case 4:
 						subregType = "volatile.Register32"
 					case 2: