4 files changed, 35 insertions, 11 deletions
diff --git a/src/syscall/asm_linux_riscv64.s b/src/syscall/asm_linux_riscv64.s
index ad0b6b17d9..f172dd3d9b 100644
--- a/src/syscall/asm_linux_riscv64.s
+++ b/src/syscall/asm_linux_riscv64.s
@@ -104,6 +104,28 @@ err:
 	MOV	A0, err+72(FP)	// errno
 	RET
 
+// func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
+TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
+	MOV	a1+8(FP), A0
+	MOV	ZERO, A1
+	MOV	ZERO, A2
+	MOV	ZERO, A3
+	MOV	ZERO, A4
+	MOV	ZERO, A5
+	MOV	trap+0(FP), A7	// syscall entry
+	ECALL
+	MOV	$-4096, T0
+	BLTU	T0, A0, err
+	MOV	A0, r1+16(FP)	// r1
+	MOV	ZERO, err+24(FP)	// errno
+	RET
+err:
+	MOV	$-1, T0
+	MOV	T0, r1+16(FP)	// r1
+	SUB	A0, ZERO, A0
+	MOV	A0, err+24(FP)	// errno
+	RET
+
 TEXT ·rawSyscallNoError(SB),NOSPLIT,$0-48
 	MOV	a1+8(FP), A0
 	MOV	a2+16(FP), A1
diff --git a/src/syscall/exec_linux.go b/src/syscall/exec_linux.go
index b7351cda82..b6acad96ea 100644
--- a/src/syscall/exec_linux.go
+++ b/src/syscall/exec_linux.go
@@ -207,7 +207,11 @@ func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, att
 		}
 	}
 
-	hasRawVforkSyscall := runtime.GOARCH == "amd64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "s390x" || runtime.GOARCH == "arm64"
+	var hasRawVforkSyscall bool
+	switch runtime.GOARCH {
+	case "amd64", "arm64", "ppc64", "riscv64", "s390x":
+		hasRawVforkSyscall = true
+	}
 
 	// About to call fork.
 	// No more allocation or calls of non-assembly functions.
diff --git a/src/syscall/syscall_linux_riscv64.go b/src/syscall/syscall_linux_riscv64.go
index d54bd38510..088e23439f 100644
--- a/src/syscall/syscall_linux_riscv64.go
+++ b/src/syscall/syscall_linux_riscv64.go
@@ -199,6 +199,4 @@ func Pause() error {
 	return err
 }
 
-func rawVforkSyscall(trap, a1 uintptr) (r1 uintptr, err Errno) {
-	panic("not implemented")
-}
+func rawVforkSyscall(trap, a1 uintptr) (r1 uintptr, err Errno)
diff --git a/src/syscall/syscall_unix_test.go b/src/syscall/syscall_unix_test.go
index 13b79ca8d8..3c7982eefe 100644
--- a/src/syscall/syscall_unix_test.go
+++ b/src/syscall/syscall_unix_test.go
@@ -336,11 +336,11 @@ func TestRlimit(t *testing.T) {
 	}
 	set := rlimit
 	set.Cur = set.Max - 1
-	if runtime.GOOS == "darwin" && set.Cur > 10240 {
-		// The max file limit is 10240, even though
-		// the max returned by Getrlimit is 1<<63-1.
-		// This is OPEN_MAX in sys/syslimits.h.
-		set.Cur = 10240
+	if runtime.GOOS == "darwin" && set.Cur > 4096 {
+		// rlim_min for RLIMIT_NOFILE should be equal to
+		// or lower than kern.maxfilesperproc, which on
+		// some machines are 4096. See #40564.
+		set.Cur = 4096
 	}
 	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &set)
 	if err != nil {
@@ -353,8 +353,8 @@ func TestRlimit(t *testing.T) {
 	}
 	set = rlimit
 	set.Cur = set.Max - 1
-	if runtime.GOOS == "darwin" && set.Cur > 10240 {
-		set.Cur = 10240
+	if runtime.GOOS == "darwin" && set.Cur > 4096 {
+		set.Cur = 4096
 	}
 	if set != get {
 		t.Fatalf("Rlimit: change failed: wanted %#v got %#v", set, get)