riscv: Move sigcode out of locore.S

It really doesn't fit here anymore as locore is all about early startup
code. Thus, move it to its own file.

Reviewed by:	br
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D45320

sys/conf/files.riscv

@@ -58,6 +58,7 @@ riscv/riscv/pmap.c		standard
 riscv/riscv/ptrace_machdep.c	standard
 riscv/riscv/riscv_console.c	optional	rcons
 riscv/riscv/riscv_syscon.c	optional	syscon riscv_syscon fdt
+riscv/riscv/sigtramp.S		standard
 riscv/riscv/sbi.c		standard
 riscv/riscv/sbi_ipi.c		optional	smp
 riscv/riscv/stack_machdep.c	optional	ddb | stack

sys/riscv/riscv/locore.S

@@ -34,7 +34,6 @@
 
 #include "assym.inc"
 
-#include <sys/syscall.h>
 #include <machine/asm.h>
 #include <machine/param.h>
 #include <machine/trap.h>
@@ -290,30 +289,6 @@ initstack:
 	.space  (PAGE_SIZE * KSTACK_PAGES)
 initstack_end:
 
-ENTRY(sigcode)
-	mv	a0, sp
-	addi	a0, a0, SF_UC
-
-1:
-	li	t0, SYS_sigreturn
-	ecall
-
-	/* sigreturn failed, exit */
-	li	t0, SYS_exit
-	ecall
-
-	j	1b
-END(sigcode)
-	/* This may be copied to the stack, keep it 16-byte aligned */
-	.align	3
-esigcode:
-
-	.data
-	.align	3
-	.global	szsigcode
-szsigcode:
-	.quad	esigcode - sigcode
-
 	.align	12
 pagetable_l1:
 	.space	PAGE_SIZE

sys/riscv/riscv/sigtramp.S

@@ -0,0 +1,71 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * Portions of this software were developed by SRI International and the
+ * University of Cambridge Computer Laboratory under DARPA/AFRL contract
+ * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Portions of this software were developed by the University of Cambridge
+ * Computer Laboratory as part of the CTSRD Project, with support from the
+ * UK Higher Education Innovation Fund (HEIF).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "assym.inc"
+
+#include <sys/syscall.h>
+
+#include <machine/asm.h>
+
+/*
+ * This code is copied to the user's stack for returning from signal handlers
+ * (see sendsig() and sigreturn()). We have to compute the address of the
+ * sigcontext struct for the sigreturn call.
+ */
+ENTRY(sigcode)
+	mv	a0, sp
+	addi	a0, a0, SF_UC
+
+1:
+	li	t0, SYS_sigreturn
+	ecall
+
+	/* sigreturn failed, exit */
+	li	t0, SYS_exit
+	ecall
+
+	j	1b
+END(sigcode)
+
+	/* This may be copied to the stack, keep it 16-byte aligned */
+	.align	3
+esigcode:
+
+	.data
+	.align	3
+	.global	szsigcode
+szsigcode:
+	.quad	esigcode - sigcode