RISC-V: ABI Implementation

This patch contains code that needs to directly know about the RISC-V
ABI, which is specified in a work-in-progress psABI document:

  https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md

This is meant to contain all the RISC-V code that needs to explicitly
name registers or manage in-memory structure layout.  This does not
contain any of the Linux-specific code.

2018-01-29  Palmer Dabbelt  <palmer@sifive.com>

        * sysdeps/riscv/__longjmp.S: New file.
        * sysdeps/riscv/backtrace.c: Likewise.
        * sysdeps/riscv/bits/endian.h: Likewise.
        * sysdeps/riscv/bits/setjmp.h: Likewise.
        * sysdeps/riscv/bits/wordsize.h: Likewise.
        * sysdeps/riscv/bsd-_setjmp.c: Likewise.
        * sysdeps/riscv/bsd-setjmp.c: Likewise.
        * sysdeps/riscv/dl-trampoline.S: Likewise.
        * sysdeps/riscv/gccframe.h: Likewise.
        * sysdeps/riscv/jmpbuf-offsets.h: Likewise.
        * sysdeps/riscv/jmpbuf-unwind.h: Likewise.
        * sysdeps/riscv/machine-gmon.h: Likewise.
        * sysdeps/riscv/memusage.h: Likewise.
        * sysdeps/riscv/setjmp.S: Likewise.
        * sysdeps/riscv/sys/asm.h: Likewise.
        * sysdeps/riscv/tls-macros.h: Likewise.

1 files changed, 74 insertions, 0 deletions

diff --git a/sysdeps/riscv/setjmp.S b/sysdeps/riscv/setjmp.S
new file mode 100644
index 0000000000..cfbd276fc3
--- /dev/null
+++ b/sysdeps/riscv/setjmp.S
@@ -0,0 +1,74 @@
+/* setjmp for RISC-V.
+   Copyright (C) 1996-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+
+ENTRY (_setjmp)
+  li	a1, 0
+  j	__sigsetjmp
+END (_setjmp)
+ENTRY (setjmp)
+  li	a1, 1
+  /* Fallthrough */
+END (setjmp)
+ENTRY (__sigsetjmp)
+	REG_S ra,  0*SZREG(a0)
+	REG_S s0,  1*SZREG(a0)
+	REG_S s1,  2*SZREG(a0)
+	REG_S s2,  3*SZREG(a0)
+	REG_S s3,  4*SZREG(a0)
+	REG_S s4,  5*SZREG(a0)
+	REG_S s5,  6*SZREG(a0)
+	REG_S s6,  7*SZREG(a0)
+	REG_S s7,  8*SZREG(a0)
+	REG_S s8,  9*SZREG(a0)
+	REG_S s9, 10*SZREG(a0)
+	REG_S s10,11*SZREG(a0)
+	REG_S s11,12*SZREG(a0)
+	REG_S sp, 13*SZREG(a0)
+
+#ifndef __riscv_float_abi_soft
+	FREG_S fs0, 14*SZREG+ 0*SZFREG(a0)
+	FREG_S fs1, 14*SZREG+ 1*SZFREG(a0)
+	FREG_S fs2, 14*SZREG+ 2*SZFREG(a0)
+	FREG_S fs3, 14*SZREG+ 3*SZFREG(a0)
+	FREG_S fs4, 14*SZREG+ 4*SZFREG(a0)
+	FREG_S fs5, 14*SZREG+ 5*SZFREG(a0)
+	FREG_S fs6, 14*SZREG+ 6*SZFREG(a0)
+	FREG_S fs7, 14*SZREG+ 7*SZFREG(a0)
+	FREG_S fs8, 14*SZREG+ 8*SZFREG(a0)
+	FREG_S fs9, 14*SZREG+ 9*SZFREG(a0)
+	FREG_S fs10,14*SZREG+10*SZFREG(a0)
+	FREG_S fs11,14*SZREG+11*SZFREG(a0)
+#endif
+
+#if !IS_IN (libc) && IS_IN (rtld)
+  /* In ld.so we never save the signal mask.  */
+  li a0, 0
+  ret
+#else
+  /* Make a tail call to __sigjmp_save; it takes the same args.  */
+  j __sigjmp_save
+#endif
+
+
+END (__sigsetjmp)
+
+hidden_def (__sigsetjmp)
+weak_alias (_setjmp, __GI__setjmp)