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, 63 insertions, 0 deletions

diff --git a/sysdeps/riscv/sys/asm.h b/sysdeps/riscv/sys/asm.h
new file mode 100644
index 0000000..ddb84b6
--- /dev/null
+++ b/sysdeps/riscv/sys/asm.h
@@ -0,0 +1,63 @@
+/* Miscellaneous macros.
+   Copyright (C) 2000-2018 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/>.  */
+
+#ifndef _SYS_ASM_H
+#define _SYS_ASM_H
+
+/* Macros to handle different pointer/register sizes for 32/64-bit code.  */
+#if __riscv_xlen == 64
+# define PTRLOG 3
+# define SZREG	8
+# define REG_S sd
+# define REG_L ld
+#elif __riscv_xlen == 32
+# error "rv32i-based targets are not supported"
+#else
+# error __riscv_xlen must equal 32 or 64
+#endif
+
+#if !defined __riscv_float_abi_soft
+/* For ABI uniformity, reserve 8 bytes for floats, even if double-precision
+   floating-point is not supported in hardware.  */
+# if defined __riscv_float_abi_double
+#  define FREG_L fld
+#  define FREG_S fsd
+#  define SZFREG 8
+# else
+#  error unsupported FLEN
+# endif
+#endif
+
+/* Declare leaf routine.  */
+#define	LEAF(symbol)				\
+		.globl	symbol;			\
+		.align	2;			\
+		.type	symbol,@function;	\
+symbol:						\
+		cfi_startproc;
+
+/* Mark end of function.  */
+#undef END
+#define END(function)				\
+		cfi_endproc;			\
+		.size	function,.-function
+
+/* Stack alignment.  */
+#define ALMASK	~15
+
+#endif /* sys/asm.h */