RISC-V: Thread-Local Storage Support

This patch implements TLS support for RISC-V.  We support all four
standard TLS addressing modes (LE, IE, LD, and GD) when running on
Linux via NPTL.  There is a draft psABI document that defines our TLS
ABI here

  https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#thread-local-storage

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

        * sysdeps/riscv/dl-tls.h: New file.
        * sysdeps/riscv/libc-tls.c: Likewise.
        * sysdeps/riscv/nptl/tcb-offsets.sym: Likewise.
        * sysdeps/riscv/nptl/tls.h: Likewise.
        * sysdeps/riscv/stackinfo.h: Likewise.

1 files changed, 48 insertions, 0 deletions

diff --git a/sysdeps/riscv/dl-tls.h b/sysdeps/riscv/dl-tls.h
new file mode 100644
index 0000000000..ab2d860314
--- /dev/null
+++ b/sysdeps/riscv/dl-tls.h
@@ -0,0 +1,48 @@
+/* Thread-local storage handling in the ELF dynamic linker.  RISC-V version.
+   Copyright (C) 2011-2018 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/>.  */
+
+
+/* Type used for the representation of TLS information in the GOT.  */
+typedef struct
+{
+  unsigned long int ti_module;
+  unsigned long int ti_offset;
+} tls_index;
+
+/* The thread pointer points to the first static TLS block.  */
+#define TLS_TP_OFFSET		0
+
+/* Dynamic thread vector pointers point 0x800 past the start of each
+   TLS block.  */
+#define TLS_DTV_OFFSET		0x800
+
+/* Compute the value for a GOTTPREL reloc.  */
+#define TLS_TPREL_VALUE(sym_map, sym) \
+  ((sym_map)->l_tls_offset + (sym)->st_value - TLS_TP_OFFSET)
+
+/* Compute the value for a DTPREL reloc.  */
+#define TLS_DTPREL_VALUE(sym) \
+  ((sym)->st_value - TLS_DTV_OFFSET)
+
+extern void *__tls_get_addr (tls_index *ti);
+
+#define GET_ADDR_OFFSET	(ti->ti_offset + TLS_DTV_OFFSET)
+#define __TLS_GET_ADDR(__ti)	(__tls_get_addr (__ti) - TLS_DTV_OFFSET)
+
+/* Value used for dtv entries for which the allocation is delayed.  */
+#define TLS_DTV_UNALLOCATED	((void *) -1l)