From 60eae0def70b8a2e768c6a5bec352da9d648b26c Mon Sep 17 00:00:00 2001
From: Waldemar Brodkorb <wbx@openadk.org>
Date: Wed, 16 Oct 2019 02:24:18 +0200
Subject: riscv64: add shared library support

---
 ldso/ldso/riscv64/dl-startup.h | 90 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 ldso/ldso/riscv64/dl-startup.h

(limited to 'ldso/ldso/riscv64/dl-startup.h')

diff --git a/ldso/ldso/riscv64/dl-startup.h b/ldso/ldso/riscv64/dl-startup.h
new file mode 100644
index 000000000..dabe1bebd
--- /dev/null
+++ b/ldso/ldso/riscv64/dl-startup.h
@@ -0,0 +1,90 @@
+/*
+ * Architecture specific code used by dl-startup.c
+ * Copyright (C) 2019 Waldemar Brodkorb <wbx@uclibc-ng.org>
+ * Ported from GNU libc
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+/* Copyright (C) 2011-2019 Free Software Foundation, Inc.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <features.h>
+#include <sys/asm.h>
+
+#ifndef _RTLD_PROLOGUE
+# define _RTLD_PROLOGUE(entry)                                          \
+        ".globl\t" __STRING (entry) "\n\t"                              \
+        ".type\t" __STRING (entry) ", @function\n"                      \
+        __STRING (entry) ":\n\t"
+#endif
+
+#ifndef _RTLD_EPILOGUE
+# define _RTLD_EPILOGUE(entry)                                          \
+        ".size\t" __STRING (entry) ", . - " __STRING (entry) "\n\t"
+#endif
+
+#define STRINGXP(X) __STRING (X)  
+
+__asm__(\
+	".text\n\
+        " _RTLD_PROLOGUE (_start) "\
+        mv a0, sp\n\
+        jal _dl_start\n\
+        # Stash user entry point in s0.\n\
+        mv s0, a0\n\
+        # See if we were run as a command with the executable file\n\
+        # name as an extra leading argument.\n\
+        lw a0, _dl_skip_args\n\
+        # Load the original argument count.\n\
+        " STRINGXP (REG_L) " a1, 0(sp)\n\
+        # Subtract _dl_skip_args from it.\n\
+        sub a1, a1, a0\n\
+        # Adjust the stack pointer to skip _dl_skip_args words.\n\
+        sll a0, a0, " STRINGXP (PTRLOG) "\n\
+        add sp, sp, a0\n\
+        # Save back the modified argument count.\n\
+        " STRINGXP (REG_S) " a1, 0(sp)\n\
+        # Pass our finalizer function to _start.\n\
+        lla a0, _dl_fini\n\
+        # Jump to the user entry point.\n\
+        jr s0\n\
+        " _RTLD_EPILOGUE (_start) "\
+        .previous" \
+);
+
+/* Get a pointer to the argv array.  On many platforms this can be just
+ * the address of the first argument, on other platforms we need to
+ * do something a little more subtle here.  */
+#define GET_ARGV(ARGVP, ARGS) ARGVP = (((unsigned long*)ARGS)+1)
+
+/* Function calls are not safe until the GOT relocations have been done.  */
+#define NO_FUNCS_BEFORE_BOOTSTRAP
+
+/* Handle relocation of the symbols in the dynamic loader. */
+static __always_inline
+void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, ElfW(Addr) *reloc_addr,
+	ElfW(Addr) symbol_addr, ElfW(Addr) load_addr, ElfW(Addr) *sym)
+{
+	switch (ELF_R_TYPE(rpnt->r_info)) {
+		case R_RISCV_NONE:
+			break;
+		case R_RISCV_JUMP_SLOT:
+			*reloc_addr = symbol_addr + rpnt->r_addend;
+			break;
+		default:
+			_dl_exit(1);
+	}
+}
-- 
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