ldso: Add ARC support

[uclinux-h8/uClibc.git] / ldso / ldso / arc / dl-startup.h

diff --git a/ldso/ldso/arc/dl-startup.h b/ldso/ldso/arc/dl-startup.h
new file mode 100644 (file)
index 0000000..4a8d5d7
--- /dev/null
+++ b/ldso/ldso/arc/dl-startup.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+/*
+ * vineetg: Refactoring/cleanup of loader entry point
+ *  Removed 6 useless insns
+ * Joern Improved it even further:
+ *  -better insn scheduling
+ *  -no need for conditional code for _dl_skip_args
+ *  -use of assembler .&2 expressions vs. @gotpc refs (avoids need for GP)
+ *
+ * What this code does:
+ *  -ldso starts execution here when kernel returns from execve()
+ *  -calls into generic ldso entry point _dl_start( )
+ *  -optionally adjusts argc for executable if exec passed as cmd
+ *  -calls into app main with address of finaliser
+ */
+__asm__(
+    ".section .text                                             \n"
+    ".align 4                                                          \n"
+    ".global _start                                             \n"
+    ".hidden _start                                             \n"
+    ".type  _start,@function                                    \n"
+
+    "_start:                                                    \n"
+    "   ; ldso entry point, returns app entry point             \n"
+    "   bl.d    _dl_start                                       \n"
+    "   mov_s   r0, sp          ; pass ptr to aux vector tbl    \n"
+
+    "   ; If ldso ran as cmd with executable file nm as arg     \n"
+    "   ; as arg, skip the extra args calc by dl_start()        \n"
+    "   ld_s    r1, [sp]       ; orig argc from aux-vec Tbl     \n"
+#ifdef STAR_9000535888_FIXED
+    "   ld      r12, [pcl, _dl_skip_args-.+(.&2)]               \n"
+#else
+    "   add     r12, pcl, _dl_skip_args-.+(.&2)                 \n"
+    "   ld      r12, [r12]                                      \n"
+#endif
+
+    "   add     r2, pcl, _dl_fini-.+(.&2)   ; finalizer         \n"
+
+    "   add2    sp, sp, r12    ; discard argv entries from stack\n"
+    "   sub_s   r1, r1, r12    ; adjusted argc, on stack        \n"
+    "   st_s    r1, [sp]                                        \n"
+
+    "   j_s.d   [r0]           ; app entry point                \n"
+    "   mov_s   r0, r2         ; ptr to finalizer _dl_fini      \n"
+
+    ".size  _start,.-_start                                     \n"
+    ".previous                                                  \n"
+);
+
+/*
+ * Get a pointer to the argv array.  On many platforms this can be just
+ * the address if 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)
+
+/*
+ * Dynamic loader bootstrapping:
+ * Since we don't modify text at runtime, these can only be data relos
+ * (so safe to assume that they are word aligned).
+ * And also they HAVE to be RELATIVE relos only
+ * @RELP is the relo entry being processed
+ * @REL is the pointer to the address we are relocating.
+ * @SYMBOL is the symbol involved in the relocation
+ * @LOAD is the load address.
+ */
+
+#define PERFORM_BOOTSTRAP_RELOC(RELP,REL,SYMBOL,LOAD,SYMTAB)           \
+do {                                                                   \
+       int type = ELF32_R_TYPE((RELP)->r_info);                        \
+       if (likely(type == R_ARC_RELATIVE))                             \
+               *REL += (unsigned long) LOAD;                           \
+       else                                                            \
+               _dl_exit(1);                                            \
+}while(0)
+
+/*
+ * This will go away once we have DT_RELACOUNT
+ */
+#define ARCH_NEEDS_BOOTSTRAP_RELOCS
+
+/* we dont need to spit out argc, argv etc for debugging */
+#define NO_EARLY_SEND_STDERR    1