dynamic linker bootstrap overhaul

this overhaul further reduces the amount of arch-specific code needed
by the dynamic linker and removes a number of assumptions, including:

- that symbolic function references inside libc are bound at link time
  via the linker option -Bsymbolic-functions.

- that libc functions used by the dynamic linker do not require
  access to data symbols.

- that static/internal function calls and data accesses can be made
  without performing any relocations, or that arch-specific startup
  code handled any such relocations needed.

removing these assumptions paves the way for allowing libc.so itself
to be built with stack protector (among other things), and is achieved
by a three-stage bootstrap process:

1. relative relocations are processed with a flat function.
2. symbolic relocations are processed with no external calls/data.
3. main program and dependency libs are processed with a
   fully-functional libc/ldso.

reduction in arch-specific code is achived through the following:

- crt_arch.h, used for generating crt1.o, now provides the entry point
  for the dynamic linker too.

- asm is no longer responsible for skipping the beginning of argv[]
  when ldso is invoked as a command.

- the functionality previously provided by __reloc_self for heavily
  GOT-dependent RISC archs is now the arch-agnostic stage-1.

- arch-specific relocation type codes are mapped directly as macros
  rather than via an inline translation function/switch statement.

1 files changed, 0 insertions, 28 deletions

diff --git a/src/ldso/microblaze/start.s b/src/ldso/microblaze/start.s
deleted file mode 100644
index 067e8613..00000000
--- a/src/ldso/microblaze/start.s
+++ /dev/null
@@ -1,28 +0,0 @@
-# FIXME: clearing argv entries
-.global _dlstart
-_dlstart:
-	add     r19, r0, r0
-
-	lw      r5, r0, r1
-	addi    r6, r1, 4
-	mfs     r7, rpc
-	addi    r7, r7, _GLOBAL_OFFSET_TABLE_+8
-	addi    r7, r7, _DYNAMIC@GOTOFF
-	brlid   r15, __reloc_self@PLT
-	addik   r1, r1, -16
-
-	lwi     r5, r1, 16
-	brlid   r15, __dynlink@PLT
-	addi    r6, r1, 20
-	addik   r1, r1, 16
-
-	lwi     r4, r1, 0
-1:	lwi     r5, r1, 4
-	addi    r5, r5, 1
-	bnei    r5, 1f
-	addi    r4, r4, -1
-	addi    r1, r1, 4
-	bri     1b
-1:	swi     r4, r1, 0
-	add     r5, r0, r0
-	bra     r3