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, 24 deletions

diff --git a/src/ldso/x32/start.s b/src/ldso/x32/start.s
deleted file mode 100644
index 3c3800aa..00000000
--- a/src/ldso/x32/start.s
+++ /dev/null
@@ -1,24 +0,0 @@
-.text
-.global _dlstart
-_dlstart:
-	mov (%rsp),%rdi  /* move argc into 1st argument slot */
-	lea 4(%rsp),%rsi /* move argv into 2nd argument slot */
-	call __dynlink
-	/* in case the dynlinker was called directly, it sets the "consumed"
-	   argv values to -1. so we must loop over the array as long as -1
-	   is in the top argv slot, decrement argc, and then set the stackpointer
-	   to the new argc as well as argc's new value.
-	   as the x32 abi has longs in the argv array, we cannot use push/pop.*/
-	movl (%rsp),%edi /* copy argc into edi */
-	xor %rdx,%rdx /* we use rdx as an offset to the current argv member */
-1:	dec %edi
-	addl $4, %edx
-	movl (%rsp, %rdx), %esi
-	cmp $-1,%esi
-	jz 1b
-	inc %edi
-	subl $4, %edx
-	lea (%rsp, %rdx), %rsp /* set rsp to new argv[-1] */
-	movl %edi, (%rsp)      /* write new argc there */
-	xor %edx,%edx
-	jmp *%rax