musl/arch/mips/reloc.h
Rich Felker f3ddd17380 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.
2015-04-13 03:04:42 -04:00

32 lines
754 B
C

#include <endian.h>
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define ENDIAN_SUFFIX "el"
#else
#define ENDIAN_SUFFIX ""
#endif
#ifdef __mips_soft_float
#define FP_SUFFIX "-sf"
#else
#define FP_SUFFIX ""
#endif
#define LDSO_ARCH "mips" ENDIAN_SUFFIX FP_SUFFIX
#define TPOFF_K (-0x7000)
#define REL_SYM_OR_REL R_MIPS_REL32
#define REL_PLT R_MIPS_JUMP_SLOT
#define REL_COPY R_MIPS_COPY
#define REL_DTPMOD R_MIPS_TLS_DTPMOD32
#define REL_DTPOFF R_MIPS_TLS_DTPREL32
#define REL_TPOFF R_MIPS_TLS_TPREL32
#define NEED_MIPS_GOT_RELOCS 1
#define DYNAMIC_IS_RO 1
#define ARCH_SYM_REJECT_UND(s) (!((s)->st_other & STO_MIPS_PLT))
#define CRTJMP(pc,sp) __asm__ __volatile__( \
"move $sp,%1 ; jr %0" : : "r"(pc), "r"(sp) : "memory" )