diff options
Diffstat (limited to 'ldso/ldso/arc/dl-sysdep.h')
| -rw-r--r-- | ldso/ldso/arc/dl-sysdep.h | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/ldso/ldso/arc/dl-sysdep.h b/ldso/ldso/arc/dl-sysdep.h new file mode 100644 index 000000000..dfde33233 --- /dev/null +++ b/ldso/ldso/arc/dl-sysdep.h @@ -0,0 +1,150 @@ +/* + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com) + * + * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball. + */ + +#include "elf.h" + +/* + * Define this if the system uses RELOCA. + */ +#define ELF_USES_RELOCA + +/* + * Dynamic Linking ABI for ARCompact ISA + * + * PLT + * -------------------------------- + * | ld r11, [pcl, off-to-GOT[1] | 0 (20 bytes) + * | | 4 + * plt0 | ld r10, [pcl, off-to-GOT[2] | 8 + * | | 12 + * | j [r10] | 16 + * -------------------------------- + * | Base address of GOT | 20 + * -------------------------------- + * | ld r12, [pcl, off-to-GOT[3] | 24 (12 bytes each) + * plt1 | | + * | j_s.d [r12] | 32 + * | mov_s r12, pcl | 34 + * -------------------------------- + * | | 36 + * ~ ~ + * ~ ~ + * | | + * -------------------------------- + * + * GOT + * -------------- + * | [0] | + * -------------- + * | [1] | Module info - setup by ldso + * -------------- + * | [2] | resolver entry point + * -------------- + * | [3] | + * | ... | Runtime address for function symbols + * | [f] | + * -------------- + * | [f+1] | + * | ... | Runtime address for data symbols + * | [last] | + * -------------- + */ + +/* + * Initialization sequence for a GOT. + * Caller elf_resolve() seeds @GOT_BASE from DT_PLTGOT - which essentially is + * pointer to first PLT entry. The actual GOT base is 5th word in PLT + * + */ +#define INIT_GOT(GOT_BASE,MODULE) \ +do { \ + unsigned long *__plt_base = (unsigned long *)GOT_BASE; \ + GOT_BASE = (unsigned long *)(__plt_base[5] + \ + (unsigned long)MODULE->loadaddr); \ + GOT_BASE[1] = (unsigned long) MODULE; \ + GOT_BASE[2] = (unsigned long) _dl_linux_resolve; \ +} while(0) + +/* Here we define the magic numbers that this dynamic loader should accept */ +#define MAGIC1 EM_ARCOMPACT +#undef MAGIC2 + +/* Used for error messages */ +#define ELF_TARGET "ARC" + +struct elf_resolve; +extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, + unsigned int plt_pc); + +extern unsigned __udivmodsi4(unsigned, unsigned) attribute_hidden; + +#define do_rem(result, n, base) ((result) = \ + \ + __builtin_constant_p (base) ? (n) % (unsigned) (base) : \ + __extension__ ({ \ + register unsigned r1 __asm__ ("r1") = (base); \ + \ + __asm("bl.d @__udivmodsi4` mov r0,%1" \ + : "=r" (r1) \ + : "r" (n), "r" (r1) \ + : "r0", "r2", "r3", "r4", "lp_count", "blink", "cc"); \ + \ + r1; \ + }) \ +) + +/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so + PLT entries should not be allowed to define the value. + ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one + of the main executable's symbols, as for a COPY reloc. */ +#define elf_machine_type_class(type) \ + ((((type) == R_ARC_JMP_SLOT) * ELF_RTYPE_CLASS_PLT) \ + | (((type) == R_ARC_COPY) * ELF_RTYPE_CLASS_COPY)) + +/* + * Get the runtime address of GOT[0] + */ +static __always_inline Elf32_Addr elf_machine_dynamic(void) +{ + Elf32_Addr dyn; + + __asm__("ld %0,[pcl,_DYNAMIC@gotpc]\n\t" : "=r" (dyn)); + return dyn; + +/* + * Another way would have been to simply return GP, which due to some + * PIC reference would be automatically setup by gcc in caller + * register Elf32_Addr *got __asm__ ("gp"); return *got; + */ +} + +/* Return the run-time load address of the shared object. */ +static __always_inline Elf32_Addr elf_machine_load_address(void) +{ + /* To find the loadaddr we subtract the runtime addr of any symbol + * say _dl_start from it's build-time addr. + */ + Elf32_Addr addr, tmp; + __asm__ ( + "ld %1, [pcl, _dl_start@gotpc] ;build addr of _dl_start \n" + "add %0, pcl, _dl_start-.+(.&2) ;runtime addr of _dl_start \n" + "sub %0, %0, %1 ;delta \n" + : "=&r" (addr), "=r"(tmp) + ); + return addr; +} + +static __always_inline void +elf_machine_relative (Elf32_Addr load_off, const Elf32_Addr rel_addr, + Elf32_Word relative_count) +{ + Elf32_Rel * rpnt = (void *) rel_addr; + --rpnt; + do { + Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset); + *reloc_addr += load_off; + } while (--relative_count); +} |