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- /*
- * Various assembly language/system dependent hacks that are required
- * so that we can minimize the amount of platform specific code.
- */
- /*
- * Define this if the system uses RELOCA.
- */
- #define ELF_USES_RELOCA
- #include <elf.h>
- /*
- * Initialization sequence for a GOT.
- */
- #define INIT_GOT(GOT_BASE,MODULE) _dl_init_got(GOT_BASE,MODULE)
- /* Stuff for the PLT. */
- #define PLT_INITIAL_ENTRY_WORDS 18
- #define PLT_LONGBRANCH_ENTRY_WORDS 0
- #define PLT_TRAMPOLINE_ENTRY_WORDS 6
- #define PLT_DOUBLE_SIZE (1<<13)
- #define PLT_ENTRY_START_WORDS(entry_number) \
- (PLT_INITIAL_ENTRY_WORDS + (entry_number)*2 \
- + ((entry_number) > PLT_DOUBLE_SIZE \
- ? ((entry_number) - PLT_DOUBLE_SIZE)*2 \
- : 0))
- #define PLT_DATA_START_WORDS(num_entries) PLT_ENTRY_START_WORDS(num_entries)
- /* Macros to build PowerPC opcode words. */
- #define OPCODE_ADDI(rd,ra,simm) \
- (0x38000000 | (rd) << 21 | (ra) << 16 | ((simm) & 0xffff))
- #define OPCODE_ADDIS(rd,ra,simm) \
- (0x3c000000 | (rd) << 21 | (ra) << 16 | ((simm) & 0xffff))
- #define OPCODE_ADD(rd,ra,rb) \
- (0x7c000214 | (rd) << 21 | (ra) << 16 | (rb) << 11)
- #define OPCODE_B(target) (0x48000000 | ((target) & 0x03fffffc))
- #define OPCODE_BA(target) (0x48000002 | ((target) & 0x03fffffc))
- #define OPCODE_BCTR() 0x4e800420
- #define OPCODE_LWZ(rd,d,ra) \
- (0x80000000 | (rd) << 21 | (ra) << 16 | ((d) & 0xffff))
- #define OPCODE_LWZU(rd,d,ra) \
- (0x84000000 | (rd) << 21 | (ra) << 16 | ((d) & 0xffff))
- #define OPCODE_MTCTR(rd) (0x7C0903A6 | (rd) << 21)
- #define OPCODE_RLWINM(ra,rs,sh,mb,me) \
- (0x54000000 | (rs) << 21 | (ra) << 16 | (sh) << 11 | (mb) << 6 | (me) << 1)
- #define OPCODE_LI(rd,simm) OPCODE_ADDI(rd,0,simm)
- #define OPCODE_ADDIS_HI(rd,ra,value) \
- OPCODE_ADDIS(rd,ra,((value) + 0x8000) >> 16)
- #define OPCODE_LIS_HI(rd,value) OPCODE_ADDIS_HI(rd,0,value)
- #define OPCODE_SLWI(ra,rs,sh) OPCODE_RLWINM(ra,rs,sh,0,31-sh)
- #define PPC_DCBST(where) __asm__ __volatile__ ("dcbst 0,%0" : : "r"(where) : "memory")
- #define PPC_SYNC __asm__ __volatile__ ("sync" : : : "memory")
- #define PPC_ISYNC __asm__ __volatile__ ("sync; isync" : : : "memory")
- #define PPC_ICBI(where) __asm__ __volatile__ ("icbi 0,%0" : : "r"(where) : "memory")
- #define PPC_DIE __asm__ __volatile__ ("tweq 0,0")
- /* Here we define the magic numbers that this dynamic loader should accept */
- #define MAGIC1 EM_PPC
- #undef MAGIC2
- /* Used for error messages */
- #define ELF_TARGET "powerpc"
- struct elf_resolve;
- extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
- void _dl_init_got(unsigned long *lpnt,struct elf_resolve *tpnt);
- /* 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. */
- /* We never want to use a PLT entry as the destination of a
- reloc, when what is being relocated is a branch. This is
- partly for efficiency, but mostly so we avoid loops. */
- #define elf_machine_type_class(type) \
- ((((type) == R_PPC_JMP_SLOT \
- || (type) == R_PPC_REL24 \
- || (type) == R_PPC_ADDR24) * ELF_RTYPE_CLASS_PLT) \
- | (((type) == R_PPC_COPY) * ELF_RTYPE_CLASS_COPY))
- /* The SVR4 ABI specifies that the JMPREL relocs must be inside the
- DT_RELA table. */
- #define ELF_MACHINE_PLTREL_OVERLAP 1
- /* Return the value of the GOT pointer. */
- static __inline__ Elf32_Addr * __attribute__ ((const))
- ppc_got (void)
- {
- Elf32_Addr *got;
- #ifdef HAVE_ASM_PPC_REL16
- __asm__ (" bcl 20,31,1f\n"
- "1:mflr %0\n"
- " addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n"
- " addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n"
- : "=b" (got) : : "lr");
- #else
- __asm__ (" bl _GLOBAL_OFFSET_TABLE_-4@local"
- : "=l" (got));
- #endif
- return got;
- }
- /* Return the link-time address of _DYNAMIC, stored as
- the first value in the GOT. */
- static __inline__ Elf32_Addr __attribute__ ((const))
- elf_machine_dynamic (void)
- {
- return *ppc_got();
- }
- /* Return the run-time load address of the shared object. */
- static __inline__ Elf32_Addr __attribute__ ((const))
- elf_machine_load_address (void)
- {
- Elf32_Addr *branchaddr;
- Elf32_Addr runtime_dynamic;
- /* This is much harder than you'd expect. Possibly I'm missing something.
- The 'obvious' way:
- Apparently, "bcl 20,31,$+4" is what should be used to load LR
- with the address of the next instruction.
- I think this is so that machines that do bl/blr pairing don't
- get confused.
- __asm__ ("bcl 20,31,0f ;"
- "0: mflr 0 ;"
- "lis %0,0b@ha;"
- "addi %0,%0,0b@l;"
- "subf %0,%0,0"
- : "=b" (addr) : : "r0", "lr");
- doesn't work, because the linker doesn't have to (and in fact doesn't)
- update the @ha and @l references; the loader (which runs after this
- code) will do that.
- Instead, we use the following trick:
- The linker puts the _link-time_ address of _DYNAMIC at the first
- word in the GOT. We could branch to that address, if we wanted,
- by using an @local reloc; the linker works this out, so it's safe
- to use now. We can't, of course, actually branch there, because
- we'd cause an illegal instruction exception; so we need to compute
- the address ourselves. That gives us the following code: */
- /* Get address of the 'b _DYNAMIC@local'... */
- __asm__ ("bcl 20,31,0f;"
- "b _DYNAMIC@local;"
- "0:"
- : "=l"(branchaddr));
- /* So now work out the difference between where the branch actually points,
- and the offset of that location in memory from the start of the file. */
- runtime_dynamic = ((Elf32_Addr) branchaddr
- + ((Elf32_Sword) (*branchaddr << 6 & 0xffffff00) >> 6));
- return runtime_dynamic - elf_machine_dynamic ();
- }
- static __inline__ void
- elf_machine_relative (Elf32_Addr load_off, const Elf32_Addr rel_addr,
- Elf32_Word relative_count)
- {
- Elf32_Rela * rpnt = (void *)rel_addr;
- --rpnt;
- do { /* PowerPC handles pre increment/decrement better */
- Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset);
- *reloc_addr = load_off + rpnt->r_addend;
- } while (--relative_count);
- }
- #define ARCH_NUM 1
- #define DT_PPC_GOT_IDX (DT_NUM + OS_NUM)
- #define ARCH_DYNAMIC_INFO(dpnt, dynamic, debug_addr) \
- do { \
- if (dpnt->d_tag == DT_PPC_GOT) \
- dynamic[DT_PPC_GOT_IDX] = dpnt->d_un.d_ptr; \
- } while (0)
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