diff options
Diffstat (limited to 'sysdeps/powerpc/dl-machine.h')
| -rw-r--r-- | sysdeps/powerpc/dl-machine.h | 152 |
1 files changed, 79 insertions, 73 deletions
diff --git a/sysdeps/powerpc/dl-machine.h b/sysdeps/powerpc/dl-machine.h index 917e4f7970..771b711a14 100644 --- a/sysdeps/powerpc/dl-machine.h +++ b/sysdeps/powerpc/dl-machine.h @@ -149,33 +149,34 @@ elf_machine_load_address (void) #define elf_machine_relplt elf_machine_rela /* This code is used in dl-runtime.c to call the `fixup' function - and then redirect to the address it returns. It is called - from code built in the PLT by elf_machine_runtime_setup. */ + and then redirect to the address it returns. It is called + from code built in the PLT by elf_machine_runtime_setup. */ #define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ .section \".text\" .align 2 .globl _dl_runtime_resolve .type _dl_runtime_resolve,@function _dl_runtime_resolve: - # We need to save the registers used to pass parameters. - # We build a stack frame to put them in. + # We need to save the registers used to pass parameters, and register 0, + # which is used by _mcount; the registers are saved in a stack frame. stwu 1,-48(1) - mflr 0 + stw 0,12(1) stw 3,16(1) stw 4,20(1) - stw 0,52(1) + # The code that calls this has put parameters for `fixup' in r12 and r11. + mr 3,12 stw 5,24(1) - # We also need to save some of the condition register fields. - mfcr 0 + mr 4,11 stw 6,28(1) + mflr 0 + # We also need to save some of the condition register fields. stw 7,32(1) + stw 0,52(1) stw 8,36(1) + mfcr 0 stw 9,40(1) stw 10,44(1) - stw 0,12(1) - # The code that calls this has put parameters for `fixup' in r12 and r11. - mr 3,12 - mr 4,11 + stw 0,8(1) bl fixup@local # 'fixup' returns the address we want to branch to. mtctr 3 @@ -184,20 +185,21 @@ _dl_runtime_resolve: lwz 10,44(1) lwz 9,40(1) mtlr 0 - lwz 0,12(1) lwz 8,36(1) + lwz 0,8(1) lwz 7,32(1) lwz 6,28(1) mtcrf 0xFF,0 lwz 5,24(1) lwz 4,20(1) lwz 3,16(1) + lwz 0,12(1) # ...unwind the stack frame, and jump to the PLT entry we updated. addi 1,1,48 bctr 0: .size _dl_runtime_resolve,0b-_dl_runtime_resolve - # undo '.section text'. + # Undo '.section text'. .previous "); @@ -213,20 +215,20 @@ asm ("\ .type _start,@function _start: # We start with the following on the stack, from top: - # argc (4 bytes) - # arguments for program (terminated by NULL) - # environment variables (terminated by NULL) - # arguments for the program loader + # argc (4 bytes); + # arguments for program (terminated by NULL); + # environment variables (terminated by NULL); + # arguments for the program loader. # FIXME: perhaps this should do the same trick as elf/start.c? # Call _dl_start with one parameter pointing at argc - mr 3,1 + mr 3,1 # (we have to frob the stack pointer a bit to allow room for # _dl_start to save the link register) - li 4,0 + li 4,0 addi 1,1,-16 - stw 4,0(1) - bl _dl_start@local + stw 4,0(1) + bl _dl_start@local # Now, we do our main work of calling initialisation procedures. # The ELF ABI doesn't say anything about parameters for these, @@ -234,70 +236,72 @@ _start: # Changing these is strongly discouraged (not least because argc is # passed by value!). - # put our GOT pointer in r31 - bl _GLOBAL_OFFSET_TABLE_-4@local + # Put our GOT pointer in r31, + bl _GLOBAL_OFFSET_TABLE_-4@local mflr 31 - # the address of _start in r30 - mr 30,3 - # &_dl_argc in 29, &_dl_argv in 27, and _dl_default_scope in 28 - lwz 28,_dl_default_scope@got(31) - lwz 29,_dl_argc@got(31) - lwz 27,_dl_argv@got(31) + # the address of _start in r30, + mr 30,3 + # &_dl_argc in 29, &_dl_argv in 27, and _dl_default_scope in 28. + lwz 28,_dl_default_scope@got(31) + lwz 29,_dl_argc@got(31) + lwz 27,_dl_argv@got(31) 0: - # call initfunc = _dl_init_next(_dl_default_scope[2]) - lwz 3,8(28) - bl _dl_init_next@plt - # if initfunc is NULL, we exit the loop - mr. 0,3 - beq 1f + # Set initfunc = _dl_init_next(_dl_default_scope[2]) + lwz 3,8(28) + bl _dl_init_next@plt + # If initfunc is NULL, we exit the loop; otherwise, + cmpwi 3,0 + beq 1f # call initfunc(_dl_argc, _dl_argv, _dl_argv+_dl_argc+1) - mtlr 0 - lwz 3,0(29) - lwz 4,0(27) + mtlr 3 + lwz 3,0(29) + lwz 4,0(27) slwi 5,3,2 - add 5,4,5 + add 5,4,5 addi 5,5,4 blrl # and loop. - b 0b + b 0b 1: # Now, to conform to the ELF ABI, we have to: - # pass argv (actually _dl_argv) in r4 - lwz 4,0(27) - # pass argc (actually _dl_argc) in r3 - lwz 3,0(29) - # pass envp (actually _dl_argv+_dl_argc+1) in r5 + # Pass argc (actually _dl_argc) in r3; + lwz 3,0(29) + # pass argv (actually _dl_argv) in r4; + lwz 4,0(27) + # pass envp (actually _dl_argv+_dl_argc+1) in r5; slwi 5,3,2 - add 5,4,5 - addi 5,5,4 - # pass the auxilary vector in r6. This is passed just after _envp. - addi 6,5,-4 + add 6,4,5 + addi 5,6,4 + # pass the auxilary vector in r6. This is passed to us just after _envp. 2: lwzu 0,4(6) - cmpwi 1,0,0 - bne 2b + cmpwi 0,0,0 + bne 2b addi 6,6,4 - # pass a termination function pointer (in this case _dl_fini) in r7 - lwz 7,_dl_fini@got(31) - # now, call the start function in r30... + # Pass a termination function pointer (in this case _dl_fini) in r7. + lwz 7,_dl_fini@got(31) + # Now, call the start function in r30... mtctr 30 - # pass the stack pointer in r1 (so far so good), pointing to a NULL value - # (this lets our startup code distinguish between a program linked statically, + lwz 26,_dl_starting_up@got(31) + # Pass the stack pointer in r1 (so far so good), pointing to a NULL value. + # (This lets our startup code distinguish between a program linked statically, # which linux will call with argc on top of the stack which will hopefully # never be zero, and a dynamically linked program which will always have # a NULL on the top of the stack). # Take the opportunity to clear LR, so anyone who accidentally returns - # from _start gets SEGV. - li 0,0 - stw 0,0(1) - mtlr 0 - # and also clear _dl_starting_up - lwz 26,_dl_starting_up@got(31) - stw 0,0(26) - # go do it! + # from _start gets SEGV. Also clear the next few words of the stack. + li 31,0 + stw 31,0(1) + mtlr 31 + stw 31,4(1) + stw 31,8(1) + stw 31,12(1) + # Clear _dl_starting_up. + stw 31,0(26) + # Go do it! bctr 0: .size _start,0b-_start - # undo '.section text'. + # Undo '.section text'. .previous "); @@ -346,7 +350,7 @@ static ElfW(Addr) _dl_preferred_address = 1 /* We require the address of the PLT entry returned from fixup, not the first word of the PLT entry. */ -#define ELF_FIXUP_RETURN_VALUE(map, result) (&(result)) +#define ELF_FIXUP_RETURN_VALUE(map, result) ((Elf32_Addr) &(result)) /* Nonzero iff TYPE should not be allowed to resolve to one of the main executable's symbols, as for a COPY reloc. */ @@ -396,7 +400,7 @@ elf_machine_runtime_setup (struct link_map *map, int lazy, int profile) { if (map->l_info[DT_JMPREL]) { - int i; + Elf32_Word i; /* Fill in the PLT. Its initial contents are directed to a function earlier in the PLT which arranges for the dynamic linker to be called back. */ @@ -516,10 +520,10 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, { #ifndef RTLD_BOOTSTRAP const Elf32_Sym *const refsym = sym; + extern char **_dl_argv; #endif Elf32_Word loadbase, finaladdr; const int rinfo = ELF32_R_TYPE (reloc->r_info); - extern char **_dl_argv; if (rinfo == R_PPC_NONE) return; @@ -551,9 +555,9 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, + reloc->r_addend); } - /* This is an if/else if chain because GCC 2.7.2.[012] turns case - statements into non-PIC table lookups. When a later version - comes out that fixes this, this should be changed. */ + /* This is still an if/else if chain because GCC uses the GOT to find + the table for table-based switch statements, and we haven't set it + up yet. */ if (rinfo == R_PPC_UADDR32 || rinfo == R_PPC_GLOB_DAT || rinfo == R_PPC_ADDR32 || @@ -561,6 +565,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, { *reloc_addr = finaladdr; } +#ifndef RTLD_BOOTSTRAP else if (rinfo == R_PPC_ADDR16_LO) { *(Elf32_Half*) reloc_addr = finaladdr; @@ -573,7 +578,6 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, { *(Elf32_Half*) reloc_addr = (finaladdr + 0x8000) >> 16; } -#ifndef RTLD_BOOTSTRAP else if (rinfo == R_PPC_REL24) { Elf32_Sword delta = finaladdr - (Elf32_Word) (char *) reloc_addr; @@ -693,12 +697,14 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, #endif } +#ifndef RTLD_BOOTSTRAP if (rinfo == R_PPC_ADDR16_LO || rinfo == R_PPC_ADDR16_HI || rinfo == R_PPC_ADDR16_HA || rinfo == R_PPC_REL24 || rinfo == R_PPC_ADDR24) MODIFIED_CODE_NOQUEUE (reloc_addr); +#endif } #define ELF_MACHINE_NO_REL 1 |