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Diffstat (limited to 'sysdeps/hppa/dl-machine.h')
| -rw-r--r-- | sysdeps/hppa/dl-machine.h | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/sysdeps/hppa/dl-machine.h b/sysdeps/hppa/dl-machine.h new file mode 100644 index 0000000..e6782b3 --- /dev/null +++ b/sysdeps/hppa/dl-machine.h @@ -0,0 +1,605 @@ +/* Machine-dependent ELF dynamic relocation inline functions. PA-RISC version. + Copyright (C) 1995, 1996, 1997, 1999, 2000 Free Software Foundation, Inc. + Contributed by David Huggins-Daines <dhd@debian.org> + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, write to the Free Software Foundation, Inc., + 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#ifndef dl_machine_h +#define dl_machine_h 1 + +#define ELF_MACHINE_NAME "hppa" + +#include <sys/param.h> +#include <string.h> +#include <link.h> +#include <assert.h> + +/* These must match the definition of the stub in bfd/elf32-hppa.c. */ +#define SIZEOF_PLT_STUB (4*4) +#define GOT_FROM_PLT_STUB (4*4) + +/* A PLABEL is a function descriptor. Properly they consist of just + FUNC and GP. But we want to traverse a binary tree too. See + dl-fptr.c for the code (it may be made common between HPPA and + IA-64 in the future). + + We call these 'fptr' to make it easier to steal code from IA-64. */ + +/* ld.so currently has 12 PLABEL32 relocs. We'll keep this constant + large for now in case we require more, as the rest of these will be + used by the dynamic program itself (libc.so has quite a few + PLABEL32 relocs in it). */ +#define HPPA_BOOT_FPTR_SIZE 256 + +struct hppa_fptr +{ + Elf32_Addr func; + Elf32_Addr gp; + struct hppa_fptr *next; +}; + +extern struct hppa_fptr __boot_ldso_fptr[]; +extern struct hppa_fptr *__fptr_root; +extern int __fptr_count; + +extern Elf32_Addr __hppa_make_fptr (const struct link_map *, Elf32_Addr, + struct hppa_fptr **, struct hppa_fptr *); + +/* Return nonzero iff E_MACHINE is compatible with the running host. */ +static inline int +elf_machine_matches_host (Elf32_Half e_machine) +{ + return e_machine == EM_PARISC; +} + + +/* Return the link-time address of _DYNAMIC. */ +static inline Elf32_Addr +elf_machine_dynamic (void) +{ + Elf32_Addr dynamic; + +#if 0 + /* Use this method if GOT address not yet set up. */ + asm ("\ + b,l 1f,%0 + depi 0,31,2,%0 +1: addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 8),%0 + ldw R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 12)(%%r1),%0" + : "=r" (dynamic) : : "r1"); +#else + /* This works because we already have our GOT address available. */ + dynamic = (Elf32_Addr) &_DYNAMIC; +#endif + + return dynamic; +} + +/* Return the run-time load address of the shared object. */ +static inline Elf32_Addr +elf_machine_load_address (void) +{ + Elf32_Addr dynamic, dynamic_linkaddress; + + asm ("\ + b,l 1f,%0 + depi 0,31,2,%0 +1: addil L'_DYNAMIC - ($PIC_pcrel$0 - 8),%0 + ldo R'_DYNAMIC - ($PIC_pcrel$0 - 12)(%%r1),%1 + addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 16),%0 + ldw R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 20)(%%r1),%0" + : "=r" (dynamic_linkaddress), "=r" (dynamic) : : "r1"); + + return dynamic - dynamic_linkaddress; +} + +/* Fixup a PLT entry to bounce directly to the function at VALUE. */ +static inline Elf32_Addr +elf_machine_fixup_plt (struct link_map *map, lookup_t t, + const Elf32_Rela *reloc, + Elf32_Addr *reloc_addr, Elf32_Addr value) +{ + /* l is the link_map for the caller, t is the link_map for the object + * being called */ + reloc_addr[1] = D_PTR (t, l_info[DT_PLTGOT]); + reloc_addr[0] = value; + /* Return the PLT slot rather than the function value so that the + trampoline can load the new LTP. */ + return (Elf32_Addr) reloc_addr; +} + +/* Return the final value of a plt relocation. */ +static inline Elf32_Addr +elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc, + Elf32_Addr value) +{ + /* We are rela only */ + return value + reloc->r_addend; +} + +/* Set up the loaded object described by L so its unrelocated PLT + entries will jump to the on-demand fixup code in dl-runtime.c. */ + +static inline int +elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) +{ + extern void _dl_runtime_resolve (void); + extern void _dl_runtime_profile (void); + Elf32_Addr jmprel = D_PTR(l, l_info[DT_JMPREL]); + + if (lazy && jmprel) + { + Elf32_Addr *got = NULL; + Elf32_Addr l_addr; + Elf32_Addr end_jmprel; + Elf32_Addr iplt; + + /* Relocate all the PLT slots. */ + l_addr = l->l_addr; + end_jmprel = jmprel + l->l_info[DT_PLTRELSZ]->d_un.d_val; + for (iplt = jmprel; iplt < end_jmprel; iplt += sizeof (Elf32_Rela)) + { + const Elf32_Rela *reloc; + Elf32_Word r_type; + Elf32_Word r_sym; + struct hppa_fptr *fptr; + + reloc = (const Elf32_Rela *) iplt; + r_type = ELF32_R_TYPE (reloc->r_info); + r_sym = ELF32_R_SYM (reloc->r_info); + + if (__builtin_expect (r_type == R_PARISC_IPLT, 1)) + { + fptr = (struct hppa_fptr *) (reloc->r_offset + l_addr); + if (r_sym != 0) + { + /* Relocate the pointer to the stub. */ + fptr->func += l_addr; + /* Instead of the LTP value, we put the reloc offset + here. The trampoline code will load the proper + LTP and pass the reloc offset to the fixup + function. */ + fptr->gp = iplt - jmprel; + if (!got) + { + static union { + unsigned char c[8]; + Elf32_Addr i[2]; + } sig = {{0x00,0xc0,0xff,0xee, 0xde,0xad,0xbe,0xef}}; + + /* Find our .got section. It's right after the + stub. */ + got = (Elf32_Addr *) (fptr->func + GOT_FROM_PLT_STUB); + + /* Sanity check to see if the address we are + going to check below is within a reasonable + approximation of the bounds of the PLT (or, + at least, is at an address that won't fault + on read). Then check for the magic signature + above. */ + if (fptr->func < (Elf32_Addr) fptr + sizeof(*fptr)) + return 0; + if (fptr->func > + ((Elf32_Addr) fptr + + SIZEOF_PLT_STUB + + ((l->l_info[DT_PLTRELSZ]->d_un.d_val / sizeof (Elf32_Rela)) + * 8))) + return 0; + if (got[-2] != sig.i[0] || got[-1] != sig.i[1]) + return 0; /* No lazy linking for you! */ + } + } + else + { + /* Relocate this *ABS* entry. */ + fptr->func = reloc->r_addend + l_addr; + fptr->gp = D_PTR (l, l_info[DT_PLTGOT]); + } + } + else if (__builtin_expect (r_type != R_PARISC_NONE, 0)) + _dl_reloc_bad_type (l, r_type, 1); + } + + if (got) + { + register Elf32_Addr ltp __asm__ ("%r19"); + /* Identify this shared object. */ + got[1] = (Elf32_Addr) l; + + /* This function will be called to perform the relocation. */ + if (__builtin_expect (!profile, 1)) + got[-2] = + (Elf32_Addr) ((struct hppa_fptr *) + ((unsigned long) &_dl_runtime_resolve & ~3))->func; + else + { + if (_dl_name_match_p (_dl_profile, l)) + { + /* This is the object we are looking for. Say that + we really want profiling and the timers are + started. */ + _dl_profile_map = l; + } + got[-2] = + (Elf32_Addr) ((struct hppa_fptr *) + ((unsigned long) &_dl_runtime_profile & ~3))->func; + } + got[-1] = ltp; + } + } + return lazy; +} + +/* Initial entry point code for the dynamic linker. + The C function `_dl_start' is the real entry point; + its return value is the user program's entry point. */ + +#define RTLD_START asm ("\ + .text + .globl _start + .type _start,@function +_start: + /* The kernel does not give us an initial stack frame. */ + ldo 64(%sp),%sp + /* Save the relevant arguments (yes, those are the correct + registers, the kernel is weird) in their stack slots. */ + stw %r25,-40(%sp) /* argc */ + stw %r24,-44(%sp) /* argv */ + + /* We need the LTP, and we need it now. */ + /* $PIC_pcrel$0 points 8 bytes past the current instruction, + just like a branch reloc. This sequence gets us the runtime + address of _DYNAMIC. */ + bl 0f,%r19 + depi 0,31,2,%r19 /* clear priviledge bits */ +0: addil L'_DYNAMIC - ($PIC_pcrel$0 - 8),%r19 + ldo R'_DYNAMIC - ($PIC_pcrel$0 - 12)(%r1),%r26 + + /* Also get the link time address from the first entry of the GOT. */ + addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 16),%r19 + ldw R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 20)(%r1),%r20 + + sub %r26,%r20,%r20 /* Calculate load offset */ + + /* Rummage through the dynamic entries, looking for DT_PLTGOT. */ + ldw,ma 8(%r26),%r19 +1: cmpib,=,n 3,%r19,2f /* tag == DT_PLTGOT? */ + cmpib,<>,n 0,%r19,1b + ldw,ma 8(%r26),%r19 + + /* Uh oh! We didn't find one. Abort. */ + iitlbp %r0,(%r0) + +2: ldw -4(%r26),%r19 /* Found it, load value. */ + add %r19,%r20,%r19 /* And add the load offset. */ + + /* Our initial stack layout is rather different from everyone + else's due to the unique PA-RISC ABI. As far as I know it + looks like this: + + ----------------------------------- (this frame created above) + | 32 bytes of magic | + |---------------------------------| + | 32 bytes argument/sp save area | + |---------------------------------| ((current->mm->env_end) + 63 & ~63) + | N bytes of slack | + |---------------------------------| + | envvar and arg strings | + |---------------------------------| + | ELF auxiliary info | + | (up to 28 words) | + |---------------------------------| + | Environment variable pointers | + | upwards to NULL | + |---------------------------------| + | Argument pointers | + | upwards to NULL | + |---------------------------------| + | argc (1 word) | + ----------------------------------- + + So, obviously, we can't just pass %sp to _dl_start. That's + okay, argv-4 will do just fine. + + The pleasant part of this is that if we need to skip + arguments we can just decrement argc and move argv, because + the stack pointer is utterly unrelated to the location of + the environment and argument vectors. */ + + /* This is always within range so we'll be okay. */ + bl _dl_start,%rp + ldo -4(%r24),%r26 + + /* FALLTHRU */ + .globl _dl_start_user + .type _dl_start_user,@function +_dl_start_user: + /* Save the entry point in %r3. */ + copy %ret0,%r3 + + /* Remember the lowest stack address. */ + addil LT'__libc_stack_end,%r19 + ldw RT'__libc_stack_end(%r1),%r20 + stw %sp,0(%r20) + + /* See if we were called as a command with the executable file + name as an extra leading argument. */ + addil LT'_dl_skip_args,%r19 + ldw RT'_dl_skip_args(%r1),%r20 + ldw 0(%r20),%r20 + + ldw -40(%sp),%r25 /* argc */ + comib,= 0,%r20,.Lnofix /* FIXME: will be mispredicted */ + ldw -44(%sp),%r24 /* argv (delay slot) */ + + sub %r25,%r20,%r25 + stw %r25,-40(%sp) + sh2add %r20,%r24,%r24 + stw %r24,-44(%sp) + +.Lnofix: + /* Call _dl_init(_dl_loaded, argc, argv, envp). */ + addil LT'_dl_loaded,%r19 + ldw RT'_dl_loaded(%r1),%r26 + ldw 0(%r26),%r26 + /* envp = argv + argc + 1 */ + sh2add %r25,%r24,%r23 + bl _dl_init,%r2 + ldo 4(%r23),%r23 /* delay slot */ + + /* Reload argc, argv to the registers start.S expects them in (feh) */ + ldw -40(%sp),%r25 + ldw -44(%sp),%r24 + + /* _dl_fini does have a PLT slot now. I don't know how to get + to it though, so this hack will remain. */ + .section .data +__dl_fini_plabel: + .word _dl_fini + .word 0xdeadbeef + .previous + + addil LT'__dl_fini_plabel,%r19 + ldw RT'__dl_fini_plabel(%r1),%r23 + stw %r19,4(%r23) + bv %r0(%r3) + depi 2,31,2,%r23 /* delay slot */"); + +/* This code gets called via the .plt stub, and is used in + dl-runtime.c to call the `fixup' function and then redirect to the + address it returns. + Enter with r19 = reloc offset, r20 = got-8, r21 = fixup ltp. */ +#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \ + extern void tramp_name (void); \ + asm ( "\ + /* Trampoline for " #tramp_name " */ + .globl " #tramp_name " + .type " #tramp_name ",@function +" #tramp_name ": + /* Save return pointer */ + stw %r2,-20(%sp) + /* Save argument registers in the call stack frame. */ + stw %r26,-36(%sp) + stw %r25,-40(%sp) + stw %r24,-44(%sp) + stw %r23,-48(%sp) + /* Build a call frame. */ + stwm %sp,64(%sp) + + /* Set up args to fixup func. */ + ldw 8+4(%r20),%r26 /* got[1] == struct link_map * */ + copy %r19,%r25 /* reloc offset */ + + /* Call the real address resolver. */ + bl " #fixup_name ",%r2 + copy %r21,%r19 /* delay slot, set fixup func ltp */ + + ldwm -64(%sp),%sp + /* Arguments. */ + ldw -36(%sp),%r26 + ldw -40(%sp),%r25 + ldw -44(%sp),%r24 + ldw -48(%sp),%r23 + /* Return pointer. */ + ldw -20(%sp),%r2 + /* Call the real function. */ + ldw 0(%r28),%r22 + bv %r0(%r22) + ldw 4(%r28),%r19 +"); + +#ifndef PROF +#define ELF_MACHINE_RUNTIME_TRAMPOLINE \ + TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup); \ + TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup); +#else +#define ELF_MACHINE_RUNTIME_TRAMPOLINE \ + TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup); \ + strong_alias (_dl_runtime_resolve, _dl_runtime_profile); +#endif + + +/* Nonzero iff TYPE describes a relocation that should + skip the executable when looking up the symbol value. */ +#define elf_machine_lookup_noexec_p(type) ((type) == R_PARISC_COPY) + +/* Nonzero iff TYPE describes relocation of a PLT entry, so + PLT entries should not be allowed to define the value. */ +#define elf_machine_lookup_noplt_p(type) ((type) == R_PARISC_IPLT \ + || (type) == R_PARISC_EPLT) + +/* Used by ld.so for ... something ... */ +#define ELF_MACHINE_JMP_SLOT R_PARISC_IPLT + +/* We only use RELA. */ +#define ELF_MACHINE_NO_REL 1 + +#endif /* !dl_machine_h */ + +/* These are only actually used where RESOLVE_MAP is defined, anyway. */ +#ifdef RESOLVE_MAP + +static inline void +elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc, + const Elf32_Sym *sym, const struct r_found_version *version, + Elf32_Addr *const reloc_addr) +{ + const Elf32_Sym *const refsym = sym; + unsigned long const r_type = ELF32_R_TYPE (reloc->r_info); + struct link_map *sym_map; + Elf32_Addr value; + +#ifndef RTLD_BOOTSTRAP + /* This is defined in rtld.c, but nowhere in the static libc.a; make the + reference weak so static programs can still link. This declaration + cannot be done when compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) + because rtld.c contains the common defn for _dl_rtld_map, which is + incompatible with a weak decl in the same file. */ + weak_extern (_dl_rtld_map); +#endif + + /* RESOLVE_MAP will return a null value for undefined syms, and + non-null for all other syms. In particular, relocs with no + symbol (symbol index of zero), also called *ABS* relocs, will be + resolved to MAP. (The first entry in a symbol table is all + zeros, and an all zero Elf32_Sym has a binding of STB_LOCAL.) + See RESOLVE_MAP definition in elf/dl-reloc.c */ +#ifdef RTLD_BOOTSTRAP + /* RESOLVE_MAP in rtld.c doesn't have the local sym test. */ + sym_map = (ELF32_ST_BIND (sym->st_info) != STB_LOCAL + ? RESOLVE_MAP (&sym, version, r_type) : map); +#else + sym_map = RESOLVE_MAP (&sym, version, r_type); +#endif + if (sym_map) + { + value = sym ? sym_map->l_addr + sym->st_value : 0; + value += reloc->r_addend; + } + else + value = 0; + + switch (r_type) + { + case R_PARISC_DIR32: +#ifndef RTLD_BOOTSTRAP + /* All hell breaks loose if we try to relocate these twice, + because any initialized variables in ld.so that refer to + other ones will have their values reset. In particular, + __fptr_next will be reset, sometimes causing endless loops in + __hppa_make_fptr(). So don't do that. */ + if (map == &_dl_rtld_map) + return; +#endif + /* Otherwise, nothing more to do here. */ + break; + + case R_PARISC_PLABEL32: + /* Easy rule: If there is a symbol and it is global, then we + need to make a dynamic function descriptor. Otherwise we + have the address of a PLT slot for a local symbol which we + know to be unique. */ + if (sym == NULL + || sym_map == NULL + || ELF32_ST_BIND (sym->st_info) == STB_LOCAL) + break; + + /* Okay, we need to make ourselves a PLABEL then. See the IA64 + code for an explanation of how this works. */ +#ifndef RTLD_BOOTSTRAP + value = __hppa_make_fptr (sym_map, value, &__fptr_root, NULL); +#else + { + struct hppa_fptr *p_boot_ldso_fptr; + struct hppa_fptr **p_fptr_root; + int *p_fptr_count; + unsigned long dot; + + /* Go from the top of __boot_ldso_fptr. As on IA64, we + probably haven't relocated the necessary values by this + point so we have to find them ourselves. */ + + asm ("bl 0f,%0 + depi 0,31,2,%0 +0: addil L'__boot_ldso_fptr - ($PIC_pcrel$0 - 8),%0 + ldo R'__boot_ldso_fptr - ($PIC_pcrel$0 - 12)(%%r1),%1 + addil L'__fptr_root - ($PIC_pcrel$0 - 16),%0 + ldo R'__fptr_root - ($PIC_pcrel$0 - 20)(%%r1),%2 + addil L'__fptr_count - ($PIC_pcrel$0 - 24),%0 + ldo R'__fptr_count - ($PIC_pcrel$0 - 28)(%%r1),%3" + : + "=r" (dot), + "=r" (p_boot_ldso_fptr), + "=r" (p_fptr_root), + "=r" (p_fptr_count)); + + value = __hppa_make_fptr (sym_map, value, p_fptr_root, + &p_boot_ldso_fptr[--*p_fptr_count]); + } +#endif + break; + + case R_PARISC_IPLT: + if (__builtin_expect (sym_map != NULL, 1)) + elf_machine_fixup_plt (NULL, sym_map, reloc, reloc_addr, value); + else + { + /* If we get here, it's a (weak) undefined sym. */ + elf_machine_fixup_plt (NULL, map, reloc, reloc_addr, value); + } + return; + + case R_PARISC_COPY: + if (__builtin_expect (sym == NULL, 0)) + /* This can happen in trace mode if an object could not be + found. */ + break; + if (__builtin_expect (sym->st_size > refsym->st_size, 0) + || (__builtin_expect (sym->st_size < refsym->st_size, 0) + && __builtin_expect (_dl_verbose, 0))) + { + const char *strtab; + + strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]); + _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", + ": Symbol `", strtab + refsym->st_name, + "' has different size in shared object, " + "consider re-linking\n", NULL); + } + memcpy (reloc_addr, (void *) value, + MIN (sym->st_size, refsym->st_size)); + return; + + case R_PARISC_NONE: /* Alright, Wilbur. */ + return; + + default: + _dl_reloc_bad_type (map, r_type, 0); + } + + *reloc_addr = value; +} + +static inline void +elf_machine_lazy_rel (struct link_map *map, + Elf32_Addr l_addr, const Elf32_Rela *reloc) +{ + /* We don't have anything to do here. elf_machine_runtime_setup has + done all the relocs already. */ +} + +#endif /* RESOLVE_MAP */ |