l4/pkg/l4re-core/uclibc/lib/contrib/uclibc/ldso/ldso/mips/dl-sysdep.h

   1 /* vi: set sw=8 ts=8: */
   2
   3 /*
   4  * Various assembly language/system dependent hacks that are required
   5  * so that we can minimize the amount of platform specific code.
   6  */
   7
   8 /* Define this if the system uses RELOCA.  */
   9 #undef ELF_USES_RELOCA
  10 #include <elf.h>
  11
  12 #ifdef __mips64 /* from glibc sysdeps/mips/elf/ldsodefs.h 1.4 */
  13 /* The 64-bit MIPS ELF ABI uses an unusual reloc format.  Each
  14    relocation entry specifies up to three actual relocations, all at
  15    the same address.  The first relocation which required a symbol
  16    uses the symbol in the r_sym field.  The second relocation which
  17    requires a symbol uses the symbol in the r_ssym field.  If all
  18    three relocations require a symbol, the third one uses a zero
  19    value.
  20
  21    We define these structures in internal headers because we're not
  22    sure we want to make them part of the ABI yet.  Eventually, some of
  23    this may move into elf/elf.h.  */
  24
  25 /* An entry in a 64 bit SHT_REL section.  */
  26
  27 typedef struct
  28 {
  29   Elf32_Word    r_sym;          /* Symbol index */
  30   unsigned char r_ssym;         /* Special symbol for 2nd relocation */
  31   unsigned char r_type3;        /* 3rd relocation type */
  32   unsigned char r_type2;        /* 2nd relocation type */
  33   unsigned char r_type1;        /* 1st relocation type */
  34 } _Elf64_Mips_R_Info;
  35
  36 typedef union
  37 {
  38   Elf64_Xword   r_info_number;
  39   _Elf64_Mips_R_Info r_info_fields;
  40 } _Elf64_Mips_R_Info_union;
  41
  42 typedef struct
  43 {
  44   Elf64_Addr    r_offset;               /* Address */
  45   _Elf64_Mips_R_Info_union r_info;      /* Relocation type and symbol index */
  46 } Elf64_Mips_Rel;
  47
  48 typedef struct
  49 {
  50   Elf64_Addr    r_offset;               /* Address */
  51   _Elf64_Mips_R_Info_union r_info;      /* Relocation type and symbol index */
  52   Elf64_Sxword  r_addend;               /* Addend */
  53 } Elf64_Mips_Rela;
  54
  55 #define ELF64_MIPS_R_SYM(i) \
  56   ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_sym)
  57 #define ELF64_MIPS_R_TYPE(i) \
  58   (((_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_type1 \
  59    | ((Elf32_Word)(__extension__ (_Elf64_Mips_R_Info_union)(i) \
  60                    ).r_info_fields.r_type2 << 8) \
  61    | ((Elf32_Word)(__extension__ (_Elf64_Mips_R_Info_union)(i) \
  62                    ).r_info_fields.r_type3 << 16) \
  63    | ((Elf32_Word)(__extension__ (_Elf64_Mips_R_Info_union)(i) \
  64                    ).r_info_fields.r_ssym << 24))
  65 #define ELF64_MIPS_R_INFO(sym, type) \
  66   (__extension__ (_Elf64_Mips_R_Info_union) \
  67    (__extension__ (_Elf64_Mips_R_Info) \
  68    { (sym), ELF64_MIPS_R_SSYM (type), \
  69        ELF64_MIPS_R_TYPE3 (type), \
  70        ELF64_MIPS_R_TYPE2 (type), \
  71        ELF64_MIPS_R_TYPE1 (type) \
  72    }).r_info_number)
  73 /* These macros decompose the value returned by ELF64_MIPS_R_TYPE, and
  74    compose it back into a value that it can be used as an argument to
  75    ELF64_MIPS_R_INFO.  */
  76 #define ELF64_MIPS_R_SSYM(i) (((i) >> 24) & 0xff)
  77 #define ELF64_MIPS_R_TYPE3(i) (((i) >> 16) & 0xff)
  78 #define ELF64_MIPS_R_TYPE2(i) (((i) >> 8) & 0xff)
  79 #define ELF64_MIPS_R_TYPE1(i) ((i) & 0xff)
  80 #define ELF64_MIPS_R_TYPEENC(type1, type2, type3, ssym) \
  81   ((type1) \
  82    | ((Elf32_Word)(type2) << 8) \
  83    | ((Elf32_Word)(type3) << 16) \
  84    | ((Elf32_Word)(ssym) << 24))
  85
  86 #undef ELF64_R_SYM
  87 #define ELF64_R_SYM(i) ELF64_MIPS_R_SYM (i)
  88 #undef ELF64_R_TYPE
  89 #define ELF64_R_TYPE(i) ELF64_MIPS_R_TYPE (i)
  90 #undef ELF64_R_INFO
  91 #define ELF64_R_INFO(sym, type) ELF64_MIPS_R_INFO ((sym), (type))
  92 #endif  /* __mips64 */
  93
  94 #include <link.h>
  95
  96 #define ARCH_NUM 4
  97 #define DT_MIPS_GOTSYM_IDX      (DT_NUM + OS_NUM)
  98 #define DT_MIPS_LOCAL_GOTNO_IDX (DT_NUM + OS_NUM +1)
  99 #define DT_MIPS_SYMTABNO_IDX    (DT_NUM + OS_NUM +2)
 100 #define DT_MIPS_PLTGOT_IDX      (DT_NUM + OS_NUM +3)
 101
 102 #define ARCH_DYNAMIC_INFO(dpnt,  dynamic, debug_addr) \
 103 do { \
 104 if (dpnt->d_tag == DT_MIPS_GOTSYM) \
 105      dynamic[DT_MIPS_GOTSYM_IDX] = dpnt->d_un.d_val; \
 106 else if (dpnt->d_tag == DT_MIPS_LOCAL_GOTNO) \
 107      dynamic[DT_MIPS_LOCAL_GOTNO_IDX] = dpnt->d_un.d_val; \
 108 else if (dpnt->d_tag == DT_MIPS_SYMTABNO) \
 109      dynamic[DT_MIPS_SYMTABNO_IDX] = dpnt->d_un.d_val; \
 110 else if (dpnt->d_tag == DT_MIPS_PLTGOT) \
 111      dynamic[DT_MIPS_PLTGOT_IDX] = dpnt->d_un.d_val; \
 112 else if ((dpnt->d_tag == DT_MIPS_RLD_MAP) && (dpnt->d_un.d_ptr)) \
 113      *(ElfW(Addr) *)(dpnt->d_un.d_ptr) =  (ElfW(Addr)) debug_addr; \
 114 } while (0)
 115
 116 #define ARCH_SKIP_RELOC(type_class, sym) \
 117      ((sym)->st_shndx == SHN_UNDEF && !((sym)->st_other & STO_MIPS_PLT))
 118
 119 /* Initialization sequence for the application/library GOT.  */
 120 #define INIT_GOT(GOT_BASE,MODULE)                                               \
 121 do {                                                                            \
 122         unsigned long idx;                                                      \
 123         unsigned long *pltgot;                                                  \
 124                                                                                 \
 125         /* Check if this is the dynamic linker itself */                        \
 126         if (MODULE->libtype == program_interpreter)                             \
 127                 continue;                                                       \
 128                                                                                 \
 129         /* Fill in first two GOT entries according to the ABI */                \
 130         GOT_BASE[0] = (unsigned long) _dl_runtime_resolve;                      \
 131         GOT_BASE[1] = (unsigned long) MODULE;                                   \
 132                                                                                 \
 133         pltgot = (unsigned long *) MODULE->dynamic_info[DT_MIPS_PLTGOT_IDX];    \
 134         if (pltgot) {                                                           \
 135                 pltgot[0] = (unsigned long) _dl_runtime_pltresolve;             \
 136                 pltgot[1] = (unsigned long) MODULE;                             \
 137         }                                                                       \
 138                                                                                 \
 139         /* Add load address displacement to all local GOT entries */            \
 140         idx = 2;                                                                        \
 141         while (idx < MODULE->dynamic_info[DT_MIPS_LOCAL_GOTNO_IDX])             \
 142                 GOT_BASE[idx++] += (unsigned long) MODULE->loadaddr;            \
 143                                                                                 \
 144 } while (0)
 145
 146
 147 /* Here we define the magic numbers that this dynamic loader should accept */
 148 #define MAGIC1 EM_MIPS
 149 #define MAGIC2 EM_MIPS_RS3_LE
 150
 151
 152 /* Used for error messages */
 153 #define ELF_TARGET "MIPS"
 154
 155 /* Need bootstrap relocations */
 156 #define ARCH_NEEDS_BOOTSTRAP_RELOCS
 157
 158 unsigned long __dl_runtime_resolve(unsigned long sym_index,
 159         unsigned long old_gpreg);
 160
 161 struct elf_resolve;
 162 unsigned long __dl_runtime_pltresolve(struct elf_resolve *tpnt,
 163         int reloc_entry);
 164
 165 void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt, int lazy);
 166
 167 /* 4096 bytes alignment */
 168 #if _MIPS_SIM == _MIPS_SIM_ABI64
 169 #define OFFS_ALIGN (0x10000000000UL-0x1000)
 170 #endif  /* O32 || N32 */
 171
 172 #if defined USE_TLS
 173 # if _MIPS_SIM == _MIPS_SIM_ABI64
 174 # define elf_machine_type_class(type)                                   \
 175   ((((type) == R_MIPS_JUMP_SLOT || (type) == R_MIPS_TLS_DTPMOD64        \
 176      || (type) == R_MIPS_TLS_DTPREL64 || (type) == R_MIPS_TLS_TPREL64)  \
 177     * ELF_RTYPE_CLASS_PLT)                                              \
 178    | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
 179 # else
 180 # define elf_machine_type_class(type)                                   \
 181   ((((type) == R_MIPS_JUMP_SLOT || (type) == R_MIPS_TLS_DTPMOD32        \
 182      || (type) == R_MIPS_TLS_DTPREL32 || (type) == R_MIPS_TLS_TPREL32)  \
 183     * ELF_RTYPE_CLASS_PLT)                                              \
 184    | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
 185 # endif /* _MIPS_SIM == _MIPS_SIM_ABI64 */
 186 #else
 187 #define elf_machine_type_class(type)                                    \
 188   ((((type) == R_MIPS_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT)                 \
 189    | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
 190 #endif /* USE_TLS */
 191
 192 #define OFFSET_GP_GOT 0x7ff0
 193
 194 static __always_inline ElfW(Addr) *
 195 elf_mips_got_from_gpreg (ElfW(Addr) gpreg)
 196 {
 197         /* FIXME: the offset of gp from GOT may be system-dependent. */
 198         return (ElfW(Addr) *) (gpreg - OFFSET_GP_GOT);
 199 }
 200
 201 /* Return the link-time address of _DYNAMIC.  Conveniently, this is the
 202    first element of the GOT.  This must be inlined in a function which
 203    uses global data.  We assume its $gp points to the primary GOT.  */
 204 static __always_inline ElfW(Addr)
 205 elf_machine_dynamic (void)
 206 {
 207         register ElfW(Addr) gp __asm__ ("$28");
 208         return *elf_mips_got_from_gpreg (gp);
 209 }
 210
 211 #define STRINGXP(X) __STRING(X)
 212 #define STRINGXV(X) STRINGV_(X)
 213 #define STRINGV_(...) # __VA_ARGS__
 214 #if _MIPS_SIM == _MIPS_SIM_ABI64
 215 #define PTR_LA               dla
 216 #define PTR_SUBU     dsubu
 217 #else
 218 #define PTR_LA               la
 219 #define PTR_SUBU     subu
 220 #endif
 221
 222 /* Return the run-time load address of the shared object.  */
 223 static __always_inline ElfW(Addr)
 224 elf_machine_load_address (void)
 225 {
 226         ElfW(Addr) addr;
 227         __asm__ ("        .set noreorder\n"
 228              "        " STRINGXP (PTR_LA) " %0, 0f\n"
 229              "        bltzal $0, 0f\n"
 230              "        nop\n"
 231              "0:      " STRINGXP (PTR_SUBU) " %0, $31, %0\n"
 232              "        .set reorder\n"
 233              :        "=r" (addr)
 234              :        /* No inputs */
 235              :        "$31");
 236         return addr;
 237 }
 238
 239 static __always_inline void
 240 elf_machine_relative (ElfW(Addr) load_off, const ElfW(Addr) rel_addr,
 241                       ElfW(Word) relative_count)
 242 {
 243         /* No RELATIVE relocs in MIPS? */
 244 }
 245
 246 #ifdef __mips64
 247 #define DL_MALLOC_ALIGN 8       /* N64/N32 needs 8 byte alignment */
 248 #endif