diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/dl-machine.c')
-rw-r--r-- | sysdeps/powerpc/powerpc32/dl-machine.c | 538 |
1 files changed, 538 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/dl-machine.c b/sysdeps/powerpc/powerpc32/dl-machine.c new file mode 100644 index 0000000000..28a31f6d91 --- /dev/null +++ b/sysdeps/powerpc/powerpc32/dl-machine.c @@ -0,0 +1,538 @@ +/* Machine-dependent ELF dynamic relocation functions. PowerPC version. + Copyright (C) 1995-2001, 2002 Free Software Foundation, Inc. + 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 Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <unistd.h> +#include <string.h> +#include <sys/param.h> +#include <link.h> +#include <ldsodefs.h> +#include <elf/dynamic-link.h> +#include <dl-machine.h> +#include <stdio-common/_itoa.h> + +/* Because ld.so is now versioned, these functions can be in their own file; + no relocations need to be done to call them. + Of course, if ld.so is not versioned... */ +#if !(DO_VERSIONING - 0) +#error This will not work with versioning turned off, sorry. +#endif + + +/* 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") + +/* Use this when you've modified some code, but it won't be in the + instruction fetch queue (or when it doesn't matter if it is). */ +#define MODIFIED_CODE_NOQUEUE(where) \ + do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); } while (0) +/* Use this when it might be in the instruction queue. */ +#define MODIFIED_CODE(where) \ + do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); PPC_ISYNC; } while (0) + + +/* The idea here is that to conform to the ABI, we are supposed to try + to load dynamic objects between 0x10000 (we actually use 0x40000 as + the lower bound, to increase the chance of a memory reference from + a null pointer giving a segfault) and the program's load address; + this may allow us to use a branch instruction in the PLT rather + than a computed jump. The address is only used as a preference for + mmap, so if we get it wrong the worst that happens is that it gets + mapped somewhere else. */ + +ElfW(Addr) +__elf_preferred_address(struct link_map *loader, size_t maplength, + ElfW(Addr) mapstartpref) +{ + ElfW(Addr) low, high; + struct link_map *l; + + /* If the object has a preference, load it there! */ + if (mapstartpref != 0) + return mapstartpref; + + /* Otherwise, quickly look for a suitable gap between 0x3FFFF and + 0x70000000. 0x3FFFF is so that references off NULL pointers will + cause a segfault, 0x70000000 is just paranoia (it should always + be superceded by the program's load address). */ + low = 0x0003FFFF; + high = 0x70000000; + for (l = GL(dl_loaded); l; l = l->l_next) + { + ElfW(Addr) mapstart, mapend; + mapstart = l->l_map_start & ~(GL(dl_pagesize) - 1); + mapend = l->l_map_end | (GL(dl_pagesize) - 1); + assert (mapend > mapstart); + + /* Prefer gaps below the main executable, note that l == + _dl_loaded does not work for static binaries loading + e.g. libnss_*.so. */ + if ((mapend >= high || l->l_type == lt_executable) + && high >= mapstart) + high = mapstart; + else if (mapend >= low && low >= mapstart) + low = mapend; + else if (high >= mapend && mapstart >= low) + { + if (high - mapend >= mapstart - low) + low = mapend; + else + high = mapstart; + } + } + + high -= 0x10000; /* Allow some room between objects. */ + maplength = (maplength | (GL(dl_pagesize) - 1)) + 1; + if (high <= low || high - low < maplength ) + return 0; + return high - maplength; /* Both high and maplength are page-aligned. */ +} + +/* 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. + Also install a small trampoline to be used by entries that have + been relocated to an address too far away for a single branch. */ + +/* There are many kinds of PLT entries: + + (1) A direct jump to the actual routine, either a relative or + absolute branch. These are set up in __elf_machine_fixup_plt. + + (2) Short lazy entries. These cover the first 8192 slots in + the PLT, and look like (where 'index' goes from 0 to 8191): + + li %r11, index*4 + b &plt[PLT_TRAMPOLINE_ENTRY_WORDS+1] + + (3) Short indirect jumps. These replace (2) when a direct jump + wouldn't reach. They look the same except that the branch + is 'b &plt[PLT_LONGBRANCH_ENTRY_WORDS]'. + + (4) Long lazy entries. These cover the slots when a short entry + won't fit ('index*4' overflows its field), and look like: + + lis %r11, %hi(index*4 + &plt[PLT_DATA_START_WORDS]) + lwzu %r12, %r11, %lo(index*4 + &plt[PLT_DATA_START_WORDS]) + b &plt[PLT_TRAMPOLINE_ENTRY_WORDS] + bctr + + (5) Long indirect jumps. These replace (4) when a direct jump + wouldn't reach. They look like: + + lis %r11, %hi(index*4 + &plt[PLT_DATA_START_WORDS]) + lwz %r12, %r11, %lo(index*4 + &plt[PLT_DATA_START_WORDS]) + mtctr %r12 + bctr + + (6) Long direct jumps. These are used when thread-safety is not + required. They look like: + + lis %r12, %hi(finaladdr) + addi %r12, %r12, %lo(finaladdr) + mtctr %r12 + bctr + + + The lazy entries, (2) and (4), are set up here in + __elf_machine_runtime_setup. (1), (3), and (5) are set up in + __elf_machine_fixup_plt. (1), (3), and (6) can also be constructed + in __process_machine_rela. + + The reason for the somewhat strange construction of the long + entries, (4) and (5), is that we need to ensure thread-safety. For + (1) and (3), this is obvious because only one instruction is + changed and the PPC architecture guarantees that aligned stores are + atomic. For (5), this is more tricky. When changing (4) to (5), + the `b' instruction is first changed to to `mtctr'; this is safe + and is why the `lwzu' instruction is not just a simple `addi'. + Once this is done, and is visible to all processors, the `lwzu' can + safely be changed to a `lwz'. */ +int +__elf_machine_runtime_setup (struct link_map *map, int lazy, int profile) +{ + if (map->l_info[DT_JMPREL]) + { + Elf32_Word i; + Elf32_Word *plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]); + Elf32_Word num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val + / sizeof (Elf32_Rela)); + Elf32_Word rel_offset_words = PLT_DATA_START_WORDS (num_plt_entries); + Elf32_Word data_words = (Elf32_Word) (plt + rel_offset_words); + Elf32_Word size_modified; + + extern void _dl_runtime_resolve (void); + extern void _dl_prof_resolve (void); + + /* Convert the index in r11 into an actual address, and get the + word at that address. */ + plt[PLT_LONGBRANCH_ENTRY_WORDS] = OPCODE_ADDIS_HI (11, 11, data_words); + plt[PLT_LONGBRANCH_ENTRY_WORDS + 1] = OPCODE_LWZ (11, data_words, 11); + + /* Call the procedure at that address. */ + plt[PLT_LONGBRANCH_ENTRY_WORDS + 2] = OPCODE_MTCTR (11); + plt[PLT_LONGBRANCH_ENTRY_WORDS + 3] = OPCODE_BCTR (); + + if (lazy) + { + Elf32_Word *tramp = plt + PLT_TRAMPOLINE_ENTRY_WORDS; + Elf32_Word dlrr = (Elf32_Word)(profile + ? _dl_prof_resolve + : _dl_runtime_resolve); + Elf32_Word offset; + + if (profile && _dl_name_match_p (GL(dl_profile), map)) + /* This is the object we are looking for. Say that we really + want profiling and the timers are started. */ + GL(dl_profile_map) = map; + + /* For the long entries, subtract off data_words. */ + tramp[0] = OPCODE_ADDIS_HI (11, 11, -data_words); + tramp[1] = OPCODE_ADDI (11, 11, -data_words); + + /* Multiply index of entry by 3 (in r11). */ + tramp[2] = OPCODE_SLWI (12, 11, 1); + tramp[3] = OPCODE_ADD (11, 12, 11); + if (dlrr <= 0x01fffffc || dlrr >= 0xfe000000) + { + /* Load address of link map in r12. */ + tramp[4] = OPCODE_LI (12, (Elf32_Word) map); + tramp[5] = OPCODE_ADDIS_HI (12, 12, (Elf32_Word) map); + + /* Call _dl_runtime_resolve. */ + tramp[6] = OPCODE_BA (dlrr); + } + else + { + /* Get address of _dl_runtime_resolve in CTR. */ + tramp[4] = OPCODE_LI (12, dlrr); + tramp[5] = OPCODE_ADDIS_HI (12, 12, dlrr); + tramp[6] = OPCODE_MTCTR (12); + + /* Load address of link map in r12. */ + tramp[7] = OPCODE_LI (12, (Elf32_Word) map); + tramp[8] = OPCODE_ADDIS_HI (12, 12, (Elf32_Word) map); + + /* Call _dl_runtime_resolve. */ + tramp[9] = OPCODE_BCTR (); + } + + /* Set up the lazy PLT entries. */ + offset = PLT_INITIAL_ENTRY_WORDS; + i = 0; + while (i < num_plt_entries && i < PLT_DOUBLE_SIZE) + { + plt[offset ] = OPCODE_LI (11, i * 4); + plt[offset+1] = OPCODE_B ((PLT_TRAMPOLINE_ENTRY_WORDS + 2 + - (offset+1)) + * 4); + i++; + offset += 2; + } + while (i < num_plt_entries) + { + plt[offset ] = OPCODE_LIS_HI (11, i * 4 + data_words); + plt[offset+1] = OPCODE_LWZU (12, i * 4 + data_words, 11); + plt[offset+2] = OPCODE_B ((PLT_TRAMPOLINE_ENTRY_WORDS + - (offset+2)) + * 4); + plt[offset+3] = OPCODE_BCTR (); + i++; + offset += 4; + } + } + + /* Now, we've modified code. We need to write the changes from + the data cache to a second-level unified cache, then make + sure that stale data in the instruction cache is removed. + (In a multiprocessor system, the effect is more complex.) + Most of the PLT shouldn't be in the instruction cache, but + there may be a little overlap at the start and the end. + + Assumes that dcbst and icbi apply to lines of 16 bytes or + more. Current known line sizes are 16, 32, and 128 bytes. */ + + size_modified = lazy ? rel_offset_words : 6; + for (i = 0; i < size_modified; i += 4) + PPC_DCBST (plt + i); + PPC_DCBST (plt + size_modified - 1); + PPC_SYNC; + PPC_ICBI (plt); + PPC_ICBI (plt + size_modified - 1); + PPC_ISYNC; + } + + return lazy; +} + +Elf32_Addr +__elf_machine_fixup_plt(struct link_map *map, const Elf32_Rela *reloc, + Elf32_Addr *reloc_addr, Elf32_Addr finaladdr) +{ + Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr; + if (delta << 6 >> 6 == delta) + *reloc_addr = OPCODE_B (delta); + else if (finaladdr <= 0x01fffffc || finaladdr >= 0xfe000000) + *reloc_addr = OPCODE_BA (finaladdr); + else + { + Elf32_Word *plt, *data_words; + Elf32_Word index, offset, num_plt_entries; + + num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val + / sizeof(Elf32_Rela)); + plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]); + offset = reloc_addr - plt; + index = (offset - PLT_INITIAL_ENTRY_WORDS)/2; + data_words = plt + PLT_DATA_START_WORDS (num_plt_entries); + + reloc_addr += 1; + + if (index < PLT_DOUBLE_SIZE) + { + data_words[index] = finaladdr; + PPC_SYNC; + *reloc_addr = OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1)) + * 4); + } + else + { + index -= (index - PLT_DOUBLE_SIZE)/2; + + data_words[index] = finaladdr; + PPC_SYNC; + + reloc_addr[1] = OPCODE_MTCTR (12); + MODIFIED_CODE_NOQUEUE (reloc_addr + 1); + PPC_SYNC; + + reloc_addr[0] = OPCODE_LWZ (12, + (Elf32_Word) (data_words + index), 11); + } + } + MODIFIED_CODE (reloc_addr); + return finaladdr; +} + +static void +dl_reloc_overflow (struct link_map *map, + const char *name, + Elf32_Addr *const reloc_addr, + const Elf32_Sym *sym, + const Elf32_Sym *refsym) +{ + char buffer[128]; + char *t; + const Elf32_Sym *errsym = sym ?: refsym; + t = stpcpy (buffer, name); + t = stpcpy (t, " relocation at 0x00000000"); + _itoa_word ((unsigned) reloc_addr, t, 16, 0); + if (errsym) + { + const char *strtab; + + strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + t = stpcpy (t, " for symbol `"); + t = stpcpy (t, strtab + errsym->st_name); + t = stpcpy (t, "'"); + } + t = stpcpy (t, " out of range"); + _dl_signal_error (0, map->l_name, NULL, buffer); +} + +void +__process_machine_rela (struct link_map *map, + const Elf32_Rela *reloc, + const Elf32_Sym *sym, + const Elf32_Sym *refsym, + Elf32_Addr *const reloc_addr, + Elf32_Addr const finaladdr, + int rinfo) +{ + switch (rinfo) + { + case R_PPC_NONE: + return; + + case R_PPC_ADDR32: + case R_PPC_UADDR32: + case R_PPC_GLOB_DAT: + case R_PPC_RELATIVE: + *reloc_addr = finaladdr; + return; + + case R_PPC_ADDR24: + if (finaladdr > 0x01fffffc && finaladdr < 0xfe000000) + dl_reloc_overflow (map, "R_PPC_ADDR24", reloc_addr, sym, refsym); + *reloc_addr = (*reloc_addr & 0xfc000003) | (finaladdr & 0x3fffffc); + break; + + case R_PPC_ADDR16: + case R_PPC_UADDR16: + if (finaladdr > 0x7fff && finaladdr < 0x8000) + dl_reloc_overflow (map, "R_PPC_ADDR16", reloc_addr, sym, refsym); + *(Elf32_Half*) reloc_addr = finaladdr; + break; + + case R_PPC_ADDR16_LO: + *(Elf32_Half*) reloc_addr = finaladdr; + break; + + case R_PPC_ADDR16_HI: + *(Elf32_Half*) reloc_addr = finaladdr >> 16; + break; + + case R_PPC_ADDR16_HA: + *(Elf32_Half*) reloc_addr = (finaladdr + 0x8000) >> 16; + break; + + case R_PPC_ADDR14: + case R_PPC_ADDR14_BRTAKEN: + case R_PPC_ADDR14_BRNTAKEN: + if (finaladdr > 0x7fff && finaladdr < 0x8000) + dl_reloc_overflow (map, "R_PPC_ADDR14", reloc_addr, sym, refsym); + *reloc_addr = (*reloc_addr & 0xffff0003) | (finaladdr & 0xfffc); + if (rinfo != R_PPC_ADDR14) + *reloc_addr = ((*reloc_addr & 0xffdfffff) + | ((rinfo == R_PPC_ADDR14_BRTAKEN) + ^ (finaladdr >> 31)) << 21); + break; + + case R_PPC_REL24: + { + Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr; + if (delta << 6 >> 6 != delta) + dl_reloc_overflow (map, "R_PPC_REL24", reloc_addr, sym, refsym); + *reloc_addr = (*reloc_addr & 0xfc000003) | (delta & 0x3fffffc); + } + break; + + case R_PPC_COPY: + if (sym == NULL) + /* This can happen in trace mode when an object could not be + found. */ + return; + if (sym->st_size > refsym->st_size + || (GL(dl_verbose) && sym->st_size < refsym->st_size)) + { + const char *strtab; + + strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + _dl_error_printf ("\ +%s: Symbol `%s' has different size in shared object, onsider re-linking\n", + rtld_progname ?: "<program name unknown>", + strtab + refsym->st_name); + } + memcpy (reloc_addr, (char *) finaladdr, MIN (sym->st_size, + refsym->st_size)); + return; + + case R_PPC_REL32: + *reloc_addr = finaladdr - (Elf32_Word) reloc_addr; + return; + + case R_PPC_JMP_SLOT: + /* It used to be that elf_machine_fixup_plt was used here, + but that doesn't work when ld.so relocates itself + for the second time. On the bright side, there's + no need to worry about thread-safety here. */ + { + Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr; + if (delta << 6 >> 6 == delta) + *reloc_addr = OPCODE_B (delta); + else if (finaladdr <= 0x01fffffc || finaladdr >= 0xfe000000) + *reloc_addr = OPCODE_BA (finaladdr); + else + { + Elf32_Word *plt, *data_words; + Elf32_Word index, offset, num_plt_entries; + + plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]); + offset = reloc_addr - plt; + + if (offset < PLT_DOUBLE_SIZE*2 + PLT_INITIAL_ENTRY_WORDS) + { + index = (offset - PLT_INITIAL_ENTRY_WORDS)/2; + num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val + / sizeof(Elf32_Rela)); + data_words = plt + PLT_DATA_START_WORDS (num_plt_entries); + data_words[index] = finaladdr; + reloc_addr[0] = OPCODE_LI (11, index * 4); + reloc_addr[1] = OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS + - (offset+1)) + * 4); + MODIFIED_CODE_NOQUEUE (reloc_addr + 1); + } + else + { + reloc_addr[0] = OPCODE_LIS_HI (12, finaladdr); + reloc_addr[1] = OPCODE_ADDI (12, 12, finaladdr); + reloc_addr[2] = OPCODE_MTCTR (12); + reloc_addr[3] = OPCODE_BCTR (); + MODIFIED_CODE_NOQUEUE (reloc_addr + 3); + } + } + } + break; + + default: + _dl_reloc_bad_type (map, rinfo, 0); + return; + } + + MODIFIED_CODE_NOQUEUE (reloc_addr); +} |