arm: Remove lazy tlsdesc initialization related code
Lazy tlsdesc initialization is no longer used in the dynamic linker so all related code can be removed. * sysdeps/arm/dl-machine.h (elf_machine_runtime_setup): Remove DT_TLSDESC_GOT initialization. * sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_lazy_resolver): Remove. (_dl_tlsdesc_resolve_hold): Likewise. * sysdeps/aarch64/dl-tlsdesc.h (_dl_tlsdesc_lazy_resolver): Remove. (_dl_tlsdesc_resolve_hold): Likewise. * sysdeps/aarch64/tlsdesc.c (_dl_tlsdesc_lazy_resolver_fixup): Remove. (_dl_tlsdesc_resolve_hold_fixup): Likewise.
This commit is contained in:
Szabolcs Nagy
parent
28e1ddf340
commit
94d2f0af15
11
ChangeLog
11
ChangeLog
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@ -1,3 +1,14 @@
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2017-11-03 Szabolcs Nagy <szabolcs.nagy@arm.com>
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* sysdeps/arm/dl-machine.h (elf_machine_runtime_setup): Remove
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DT_TLSDESC_GOT initialization.
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* sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_lazy_resolver): Remove.
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(_dl_tlsdesc_resolve_hold): Likewise.
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* sysdeps/aarch64/dl-tlsdesc.h (_dl_tlsdesc_lazy_resolver): Remove.
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(_dl_tlsdesc_resolve_hold): Likewise.
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* sysdeps/aarch64/tlsdesc.c (_dl_tlsdesc_lazy_resolver_fixup): Remove.
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(_dl_tlsdesc_resolve_hold_fixup): Likewise.
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2017-11-03 Szabolcs Nagy <szabolcs.nagy@arm.com>
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* sysdeps/arm/dl-machine.h (elf_machine_rel): Remove volatile.
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@ -127,10 +127,6 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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got[2] = (Elf32_Addr) &_dl_runtime_resolve;
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}
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if (l->l_info[ADDRIDX (DT_TLSDESC_GOT)] && lazy)
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*(Elf32_Addr*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_GOT)]) + l->l_addr)
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= (Elf32_Addr) &_dl_tlsdesc_lazy_resolver;
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return lazy;
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}
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@ -132,87 +132,3 @@ _dl_tlsdesc_dynamic:
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cfi_endproc
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.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
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#endif /* SHARED */
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/* lazy resolved for tls descriptors. */
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.hidden _dl_tlsdesc_lazy_resolver
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.global _dl_tlsdesc_lazy_resolver
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.type _dl_tlsdesc_lazy_resolver,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_lazy_resolver:
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/* r0 points at the tlsdesc,
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r1 points at the GOT
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r2 was pushed by the trampoline and used as a temp,
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we need to pop it here.
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We push the remaining call-clobbered registers here, and also
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R1 -- to keep the stack correctly aligned. */
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/* Tell the unwinder that r2 has already been pushed. */
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eabi_save ({r2})
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (r2, 0)
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eabi_save ({r0,r1,r3,ip,lr})
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push {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (20)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r3, 8)
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cfi_rel_offset (ip, 12)
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cfi_rel_offset (lr, 16)
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bl _dl_tlsdesc_lazy_resolver_fixup
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pop {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (-20)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r1)
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cfi_restore (r0)
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pop {r2}
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cfi_adjust_cfa_offset (-4)
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cfi_restore (r2)
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ldr r1, [r0, #4]
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BX (r1)
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
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/* Holder for lazy tls descriptors being resolve in another thread.
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Our calling convention is to clobber r0, r1 and the processor
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flags. All others that are modified must be saved */
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.hidden _dl_tlsdesc_resolve_hold
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.global _dl_tlsdesc_resolve_hold
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.type _dl_tlsdesc_resolve_hold,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_resolve_hold:
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/* r0 is saved so its original value can be used after the call and
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r1 is saved only to keep the stack aligned. (r0 points to the tls
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descriptor, it is passed to _dl_tlsdesc_resolve_hold_fixup which
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is a void function that may clobber r0, later r0 is used to load
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the new resolver.) */
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eabi_save ({r0,r1,r2,r3,ip,lr})
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push {r0, r1, r2, r3, ip, lr}
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cfi_adjust_cfa_offset (24)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r2, 8)
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cfi_rel_offset (r3, 12)
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cfi_rel_offset (ip, 16)
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cfi_rel_offset (lr, 20)
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adr r1, _dl_tlsdesc_resolve_hold
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bl _dl_tlsdesc_resolve_hold_fixup
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pop {r0, r1, r2, r3, ip, lr}
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cfi_adjust_cfa_offset (-24)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r2)
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cfi_restore (r1)
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cfi_restore (r0)
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ldr r1, [r0, #4]
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BX (r1)
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
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@ -48,9 +48,7 @@ struct tlsdesc_dynamic_arg
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extern ptrdiff_t attribute_hidden
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_dl_tlsdesc_return(struct tlsdesc *),
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_dl_tlsdesc_undefweak(struct tlsdesc *),
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_dl_tlsdesc_resolve_hold(struct tlsdesc *),
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_dl_tlsdesc_lazy_resolver(struct tlsdesc *);
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_dl_tlsdesc_undefweak(struct tlsdesc *);
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# ifdef SHARED
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extern void *_dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset);
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@ -16,130 +16,13 @@
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <link.h>
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#include <ldsodefs.h>
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#include <elf/dynamic-link.h>
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#include <tls.h>
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#include <dl-tlsdesc.h>
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#include <dl-unmap-segments.h>
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#define _dl_tlsdesc_resolve_hold 0
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#include <tlsdeschtab.h>
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/* This function is used to lazily resolve TLS_DESC REL relocations
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Besides the TLS descriptor itself, we get the module's got address
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as the second parameter. */
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void
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attribute_hidden
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_dl_tlsdesc_lazy_resolver_fixup (struct tlsdesc volatile *td,
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Elf32_Addr *got)
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{
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struct link_map *l = (struct link_map *)got[1];
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lookup_t result;
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unsigned long value;
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if (_dl_tlsdesc_resolve_early_return_p
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(td, (void*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_PLT)]) + l->l_addr)))
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return;
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if (td->argument.value & 0x80000000)
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{
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/* A global symbol, this is the symbol index. */
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/* The code below was borrowed from _dl_fixup(). */
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const Elf_Symndx symndx = td->argument.value ^ 0x80000000;
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const ElfW(Sym) *const symtab
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= (const void *) D_PTR (l, l_info[DT_SYMTAB]);
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const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
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const ElfW(Sym) *sym = &symtab[symndx];
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/* Look up the target symbol. If the normal lookup rules are not
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used don't look in the global scope. */
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if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL
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&& __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)
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{
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const struct r_found_version *version = NULL;
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if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
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{
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const ElfW(Half) *vernum =
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(const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);
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ElfW(Half) ndx = vernum[symndx] & 0x7fff;
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version = &l->l_versions[ndx];
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if (version->hash == 0)
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version = NULL;
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}
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result = _dl_lookup_symbol_x
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(strtab + sym->st_name, l, &sym,
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l->l_scope, version, ELF_RTYPE_CLASS_PLT,
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DL_LOOKUP_ADD_DEPENDENCY, NULL);
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if (sym)
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value = sym->st_value;
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else
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{
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td->entry = _dl_tlsdesc_undefweak;
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goto done;
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}
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}
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else
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{
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/* We already found the symbol. The module (and therefore its load
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address) is also known. */
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result = l;
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value = sym->st_value;
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}
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}
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else
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{
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/* A local symbol, this is the offset within our tls section.
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*/
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value = td->argument.value;
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result = l;
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}
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#ifndef SHARED
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CHECK_STATIC_TLS (l, result);
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#else
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if (!TRY_STATIC_TLS (l, result))
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{
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td->argument.pointer = _dl_make_tlsdesc_dynamic (result, value);
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td->entry = _dl_tlsdesc_dynamic;
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}
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else
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#endif
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{
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td->argument.value = value + result->l_tls_offset;
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td->entry = _dl_tlsdesc_return;
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}
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done:
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_dl_tlsdesc_wake_up_held_fixups ();
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}
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/* This function is used to avoid busy waiting for other threads to
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complete the lazy relocation. Once another thread wins the race to
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relocate a TLS descriptor, it sets the descriptor up such that this
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function is called to wait until the resolver releases the
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lock. */
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void
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attribute_hidden
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_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td,
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void *caller)
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{
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/* Maybe we're lucky and can return early. */
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if (caller != td->entry)
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return;
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/* Locking here will stop execution until the running resolver runs
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_dl_tlsdesc_wake_up_held_fixups(), releasing the lock.
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FIXME: We'd be better off waiting on a condition variable, such
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that we didn't have to hold the lock throughout the relocation
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processing. */
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__rtld_lock_lock_recursive (GL(dl_load_lock));
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__rtld_lock_unlock_recursive (GL(dl_load_lock));
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}
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/* Unmap the dynamic object, but also release its TLS descriptor table
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if there is one. */
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