| commit 55c9f3238080e9aba733bc0902779c46cfa16446 |
| Author: Szabolcs Nagy <szabolcs.nagy@arm.com> |
| Date: Thu Feb 11 11:52:24 2021 +0000 |
| |
| x86_64: Remove lazy tlsdesc relocation related code |
| |
| _dl_tlsdesc_resolve_rela and _dl_tlsdesc_resolve_hold are only used for |
| lazy tlsdesc relocation processing which is no longer supported. |
| |
| diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h |
| index ef5740ba281c7282..b94d3b39ec1dca64 100644 |
| |
| |
| @@ -127,10 +127,6 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) |
| } |
| } |
| |
| - if (l->l_info[ADDRIDX (DT_TLSDESC_GOT)] && lazy) |
| - *(ElfW(Addr)*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_GOT)]) + l->l_addr) |
| - = (ElfW(Addr)) &_dl_tlsdesc_resolve_rela; |
| - |
| return lazy; |
| } |
| |
| diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S |
| index 80d771cd887dd626..77e78cf0a6d8babc 100644 |
| |
| |
| @@ -148,107 +148,3 @@ _dl_tlsdesc_dynamic: |
| cfi_endproc |
| .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic |
| #endif /* SHARED */ |
| - |
| - /* This function is a wrapper for a lazy resolver for TLS_DESC |
| - RELA relocations. The incoming 0(%rsp) points to the caller's |
| - link map, pushed by the dynamic object's internal lazy TLS |
| - resolver front-end before tail-calling us. We need to pop it |
| - ourselves. %rax points to a TLS descriptor, such that 0(%rax) |
| - holds the address of the internal resolver front-end (unless |
| - some other thread beat us to resolving it) and 8(%rax) holds a |
| - pointer to the relocation. |
| - |
| - When the actual resolver returns, it will have adjusted the |
| - TLS descriptor such that we can tail-call it for it to return |
| - the TP offset of the symbol. */ |
| - |
| - .hidden _dl_tlsdesc_resolve_rela |
| - .global _dl_tlsdesc_resolve_rela |
| - .type _dl_tlsdesc_resolve_rela,@function |
| - cfi_startproc |
| - .align 16 |
| - /* The PLT entry will have pushed the link_map pointer. */ |
| -_dl_tlsdesc_resolve_rela: |
| - _CET_ENDBR |
| - cfi_adjust_cfa_offset (8) |
| - /* Save all call-clobbered registers. Add 8 bytes for push in |
| - the PLT entry to align the stack. */ |
| - subq $80, %rsp |
| - cfi_adjust_cfa_offset (80) |
| - movq %rax, (%rsp) |
| - movq %rdi, 8(%rsp) |
| - movq %rax, %rdi /* Pass tlsdesc* in %rdi. */ |
| - movq %rsi, 16(%rsp) |
| - movq 80(%rsp), %rsi /* Pass link_map* in %rsi. */ |
| - movq %r8, 24(%rsp) |
| - movq %r9, 32(%rsp) |
| - movq %r10, 40(%rsp) |
| - movq %r11, 48(%rsp) |
| - movq %rdx, 56(%rsp) |
| - movq %rcx, 64(%rsp) |
| - call _dl_tlsdesc_resolve_rela_fixup |
| - movq (%rsp), %rax |
| - movq 8(%rsp), %rdi |
| - movq 16(%rsp), %rsi |
| - movq 24(%rsp), %r8 |
| - movq 32(%rsp), %r9 |
| - movq 40(%rsp), %r10 |
| - movq 48(%rsp), %r11 |
| - movq 56(%rsp), %rdx |
| - movq 64(%rsp), %rcx |
| - addq $88, %rsp |
| - cfi_adjust_cfa_offset (-88) |
| - jmp *(%rax) |
| - cfi_endproc |
| - .size _dl_tlsdesc_resolve_rela, .-_dl_tlsdesc_resolve_rela |
| - |
| - /* This function is a placeholder for lazy resolving of TLS |
| - relocations. Once some thread starts resolving a TLS |
| - relocation, it sets up the TLS descriptor to use this |
| - resolver, such that other threads that would attempt to |
| - resolve it concurrently may skip the call to the original lazy |
| - resolver and go straight to a condition wait. |
| - |
| - When the actual resolver returns, it will have adjusted the |
| - TLS descriptor such that we can tail-call it for it to return |
| - the TP offset of the symbol. */ |
| - |
| - .hidden _dl_tlsdesc_resolve_hold |
| - .global _dl_tlsdesc_resolve_hold |
| - .type _dl_tlsdesc_resolve_hold,@function |
| - cfi_startproc |
| - .align 16 |
| -_dl_tlsdesc_resolve_hold: |
| -0: |
| - _CET_ENDBR |
| - /* Save all call-clobbered registers. */ |
| - subq $72, %rsp |
| - cfi_adjust_cfa_offset (72) |
| - movq %rax, (%rsp) |
| - movq %rdi, 8(%rsp) |
| - movq %rax, %rdi /* Pass tlsdesc* in %rdi. */ |
| - movq %rsi, 16(%rsp) |
| - /* Pass _dl_tlsdesc_resolve_hold's address in %rsi. */ |
| - leaq . - _dl_tlsdesc_resolve_hold(%rip), %rsi |
| - movq %r8, 24(%rsp) |
| - movq %r9, 32(%rsp) |
| - movq %r10, 40(%rsp) |
| - movq %r11, 48(%rsp) |
| - movq %rdx, 56(%rsp) |
| - movq %rcx, 64(%rsp) |
| - call _dl_tlsdesc_resolve_hold_fixup |
| -1: |
| - movq (%rsp), %rax |
| - movq 8(%rsp), %rdi |
| - movq 16(%rsp), %rsi |
| - movq 24(%rsp), %r8 |
| - movq 32(%rsp), %r9 |
| - movq 40(%rsp), %r10 |
| - movq 48(%rsp), %r11 |
| - movq 56(%rsp), %rdx |
| - movq 64(%rsp), %rcx |
| - addq $72, %rsp |
| - cfi_adjust_cfa_offset (-72) |
| - jmp *(%rax) |
| - cfi_endproc |
| - .size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold |
| diff --git a/sysdeps/x86_64/dl-tlsdesc.h b/sysdeps/x86_64/dl-tlsdesc.h |
| index 66e659bb5c7ede74..1cde1ee9664f4908 100644 |
| |
| |
| @@ -55,9 +55,7 @@ struct tlsdesc_dynamic_arg |
| |
| extern ptrdiff_t attribute_hidden |
| _dl_tlsdesc_return(struct tlsdesc *on_rax), |
| - _dl_tlsdesc_undefweak(struct tlsdesc *on_rax), |
| - _dl_tlsdesc_resolve_rela(struct tlsdesc *on_rax), |
| - _dl_tlsdesc_resolve_hold(struct tlsdesc *on_rax); |
| + _dl_tlsdesc_undefweak(struct tlsdesc *on_rax); |
| |
| # ifdef SHARED |
| extern void *_dl_make_tlsdesc_dynamic (struct link_map *map, |
| diff --git a/sysdeps/x86_64/tlsdesc.c b/sysdeps/x86_64/tlsdesc.c |
| index 302d097dbb0c4f1e..61a19ae26944c84f 100644 |
| |
| |
| @@ -16,120 +16,13 @@ |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| -#include <link.h> |
| #include <ldsodefs.h> |
| -#include <elf/dynamic-link.h> |
| #include <tls.h> |
| #include <dl-tlsdesc.h> |
| #include <dl-unmap-segments.h> |
| +#define _dl_tlsdesc_resolve_hold 0 |
| #include <tlsdeschtab.h> |
| |
| -/* The following 2 functions take a caller argument, that contains the |
| - address expected to be in the TLS descriptor. If it's changed, we |
| - want to return immediately. */ |
| - |
| -/* This function is used to lazily resolve TLS_DESC RELA relocations. |
| - The argument location is used to hold a pointer to the relocation. */ |
| - |
| -void |
| -attribute_hidden |
| -_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, |
| - struct link_map *l) |
| -{ |
| - const ElfW(Rela) *reloc = td->arg; |
| - |
| - if (_dl_tlsdesc_resolve_early_return_p |
| - (td, (void*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_PLT)]) + l->l_addr))) |
| - return; |
| - |
| - /* The code below was borrowed from _dl_fixup(). */ |
| - const ElfW(Sym) *const symtab |
| - = (const void *) D_PTR (l, l_info[DT_SYMTAB]); |
| - const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); |
| - const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; |
| - lookup_t result; |
| - |
| - /* Look up the target symbol. If the normal lookup rules are not |
| - used don't look in the global scope. */ |
| - if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL |
| - && __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) |
| - { |
| - const struct r_found_version *version = NULL; |
| - |
| - if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) |
| - { |
| - const ElfW(Half) *vernum = |
| - (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]); |
| - ElfW(Half) ndx = vernum[ELFW(R_SYM) (reloc->r_info)] & 0x7fff; |
| - version = &l->l_versions[ndx]; |
| - if (version->hash == 0) |
| - version = NULL; |
| - } |
| - |
| - result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, |
| - l->l_scope, version, ELF_RTYPE_CLASS_PLT, |
| - DL_LOOKUP_ADD_DEPENDENCY, NULL); |
| - } |
| - else |
| - { |
| - /* We already found the symbol. The module (and therefore its load |
| - address) is also known. */ |
| - result = l; |
| - } |
| - |
| - if (! sym) |
| - { |
| - td->arg = (void*)reloc->r_addend; |
| - td->entry = _dl_tlsdesc_undefweak; |
| - } |
| - else |
| - { |
| -# ifndef SHARED |
| - CHECK_STATIC_TLS (l, result); |
| -# else |
| - if (!TRY_STATIC_TLS (l, result)) |
| - { |
| - td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value |
| - + reloc->r_addend); |
| - td->entry = _dl_tlsdesc_dynamic; |
| - } |
| - else |
| -# endif |
| - { |
| - td->arg = (void*)(sym->st_value - result->l_tls_offset |
| - + reloc->r_addend); |
| - td->entry = _dl_tlsdesc_return; |
| - } |
| - } |
| - |
| - _dl_tlsdesc_wake_up_held_fixups (); |
| -} |
| - |
| -/* This function is used to avoid busy waiting for other threads to |
| - complete the lazy relocation. Once another thread wins the race to |
| - relocate a TLS descriptor, it sets the descriptor up such that this |
| - function is called to wait until the resolver releases the |
| - lock. */ |
| - |
| -void |
| -attribute_hidden |
| -_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td, |
| - void *caller) |
| -{ |
| - /* Maybe we're lucky and can return early. */ |
| - if (caller != td->entry) |
| - return; |
| - |
| - /* Locking here will stop execution until the running resolver runs |
| - _dl_tlsdesc_wake_up_held_fixups(), releasing the lock. |
| - |
| - FIXME: We'd be better off waiting on a condition variable, such |
| - that we didn't have to hold the lock throughout the relocation |
| - processing. */ |
| - __rtld_lock_lock_recursive (GL(dl_load_lock)); |
| - __rtld_lock_unlock_recursive (GL(dl_load_lock)); |
| -} |
| - |
| /* Unmap the dynamic object, but also release its TLS descriptor table |
| if there is one. */ |
| |