| commit a75a02a696f9f869d77b17b99964823aa8833a8b |
| Author: Szabolcs Nagy <szabolcs.nagy@arm.com> |
| Date: Thu Feb 11 11:58:20 2021 +0000 |
| |
| i386: Remove lazy tlsdesc relocation related code |
| |
| Like in commit e75711ebfa976d5468ec292282566a18b07e4d67 for x86_64, |
| remove unused lazy tlsdesc relocation processing code: |
| |
| _dl_tlsdesc_resolve_abs_plus_addend |
| _dl_tlsdesc_resolve_rel |
| _dl_tlsdesc_resolve_rela |
| _dl_tlsdesc_resolve_hold |
| |
| diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S |
| index 128f0af3188f46bb..22ecb2c6adc6cc6e 100644 |
| |
| |
| @@ -138,159 +138,3 @@ _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 |
| - REL relocations that reference the *ABS* segment in their own |
| - link maps. %ebx points to the caller's GOT. %eax points to a |
| - TLS descriptor, such that 0(%eax) holds the address of the |
| - resolver wrapper itself (unless some other thread beat us to |
| - it) and 4(%eax) holds the addend in 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_abs_plus_addend |
| - .global _dl_tlsdesc_resolve_abs_plus_addend |
| - .type _dl_tlsdesc_resolve_abs_plus_addend,@function |
| - cfi_startproc |
| - .align 16 |
| -_dl_tlsdesc_resolve_abs_plus_addend: |
| -0: |
| - _CET_ENDBR |
| - pushl %eax |
| - cfi_adjust_cfa_offset (4) |
| - pushl %ecx |
| - cfi_adjust_cfa_offset (4) |
| - pushl %edx |
| - cfi_adjust_cfa_offset (4) |
| - movl $1f - 0b, %ecx |
| - movl 4(%ebx), %edx |
| - call _dl_tlsdesc_resolve_abs_plus_addend_fixup |
| -1: |
| - popl %edx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %ecx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %eax |
| - cfi_adjust_cfa_offset (-4) |
| - jmp *(%eax) |
| - cfi_endproc |
| - .size _dl_tlsdesc_resolve_abs_plus_addend, .-_dl_tlsdesc_resolve_abs_plus_addend |
| - |
| - /* This function is a wrapper for a lazy resolver for TLS_DESC |
| - REL relocations that had zero addends. %ebx points to the |
| - caller's GOT. %eax points to a TLS descriptor, such that |
| - 0(%eax) holds the address of the resolver wrapper itself |
| - (unless some other thread beat us to it) and 4(%eax) 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_rel |
| - .global _dl_tlsdesc_resolve_rel |
| - .type _dl_tlsdesc_resolve_rel,@function |
| - cfi_startproc |
| - .align 16 |
| -_dl_tlsdesc_resolve_rel: |
| -0: |
| - _CET_ENDBR |
| - pushl %eax |
| - cfi_adjust_cfa_offset (4) |
| - pushl %ecx |
| - cfi_adjust_cfa_offset (4) |
| - pushl %edx |
| - cfi_adjust_cfa_offset (4) |
| - movl $1f - 0b, %ecx |
| - movl 4(%ebx), %edx |
| - call _dl_tlsdesc_resolve_rel_fixup |
| -1: |
| - popl %edx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %ecx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %eax |
| - cfi_adjust_cfa_offset (-4) |
| - jmp *(%eax) |
| - cfi_endproc |
| - .size _dl_tlsdesc_resolve_rel, .-_dl_tlsdesc_resolve_rel |
| - |
| - /* This function is a wrapper for a lazy resolver for TLS_DESC |
| - RELA relocations. %ebx points to the caller's GOT. %eax |
| - points to a TLS descriptor, such that 0(%eax) holds the |
| - address of the resolver wrapper itself (unless some other |
| - thread beat us to it) and 4(%eax) 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 |
| -_dl_tlsdesc_resolve_rela: |
| -0: |
| - _CET_ENDBR |
| - pushl %eax |
| - cfi_adjust_cfa_offset (4) |
| - pushl %ecx |
| - cfi_adjust_cfa_offset (4) |
| - pushl %edx |
| - cfi_adjust_cfa_offset (4) |
| - movl $1f - 0b, %ecx |
| - movl 4(%ebx), %edx |
| - call _dl_tlsdesc_resolve_rela_fixup |
| -1: |
| - popl %edx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %ecx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %eax |
| - cfi_adjust_cfa_offset (-4) |
| - jmp *(%eax) |
| - 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 |
| - pushl %eax |
| - cfi_adjust_cfa_offset (4) |
| - pushl %ecx |
| - cfi_adjust_cfa_offset (4) |
| - pushl %edx |
| - cfi_adjust_cfa_offset (4) |
| - movl $1f - 0b, %ecx |
| - movl 4(%ebx), %edx |
| - call _dl_tlsdesc_resolve_hold_fixup |
| -1: |
| - popl %edx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %ecx |
| - cfi_adjust_cfa_offset (-4) |
| - popl %eax |
| - cfi_adjust_cfa_offset (-4) |
| - jmp *(%eax) |
| - cfi_endproc |
| - .size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold |
| diff --git a/sysdeps/i386/dl-tlsdesc.h b/sysdeps/i386/dl-tlsdesc.h |
| index c8a1e056150dc418..1a1a22c303baf85b 100644 |
| |
| |
| @@ -43,11 +43,7 @@ struct tlsdesc_dynamic_arg |
| |
| extern ptrdiff_t attribute_hidden __attribute__ ((regparm (1))) |
| _dl_tlsdesc_return (struct tlsdesc *), |
| - _dl_tlsdesc_undefweak (struct tlsdesc *), |
| - _dl_tlsdesc_resolve_abs_plus_addend (struct tlsdesc *), |
| - _dl_tlsdesc_resolve_rel (struct tlsdesc *), |
| - _dl_tlsdesc_resolve_rela (struct tlsdesc *), |
| - _dl_tlsdesc_resolve_hold (struct tlsdesc *); |
| + _dl_tlsdesc_undefweak (struct tlsdesc *); |
| |
| # ifdef SHARED |
| extern void *_dl_make_tlsdesc_dynamic (struct link_map *map, |
| diff --git a/sysdeps/i386/tlsdesc.c b/sysdeps/i386/tlsdesc.c |
| index 82fa8a1d35fd1912..1b4227c8381e1b3d 100644 |
| |
| |
| @@ -16,242 +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 4 functions take an entry_check_offset argument. |
| - It's computed by the caller as an offset between its entry point |
| - and the call site, such that by adding the built-in return address |
| - that is implicitly passed to the function with this offset, we can |
| - easily obtain the caller's entry point to compare with the entry |
| - point given in the TLS descriptor. If it's changed, we want to |
| - return immediately. */ |
| - |
| -/* This function is used to lazily resolve TLS_DESC REL relocations |
| - that reference the *ABS* segment in their own link maps. The |
| - argument is the addend originally stored there. */ |
| - |
| -void |
| -__attribute__ ((regparm (3))) attribute_hidden |
| -_dl_tlsdesc_resolve_abs_plus_addend_fixup (struct tlsdesc volatile *td, |
| - struct link_map *l, |
| - ptrdiff_t entry_check_offset) |
| -{ |
| - ptrdiff_t addend = (ptrdiff_t) td->arg; |
| - |
| - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) |
| - - entry_check_offset)) |
| - return; |
| - |
| -#ifndef SHARED |
| - CHECK_STATIC_TLS (l, l); |
| -#else |
| - if (!TRY_STATIC_TLS (l, l)) |
| - { |
| - td->arg = _dl_make_tlsdesc_dynamic (l, addend); |
| - td->entry = _dl_tlsdesc_dynamic; |
| - } |
| - else |
| -#endif |
| - { |
| - td->arg = (void*) (addend - l->l_tls_offset); |
| - td->entry = _dl_tlsdesc_return; |
| - } |
| - |
| - _dl_tlsdesc_wake_up_held_fixups (); |
| -} |
| - |
| -/* This function is used to lazily resolve TLS_DESC REL relocations |
| - that originally had zero addends. The argument location, that |
| - originally held the addend, is used to hold a pointer to the |
| - relocation, but it has to be restored before we call the function |
| - that applies relocations. */ |
| - |
| -void |
| -__attribute__ ((regparm (3))) attribute_hidden |
| -_dl_tlsdesc_resolve_rel_fixup (struct tlsdesc volatile *td, |
| - struct link_map *l, |
| - ptrdiff_t entry_check_offset) |
| -{ |
| - const ElfW(Rel) *reloc = td->arg; |
| - |
| - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) |
| - - entry_check_offset)) |
| - return; |
| - |
| - /* The code below was borrowed from _dl_fixup(), |
| - except for checking for STB_LOCAL. */ |
| - 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 = 0; |
| - 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); |
| - td->entry = _dl_tlsdesc_dynamic; |
| - } |
| - else |
| -# endif |
| - { |
| - td->arg = (void*)(sym->st_value - result->l_tls_offset); |
| - td->entry = _dl_tlsdesc_return; |
| - } |
| - } |
| - |
| - _dl_tlsdesc_wake_up_held_fixups (); |
| -} |
| - |
| -/* 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__ ((regparm (3))) attribute_hidden |
| -_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, |
| - struct link_map *l, |
| - ptrdiff_t entry_check_offset) |
| -{ |
| - const ElfW(Rela) *reloc = td->arg; |
| - |
| - if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0) |
| - - entry_check_offset)) |
| - return; |
| - |
| - /* The code below was borrowed from _dl_fixup(), |
| - except for checking for STB_LOCAL. */ |
| - 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__ ((regparm (3))) attribute_hidden |
| -_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td, |
| - struct link_map *l __attribute__((__unused__)), |
| - ptrdiff_t entry_check_offset) |
| -{ |
| - /* Maybe we're lucky and can return early. */ |
| - if (__builtin_return_address (0) - entry_check_offset != 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. */ |
| |