diff options
Diffstat (limited to 'sysdeps/aarch64/dl-tlsdesc.S')
| -rw-r--r-- | sysdeps/aarch64/dl-tlsdesc.S | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/sysdeps/aarch64/dl-tlsdesc.S b/sysdeps/aarch64/dl-tlsdesc.S index be9b9b394c..c7adf79baf 100644 --- a/sysdeps/aarch64/dl-tlsdesc.S +++ b/sysdeps/aarch64/dl-tlsdesc.S @@ -79,6 +79,29 @@ _dl_tlsdesc_return: cfi_endproc .size _dl_tlsdesc_return, .-_dl_tlsdesc_return + /* Same as _dl_tlsdesc_return but with synchronization for + lazy relocation. + Prototype: + _dl_tlsdesc_return_lazy (tlsdesc *) ; + */ + .hidden _dl_tlsdesc_return_lazy + .global _dl_tlsdesc_return_lazy + .type _dl_tlsdesc_return_lazy,%function + cfi_startproc + .align 2 +_dl_tlsdesc_return_lazy: + /* The ldar here happens after the load from [x0] at the call site + (that is generated by the compiler as part of the TLS access ABI), + so it reads the same value (this function is the final value of + td->entry) and thus it synchronizes with the release store to + td->entry in _dl_tlsdesc_resolve_rela_fixup ensuring that the load + from [x0,#8] here happens after the initialization of td->arg. */ + ldar xzr, [x0] + ldr x0, [x0, #8] + RET + cfi_endproc + .size _dl_tlsdesc_return_lazy, .-_dl_tlsdesc_return_lazy + /* Handler for undefined weak TLS symbols. Prototype: _dl_tlsdesc_undefweak (tlsdesc *); @@ -96,6 +119,13 @@ _dl_tlsdesc_return: _dl_tlsdesc_undefweak: str x1, [sp, #-16]! cfi_adjust_cfa_offset(16) + /* The ldar here happens after the load from [x0] at the call site + (that is generated by the compiler as part of the TLS access ABI), + so it reads the same value (this function is the final value of + td->entry) and thus it synchronizes with the release store to + td->entry in _dl_tlsdesc_resolve_rela_fixup ensuring that the load + from [x0,#8] here happens after the initialization of td->arg. */ + ldar xzr, [x0] ldr x0, [x0, #8] mrs x1, tpidr_el0 sub x0, x0, x1 @@ -152,6 +182,13 @@ _dl_tlsdesc_dynamic: stp x3, x4, [sp, #32+16*1] mrs x4, tpidr_el0 + /* The ldar here happens after the load from [x0] at the call site + (that is generated by the compiler as part of the TLS access ABI), + so it reads the same value (this function is the final value of + td->entry) and thus it synchronizes with the release store to + td->entry in _dl_tlsdesc_resolve_rela_fixup ensuring that the load + from [x0,#8] here happens after the initialization of td->arg. */ + ldar xzr, [x0] ldr x1, [x0,#8] ldr x0, [x4] ldr x3, [x1,#16] |