usr/src/lib/libc/amd64/threads/tls_get_addr.s

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26         .file   "tls_get_addr.s"
  27
  28 /*
  29  * To make thread-local storage accesses as fast as possible, we
  30  * hand-craft the __tls_get_addr() function below, from this C code:
  31  * void *
  32  * __tls_get_addr(TLS_index *tls_index)
  33  * {
  34  *      ulwp_t *self = curthread;
  35  *      tls_t *tlsent = self->ul_tlsent;
  36  *      ulong_t moduleid;
  37  *      caddr_t base;
  38  *
  39  *      if ((moduleid = tls_index->ti_moduleid) < self->ul_ntlsent &&
  40  *          (base = tlsent[moduleid].tls_data) != NULL)
  41  *              return (base + tls_index->ti_tlsoffset);
  42  *
  43  *      return (slow_tls_get_addr(tls_index));
  44  * }
  45  *
  46  * ___tls_get_addr() is identical to __tls_get_addr() except that it
  47  * assumes its argument is passed in %eax rather than on the stack.
  48  */
  49
  50 #include "SYS.h"
  51 #include <../assym.h>
  52
  53         ENTRY_NP(__tls_get_addr)
  54         ALTENTRY(___tls_get_addr)
  55         movq    %fs:UL_TLSENT, %rax
  56         movq    TI_MODULEID (%rdi), %rdx
  57         cmpq    %fs:UL_NTLSENT, %rdx
  58         jae     slow_tls_get_addr       /* tail call */
  59         /* movq TLS_DATA (%rax,%rdx,SIZEOF_TLS_T), %rax */
  60         shlq    $4, %rdx        /* SIZEOF_TLS_T == 16 */
  61         movq    TLS_DATA (%rax,%rdx), %rax
  62         testq   %rax, %rax
  63         je      slow_tls_get_addr       /* tail call */
  64         addq    TI_TLSOFFSET (%rdi), %rax
  65         ret
  66         SET_SIZE(___tls_get_addr)
  67         SET_SIZE(__tls_get_addr)