sysdeps/powerpc/nptl/tls.h

   1 /* Definition for thread-local data handling.  NPTL/PowerPC version.
   2    Copyright (C) 2003-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _TLS_H
  20 #define _TLS_H  1
  21
  22 # include <dl-sysdep.h>
  23
  24 #ifndef __ASSEMBLER__
  25 # include <stdbool.h>
  26 # include <stddef.h>
  27 # include <stdint.h>
  28 # include <dl-dtv.h>
  29
  30 #else /* __ASSEMBLER__ */
  31 # include <tcb-offsets.h>
  32 # define __ASSEMBLY__
  33 # include <asm/ptrace.h>
  34 #endif /* __ASSEMBLER__ */
  35
  36 #ifndef __powerpc64__
  37 /* Register r2 (tp) is reserved by the ABI as "thread pointer". */
  38 # define PT_THREAD_POINTER PT_R2
  39 # ifndef __ASSEMBLER__
  40 register void *__thread_register __asm__ ("r2");
  41 # endif
  42
  43 #else /* __powerpc64__ */
  44 /* Register r13 (tp) is reserved by the ABI as "thread pointer". */
  45 # define PT_THREAD_POINTER PT_R13
  46 # ifndef __ASSEMBLER__
  47 register void *__thread_register __asm__ ("r13");
  48 # endif
  49 #endif /* __powerpc64__ */
  50
  51 #ifndef __ASSEMBLER__
  52
  53 # include <hwcapinfo.h>
  54
  55 /* Get system call information.  */
  56 # include <sysdep.h>
  57
  58 /* The TP points to the start of the thread blocks.  */
  59 # define TLS_DTV_AT_TP  1
  60 # define TLS_TCB_AT_TP  0
  61
  62 /* We use the multiple_threads field in the pthread struct */
  63 #define TLS_MULTIPLE_THREADS_IN_TCB     1
  64
  65 /* Get the thread descriptor definition.  */
  66 # include <nptl/descr.h>
  67
  68
  69 /* The stack_guard is accessed directly by GCC -fstack-protector code,
  70    so it is a part of public ABI.  The dtv and pointer_guard fields
  71    are private.  */
  72 typedef struct
  73 {
  74   /* Reservation for HWCAP data.  To be accessed by GCC in
  75      __builtin_cpu_supports(), so it is a part of public ABI.  */
  76   uint64_t hwcap;
  77   /* Reservation for AT_PLATFORM data.  To be accessed by GCC in
  78      __builtin_cpu_is(), so it is a part of public ABI.  Since there
  79      are different ABIs for 32 and 64 bit, we put this field in a
  80      previously empty padding space for powerpc64.  */
  81 #ifndef __powerpc64__
  82   /* Padding to maintain alignment.  */
  83   uint32_t padding;
  84   uint32_t at_platform;
  85 #endif
  86   uint32_t __unused;
  87   /* Reservation for AT_PLATFORM data - powerpc64.  */
  88 #ifdef __powerpc64__
  89   uint32_t at_platform;
  90 #endif
  91   /* Reservation for Dynamic System Optimizer ABI.  */
  92   uintptr_t dso_slot2;
  93   uintptr_t dso_slot1;
  94   /* Reservation for tar register (ISA 2.07).  */
  95   uintptr_t tar_save;
  96   /* GCC split stack support.  */
  97   void *__private_ss;
  98   /* Reservation for the Event-Based Branching ABI.  */
  99   uintptr_t ebb_handler;
 100   uintptr_t ebb_ctx_pointer;
 101   uintptr_t ebb_reserved1;
 102   uintptr_t ebb_reserved2;
 103   uintptr_t pointer_guard;
 104   uintptr_t stack_guard;
 105   dtv_t *dtv;
 106 } tcbhead_t;
 107
 108 /* This is the size of the initial TCB.  */
 109 # define TLS_INIT_TCB_SIZE      0
 110
 111 /* This is the size of the TCB.  */
 112 # define TLS_TCB_SIZE           0
 113
 114 /* This is the size we need before TCB.  */
 115 # define TLS_PRE_TCB_SIZE \
 116   (sizeof (struct pthread)                                                    \
 117    + ((sizeof (tcbhead_t) + __alignof (struct pthread) - 1)                   \
 118       & ~(__alignof (struct pthread) - 1)))
 119
 120 /* The following assumes that TP (R2 or R13) points to the end of the
 121    TCB + 0x7000 (per the ABI).  This implies that TCB address is
 122    TP - 0x7000.  As we define TLS_DTV_AT_TP we can
 123    assume that the pthread struct is allocated immediately ahead of the
 124    TCB.  This implies that the pthread_descr address is
 125    TP - (TLS_PRE_TCB_SIZE + 0x7000).  */
 126 # define TLS_TCB_OFFSET 0x7000
 127
 128 /* Install the dtv pointer.  The pointer passed is to the element with
 129    index -1 which contain the length.  */
 130 # define INSTALL_DTV(tcbp, dtvp) \
 131   ((tcbhead_t *) (tcbp))[-1].dtv = dtvp + 1
 132
 133 /* Install new dtv for current thread.  */
 134 # define INSTALL_NEW_DTV(dtv) (THREAD_DTV() = (dtv))
 135
 136 /* Return dtv of given thread descriptor.  */
 137 # define GET_DTV(tcbp)  (((tcbhead_t *) (tcbp))[-1].dtv)
 138
 139 /* Code to initially initialize the thread pointer.  This might need
 140    special attention since 'errno' is not yet available and if the
 141    operation can cause a failure 'errno' must not be touched.  */
 142 # define TLS_INIT_TP(tcbp) \
 143   ({                                                                          \
 144     __thread_register = (void *) (tcbp) + TLS_TCB_OFFSET;                     \
 145     THREAD_SET_HWCAP (__tcb_hwcap);                                           \
 146     THREAD_SET_AT_PLATFORM (__tcb_platform);                                  \
 147     NULL;                                                                     \
 148   })
 149
 150 /* Value passed to 'clone' for initialization of the thread register.  */
 151 # define TLS_DEFINE_INIT_TP(tp, pd) \
 152     void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE;             \
 153     (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].hwcap) =              \
 154       THREAD_GET_HWCAP ();                                                    \
 155     (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].at_platform) =        \
 156       THREAD_GET_AT_PLATFORM ();
 157
 158 /* Return the address of the dtv for the current thread.  */
 159 # define THREAD_DTV() \
 160     (((tcbhead_t *) (__thread_register - TLS_TCB_OFFSET))[-1].dtv)
 161
 162 /* Return the thread descriptor for the current thread.  */
 163 # define THREAD_SELF \
 164     ((struct pthread *) (__thread_register \
 165                          - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
 166
 167 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 168 # define DB_THREAD_SELF                                                       \
 169   REGISTER (32, 32, PT_THREAD_POINTER * 4,                                    \
 170             - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)                              \
 171   REGISTER (64, 64, PT_THREAD_POINTER * 8,                                    \
 172             - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE)
 173
 174 # include <tcb-access.h>
 175
 176 /* Set the stack guard field in TCB head.  */
 177 # define THREAD_SET_STACK_GUARD(value) \
 178     (((tcbhead_t *) ((char *) __thread_register                               \
 179                      - TLS_TCB_OFFSET))[-1].stack_guard = (value))
 180 # define THREAD_COPY_STACK_GUARD(descr) \
 181     (((tcbhead_t *) ((char *) (descr)                                         \
 182                      + TLS_PRE_TCB_SIZE))[-1].stack_guard                     \
 183      = ((tcbhead_t *) ((char *) __thread_register                             \
 184                        - TLS_TCB_OFFSET))[-1].stack_guard)
 185
 186 /* Set the stack guard field in TCB head.  */
 187 # define THREAD_GET_POINTER_GUARD() \
 188     (((tcbhead_t *) ((char *) __thread_register                               \
 189                      - TLS_TCB_OFFSET))[-1].pointer_guard)
 190 # define THREAD_SET_POINTER_GUARD(value) \
 191     (THREAD_GET_POINTER_GUARD () = (value))
 192 # define THREAD_COPY_POINTER_GUARD(descr) \
 193     (((tcbhead_t *) ((char *) (descr)                                         \
 194                      + TLS_PRE_TCB_SIZE))[-1].pointer_guard                   \
 195      = THREAD_GET_POINTER_GUARD())
 196
 197 /* hwcap field in TCB head.  */
 198 # define THREAD_GET_HWCAP() \
 199     (((tcbhead_t *) ((char *) __thread_register                               \
 200                      - TLS_TCB_OFFSET))[-1].hwcap)
 201 # define THREAD_SET_HWCAP(value) \
 202     (THREAD_GET_HWCAP () = (value))
 203
 204 /* at_platform field in TCB head.  */
 205 # define THREAD_GET_AT_PLATFORM() \
 206     (((tcbhead_t *) ((char *) __thread_register                               \
 207                      - TLS_TCB_OFFSET))[-1].at_platform)
 208 # define THREAD_SET_AT_PLATFORM(value) \
 209     (THREAD_GET_AT_PLATFORM () = (value))
 210
 211 /* l_tls_offset == 0 is perfectly valid on PPC, so we have to use some
 212    different value to mean unset l_tls_offset.  */
 213 # define NO_TLS_OFFSET          -1
 214
 215 /* Get and set the global scope generation counter in struct pthread.  */
 216 #define THREAD_GSCOPE_FLAG_UNUSED 0
 217 #define THREAD_GSCOPE_FLAG_USED   1
 218 #define THREAD_GSCOPE_FLAG_WAIT   2
 219 #define THREAD_GSCOPE_RESET_FLAG() \
 220   do                                                                         \
 221     { int __res                                                              \
 222         = atomic_exchange_rel (&THREAD_SELF->header.gscope_flag,             \
 223                                THREAD_GSCOPE_FLAG_UNUSED);                   \
 224       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                  \
 225         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);   \
 226     }                                                                        \
 227   while (0)
 228 #define THREAD_GSCOPE_SET_FLAG() \
 229   do                                                                         \
 230     {                                                                        \
 231       THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;             \
 232       atomic_write_barrier ();                                               \
 233     }                                                                        \
 234   while (0)
 235
 236 #endif /* __ASSEMBLER__ */
 237
 238 #endif  /* tls.h */