ports/sysdeps/unix/sysv/linux/tile/setcontext.S

   1 /* Copyright (C) 2011-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20 #include <asm/errno.h>
  21 #include <arch/spr_def.h>
  22 #include <arch/abi.h>
  23
  24 #include "ucontext_i.h"
  25
  26 /* PL to return to via iret in setcontext */
  27 #define RETURN_PL 0
  28
  29 /* int setcontext (const ucontext_t *ucp) */
  30
  31         .text
  32 ENTRY (__setcontext)
  33         FEEDBACK_ENTER(__setcontext)
  34
  35         /* See if this is a true signal context (flags == 0).
  36            If so, restore by invoking rt_sigreturn().  */
  37 #if UC_FLAGS_OFFSET != 0
  38 # error "Add offset to r0 prior to load."
  39 #endif
  40         LD_PTR r10, r0
  41         {
  42          BEQZ r10, .Lsigreturn
  43          addi r10, r10, -1  /* Confirm that it has value "1".  */
  44         }
  45         BNEZ r10, .Lbadcontext
  46
  47         /* Save lr and r0 briefly on the stack and set the signal mask:
  48            rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, NULL, _NSIG / 8).  */
  49         {
  50          ST sp, lr
  51          ADDI_PTR r11, sp, -(2 * REGSIZE)
  52          move r10, sp
  53         }
  54         ADDI_PTR sp, sp, -(3 * REGSIZE)
  55         cfi_def_cfa_offset (3 * REGSIZE)
  56         cfi_offset (lr, 0)
  57         {
  58          ST r11, r10
  59          ADDI_PTR r10, sp, (2 * REGSIZE)
  60         }
  61         {
  62          ST r10, r0
  63          ADDLI_PTR r1, r0, UC_SIGMASK_OFFSET
  64         }
  65         cfi_offset (r0, -REGSIZE)
  66         {
  67          movei r3, _NSIG / 8
  68          movei r2, 0
  69         }
  70         {
  71          movei r0, SIG_SETMASK
  72          moveli TREG_SYSCALL_NR_NAME, __NR_rt_sigprocmask
  73         }
  74         swint1
  75         ADDI_PTR r11, sp, 2 * REGSIZE  /* Restore uc_context to r11. */
  76         {
  77          LD r11, r11
  78          ADDI_PTR sp, sp, 3 * REGSIZE
  79         }
  80         cfi_def_cfa_offset (0)
  81         LD lr, sp
  82         {
  83          ADDI_PTR r10, r11, UC_REG(0)
  84          BNEZ r1, .Lsyscall_error
  85         }
  86
  87         /* Restore the argument registers; note they will be random
  88            unless makecontext() has been called.  */
  89         { LD r0, r10; ADDI_PTR r10, r10, REGSIZE }
  90         { LD r1, r10; ADDI_PTR r10, r10, REGSIZE }
  91         { LD r2, r10; ADDI_PTR r10, r10, REGSIZE }
  92         { LD r3, r10; ADDI_PTR r10, r10, REGSIZE }
  93         { LD r4, r10; ADDI_PTR r10, r10, REGSIZE }
  94         { LD r5, r10; ADDI_PTR r10, r10, REGSIZE }
  95         { LD r6, r10; ADDI_PTR r10, r10, REGSIZE }
  96         { LD r7, r10; ADDI_PTR r10, r10, REGSIZE }
  97         { LD r8, r10; ADDI_PTR r10, r10, REGSIZE }
  98         { LD r9, r10; ADDLI_PTR r10, r10, UC_REG(30) - UC_REG(9) }
  99
 100         /* Restore the callee-saved GPRs.  */
 101         { LD r30, r10; ADDI_PTR r10, r10, REGSIZE }
 102         { LD r31, r10; ADDI_PTR r10, r10, REGSIZE }
 103         { LD r32, r10; ADDI_PTR r10, r10, REGSIZE }
 104         { LD r33, r10; ADDI_PTR r10, r10, REGSIZE }
 105         { LD r34, r10; ADDI_PTR r10, r10, REGSIZE }
 106         { LD r35, r10; ADDI_PTR r10, r10, REGSIZE }
 107         { LD r36, r10; ADDI_PTR r10, r10, REGSIZE }
 108         { LD r37, r10; ADDI_PTR r10, r10, REGSIZE }
 109         { LD r38, r10; ADDI_PTR r10, r10, REGSIZE }
 110         { LD r39, r10; ADDI_PTR r10, r10, REGSIZE }
 111         { LD r40, r10; ADDI_PTR r10, r10, REGSIZE }
 112         { LD r41, r10; ADDI_PTR r10, r10, REGSIZE }
 113         { LD r42, r10; ADDI_PTR r10, r10, REGSIZE }
 114         { LD r43, r10; ADDI_PTR r10, r10, REGSIZE }
 115         { LD r44, r10; ADDI_PTR r10, r10, REGSIZE }
 116         { LD r45, r10; ADDI_PTR r10, r10, REGSIZE }
 117         { LD r46, r10; ADDI_PTR r10, r10, REGSIZE }
 118         { LD r47, r10; ADDI_PTR r10, r10, REGSIZE }
 119         { LD r48, r10; ADDI_PTR r10, r10, REGSIZE }
 120         { LD r49, r10; ADDI_PTR r10, r10, REGSIZE }
 121         { LD r50, r10; ADDI_PTR r10, r10, REGSIZE }
 122         { LD r51, r10; ADDI_PTR r10, r10, REGSIZE }
 123         { LD r52, r10; ADDI_PTR r10, r10, REGSIZE * 2 }
 124         /* Skip tp since it must not change for a given thread.  */
 125         { LD sp, r10;  ADDI_PTR r10, r10, REGSIZE }
 126         { LD lr, r10;  ADDI_PTR r10, r10, REGSIZE }
 127         { LD r11, r10; ADDI_PTR r10, r10, REGSIZE }
 128
 129         /* Construct an iret context; we set ICS so we can validly load
 130            EX_CONTEXT for iret without being interrupted halfway through.  */
 131         {
 132          LD r12, r10
 133          movei r13, 1
 134         }
 135         {
 136          mtspr INTERRUPT_CRITICAL_SECTION, r13
 137          shli r12, r12, SPR_EX_CONTEXT_0_1__ICS_SHIFT
 138         }
 139         {
 140          mtspr EX_CONTEXT_0_0, r11
 141          ori r12, r12, RETURN_PL
 142         }
 143         mtspr EX_CONTEXT_0_1, r12
 144         iret
 145         jrp lr    /* keep the backtracer happy */
 146
 147 .Lsigreturn:
 148         /* This is a context obtained from a signal handler.
 149            Perform a full restore by pushing the context
 150            passed onto a simulated signal frame on the stack
 151            and call the signal return syscall as if a signal
 152            handler exited normally.  */
 153         {
 154          ADDLI_PTR sp, sp, -(C_ABI_SAVE_AREA_SIZE + SI_MAX_SIZE + UC_SIZE)
 155          ADDLI_PTR r1, sp, -UC_SIZE
 156         }
 157         cfi_def_cfa_offset (C_ABI_SAVE_AREA_SIZE + SI_MAX_SIZE + UC_SIZE)
 158         moveli r2, UC_SIZE / REGSIZE
 159 0:      {
 160          LD r10, r0
 161          ADDI_PTR r0, r0, REGSIZE
 162         }
 163         {
 164          ST r1, r10
 165          ADDI_PTR r1, r1, REGSIZE
 166          addi r2, r2, -1
 167         }
 168         BNEZ r2, 0b
 169         moveli TREG_SYSCALL_NR_NAME, __NR_rt_sigreturn
 170         swint1
 171
 172         /* Restore the stack and fall through to the error
 173            path.  Successful rt_sigreturn never returns to
 174            its calling place.  */
 175         ADDLI_PTR sp, sp, (C_ABI_SAVE_AREA_SIZE + SI_MAX_SIZE + UC_SIZE)
 176         cfi_def_cfa_offset (0)
 177
 178 .Lsyscall_error:
 179         j SYSCALL_ERROR_NAME
 180
 181 .Lbadcontext:
 182         {
 183          movei r1, EINVAL
 184          j SYSCALL_ERROR_NAME
 185         }
 186
 187 END (__setcontext)
 188
 189 .hidden __setcontext
 190 weak_alias (__setcontext, setcontext)
 191
 192 ENTRY (__startcontext)
 193         FEEDBACK_ENTER(__startcontext)
 194         BEQZ r30, 1f
 195         {
 196          move r0, r30
 197          jal __setcontext
 198         }
 199 1:      {
 200          movei r0, 0
 201          j HIDDEN_JUMPTARGET(exit)
 202         }
 203 END (__startcontext)
 204 .hidden __startcontext