swapcontext.s

glibc 2.9,最新版的C语言库函数

  stfd  fp19,(SIGCONTEXT_FP_REGS+(PT_R19*8))(r3)
  stfd  fp20,(SIGCONTEXT_FP_REGS+(PT_R20*8))(r3)
  stfd  fp21,(SIGCONTEXT_FP_REGS+(PT_R21*8))(r3)
  stfd  fp22,(SIGCONTEXT_FP_REGS+(PT_R22*8))(r3)
  stfd  fp23,(SIGCONTEXT_FP_REGS+(PT_R23*8))(r3)
  stfd  fp24,(SIGCONTEXT_FP_REGS+(PT_R24*8))(r3)
  stfd  fp25,(SIGCONTEXT_FP_REGS+(PT_R25*8))(r3)
  stfd  fp26,(SIGCONTEXT_FP_REGS+(PT_R26*8))(r3)
  stfd  fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r3)
  stfd  fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r3)
  stfd  fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r3)
  mffs  fp0
  stfd  fp30,(SIGCONTEXT_FP_REGS+(PT_R30*8))(r3)
  stfd  fp31,(SIGCONTEXT_FP_REGS+(PT_R31*8))(r3)
  stfd  fp0,(SIGCONTEXT_FP_REGS+(32*8))(r3)

  ld    r8,.LC__dl_hwcap@toc(r2)
#ifdef SHARED
/* Load _rtld-global._dl_hwcap.  */
  ld    r8,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET(r8)
#else
  ld    r8,0(r8) /* Load extern _dl_hwcap.  */
#endif
  la    r10,(SIGCONTEXT_V_RESERVE+8)(r3)
  la    r9,(SIGCONTEXT_V_RESERVE+24)(r3)

  andis.  r8,r8,(PPC_FEATURE_HAS_ALTIVEC >> 16)

  clrrdi  r10,r10,4
  beq   L(has_no_vec)

  clrrdi  r9,r9,4
  mr    r8,r10	/* Capture *v_regs value in r5.  */

  stvx  v0,0,r10
  stvx  v1,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v2,0,r10
  stvx  v3,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v4,0,r10
  stvx  v5,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v6,0,r10
  stvx  v7,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v8,0,r10
  stvx  v9,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v10,0,r10
  stvx  v11,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v12,0,r10
  stvx  v13,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v14,0,r10
  stvx  v15,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v16,0,r10
  stvx  v17,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v18,0,r10
  stvx  v19,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v20,0,r10
  stvx  v21,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v22,0,r10
  stvx  v23,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v24,0,r10
  stvx  v25,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v26,0,r10
  stvx  v27,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v28,0,r10
  stvx  v29,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  stvx  v30,0,r10
  stvx  v31,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  mfvscr  v0
  mfspr r0,VRSAVE
  stvx  v0,0,r10
  stw   r0,0(r9)

L(has_no_vec):
/*
   Store either a NULL or a quadword aligned pointer to the Vector register
   array into *v_regs.
*/
  std   r8,(SIGCONTEXT_V_REGS_PTR)(r3)

  mr    r31,r4
  addi  r5,r3,UCONTEXT_SIGMASK
  addi  r4,r4,UCONTEXT_SIGMASK
  li    r3,SIG_SETMASK
  bl    JUMPTARGET(__sigprocmask)
  nop
  cmpdi  r3,0
  bne   L(error_exit)

/*
 * If this new ucontext refers to the point where we were interrupted
 * by a signal, we have to use the rt_sigreturn system call to
 * return to the context so we get both LR and CTR restored.
 *
 * Otherwise, the context we are restoring is either just after
 * a procedure call (getcontext/swapcontext) or at the beginning
 * of a procedure call (makecontext), so we don't need to restore
 * msr and ctr.  We don't restore r13 since it will be used as
 * the TLS pointer.  */
  ld	  r0,(SIGCONTEXT_GP_REGS+(PT_MSR*8))(r31)
  cmpdi r0,0
  bne	  L(do_sigret)

  ld    r8,.LC__dl_hwcap@toc(r2)
  ld    r10,(SIGCONTEXT_V_REGS_PTR)(r31)
# ifdef SHARED
/* Load _rtld-global._dl_hwcap.  */
  ld    r8,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET(r8)
# else
  ld    r8,0(r8) /* Load extern _dl_hwcap.  */
# endif
  andis.  r8,r8,(PPC_FEATURE_HAS_ALTIVEC >> 16)
  beq   L(has_no_vec2)

  cmpdi r10,0
  beq   L(has_no_vec2)
  lwz   r0,(33*16)(r10)

  li    r9,(16*32)
  mtspr VRSAVE,r0
  cmpwi r0,0
  beq   L(has_no_vec2)

  lvx   v19,r9,r10
  la    r9,(16)(r10)

  lvx   v0,0,r10
  lvx   v1,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  mtvscr  v19
  lvx   v2,0,r10
  lvx   v3,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v4,0,r10
  lvx   v5,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v6,0,r10
  lvx   v7,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v8,0,r10
  lvx   v9,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v10,0,r10
  lvx   v11,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v12,0,r10
  lvx   v13,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v14,0,r10
  lvx   v15,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v16,0,r10
  lvx   v17,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v18,0,r10
  lvx   v19,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v20,0,r10
  lvx   v21,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v22,0,r10
  lvx   v23,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v24,0,r10
  lvx   v25,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v26,0,r10
  lvx   v27,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v28,0,r10
  lvx   v29,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v30,0,r10
  lvx   v31,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

  lvx   v10,0,r10
  lvx   v11,0,r9
  addi  r10,r10,32
  addi  r9,r9,32

L(has_no_vec2):

  lfd  fp0,(SIGCONTEXT_FP_REGS+(32*8))(r31)
  lfd  fp31,(SIGCONTEXT_FP_REGS+(PT_R31*8))(r31)
  lfd  fp30,(SIGCONTEXT_FP_REGS+(PT_R30*8))(r31)
  mtfsf  0xff,fp0
  lfd  fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r31)
  lfd  fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r31)
  lfd  fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r31)
  lfd  fp26,(SIGCONTEXT_FP_REGS+(PT_R26*8))(r31)
  lfd  fp25,(SIGCONTEXT_FP_REGS+(PT_R25*8))(r31)
  lfd  fp24,(SIGCONTEXT_FP_REGS+(PT_R24*8))(r31)
  lfd  fp23,(SIGCONTEXT_FP_REGS+(PT_R23*8))(r31)
  lfd  fp22,(SIGCONTEXT_FP_REGS+(PT_R22*8))(r31)
  lfd  fp21,(SIGCONTEXT_FP_REGS+(PT_R21*8))(r31)
  lfd  fp20,(SIGCONTEXT_FP_REGS+(PT_R20*8))(r31)
  lfd  fp19,(SIGCONTEXT_FP_REGS+(PT_R19*8))(r31)
  lfd  fp18,(SIGCONTEXT_FP_REGS+(PT_R18*8))(r31)
  lfd  fp17,(SIGCONTEXT_FP_REGS+(PT_R17*8))(r31)
  lfd  fp16,(SIGCONTEXT_FP_REGS+(PT_R16*8))(r31)
  lfd  fp15,(SIGCONTEXT_FP_REGS+(PT_R15*8))(r31)
  lfd  fp14,(SIGCONTEXT_FP_REGS+(PT_R14*8))(r31)
  lfd  fp13,(SIGCONTEXT_FP_REGS+(PT_R13*8))(r31)
  lfd  fp12,(SIGCONTEXT_FP_REGS+(PT_R12*8))(r31)
  lfd  fp11,(SIGCONTEXT_FP_REGS+(PT_R11*8))(r31)
  lfd  fp10,(SIGCONTEXT_FP_REGS+(PT_R10*8))(r31)
  lfd  fp9,(SIGCONTEXT_FP_REGS+(PT_R9*8))(r31)
  lfd  fp8,(SIGCONTEXT_FP_REGS+(PT_R8*8))(r31)
  lfd  fp7,(SIGCONTEXT_FP_REGS+(PT_R7*8))(r31)
  lfd  fp6,(SIGCONTEXT_FP_REGS+(PT_R6*8))(r31)
  lfd  fp5,(SIGCONTEXT_FP_REGS+(PT_R5*8))(r31)
  lfd  fp4,(SIGCONTEXT_FP_REGS+(PT_R4*8))(r31)
  lfd  fp3,(SIGCONTEXT_FP_REGS+(PT_R3*8))(r31)
  lfd  fp2,(SIGCONTEXT_FP_REGS+(PT_R2*8))(r31)
  lfd  fp1,(SIGCONTEXT_FP_REGS+(PT_R1*8))(r31)
  lfd  fp0,(SIGCONTEXT_FP_REGS+(PT_R0*8))(r31)

  ld   r0,(SIGCONTEXT_GP_REGS+(PT_LNK*8))(r31)
  ld   r1,(SIGCONTEXT_GP_REGS+(PT_R1*8))(r31)
  mtlr r0
  ld   r2,(SIGCONTEXT_GP_REGS+(PT_R2*8))(r31)
  ld   r0,(SIGCONTEXT_GP_REGS+(PT_XER*8))(r31)
  ld   r3,(SIGCONTEXT_GP_REGS+(PT_R3*8))(r31)
  mtxer r0
  ld   r4,(SIGCONTEXT_GP_REGS+(PT_R4*8))(r31)
  ld   r0,(SIGCONTEXT_GP_REGS+(PT_CCR*8))(r31)
  ld   r5,(SIGCONTEXT_GP_REGS+(PT_R5*8))(r31)
  ld   r6,(SIGCONTEXT_GP_REGS+(PT_R6*8))(r31)
  ld   r7,(SIGCONTEXT_GP_REGS+(PT_R7*8))(r31)
  ld   r8,(SIGCONTEXT_GP_REGS+(PT_R8*8))(r31)
  ld   r9,(SIGCONTEXT_GP_REGS+(PT_R9*8))(r31)
  mtcr r0
  ld   r10,(SIGCONTEXT_GP_REGS+(PT_R10*8))(r31)
  ld   r11,(SIGCONTEXT_GP_REGS+(PT_R11*8))(r31)
  ld   r12,(SIGCONTEXT_GP_REGS+(PT_R12*8))(r31)
  /* Don't reload the thread ID or TLS pointer (r13).  */
  ld   r14,(SIGCONTEXT_GP_REGS+(PT_R14*8))(r31)
  ld   r15,(SIGCONTEXT_GP_REGS+(PT_R15*8))(r31)
  ld   r16,(SIGCONTEXT_GP_REGS+(PT_R16*8))(r31)
  ld   r17,(SIGCONTEXT_GP_REGS+(PT_R17*8))(r31)
  ld   r18,(SIGCONTEXT_GP_REGS+(PT_R18*8))(r31)
  ld   r19,(SIGCONTEXT_GP_REGS+(PT_R19*8))(r31)
  ld   r20,(SIGCONTEXT_GP_REGS+(PT_R20*8))(r31)
  ld   r21,(SIGCONTEXT_GP_REGS+(PT_R21*8))(r31)
  ld   r22,(SIGCONTEXT_GP_REGS+(PT_R22*8))(r31)
  ld   r23,(SIGCONTEXT_GP_REGS+(PT_R23*8))(r31)
  ld   r24,(SIGCONTEXT_GP_REGS+(PT_R24*8))(r31)
  ld   r25,(SIGCONTEXT_GP_REGS+(PT_R25*8))(r31)
  ld   r26,(SIGCONTEXT_GP_REGS+(PT_R26*8))(r31)
  ld   r27,(SIGCONTEXT_GP_REGS+(PT_R27*8))(r31)
  ld   r28,(SIGCONTEXT_GP_REGS+(PT_R28*8))(r31)
  ld   r29,(SIGCONTEXT_GP_REGS+(PT_R29*8))(r31)
  ld   r30,(SIGCONTEXT_GP_REGS+(PT_R30*8))(r31)

  /* Now we branch to the "Next Instruction Pointer" from the saved
     context.  With the powerpc64 instruction set there is no good way to
     do this (from user state) without clobbering either the LR or CTR.
     The makecontext and swapcontext functions depend on the callers
     LR being preserved so we use the CTR.  */
  ld   r0,(SIGCONTEXT_GP_REGS+(PT_NIP*8))(r31)
  mtctr r0
  ld   r0,(SIGCONTEXT_GP_REGS+(PT_R0*8))(r31)
  ld   r31,(SIGCONTEXT_GP_REGS+(PT_R31*8))(r31)
  bctr

L(error_exit):
  ld    r0,128+FRAME_LR_SAVE(r1)
  addi  r1,r1,128
  mtlr  r0
  ld    r31,-8(r1)
  blr

  /* At this point we assume that the ucontext was created by a
     rt_signal and we should use rt_sigreturn to restore the original
     state.  As of the 2.4.21 kernel the ucontext is the first thing
     (offset 0) in the rt_signal frame and rt_sigreturn expects the
     ucontext address in R1.  Normally the rt-signal trampoline handles
     this by popping dummy frame before the rt_signal syscall.  In our
     case the stack may not be in its original (signal handler return with
     R1 pointing at the dummy frame) state.  We do have the ucontext
     address in R3, so simply copy R3 to R1 before the syscall.  */
L(do_sigret):
  mr   r1,r3,
  li   r0,SYS_ify(rt_sigreturn)
  sc
  /* No return.  */
#else
  /* If the kernel is not at least 2.4.21 then generate a ENOSYS stub.  */
  mflr r0
  std  r0,FRAME_LR_SAVE(r1)
  cfi_offset (lr, FRAME_LR_SAVE)
  stdu r1,-128(r1)
  cfi_adjust_cfa_offset (128)
  li   r3,ENOSYS
  bl   JUMPTARGET(__syscall_error)
  nop
  li   r3,-1
  ld   r0,128+FRAME_LR_SAVE(r1)
  addi r1,r1,128
  mtlr r0
  blr
#endif

PSEUDO_END(__swapcontext)

versioned_symbol (libc, __swapcontext, swapcontext, GLIBC_2_3_4)