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# x86/x86_64 support for -fsplit-stack.

# Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.

# Contributed by Ian Lance Taylor .

# This file is part of GCC.

# GCC is free software; you can redistribute it and/or modify it under

# the terms of the GNU General Public License as published by the Free

# Software Foundation; either version 3, or (at your option) any later

# version.

# GCC is distributed in the hope that it will be useful, but WITHOUT ANY

# WARRANTY; without even the implied warranty of MERCHANTABILITY or

# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

# for more details.

# Under Section 7 of GPL version 3, you are granted additional

# permissions described in the GCC Runtime Library Exception, version

# 3.1, as published by the Free Software Foundation.

# You should have received a copy of the GNU General Public License and

# a copy of the GCC Runtime Library Exception along with this program;

# see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

# .

# Support for allocating more stack space when using -fsplit-stack.

# When a function discovers that it needs more stack space, it will

# call __morestack with the size of the stack frame and the size of

# the parameters to copy from the old stack frame to the new one.

# The __morestack function preserves the parameter registers and

# calls __generic_morestack to actually allocate the stack space.

# When this is called stack space is very low, but we ensure that

# there is enough space to push the parameter registers and to call

# __generic_morestack.

# When calling __generic_morestack, FRAME_SIZE points to the size of

# the desired frame when the function is called, and the function

# sets it to the size of the allocated stack.  OLD_STACK points to

# the parameters on the old stack and PARAM_SIZE is the number of

# bytes of parameters to copy to the new stack.  These are the

# parameters of the function that called __morestack.  The

# __generic_morestack function returns the new stack pointer,

# pointing to the address of the first copied parameter.  The return

# value minus the returned *FRAME_SIZE will be the first address on

# the stack which we should not use.

# void *__generic_morestack (size_t *frame_size, void *old_stack,

#                            size_t param_size);

# The __morestack routine has to arrange for the caller to return to a

# stub on the new stack.  The stub is responsible for restoring the

# old stack pointer and returning to the caller's caller.  This calls

# __generic_releasestack to retrieve the old stack pointer and release

# the newly allocated stack.

# void *__generic_releasestack (size_t *available);

# We do a little dance so that the processor's call/return return

# address prediction works out.  The compiler arranges for the caller

# to look like this:

#   call __generic_morestack

#   ret

#  L:

#   // carry on with function

# After we allocate more stack, we call L, which is in our caller.

# When that returns (to the predicted instruction), we release the

# stack segment and reset the stack pointer.  We then return to the

# predicted instruction, namely the ret instruction immediately after

# the call to __generic_morestack.  That then returns to the caller of

# the original caller.

# The amount of extra space we ask for.  In general this has to be

# enough for the dynamic loader to find a symbol and for a signal

# handler to run.

#ifndef __x86_64__

#define BACKOFF (1024)

#else

#define BACKOFF (1536)

#endif

# This entry point is for split-stack code which calls non-split-stack

# code.  When the linker sees this case, it converts the call to

# __morestack to call __morestack_non_split instead.  We just bump the

# requested stack space by 16K.

        .global __morestack_non_split

        .hidden __morestack_non_split

#ifdef __ELF__

       .type    __morestack_non_split,@function

#endif

__morestack_non_split:

        .cfi_startproc

#ifndef __x86_64__

        # See below for an extended explanation of this.

        .cfi_def_cfa %esp,16

        pushl   %eax                    # Save %eax in case it is a parameter.

        .cfi_adjust_cfa_offset 4        # Account for pushed register.

        movl    %esp,%eax               # Current stack,

        subl    8(%esp),%eax            # less required stack frame size,

        subl    $0x4000,%eax            # less space for non-split code.

        cmpl    %gs:0x30,%eax           # See if we have enough space.

        jb      2f                      # Get more space if we need it.

        # Here the stack is

        #       %esp + 20:      stack pointer after two returns

        #       %esp + 16:      return address of morestack caller's caller

        #       %esp + 12:      size of parameters

        #       %esp + 8:       new stack frame size

        #       %esp + 4:       return address of this function

        #       %esp:           saved %eax

        #

        # Since we aren't doing a full split stack, we don't need to

        # do anything when our caller returns.  So we return to our

        # caller rather than calling it, and let it return as usual.

        # To make that work we adjust the return address.

        # This breaks call/return address prediction for the call to

        # this function.  I can't figure out a way to make it work

        # short of copying the parameters down the stack, which will

        # probably take more clock cycles than we will lose breaking

        # call/return address prediction.  We will only break

        # prediction for this call, not for our caller.

        movl    4(%esp),%eax            # Increment the return address

        cmpb    $0xc3,(%eax)            # to skip the ret instruction;

        je      1f                      # see above.

        addl    $2,%eax

1:      inc     %eax

        movl    %eax,4(%esp)            # Update return address.

        popl    %eax                    # Restore %eax and stack.

        .cfi_adjust_cfa_offset -4       # Account for popped register.

        ret     $8                      # Return to caller, popping args.

2:

        .cfi_adjust_cfa_offset 4        # Back to where we were.

        popl    %eax                    # Restore %eax and stack.

        .cfi_adjust_cfa_offset -4       # Account for popped register.

        addl    $0x5000+BACKOFF,4(%esp) # Increment space we request.

        # Fall through into morestack.

#else

        # See below for an extended explanation of this.

        .cfi_def_cfa %rsp,16

        pushq   %rax                    # Save %rax in case caller is using

                                        # it to preserve original %r10.

        .cfi_adjust_cfa_offset 8        # Adjust for pushed register.

        movq    %rsp,%rax               # Current stack,

        subq    %r10,%rax               # less required stack frame size,

        subq    $0x4000,%rax            # less space for non-split code.

#ifdef __LP64__

        cmpq    %fs:0x70,%rax           # See if we have enough space.

#else

        cmpl    %fs:0x40,%eax

#endif

        popq    %rax                    # Restore register.

        .cfi_adjust_cfa_offset -8       # Adjust for popped register.

        jb      2f                      # Get more space if we need it.

        # This breaks call/return prediction, as described above.

        incq    (%rsp)                  # Increment the return address.

        ret                             # Return to caller.

2:

        addq    $0x5000+BACKOFF,%r10    # Increment space we request.

        # Fall through into morestack.

#endif

        .cfi_endproc

#ifdef __ELF__

        .size   __morestack_non_split, . - __morestack_non_split

#endif

# __morestack_non_split falls through into __morestack.

# The __morestack function.

        .global __morestack

        .hidden __morestack

#ifdef __ELF__

        .type   __morestack,@function

#endif

__morestack:

.LFB1:

        .cfi_startproc

#ifndef __x86_64__

# The 32-bit __morestack function.

        # We use a cleanup to restore the stack guard if an exception

        # is thrown through this code.

#ifndef __PIC__

        .cfi_personality 0,__gcc_personality_v0

        .cfi_lsda 0,.LLSDA1

#else

        .cfi_personality 0x9b,DW.ref.__gcc_personality_v0

        .cfi_lsda 0x1b,.LLSDA1

#endif

        # We return below with a ret $8.  We will return to a single

        # return instruction, which will return to the caller of our

        # caller.  We let the unwinder skip that single return

        # instruction, and just return to the real caller.

        # Here CFA points just past the return address on the stack,

        # e.g., on function entry it is %esp + 4.  The stack looks

        # like this:

        #       CFA + 12:       stack pointer after two returns

        #       CFA + 8:        return address of morestack caller's caller

        #       CFA + 4:        size of parameters

        #       CFA:            new stack frame size

        #       CFA - 4:        return address of this function

        #       CFA - 8:        previous value of %ebp; %ebp points here

        # Setting the new CFA to be the current CFA + 12 (i.e., %esp +

        # 16) will make the unwinder pick up the right return address.

        .cfi_def_cfa %esp,16

        pushl   %ebp

        .cfi_adjust_cfa_offset 4

        .cfi_offset %ebp, -20

        movl    %esp,%ebp

        .cfi_def_cfa_register %ebp

        # In 32-bit mode the parameters are pushed on the stack.  The

        # argument size is pushed then the new stack frame size is

        # pushed.

        # Align stack to 16-byte boundary with enough space for saving

        # registers and passing parameters to functions we call.

        subl    $40,%esp

        # Because our cleanup code may need to clobber %ebx, we need

        # to save it here so the unwinder can restore the value used

        # by the caller.  Note that we don't have to restore the

        # register, since we don't change it, we just have to save it

        # for the unwinder.

        movl    %ebx,-4(%ebp)

        .cfi_offset %ebx, -24

        # In 32-bit mode the registers %eax, %edx, and %ecx may be

        # used for parameters, depending on the regparm and fastcall

        # attributes.

        movl    %eax,-8(%ebp)

        movl    %edx,-12(%ebp)

        movl    %ecx,-16(%ebp)

        call    __morestack_block_signals

        movl    12(%ebp),%eax           # The size of the parameters.

        movl    %eax,8(%esp)

        leal    20(%ebp),%eax           # Address of caller's parameters.

        movl    %eax,4(%esp)

        addl    $BACKOFF,8(%ebp)        # Ask for backoff bytes.

        leal    8(%ebp),%eax            # The address of the new frame size.

        movl    %eax,(%esp)

        call    __generic_morestack

        movl    %eax,%esp               # Switch to the new stack.

        subl    8(%ebp),%eax            # The end of the stack space.

        addl    $BACKOFF,%eax           # Back off 512 bytes.

.LEHB0:

        # FIXME: The offset must match

        # TARGET_THREAD_SPLIT_STACK_OFFSET in

        # gcc/config/i386/linux.h.

        movl    %eax,%gs:0x30           # Save the new stack boundary.

        call    __morestack_unblock_signals

        movl    -12(%ebp),%edx          # Restore registers.

        movl    -16(%ebp),%ecx

        movl    4(%ebp),%eax            # Increment the return address

        cmpb    $0xc3,(%eax)            # to skip the ret instruction;

        je      1f                      # see above.

        addl    $2,%eax

1:      inc     %eax

        movl    %eax,-12(%ebp)          # Store return address in an

                                        # unused slot.

        movl    -8(%ebp),%eax           # Restore the last register.

        call    *-12(%ebp)              # Call our caller!

        # The caller will return here, as predicted.

        # Save the registers which may hold a return value.  We

        # assume that __generic_releasestack does not touch any

        # floating point or vector registers.

        pushl   %eax

        pushl   %edx

        # Push the arguments to __generic_releasestack now so that the

        # stack is at a 16-byte boundary for

        # __morestack_block_signals.

        pushl   $0                      # Where the available space is returned.

        leal    0(%esp),%eax            # Push its address.

        push    %eax

        call    __morestack_block_signals

        call    __generic_releasestack

        subl    4(%esp),%eax            # Subtract available space.

        addl    $BACKOFF,%eax           # Back off 512 bytes.

.LEHE0:

        movl    %eax,%gs:0x30           # Save the new stack boundary.

        addl    $8,%esp                 # Remove values from stack.

        # We need to restore the old stack pointer, which is in %rbp,

        # before we unblock signals.  We also need to restore %eax and

        # %edx after we unblock signals but before we return.  Do this

        # by moving %eax and %edx from the current stack to the old

        # stack.

        popl    %edx                    # Pop return value from current stack.

        popl    %eax

        movl    %ebp,%esp               # Restore stack pointer.

        pushl   %eax                    # Push return value on old stack.

        pushl   %edx

        subl    $8,%esp                 # Align stack to 16-byte boundary.

        call    __morestack_unblock_signals

        addl    $8,%esp

        popl    %edx                    # Restore return value.

        popl    %eax

        .cfi_remember_state

        # We never changed %ebx, so we don't have to actually restore it.

        .cfi_restore %ebx

        popl    %ebp

        .cfi_restore %ebp

        .cfi_def_cfa %esp, 16

        ret     $8                      # Return to caller, which will

                                        # immediately return.  Pop

                                        # arguments as we go.

# This is the cleanup code called by the stack unwinder when unwinding

# through the code between .LEHB0 and .LEHE0 above.

.L1:

        .cfi_restore_state

        subl    $16,%esp                # Maintain 16 byte alignment.

        movl    %eax,4(%esp)            # Save exception header.

        movl    %ebp,(%esp)             # Stack pointer after resume.

        call    __generic_findstack

        movl    %ebp,%ecx               # Get the stack pointer.

        subl    %eax,%ecx               # Subtract available space.

        addl    $BACKOFF,%ecx           # Back off 512 bytes.

        movl    %ecx,%gs:0x30           # Save new stack boundary.

        movl    4(%esp),%eax            # Function argument.

        movl    %eax,(%esp)

#ifdef __PIC__

        call    __x86.get_pc_thunk.bx   # %ebx may not be set up for us.

        addl    $_GLOBAL_OFFSET_TABLE_, %ebx

        call    _Unwind_Resume@PLT      # Resume unwinding.

#else

        call    _Unwind_Resume

#endif

#else /* defined(__x86_64__) */

# The 64-bit __morestack function.

        # We use a cleanup to restore the stack guard if an exception

        # is thrown through this code.

#ifndef __PIC__

        .cfi_personality 0x3,__gcc_personality_v0

        .cfi_lsda 0x3,.LLSDA1

#else

        .cfi_personality 0x9b,DW.ref.__gcc_personality_v0

        .cfi_lsda 0x1b,.LLSDA1

#endif

        # We will return a single return instruction, which will

        # return to the caller of our caller.  Let the unwinder skip

        # that single return instruction, and just return to the real

        # caller.

        .cfi_def_cfa %rsp,16

        # Set up a normal backtrace.

        pushq   %rbp

        .cfi_adjust_cfa_offset 8

        .cfi_offset %rbp, -24

        movq    %rsp, %rbp

        .cfi_def_cfa_register %rbp

        # In 64-bit mode the new stack frame size is passed in r10

        # and the argument size is passed in r11.

        addq    $BACKOFF,%r10           # Ask for backoff bytes.

        pushq   %r10                    # Save new frame size.

        # In 64-bit mode the registers %rdi, %rsi, %rdx, %rcx, %r8,

        # and %r9 may be used for parameters.  We also preserve %rax

        # which the caller may use to hold %r10.

        pushq   %rax

        pushq   %rdi

        pushq   %rsi

        pushq   %rdx

        pushq   %rcx

        pushq   %r8

        pushq   %r9

        pushq   %r11

        pushq   $0                      # For alignment.

        call    __morestack_block_signals

        leaq    -8(%rbp),%rdi           # Address of new frame size.

        leaq    24(%rbp),%rsi           # The caller's parameters.

        addq    $8,%rsp

        popq    %rdx                    # The size of the parameters.

        call    __generic_morestack

        movq    -8(%rbp),%r10           # Reload modified frame size

        movq    %rax,%rsp               # Switch to the new stack.

        subq    %r10,%rax               # The end of the stack space.

        addq    $BACKOFF,%rax           # Back off 1024 bytes.

.LEHB0:

        # FIXME: The offset must match

        # TARGET_THREAD_SPLIT_STACK_OFFSET in

        # gcc/config/i386/linux64.h.

        # Macro to save the new stack boundary.

#ifdef __LP64__

#define X86_64_SAVE_NEW_STACK_BOUNDARY(reg)     movq    %r##reg,%fs:0x70

#else

#define X86_64_SAVE_NEW_STACK_BOUNDARY(reg)     movl    %e##reg,%fs:0x40

#endif

        X86_64_SAVE_NEW_STACK_BOUNDARY (ax)

        call    __morestack_unblock_signals

        movq    -24(%rbp),%rdi          # Restore registers.

        movq    -32(%rbp),%rsi

        movq    -40(%rbp),%rdx

        movq    -48(%rbp),%rcx

        movq    -56(%rbp),%r8

        movq    -64(%rbp),%r9

        movq    8(%rbp),%r10            # Increment the return address

        incq    %r10                    # to skip the ret instruction;

                                        # see above.

        movq    -16(%rbp),%rax          # Restore caller's %rax.

        call    *%r10                   # Call our caller!

        # The caller will return here, as predicted.

        # Save the registers which may hold a return value.  We

        # assume that __generic_releasestack does not touch any

        # floating point or vector registers.

        pushq   %rax

        pushq   %rdx

        call    __morestack_block_signals

        pushq   $0                      # For alignment.

        pushq   $0                      # Where the available space is returned.

        leaq    0(%rsp),%rdi            # Pass its address.

        call    __generic_releasestack

        subq    0(%rsp),%rax            # Subtract available space.

        addq    $BACKOFF,%rax           # Back off 1024 bytes.

.LEHE0:

        X86_64_SAVE_NEW_STACK_BOUNDARY (ax)

        addq    $16,%rsp                # Remove values from stack.

        # We need to restore the old stack pointer, which is in %rbp,

        # before we unblock signals.  We also need to restore %rax and

        # %rdx after we unblock signals but before we return.  Do this

        # by moving %rax and %rdx from the current stack to the old

        # stack.

        popq    %rdx                    # Pop return value from current stack.

        popq    %rax

        movq    %rbp,%rsp               # Restore stack pointer.

        pushq   %rax                    # Push return value on old stack.

        pushq   %rdx

        call    __morestack_unblock_signals

        popq    %rdx                    # Restore return value.

        popq    %rax

        .cfi_remember_state

        popq    %rbp

        .cfi_restore %rbp

        .cfi_def_cfa %rsp, 16

        ret                             # Return to caller, which will

                                        # immediately return.

# This is the cleanup code called by the stack unwinder when unwinding

# through the code between .LEHB0 and .LEHE0 above.

.L1:

        .cfi_restore_state

        subq    $16,%rsp                # Maintain 16 byte alignment.

        movq    %rax,(%rsp)             # Save exception header.

        movq    %rbp,%rdi               # Stack pointer after resume.

        call    __generic_findstack

        movq    %rbp,%rcx               # Get the stack pointer.

        subq    %rax,%rcx               # Subtract available space.

        addq    $BACKOFF,%rcx           # Back off 1024 bytes.

        X86_64_SAVE_NEW_STACK_BOUNDARY (cx)

        movq    (%rsp),%rdi             # Restore exception data for call.

#ifdef __PIC__

        call    _Unwind_Resume@PLT      # Resume unwinding.

#else

        call    _Unwind_Resume          # Resume unwinding.

#endif

#endif /* defined(__x86_64__) */

        .cfi_endproc

#ifdef __ELF__

        .size   __morestack, . - __morestack

#endif

#if !defined(__x86_64__) && defined(__PIC__)

# Output the thunk to get PC into bx, since we use it above.

        .section        .text.__x86.get_pc_thunk.bx,"axG",@progbits,__x86.get_pc_thunk.bx,comdat

        .globl  __x86.get_pc_thunk.bx

        .hidden __x86.get_pc_thunk.bx

#ifdef __ELF__

        .type   __x86.get_pc_thunk.bx, @function

#endif

__x86.get_pc_thunk.bx:

        .cfi_startproc

        movl    (%esp), %ebx

        ret

        .cfi_endproc

#ifdef __ELF__

        .size   __x86.get_pc_thunk.bx, . - __x86.get_pc_thunk.bx

#endif

#endif

# The exception table.  This tells the personality routine to execute

# the exception handler.

        .section        .gcc_except_table,"a",@progbits

        .align  4

.LLSDA1:

        .byte   0xff    # @LPStart format (omit)

        .byte   0xff    # @TType format (omit)

        .byte   0x1     # call-site format (uleb128)

        .uleb128 .LLSDACSE1-.LLSDACSB1  # Call-site table length

.LLSDACSB1:

        .uleb128 .LEHB0-.LFB1   # region 0 start

        .uleb128 .LEHE0-.LEHB0  # length

        .uleb128 .L1-.LFB1      # landing pad

        .uleb128 0              # action

.LLSDACSE1:

        .global __gcc_personality_v0

#ifdef __PIC__

        # Build a position independent reference to the basic

        # personality function.

        .hidden DW.ref.__gcc_personality_v0

        .weak   DW.ref.__gcc_personality_v0

        .section .data.DW.ref.__gcc_personality_v0,"awG",@progbits,DW.ref.__gcc_personality_v0,comdat

        .type   DW.ref.__gcc_personality_v0, @object

DW.ref.__gcc_personality_v0:

#ifndef __LP64__

        .align 4

        .size   DW.ref.__gcc_personality_v0, 4

        .long   __gcc_personality_v0

#else

        .align 8

        .size   DW.ref.__gcc_personality_v0, 8

        .quad   __gcc_personality_v0

#endif

#endif

#if defined __x86_64__ && defined __LP64__

# This entry point is used for the large model.  With this entry point

# the upper 32 bits of %r10 hold the argument size and the lower 32

# bits hold the new stack frame size.  There doesn't seem to be a way

# to know in the assembler code that we are assembling for the large

# model, and there doesn't seem to be a large model multilib anyhow.

# If one is developed, then the non-PIC code is probably OK since we

# will probably be close to the morestack code, but the PIC code

# almost certainly needs to be changed.  FIXME.

        .text

        .global __morestack_large_model

        .hidden __morestack_large_model

#ifdef __ELF__

        .type   __morestack_large_model,@function

#endif

__morestack_large_model:

        .cfi_startproc

        movq    %r10, %r11

        andl    $0xffffffff, %r10d

        sarq    $32, %r11

        jmp     __morestack

        .cfi_endproc

#ifdef __ELF__

       .size    __morestack_large_model, . - __morestack_large_model

#endif

#endif /* __x86_64__ && __LP64__ */

# Initialize the stack test value when the program starts or when a

# new thread starts.  We don't know how large the main stack is, so we

# guess conservatively.  We might be able to use getrlimit here.

        .text

        .global __stack_split_initialize

        .hidden __stack_split_initialize

#ifdef __ELF__

        .type   __stack_split_initialize, @function

#endif

__stack_split_initialize:

#ifndef __x86_64__

        leal    -16000(%esp),%eax       # We should have at least 16K.

        movl    %eax,%gs:0x30

        pushl   $16000

        pushl   %esp

#ifdef __PIC__

        call    __generic_morestack_set_initial_sp@PLT

#else

        call    __generic_morestack_set_initial_sp

#endif

        addl    $8,%esp

        ret

#else /* defined(__x86_64__) */

        leaq    -16000(%rsp),%rax       # We should have at least 16K.

        X86_64_SAVE_NEW_STACK_BOUNDARY (ax)

        movq    %rsp,%rdi

        movq    $16000,%rsi

#ifdef __PIC__

        call    __generic_morestack_set_initial_sp@PLT

#else

        call    __generic_morestack_set_initial_sp

#endif

        ret

#endif /* defined(__x86_64__) */

#ifdef __ELF__

        .size   __stack_split_initialize, . - __stack_split_initialize

#endif

# Routines to get and set the guard, for __splitstack_getcontext,

# __splitstack_setcontext, and __splitstack_makecontext.

# void *__morestack_get_guard (void) returns the current stack guard.

        .text

        .global __morestack_get_guard

        .hidden __morestack_get_guard

#ifdef __ELF__

        .type   __morestack_get_guard,@function

#endif

__morestack_get_guard:

#ifndef __x86_64__

        movl    %gs:0x30,%eax

#else

#ifdef __LP64__

        movq    %fs:0x70,%rax

#else

        movl    %fs:0x40,%eax

#endif

#endif

        ret

#ifdef __ELF__

        .size   __morestack_get_guard, . - __morestack_get_guard

#endif

# void __morestack_set_guard (void *) sets the stack guard.

        .global __morestack_set_guard

        .hidden __morestack_set_guard

#ifdef __ELF__

        .type   __morestack_set_guard,@function

#endif

__morestack_set_guard:

#ifndef __x86_64__

        movl    4(%esp),%eax

        movl    %eax,%gs:0x30

#else

        X86_64_SAVE_NEW_STACK_BOUNDARY (di)

#endif

        ret

#ifdef __ELF__

        .size   __morestack_set_guard, . - __morestack_set_guard

#endif

# void *__morestack_make_guard (void *, size_t) returns the stack

# guard value for a stack.

        .global __morestack_make_guard

        .hidden __morestack_make_guard

#ifdef __ELF__

        .type   __morestack_make_guard,@function

#endif

__morestack_make_guard:

#ifndef __x86_64__

        movl    4(%esp),%eax

        subl    8(%esp),%eax

        addl    $BACKOFF,%eax

#else

        subq    %rsi,%rdi

        addq    $BACKOFF,%rdi

        movq    %rdi,%rax

#endif

        ret

#ifdef __ELF__

        .size   __morestack_make_guard, . - __morestack_make_guard

#endif

# Make __stack_split_initialize a high priority constructor.  FIXME:

# This is ELF specific.

        .section        .ctors.65535,"aw",@progbits

#ifndef __LP64__

        .align  4

        .long   __stack_split_initialize

        .long   __morestack_load_mmap

#else

        .align  8

        .quad   __stack_split_initialize

        .quad   __morestack_load_mmap

#endif

#ifdef __ELF__

        .section        .note.GNU-stack,"",@progbits

        .section        .note.GNU-split-stack,"",@progbits

        .section        .note.GNU-no-split-stack,"",@progbits

#endif