| # x86/x86_64 support for -fsplit-stack. |
| # Copyright (C) 2009-2021 Free Software Foundation, Inc. |
| # Contributed by Ian Lance Taylor <iant@google.com>. |
| |
| # 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 |
| # <http://www.gnu.org/licenses/>. |
| |
| |
| # 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 (3584) |
| #endif |
| |
| |
| # The amount of space we ask for when calling non-split-stack code. |
| #define NON_SPLIT_STACK 0x100000 |
| |
| # 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. |
| |
| #include <cet.h> |
| |
| .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 $NON_SPLIT_STACK,%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 |
| |
| # If the instruction that we return to is |
| # leal 20(%ebp),{%eax,%ecx,%edx} |
| # then we have been called by a varargs function that expects |
| # %ebp to hold a real value. That can only work if we do the |
| # full stack split routine. FIXME: This is fragile. |
| cmpb $0x8d,(%eax) |
| jne 3f |
| cmpb $0x14,2(%eax) |
| jne 3f |
| cmpb $0x45,1(%eax) |
| je 2f |
| cmpb $0x4d,1(%eax) |
| je 2f |
| cmpb $0x55,1(%eax) |
| je 2f |
| |
| 3: |
| 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. |
| |
| # Increment space we request. |
| addl $NON_SPLIT_STACK+0x1000+BACKOFF,4(%esp) |
| |
| # 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 $NON_SPLIT_STACK,%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 |
| |
| jb 2f # Get more space if we need it. |
| |
| # If the instruction that we return to is |
| # leaq 24(%rbp), %r11n |
| # then we have been called by a varargs function that expects |
| # %ebp to hold a real value. That can only work if we do the |
| # full stack split routine. FIXME: This is fragile. |
| movq 8(%rsp),%rax |
| incq %rax # Skip ret instruction in caller. |
| cmpl $0x185d8d4c,(%rax) |
| je 2f |
| |
| # This breaks call/return prediction, as described above. |
| incq 8(%rsp) # Increment the return address. |
| |
| popq %rax # Restore register. |
| |
| .cfi_adjust_cfa_offset -8 # Adjust for popped register. |
| |
| ret # Return to caller. |
| |
| 2: |
| popq %rax # Restore register. |
| |
| .cfi_adjust_cfa_offset -8 # Adjust for popped register. |
| |
| # Increment space we request. |
| addq $NON_SPLIT_STACK+0x1000+BACKOFF,%r10 |
| |
| # 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. |
| |
| # In the body of a non-leaf function, the stack pointer will |
| # be aligned to a 16-byte boundary. That is CFA + 12 in the |
| # stack picture above: (CFA + 12) % 16 == 0. At this point we |
| # have %esp == CFA - 8, so %esp % 16 == 12. We need some |
| # space for saving registers and passing parameters, and we |
| # need to wind up with %esp % 16 == 0. |
| subl $44,%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. |
| |
| # As before, we now have %esp % 16 == 12. |
| |
| pushl %eax # Push return value on old stack. |
| pushl %edx |
| subl $4,%esp # Align stack to 16-byte boundary. |
| |
| call __morestack_unblock_signals |
| |
| addl $4,%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 |
| |
| # We entered morestack with the stack pointer aligned to a |
| # 16-byte boundary (the call to morestack's caller used 8 |
| # bytes, and the call to morestack used 8 bytes). We have now |
| # pushed 10 registers, so we are still aligned to a 16-byte |
| # boundary. |
| |
| call __morestack_block_signals |
| |
| leaq -8(%rbp),%rdi # Address of new frame size. |
| leaq 24(%rbp),%rsi # The caller's parameters. |
| popq %rdx # The size of the parameters. |
| |
| subq $8,%rsp # Align stack. |
| |
| 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. |
| |
| # Now (%rsp & 16) == 8. |
| |
| subq $8,%rsp # For alignment. |
| pushq %rax # Push return value on old stack. |
| pushq %rdx |
| |
| call __morestack_unblock_signals |
| |
| popq %rdx # Restore return value. |
| popq %rax |
| addq $8,%rsp |
| |
| .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 |
| _CET_ENDBR |
| |
| 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: |
| _CET_ENDBR |
| |
| #ifndef __x86_64__ |
| |
| leal -16000(%esp),%eax # We should have at least 16K. |
| movl %eax,%gs:0x30 |
| subl $4,%esp # Align stack. |
| pushl $16000 |
| pushl %esp |
| #ifdef __PIC__ |
| call __generic_morestack_set_initial_sp@PLT |
| #else |
| call __generic_morestack_set_initial_sp |
| #endif |
| addl $12,%esp |
| ret |
| |
| #else /* defined(__x86_64__) */ |
| |
| leaq -16000(%rsp),%rax # We should have at least 16K. |
| X86_64_SAVE_NEW_STACK_BOUNDARY (ax) |
| subq $8,%rsp # Align stack. |
| movq %rsp,%rdi |
| movq $16000,%rsi |
| #ifdef __PIC__ |
| call __generic_morestack_set_initial_sp@PLT |
| #else |
| call __generic_morestack_set_initial_sp |
| #endif |
| addq $8,%rsp |
| 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 |