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# s390 support for -fsplit-stack.
# Copyright (C) 2015-2021 Free Software Foundation, Inc.
# Contributed by Marcin Koƛcielnicki <koriakin@0x04.net>.
# 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/>.
# Excess space needed to call ld.so resolver for lazy plt
# resolution. Go uses sigaltstack so this doesn't need to
# also cover signal frame size.
#define BACKOFF 0x1000
#include <auto-host.h>
# The __morestack function.
.global __morestack
.hidden __morestack
.type __morestack,@function
__morestack:
.LFB1:
.cfi_startproc
#ifndef __s390x__
# The 31-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
stm %r2, %r15, 0x8(%r15) # Save %r2-%r15.
.cfi_offset %r6, -0x48
.cfi_offset %r7, -0x44
.cfi_offset %r8, -0x40
.cfi_offset %r9, -0x3c
.cfi_offset %r10, -0x38
.cfi_offset %r11, -0x34
.cfi_offset %r12, -0x30
.cfi_offset %r13, -0x2c
.cfi_offset %r14, -0x28
.cfi_offset %r15, -0x24
lr %r11, %r15 # Make frame pointer for vararg.
.cfi_def_cfa_register %r11
ahi %r15, -0x60 # 0x60 for standard frame.
st %r11, 0(%r15) # Save back chain.
lr %r8, %r0 # Save %r0 (static chain).
lr %r10, %r1 # Save %r1 (address of parameter block).
l %r7, 0(%r10) # Required frame size to %r7
ear %r1, %a0 # Extract thread pointer.
l %r1, 0x20(%r1) # Get stack bounduary
ar %r1, %r7 # Stack bounduary + frame size
a %r1, 4(%r10) # + stack param size
clr %r1, %r15 # Compare with current stack pointer
jle .Lnoalloc # guard > sp - frame-size: need alloc
brasl %r14, __morestack_block_signals
# We abuse one of caller's fpr save slots (which we don't use for fprs)
# as a local variable. Not needed here, but done to be consistent with
# the below use.
ahi %r7, BACKOFF # Bump requested size a bit.
st %r7, 0x40(%r11) # Stuff frame size on stack.
la %r2, 0x40(%r11) # Pass its address as parameter.
la %r3, 0x60(%r11) # Caller's stack parameters.
l %r4, 4(%r10) # Size of stack parameters.
brasl %r14, __generic_morestack
lr %r15, %r2 # Switch to the new stack.
ahi %r15, -0x60 # Make a stack frame on it.
st %r11, 0(%r15) # Save back chain.
s %r2, 0x40(%r11) # The end of stack space.
ahi %r2, BACKOFF # Back off a bit.
ear %r1, %a0 # Extract thread pointer.
.LEHB0:
st %r2, 0x20(%r1) # Save the new stack boundary.
brasl %r14, __morestack_unblock_signals
lr %r0, %r8 # Static chain.
lm %r2, %r6, 0x8(%r11) # Paremeter registers.
# Third parameter is address of function meat - address of parameter
# block.
a %r10, 0x8(%r10)
# Leave vararg pointer in %r1, in case function uses it
la %r1, 0x60(%r11)
# State of registers:
# %r0: Static chain from entry.
# %r1: Vararg pointer.
# %r2-%r6: Parameters from entry.
# %r7-%r10: Indeterminate.
# %r11: Frame pointer (%r15 from entry).
# %r12-%r13: Indeterminate.
# %r14: Return address.
# %r15: Stack pointer.
basr %r14, %r10 # Call our caller.
stm %r2, %r3, 0x8(%r11) # Save return registers.
brasl %r14, __morestack_block_signals
# We need a stack slot now, but have no good way to get it - the frame
# on new stack had to be exactly 0x60 bytes, or stack parameters would
# be passed wrong. Abuse fpr save area in caller's frame (we don't
# save actual fprs).
la %r2, 0x40(%r11)
brasl %r14, __generic_releasestack
s %r2, 0x40(%r11) # Subtract available space.
ahi %r2, BACKOFF # Back off a bit.
ear %r1, %a0 # Extract thread pointer.
.LEHE0:
st %r2, 0x20(%r1) # Save the new stack boundary.
# We need to restore the old stack pointer before unblocking signals.
# We also need 0x60 bytes for a stack frame. Since we had a stack
# frame at this place before the stack switch, there's no need to
# write the back chain again.
lr %r15, %r11
ahi %r15, -0x60
brasl %r14, __morestack_unblock_signals
lm %r2, %r15, 0x8(%r11) # Restore all registers.
.cfi_remember_state
.cfi_restore %r15
.cfi_restore %r14
.cfi_restore %r13
.cfi_restore %r12
.cfi_restore %r11
.cfi_restore %r10
.cfi_restore %r9
.cfi_restore %r8
.cfi_restore %r7
.cfi_restore %r6
.cfi_def_cfa_register %r15
br %r14 # Return to caller's caller.
# Executed if no new stack allocation is needed.
.Lnoalloc:
.cfi_restore_state
# We may need to copy stack parameters.
l %r9, 0x4(%r10) # Load stack parameter size.
ltr %r9, %r9 # And check if it's 0.
je .Lnostackparm # Skip the copy if not needed.
sr %r15, %r9 # Make space on the stack.
la %r8, 0x60(%r15) # Destination.
la %r12, 0x60(%r11) # Source.
lr %r13, %r9 # Source size.
.Lcopy:
mvcle %r8, %r12, 0 # Copy.
jo .Lcopy
.Lnostackparm:
# Third parameter is address of function meat - address of parameter
# block.
a %r10, 0x8(%r10)
# Leave vararg pointer in %r1, in case function uses it
la %r1, 0x60(%r11)
# OK, no stack allocation needed. We still follow the protocol and
# call our caller - it doesn't cost much and makes sure vararg works.
# No need to set any registers here - %r0 and %r2-%r6 weren't modified.
basr %r14, %r10 # Call our caller.
lm %r6, %r15, 0x18(%r11) # Restore all callee-saved registers.
.cfi_remember_state
.cfi_restore %r15
.cfi_restore %r14
.cfi_restore %r13
.cfi_restore %r12
.cfi_restore %r11
.cfi_restore %r10
.cfi_restore %r9
.cfi_restore %r8
.cfi_restore %r7
.cfi_restore %r6
.cfi_def_cfa_register %r15
br %r14 # Return to caller's caller.
# This is the cleanup code called by the stack unwinder when unwinding
# through the code between .LEHB0 and .LEHE0 above.
.L1:
.cfi_restore_state
lr %r2, %r11 # Stack pointer after resume.
brasl %r14, __generic_findstack
lr %r3, %r11 # Get the stack pointer.
sr %r3, %r2 # Subtract available space.
ahi %r3, BACKOFF # Back off a bit.
ear %r1, %a0 # Extract thread pointer.
st %r3, 0x20(%r1) # Save the new stack boundary.
# We need GOT pointer in %r12 for PLT entry.
larl %r12,_GLOBAL_OFFSET_TABLE_
lr %r2, %r6 # Exception header.
#ifdef __PIC__
brasl %r14, _Unwind_Resume@PLT
#else
brasl %r14, _Unwind_Resume
#endif
#else /* defined(__s390x__) */
# 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
stmg %r2, %r15, 0x10(%r15) # Save %r2-%r15.
.cfi_offset %r6, -0x70
.cfi_offset %r7, -0x68
.cfi_offset %r8, -0x60
.cfi_offset %r9, -0x58
.cfi_offset %r10, -0x50
.cfi_offset %r11, -0x48
.cfi_offset %r12, -0x40
.cfi_offset %r13, -0x38
.cfi_offset %r14, -0x30
.cfi_offset %r15, -0x28
lgr %r11, %r15 # Make frame pointer for vararg.
.cfi_def_cfa_register %r11
aghi %r15, -0xa0 # 0xa0 for standard frame.
stg %r11, 0(%r15) # Save back chain.
lgr %r8, %r0 # Save %r0 (static chain).
lgr %r10, %r1 # Save %r1 (address of parameter block).
lg %r7, 0(%r10) # Required frame size to %r7
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1 # Extract thread pointer.
lg %r1, 0x38(%r1) # Get stack bounduary
agr %r1, %r7 # Stack bounduary + frame size
ag %r1, 8(%r10) # + stack param size
clgr %r1, %r15 # Compare with current stack pointer
jle .Lnoalloc # guard > sp - frame-size: need alloc
brasl %r14, __morestack_block_signals
# We abuse one of caller's fpr save slots (which we don't use for fprs)
# as a local variable. Not needed here, but done to be consistent with
# the below use.
aghi %r7, BACKOFF # Bump requested size a bit.
stg %r7, 0x80(%r11) # Stuff frame size on stack.
la %r2, 0x80(%r11) # Pass its address as parameter.
la %r3, 0xa0(%r11) # Caller's stack parameters.
lg %r4, 8(%r10) # Size of stack parameters.
brasl %r14, __generic_morestack
lgr %r15, %r2 # Switch to the new stack.
aghi %r15, -0xa0 # Make a stack frame on it.
stg %r11, 0(%r15) # Save back chain.
sg %r2, 0x80(%r11) # The end of stack space.
aghi %r2, BACKOFF # Back off a bit.
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1 # Extract thread pointer.
.LEHB0:
stg %r2, 0x38(%r1) # Save the new stack boundary.
brasl %r14, __morestack_unblock_signals
lgr %r0, %r8 # Static chain.
lmg %r2, %r6, 0x10(%r11) # Paremeter registers.
# Third parameter is address of function meat - address of parameter
# block.
ag %r10, 0x10(%r10)
# Leave vararg pointer in %r1, in case function uses it
la %r1, 0xa0(%r11)
# State of registers:
# %r0: Static chain from entry.
# %r1: Vararg pointer.
# %r2-%r6: Parameters from entry.
# %r7-%r10: Indeterminate.
# %r11: Frame pointer (%r15 from entry).
# %r12-%r13: Indeterminate.
# %r14: Return address.
# %r15: Stack pointer.
basr %r14, %r10 # Call our caller.
stg %r2, 0x10(%r11) # Save return register.
brasl %r14, __morestack_block_signals
# We need a stack slot now, but have no good way to get it - the frame
# on new stack had to be exactly 0xa0 bytes, or stack parameters would
# be passed wrong. Abuse fpr save area in caller's frame (we don't
# save actual fprs).
la %r2, 0x80(%r11)
brasl %r14, __generic_releasestack
sg %r2, 0x80(%r11) # Subtract available space.
aghi %r2, BACKOFF # Back off a bit.
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1 # Extract thread pointer.
.LEHE0:
stg %r2, 0x38(%r1) # Save the new stack boundary.
# We need to restore the old stack pointer before unblocking signals.
# We also need 0xa0 bytes for a stack frame. Since we had a stack
# frame at this place before the stack switch, there's no need to
# write the back chain again.
lgr %r15, %r11
aghi %r15, -0xa0
brasl %r14, __morestack_unblock_signals
lmg %r2, %r15, 0x10(%r11) # Restore all registers.
.cfi_remember_state
.cfi_restore %r15
.cfi_restore %r14
.cfi_restore %r13
.cfi_restore %r12
.cfi_restore %r11
.cfi_restore %r10
.cfi_restore %r9
.cfi_restore %r8
.cfi_restore %r7
.cfi_restore %r6
.cfi_def_cfa_register %r15
br %r14 # Return to caller's caller.
# Executed if no new stack allocation is needed.
.Lnoalloc:
.cfi_restore_state
# We may need to copy stack parameters.
lg %r9, 0x8(%r10) # Load stack parameter size.
ltgr %r9, %r9 # Check if it's 0.
je .Lnostackparm # Skip the copy if not needed.
sgr %r15, %r9 # Make space on the stack.
la %r8, 0xa0(%r15) # Destination.
la %r12, 0xa0(%r11) # Source.
lgr %r13, %r9 # Source size.
.Lcopy:
mvcle %r8, %r12, 0 # Copy.
jo .Lcopy
.Lnostackparm:
# Third parameter is address of function meat - address of parameter
# block.
ag %r10, 0x10(%r10)
# Leave vararg pointer in %r1, in case function uses it
la %r1, 0xa0(%r11)
# OK, no stack allocation needed. We still follow the protocol and
# call our caller - it doesn't cost much and makes sure vararg works.
# No need to set any registers here - %r0 and %r2-%r6 weren't modified.
basr %r14, %r10 # Call our caller.
lmg %r6, %r15, 0x30(%r11) # Restore all callee-saved registers.
.cfi_remember_state
.cfi_restore %r15
.cfi_restore %r14
.cfi_restore %r13
.cfi_restore %r12
.cfi_restore %r11
.cfi_restore %r10
.cfi_restore %r9
.cfi_restore %r8
.cfi_restore %r7
.cfi_restore %r6
.cfi_def_cfa_register %r15
br %r14 # Return to caller's caller.
# This is the cleanup code called by the stack unwinder when unwinding
# through the code between .LEHB0 and .LEHE0 above.
.L1:
.cfi_restore_state
lgr %r2, %r11 # Stack pointer after resume.
brasl %r14, __generic_findstack
lgr %r3, %r11 # Get the stack pointer.
sgr %r3, %r2 # Subtract available space.
aghi %r3, BACKOFF # Back off a bit.
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1 # Extract thread pointer.
stg %r3, 0x38(%r1) # Save the new stack boundary.
lgr %r2, %r6 # Exception header.
#ifdef __PIC__
brasl %r14, _Unwind_Resume@PLT
#else
brasl %r14, _Unwind_Resume
#endif
#endif /* defined(__s390x__) */
.cfi_endproc
.size __morestack, . - __morestack
# 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
# 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
.type __stack_split_initialize, @function
__stack_split_initialize:
#ifndef __s390x__
ear %r1, %a0
lr %r0, %r15
ahi %r0, -0x4000 # We should have at least 16K.
st %r0, 0x20(%r1)
lr %r2, %r15
lhi %r3, 0x4000
#ifdef __PIC__
jg __generic_morestack_set_initial_sp@PLT # Tail call
#else
jg __generic_morestack_set_initial_sp # Tail call
#endif
#else /* defined(__s390x__) */
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1
lgr %r0, %r15
aghi %r0, -0x4000 # We should have at least 16K.
stg %r0, 0x38(%r1)
lgr %r2, %r15
lghi %r3, 0x4000
#ifdef __PIC__
jg __generic_morestack_set_initial_sp@PLT # Tail call
#else
jg __generic_morestack_set_initial_sp # Tail call
#endif
#endif /* defined(__s390x__) */
.size __stack_split_initialize, . - __stack_split_initialize
# 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
.type __morestack_get_guard,@function
__morestack_get_guard:
#ifndef __s390x__
ear %r1, %a0
l %r2, 0x20(%r1)
#else
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1
lg %r2, 0x38(%r1)
#endif
br %r14
.size __morestack_get_guard, . - __morestack_get_guard
# void __morestack_set_guard (void *) sets the stack guard.
.global __morestack_set_guard
.hidden __morestack_set_guard
.type __morestack_set_guard,@function
__morestack_set_guard:
#ifndef __s390x__
ear %r1, %a0
st %r2, 0x20(%r1)
#else
ear %r1, %a0
sllg %r1, %r1, 32
ear %r1, %a1
stg %r2, 0x38(%r1)
#endif
br %r14
.size __morestack_set_guard, . - __morestack_set_guard
# void *__morestack_make_guard (void *, size_t) returns the stack
# guard value for a stack.
.global __morestack_make_guard
.hidden __morestack_make_guard
.type __morestack_make_guard,@function
__morestack_make_guard:
#ifndef __s390x__
sr %r2, %r3
ahi %r2, BACKOFF
#else
sgr %r2, %r3
aghi %r2, BACKOFF
#endif
br %r14
.size __morestack_make_guard, . - __morestack_make_guard
# Make __stack_split_initialize a high priority constructor.
#if HAVE_INITFINI_ARRAY_SUPPORT
.section .init_array.00000,"aw",@progbits
#else
.section .ctors.65535,"aw",@progbits
#endif
#ifndef __LP64__
.align 4
.long __stack_split_initialize
.long __morestack_load_mmap
#else
.align 8
.quad __stack_split_initialize
.quad __morestack_load_mmap
#endif
.section .note.GNU-stack,"",@progbits
.section .note.GNU-split-stack,"",@progbits
.section .note.GNU-no-split-stack,"",@progbits