/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* rtrap.S: Return from Sparc trap low-level code.
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*
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* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
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*/
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#include <asm/page.h>
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#include <asm/ptrace.h>
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#include <asm/psr.h>
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#include <asm/asi.h>
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#include <asm/smp.h>
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#include <asm/contregs.h>
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#include <asm/winmacro.h>
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#include <asm/asmmacro.h>
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#include <asm/thread_info.h>
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#define t_psr l0
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#define t_pc l1
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#define t_npc l2
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#define t_wim l3
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#define twin_tmp1 l4
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#define glob_tmp g4
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#define curptr g6
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/* 7 WINDOW SPARC PATCH INSTRUCTIONS */
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.globl rtrap_7win_patch1, rtrap_7win_patch2, rtrap_7win_patch3
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.globl rtrap_7win_patch4, rtrap_7win_patch5
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rtrap_7win_patch1: srl %t_wim, 0x6, %glob_tmp
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rtrap_7win_patch2: and %glob_tmp, 0x7f, %glob_tmp
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rtrap_7win_patch3: srl %g1, 7, %g2
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rtrap_7win_patch4: srl %g2, 6, %g2
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rtrap_7win_patch5: and %g1, 0x7f, %g1
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/* END OF PATCH INSTRUCTIONS */
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/* We need to check for a few things which are:
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* 1) The need to call schedule() because this
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* processes quantum is up.
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* 2) Pending signals for this process, if any
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* exist we need to call do_signal() to do
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* the needy.
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*
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* Else we just check if the rett would land us
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* in an invalid window, if so we need to grab
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* it off the user/kernel stack first.
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*/
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.globl ret_trap_entry, rtrap_patch1, rtrap_patch2
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.globl rtrap_patch3, rtrap_patch4, rtrap_patch5
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.globl ret_trap_lockless_ipi
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ret_trap_entry:
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ret_trap_lockless_ipi:
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andcc %t_psr, PSR_PS, %g0
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sethi %hi(PSR_SYSCALL), %g1
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be 1f
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andn %t_psr, %g1, %t_psr
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wr %t_psr, 0x0, %psr
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b ret_trap_kernel
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nop
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1:
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ld [%curptr + TI_FLAGS], %g2
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andcc %g2, (_TIF_NEED_RESCHED), %g0
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be signal_p
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nop
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call schedule
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nop
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ld [%curptr + TI_FLAGS], %g2
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signal_p:
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andcc %g2, _TIF_DO_NOTIFY_RESUME_MASK, %g0
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bz,a ret_trap_continue
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ld [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
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mov %g2, %o2
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mov %l5, %o1
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call do_notify_resume
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add %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
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b signal_p
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ld [%curptr + TI_FLAGS], %g2
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ret_trap_continue:
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sethi %hi(PSR_SYSCALL), %g1
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andn %t_psr, %g1, %t_psr
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wr %t_psr, 0x0, %psr
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WRITE_PAUSE
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ld [%curptr + TI_W_SAVED], %twin_tmp1
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orcc %g0, %twin_tmp1, %g0
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be ret_trap_nobufwins
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nop
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wr %t_psr, PSR_ET, %psr
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WRITE_PAUSE
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mov 1, %o1
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call try_to_clear_window_buffer
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add %sp, STACKFRAME_SZ, %o0
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b signal_p
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ld [%curptr + TI_FLAGS], %g2
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ret_trap_nobufwins:
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/* Load up the user's out registers so we can pull
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* a window from the stack, if necessary.
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*/
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LOAD_PT_INS(sp)
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/* If there are already live user windows in the
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* set we can return from trap safely.
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*/
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ld [%curptr + TI_UWINMASK], %twin_tmp1
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orcc %g0, %twin_tmp1, %g0
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bne ret_trap_userwins_ok
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nop
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/* Calculate new %wim, we have to pull a register
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* window from the users stack.
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*/
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ret_trap_pull_one_window:
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rd %wim, %t_wim
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sll %t_wim, 0x1, %twin_tmp1
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rtrap_patch1: srl %t_wim, 0x7, %glob_tmp
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or %glob_tmp, %twin_tmp1, %glob_tmp
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rtrap_patch2: and %glob_tmp, 0xff, %glob_tmp
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wr %glob_tmp, 0x0, %wim
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/* Here comes the architecture specific
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* branch to the user stack checking routine
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* for return from traps.
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*/
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b srmmu_rett_stackchk
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andcc %fp, 0x7, %g0
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ret_trap_userwins_ok:
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LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc)
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or %t_pc, %t_npc, %g2
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andcc %g2, 0x3, %g0
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sethi %hi(PSR_SYSCALL), %g2
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be 1f
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andn %t_psr, %g2, %t_psr
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b ret_trap_unaligned_pc
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add %sp, STACKFRAME_SZ, %o0
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1:
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LOAD_PT_YREG(sp, g1)
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LOAD_PT_GLOBALS(sp)
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wr %t_psr, 0x0, %psr
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WRITE_PAUSE
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jmp %t_pc
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rett %t_npc
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ret_trap_unaligned_pc:
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ld [%sp + STACKFRAME_SZ + PT_PC], %o1
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ld [%sp + STACKFRAME_SZ + PT_NPC], %o2
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ld [%sp + STACKFRAME_SZ + PT_PSR], %o3
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wr %t_wim, 0x0, %wim ! or else...
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wr %t_psr, PSR_ET, %psr
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WRITE_PAUSE
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call do_memaccess_unaligned
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nop
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b signal_p
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ld [%curptr + TI_FLAGS], %g2
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ret_trap_kernel:
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/* Will the rett land us in the invalid window? */
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mov 2, %g1
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sll %g1, %t_psr, %g1
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rtrap_patch3: srl %g1, 8, %g2
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or %g1, %g2, %g1
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rd %wim, %g2
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andcc %g2, %g1, %g0
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be 1f ! Nope, just return from the trap
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sll %g2, 0x1, %g1
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/* We have to grab a window before returning. */
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rtrap_patch4: srl %g2, 7, %g2
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or %g1, %g2, %g1
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rtrap_patch5: and %g1, 0xff, %g1
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wr %g1, 0x0, %wim
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/* Grrr, make sure we load from the right %sp... */
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LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
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restore %g0, %g0, %g0
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LOAD_WINDOW(sp)
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b 2f
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save %g0, %g0, %g0
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/* Reload the entire frame in case this is from a
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* kernel system call or whatever...
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*/
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1:
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LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
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2:
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sethi %hi(PSR_SYSCALL), %twin_tmp1
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andn %t_psr, %twin_tmp1, %t_psr
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wr %t_psr, 0x0, %psr
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WRITE_PAUSE
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jmp %t_pc
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rett %t_npc
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ret_trap_user_stack_is_bolixed:
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wr %t_wim, 0x0, %wim
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wr %t_psr, PSR_ET, %psr
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WRITE_PAUSE
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call window_ret_fault
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add %sp, STACKFRAME_SZ, %o0
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b signal_p
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ld [%curptr + TI_FLAGS], %g2
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.globl srmmu_rett_stackchk
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srmmu_rett_stackchk:
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bne ret_trap_user_stack_is_bolixed
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sethi %hi(PAGE_OFFSET), %g1
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cmp %g1, %fp
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bleu ret_trap_user_stack_is_bolixed
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mov AC_M_SFSR, %g1
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LEON_PI(lda [%g1] ASI_LEON_MMUREGS, %g0)
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SUN_PI_(lda [%g1] ASI_M_MMUREGS, %g0)
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LEON_PI(lda [%g0] ASI_LEON_MMUREGS, %g1)
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SUN_PI_(lda [%g0] ASI_M_MMUREGS, %g1)
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or %g1, 0x2, %g1
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LEON_PI(sta %g1, [%g0] ASI_LEON_MMUREGS)
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SUN_PI_(sta %g1, [%g0] ASI_M_MMUREGS)
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restore %g0, %g0, %g0
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LOAD_WINDOW(sp)
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save %g0, %g0, %g0
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andn %g1, 0x2, %g1
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LEON_PI(sta %g1, [%g0] ASI_LEON_MMUREGS)
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SUN_PI_(sta %g1, [%g0] ASI_M_MMUREGS)
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mov AC_M_SFAR, %g2
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LEON_PI(lda [%g2] ASI_LEON_MMUREGS, %g2)
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SUN_PI_(lda [%g2] ASI_M_MMUREGS, %g2)
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mov AC_M_SFSR, %g1
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LEON_PI(lda [%g1] ASI_LEON_MMUREGS, %g1)
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SUN_PI_(lda [%g1] ASI_M_MMUREGS, %g1)
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andcc %g1, 0x2, %g0
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be ret_trap_userwins_ok
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nop
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b,a ret_trap_user_stack_is_bolixed
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