563 lines
14 KiB
ArmAsm
563 lines
14 KiB
ArmAsm
/*
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* linux/arch/nios2/kernel/entry.S
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*
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* Copyright (C) 2013-2014 Altera Corporation
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* Copyright (C) 2009, Wind River Systems Inc
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*
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* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
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*
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* Copyright (C) 1999-2002, Greg Ungerer (gerg@snapgear.com)
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* Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
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* Kenneth Albanowski <kjahds@kjahds.com>,
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* Copyright (C) 2000 Lineo Inc. (www.lineo.com)
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* Copyright (C) 2004 Microtronix Datacom Ltd.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Linux/m68k support by Hamish Macdonald
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*
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* 68060 fixes by Jesper Skov
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* ColdFire support by Greg Ungerer (gerg@snapgear.com)
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* 5307 fixes by David W. Miller
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* linux 2.4 support David McCullough <davidm@snapgear.com>
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*/
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#include <linux/sys.h>
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#include <linux/linkage.h>
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#include <asm/asm-offsets.h>
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#include <asm/asm-macros.h>
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#include <asm/thread_info.h>
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#include <asm/errno.h>
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#include <asm/setup.h>
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#include <asm/entry.h>
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#include <asm/unistd.h>
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#include <asm/processor.h>
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.macro GET_THREAD_INFO reg
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.if THREAD_SIZE & 0xffff0000
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andhi \reg, sp, %hi(~(THREAD_SIZE-1))
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.else
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addi \reg, r0, %lo(~(THREAD_SIZE-1))
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and \reg, \reg, sp
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.endif
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.endm
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.macro kuser_cmpxchg_check
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/*
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* Make sure our user space atomic helper is restarted if it was
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* interrupted in a critical region.
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* ea-4 = address of interrupted insn (ea must be preserved).
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* sp = saved regs.
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* cmpxchg_ldw = first critical insn, cmpxchg_stw = last critical insn.
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* If ea <= cmpxchg_stw and ea > cmpxchg_ldw then saved EA is set to
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* cmpxchg_ldw + 4.
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*/
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/* et = cmpxchg_stw + 4 */
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movui et, (KUSER_BASE + 4 + (cmpxchg_stw - __kuser_helper_start))
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bgtu ea, et, 1f
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subi et, et, (cmpxchg_stw - cmpxchg_ldw) /* et = cmpxchg_ldw + 4 */
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bltu ea, et, 1f
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stw et, PT_EA(sp) /* fix up EA */
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mov ea, et
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1:
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.endm
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.section .rodata
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.align 4
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exception_table:
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.word unhandled_exception /* 0 - Reset */
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.word unhandled_exception /* 1 - Processor-only Reset */
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.word external_interrupt /* 2 - Interrupt */
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.word handle_trap /* 3 - Trap Instruction */
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.word instruction_trap /* 4 - Unimplemented instruction */
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.word handle_illegal /* 5 - Illegal instruction */
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.word handle_unaligned /* 6 - Misaligned data access */
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.word handle_unaligned /* 7 - Misaligned destination address */
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.word handle_diverror /* 8 - Division error */
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.word protection_exception_ba /* 9 - Supervisor-only instr. address */
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.word protection_exception_instr /* 10 - Supervisor only instruction */
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.word protection_exception_ba /* 11 - Supervisor only data address */
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.word unhandled_exception /* 12 - Double TLB miss (data) */
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.word protection_exception_pte /* 13 - TLB permission violation (x) */
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.word protection_exception_pte /* 14 - TLB permission violation (r) */
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.word protection_exception_pte /* 15 - TLB permission violation (w) */
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.word unhandled_exception /* 16 - MPU region violation */
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trap_table:
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.word handle_system_call /* 0 */
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.word handle_trap_1 /* 1 */
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.word handle_trap_2 /* 2 */
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.word handle_trap_3 /* 3 */
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.word handle_trap_reserved /* 4 */
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.word handle_trap_reserved /* 5 */
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.word handle_trap_reserved /* 6 */
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.word handle_trap_reserved /* 7 */
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.word handle_trap_reserved /* 8 */
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.word handle_trap_reserved /* 9 */
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.word handle_trap_reserved /* 10 */
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.word handle_trap_reserved /* 11 */
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.word handle_trap_reserved /* 12 */
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.word handle_trap_reserved /* 13 */
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.word handle_trap_reserved /* 14 */
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.word handle_trap_reserved /* 15 */
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.word handle_trap_reserved /* 16 */
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.word handle_trap_reserved /* 17 */
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.word handle_trap_reserved /* 18 */
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.word handle_trap_reserved /* 19 */
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.word handle_trap_reserved /* 20 */
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.word handle_trap_reserved /* 21 */
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.word handle_trap_reserved /* 22 */
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.word handle_trap_reserved /* 23 */
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.word handle_trap_reserved /* 24 */
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.word handle_trap_reserved /* 25 */
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.word handle_trap_reserved /* 26 */
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.word handle_trap_reserved /* 27 */
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.word handle_trap_reserved /* 28 */
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.word handle_trap_reserved /* 29 */
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#ifdef CONFIG_KGDB
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.word handle_kgdb_breakpoint /* 30 KGDB breakpoint */
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#else
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.word instruction_trap /* 30 */
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#endif
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.word handle_breakpoint /* 31 */
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.text
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.set noat
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.set nobreak
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ENTRY(inthandler)
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SAVE_ALL
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kuser_cmpxchg_check
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/* Clear EH bit before we get a new excpetion in the kernel
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* and after we have saved it to the exception frame. This is done
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* whether it's trap, tlb-miss or interrupt. If we don't do this
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* estatus is not updated the next exception.
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*/
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rdctl r24, status
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movi r9, %lo(~STATUS_EH)
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and r24, r24, r9
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wrctl status, r24
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/* Read cause and vector and branch to the associated handler */
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mov r4, sp
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rdctl r5, exception
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movia r9, exception_table
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add r24, r9, r5
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ldw r24, 0(r24)
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jmp r24
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/***********************************************************************
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* Handle traps
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***********************************************************************
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*/
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ENTRY(handle_trap)
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ldwio r24, -4(ea) /* instruction that caused the exception */
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srli r24, r24, 4
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andi r24, r24, 0x7c
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movia r9,trap_table
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add r24, r24, r9
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ldw r24, 0(r24)
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jmp r24
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/***********************************************************************
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* Handle system calls
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***********************************************************************
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*/
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ENTRY(handle_system_call)
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/* Enable interrupts */
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rdctl r10, status
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ori r10, r10, STATUS_PIE
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wrctl status, r10
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/* Reload registers destroyed by common code. */
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ldw r4, PT_R4(sp)
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ldw r5, PT_R5(sp)
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local_restart:
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/* Check that the requested system call is within limits */
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movui r1, __NR_syscalls
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bgeu r2, r1, ret_invsyscall
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slli r1, r2, 2
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movhi r11, %hiadj(sys_call_table)
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add r1, r1, r11
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ldw r1, %lo(sys_call_table)(r1)
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beq r1, r0, ret_invsyscall
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/* Check if we are being traced */
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GET_THREAD_INFO r11
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ldw r11,TI_FLAGS(r11)
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BTBNZ r11,r11,TIF_SYSCALL_TRACE,traced_system_call
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/* Execute the system call */
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callr r1
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/* If the syscall returns a negative result:
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* Set r7 to 1 to indicate error,
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* Negate r2 to get a positive error code
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* If the syscall returns zero or a positive value:
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* Set r7 to 0.
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* The sigreturn system calls will skip the code below by
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* adding to register ra. To avoid destroying registers
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*/
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translate_rc_and_ret:
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movi r1, 0
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bge r2, zero, 3f
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sub r2, zero, r2
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movi r1, 1
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3:
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stw r2, PT_R2(sp)
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stw r1, PT_R7(sp)
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end_translate_rc_and_ret:
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ret_from_exception:
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ldw r1, PT_ESTATUS(sp)
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/* if so, skip resched, signals */
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TSTBNZ r1, r1, ESTATUS_EU, Luser_return
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restore_all:
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rdctl r10, status /* disable intrs */
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andi r10, r10, %lo(~STATUS_PIE)
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wrctl status, r10
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RESTORE_ALL
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eret
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/* If the syscall number was invalid return ENOSYS */
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ret_invsyscall:
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movi r2, -ENOSYS
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br translate_rc_and_ret
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/* This implements the same as above, except it calls
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* do_syscall_trace_enter and do_syscall_trace_exit before and after the
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* syscall in order for utilities like strace and gdb to work.
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*/
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traced_system_call:
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SAVE_SWITCH_STACK
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call do_syscall_trace_enter
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RESTORE_SWITCH_STACK
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/* Create system call register arguments. The 5th and 6th
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arguments on stack are already in place at the beginning
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of pt_regs. */
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ldw r2, PT_R2(sp)
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ldw r4, PT_R4(sp)
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ldw r5, PT_R5(sp)
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ldw r6, PT_R6(sp)
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ldw r7, PT_R7(sp)
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/* Fetch the syscall function, we don't need to check the boundaries
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* since this is already done.
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*/
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slli r1, r2, 2
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movhi r11,%hiadj(sys_call_table)
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add r1, r1, r11
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ldw r1, %lo(sys_call_table)(r1)
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callr r1
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/* If the syscall returns a negative result:
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* Set r7 to 1 to indicate error,
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* Negate r2 to get a positive error code
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* If the syscall returns zero or a positive value:
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* Set r7 to 0.
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* The sigreturn system calls will skip the code below by
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* adding to register ra. To avoid destroying registers
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*/
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translate_rc_and_ret2:
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movi r1, 0
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bge r2, zero, 4f
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sub r2, zero, r2
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movi r1, 1
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4:
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stw r2, PT_R2(sp)
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stw r1, PT_R7(sp)
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end_translate_rc_and_ret2:
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SAVE_SWITCH_STACK
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call do_syscall_trace_exit
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RESTORE_SWITCH_STACK
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br ret_from_exception
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Luser_return:
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GET_THREAD_INFO r11 /* get thread_info pointer */
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ldw r10, TI_FLAGS(r11) /* get thread_info->flags */
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ANDI32 r11, r10, _TIF_WORK_MASK
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beq r11, r0, restore_all /* Nothing to do */
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BTBZ r1, r10, TIF_NEED_RESCHED, Lsignal_return
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/* Reschedule work */
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call schedule
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br ret_from_exception
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Lsignal_return:
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ANDI32 r1, r10, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
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beq r1, r0, restore_all
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mov r4, sp /* pt_regs */
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SAVE_SWITCH_STACK
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call do_notify_resume
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beq r2, r0, no_work_pending
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RESTORE_SWITCH_STACK
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/* prepare restart syscall here without leaving kernel */
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ldw r2, PT_R2(sp) /* reload syscall number in r2 */
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ldw r4, PT_R4(sp) /* reload syscall arguments r4-r9 */
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ldw r5, PT_R5(sp)
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ldw r6, PT_R6(sp)
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ldw r7, PT_R7(sp)
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ldw r8, PT_R8(sp)
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ldw r9, PT_R9(sp)
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br local_restart /* restart syscall */
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no_work_pending:
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RESTORE_SWITCH_STACK
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br ret_from_exception
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/***********************************************************************
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* Handle external interrupts.
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***********************************************************************
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*/
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/*
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* This is the generic interrupt handler (for all hardware interrupt
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* sources). It figures out the vector number and calls the appropriate
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* interrupt service routine directly.
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*/
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external_interrupt:
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rdctl r12, ipending
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rdctl r9, ienable
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and r12, r12, r9
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/* skip if no interrupt is pending */
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beq r12, r0, ret_from_interrupt
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movi r24, -1
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stw r24, PT_ORIG_R2(sp)
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/*
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* Process an external hardware interrupt.
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*/
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addi ea, ea, -4 /* re-issue the interrupted instruction */
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stw ea, PT_EA(sp)
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2: movi r4, %lo(-1) /* Start from bit position 0,
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highest priority */
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/* This is the IRQ # for handler call */
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1: andi r10, r12, 1 /* Isolate bit we are interested in */
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srli r12, r12, 1 /* shift count is costly without hardware
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multiplier */
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addi r4, r4, 1
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beq r10, r0, 1b
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mov r5, sp /* Setup pt_regs pointer for handler call */
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call do_IRQ
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rdctl r12, ipending /* check again if irq still pending */
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rdctl r9, ienable /* Isolate possible interrupts */
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and r12, r12, r9
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bne r12, r0, 2b
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/* br ret_from_interrupt */ /* fall through to ret_from_interrupt */
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ENTRY(ret_from_interrupt)
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ldw r1, PT_ESTATUS(sp) /* check if returning to kernel */
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TSTBNZ r1, r1, ESTATUS_EU, Luser_return
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#ifdef CONFIG_PREEMPT
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GET_THREAD_INFO r1
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ldw r4, TI_PREEMPT_COUNT(r1)
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bne r4, r0, restore_all
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ldw r4, TI_FLAGS(r1) /* ? Need resched set */
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BTBZ r10, r4, TIF_NEED_RESCHED, restore_all
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ldw r4, PT_ESTATUS(sp) /* ? Interrupts off */
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andi r10, r4, ESTATUS_EPIE
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beq r10, r0, restore_all
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call preempt_schedule_irq
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#endif
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br restore_all
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/***********************************************************************
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* A few syscall wrappers
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***********************************************************************
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*/
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/*
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* int clone(unsigned long clone_flags, unsigned long newsp,
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* int __user * parent_tidptr, int __user * child_tidptr,
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* int tls_val)
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*/
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ENTRY(sys_clone)
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SAVE_SWITCH_STACK
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addi sp, sp, -4
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stw r7, 0(sp) /* Pass 5th arg thru stack */
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mov r7, r6 /* 4th arg is 3rd of clone() */
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mov r6, zero /* 3rd arg always 0 */
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call do_fork
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addi sp, sp, 4
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RESTORE_SWITCH_STACK
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ret
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ENTRY(sys_rt_sigreturn)
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SAVE_SWITCH_STACK
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mov r4, sp
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call do_rt_sigreturn
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RESTORE_SWITCH_STACK
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addi ra, ra, (end_translate_rc_and_ret - translate_rc_and_ret)
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ret
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/***********************************************************************
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* A few other wrappers and stubs
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***********************************************************************
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*/
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protection_exception_pte:
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rdctl r6, pteaddr
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slli r6, r6, 10
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call do_page_fault
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br ret_from_exception
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protection_exception_ba:
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rdctl r6, badaddr
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call do_page_fault
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br ret_from_exception
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protection_exception_instr:
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call handle_supervisor_instr
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br ret_from_exception
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handle_breakpoint:
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call breakpoint_c
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br ret_from_exception
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#ifdef CONFIG_NIOS2_ALIGNMENT_TRAP
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handle_unaligned:
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SAVE_SWITCH_STACK
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call handle_unaligned_c
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RESTORE_SWITCH_STACK
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br ret_from_exception
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#else
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handle_unaligned:
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call handle_unaligned_c
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br ret_from_exception
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#endif
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handle_illegal:
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call handle_illegal_c
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br ret_from_exception
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handle_diverror:
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call handle_diverror_c
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br ret_from_exception
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#ifdef CONFIG_KGDB
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handle_kgdb_breakpoint:
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call kgdb_breakpoint_c
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br ret_from_exception
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#endif
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handle_trap_1:
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call handle_trap_1_c
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br ret_from_exception
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handle_trap_2:
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call handle_trap_2_c
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br ret_from_exception
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handle_trap_3:
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handle_trap_reserved:
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call handle_trap_3_c
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br ret_from_exception
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/*
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* Beware - when entering resume, prev (the current task) is
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* in r4, next (the new task) is in r5, don't change these
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* registers.
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*/
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ENTRY(resume)
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rdctl r7, status /* save thread status reg */
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stw r7, TASK_THREAD + THREAD_KPSR(r4)
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andi r7, r7, %lo(~STATUS_PIE) /* disable interrupts */
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wrctl status, r7
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SAVE_SWITCH_STACK
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stw sp, TASK_THREAD + THREAD_KSP(r4)/* save kernel stack pointer */
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ldw sp, TASK_THREAD + THREAD_KSP(r5)/* restore new thread stack */
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movia r24, _current_thread /* save thread */
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GET_THREAD_INFO r1
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stw r1, 0(r24)
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RESTORE_SWITCH_STACK
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ldw r7, TASK_THREAD + THREAD_KPSR(r5)/* restore thread status reg */
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wrctl status, r7
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ret
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ENTRY(ret_from_fork)
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call schedule_tail
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br ret_from_exception
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ENTRY(ret_from_kernel_thread)
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call schedule_tail
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mov r4,r17 /* arg */
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callr r16 /* function */
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br ret_from_exception
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/*
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* Kernel user helpers.
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*
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* Each segment is 64-byte aligned and will be mapped to the <User space>.
|
|
* New segments (if ever needed) must be added after the existing ones.
|
|
* This mechanism should be used only for things that are really small and
|
|
* justified, and not be abused freely.
|
|
*
|
|
*/
|
|
|
|
/* Filling pads with undefined instructions. */
|
|
.macro kuser_pad sym size
|
|
.if ((. - \sym) & 3)
|
|
.rept (4 - (. - \sym) & 3)
|
|
.byte 0
|
|
.endr
|
|
.endif
|
|
.rept ((\size - (. - \sym)) / 4)
|
|
.word 0xdeadbeef
|
|
.endr
|
|
.endm
|
|
|
|
.align 6
|
|
.globl __kuser_helper_start
|
|
__kuser_helper_start:
|
|
|
|
__kuser_helper_version: /* @ 0x1000 */
|
|
.word ((__kuser_helper_end - __kuser_helper_start) >> 6)
|
|
|
|
__kuser_cmpxchg: /* @ 0x1004 */
|
|
/*
|
|
* r4 pointer to exchange variable
|
|
* r5 old value
|
|
* r6 new value
|
|
*/
|
|
cmpxchg_ldw:
|
|
ldw r2, 0(r4) /* load current value */
|
|
sub r2, r2, r5 /* compare with old value */
|
|
bne r2, zero, cmpxchg_ret
|
|
|
|
/* We had a match, store the new value */
|
|
cmpxchg_stw:
|
|
stw r6, 0(r4)
|
|
cmpxchg_ret:
|
|
ret
|
|
|
|
kuser_pad __kuser_cmpxchg, 64
|
|
|
|
.globl __kuser_sigtramp
|
|
__kuser_sigtramp:
|
|
movi r2, __NR_rt_sigreturn
|
|
trap
|
|
|
|
kuser_pad __kuser_sigtramp, 64
|
|
|
|
.globl __kuser_helper_end
|
|
__kuser_helper_end:
|