| /* |
| * linux/arch/nios2/kernel/entry.S |
| * |
| * Copyright (C) 2013-2014 Altera Corporation |
| * Copyright (C) 2009, Wind River Systems Inc |
| * |
| * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com |
| * |
| * Copyright (C) 1999-2002, Greg Ungerer (gerg@snapgear.com) |
| * Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>, |
| * Kenneth Albanowski <kjahds@kjahds.com>, |
| * Copyright (C) 2000 Lineo Inc. (www.lineo.com) |
| * Copyright (C) 2004 Microtronix Datacom Ltd. |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| * |
| * Linux/m68k support by Hamish Macdonald |
| * |
| * 68060 fixes by Jesper Skov |
| * ColdFire support by Greg Ungerer (gerg@snapgear.com) |
| * 5307 fixes by David W. Miller |
| * linux 2.4 support David McCullough <davidm@snapgear.com> |
| */ |
| |
| #include <linux/sys.h> |
| #include <linux/linkage.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/asm-macros.h> |
| #include <asm/thread_info.h> |
| #include <asm/errno.h> |
| #include <asm/setup.h> |
| #include <asm/entry.h> |
| #include <asm/unistd.h> |
| #include <asm/processor.h> |
| |
| .macro GET_THREAD_INFO reg |
| .if THREAD_SIZE & 0xffff0000 |
| andhi \reg, sp, %hi(~(THREAD_SIZE-1)) |
| .else |
| addi \reg, r0, %lo(~(THREAD_SIZE-1)) |
| and \reg, \reg, sp |
| .endif |
| .endm |
| |
| .macro kuser_cmpxchg_check |
| /* |
| * Make sure our user space atomic helper is restarted if it was |
| * interrupted in a critical region. |
| * ea-4 = address of interrupted insn (ea must be preserved). |
| * sp = saved regs. |
| * cmpxchg_ldw = first critical insn, cmpxchg_stw = last critical insn. |
| * If ea <= cmpxchg_stw and ea > cmpxchg_ldw then saved EA is set to |
| * cmpxchg_ldw + 4. |
| */ |
| /* et = cmpxchg_stw + 4 */ |
| movui et, (KUSER_BASE + 4 + (cmpxchg_stw - __kuser_helper_start)) |
| bgtu ea, et, 1f |
| |
| subi et, et, (cmpxchg_stw - cmpxchg_ldw) /* et = cmpxchg_ldw + 4 */ |
| bltu ea, et, 1f |
| stw et, PT_EA(sp) /* fix up EA */ |
| mov ea, et |
| 1: |
| .endm |
| |
| .section .rodata |
| .align 4 |
| exception_table: |
| .word unhandled_exception /* 0 - Reset */ |
| .word unhandled_exception /* 1 - Processor-only Reset */ |
| .word external_interrupt /* 2 - Interrupt */ |
| .word handle_trap /* 3 - Trap Instruction */ |
| |
| .word instruction_trap /* 4 - Unimplemented instruction */ |
| .word handle_illegal /* 5 - Illegal instruction */ |
| .word handle_unaligned /* 6 - Misaligned data access */ |
| .word handle_unaligned /* 7 - Misaligned destination address */ |
| |
| .word handle_diverror /* 8 - Division error */ |
| .word protection_exception_ba /* 9 - Supervisor-only instr. address */ |
| .word protection_exception_instr /* 10 - Supervisor only instruction */ |
| .word protection_exception_ba /* 11 - Supervisor only data address */ |
| |
| .word unhandled_exception /* 12 - Double TLB miss (data) */ |
| .word protection_exception_pte /* 13 - TLB permission violation (x) */ |
| .word protection_exception_pte /* 14 - TLB permission violation (r) */ |
| .word protection_exception_pte /* 15 - TLB permission violation (w) */ |
| |
| .word unhandled_exception /* 16 - MPU region violation */ |
| |
| trap_table: |
| .word handle_system_call /* 0 */ |
| .word handle_trap_1 /* 1 */ |
| .word handle_trap_2 /* 2 */ |
| .word handle_trap_3 /* 3 */ |
| .word handle_trap_reserved /* 4 */ |
| .word handle_trap_reserved /* 5 */ |
| .word handle_trap_reserved /* 6 */ |
| .word handle_trap_reserved /* 7 */ |
| .word handle_trap_reserved /* 8 */ |
| .word handle_trap_reserved /* 9 */ |
| .word handle_trap_reserved /* 10 */ |
| .word handle_trap_reserved /* 11 */ |
| .word handle_trap_reserved /* 12 */ |
| .word handle_trap_reserved /* 13 */ |
| .word handle_trap_reserved /* 14 */ |
| .word handle_trap_reserved /* 15 */ |
| .word handle_trap_reserved /* 16 */ |
| .word handle_trap_reserved /* 17 */ |
| .word handle_trap_reserved /* 18 */ |
| .word handle_trap_reserved /* 19 */ |
| .word handle_trap_reserved /* 20 */ |
| .word handle_trap_reserved /* 21 */ |
| .word handle_trap_reserved /* 22 */ |
| .word handle_trap_reserved /* 23 */ |
| .word handle_trap_reserved /* 24 */ |
| .word handle_trap_reserved /* 25 */ |
| .word handle_trap_reserved /* 26 */ |
| .word handle_trap_reserved /* 27 */ |
| .word handle_trap_reserved /* 28 */ |
| .word handle_trap_reserved /* 29 */ |
| #ifdef CONFIG_KGDB |
| .word handle_kgdb_breakpoint /* 30 KGDB breakpoint */ |
| #else |
| .word instruction_trap /* 30 */ |
| #endif |
| .word handle_breakpoint /* 31 */ |
| |
| .text |
| .set noat |
| .set nobreak |
| |
| ENTRY(inthandler) |
| SAVE_ALL |
| |
| kuser_cmpxchg_check |
| |
| /* Clear EH bit before we get a new excpetion in the kernel |
| * and after we have saved it to the exception frame. This is done |
| * whether it's trap, tlb-miss or interrupt. If we don't do this |
| * estatus is not updated the next exception. |
| */ |
| rdctl r24, status |
| movi r9, %lo(~STATUS_EH) |
| and r24, r24, r9 |
| wrctl status, r24 |
| |
| /* Read cause and vector and branch to the associated handler */ |
| mov r4, sp |
| rdctl r5, exception |
| movia r9, exception_table |
| add r24, r9, r5 |
| ldw r24, 0(r24) |
| jmp r24 |
| |
| |
| /*********************************************************************** |
| * Handle traps |
| *********************************************************************** |
| */ |
| ENTRY(handle_trap) |
| ldwio r24, -4(ea) /* instruction that caused the exception */ |
| srli r24, r24, 4 |
| andi r24, r24, 0x7c |
| movia r9,trap_table |
| add r24, r24, r9 |
| ldw r24, 0(r24) |
| jmp r24 |
| |
| |
| /*********************************************************************** |
| * Handle system calls |
| *********************************************************************** |
| */ |
| ENTRY(handle_system_call) |
| /* Enable interrupts */ |
| rdctl r10, status |
| ori r10, r10, STATUS_PIE |
| wrctl status, r10 |
| |
| /* Reload registers destroyed by common code. */ |
| ldw r4, PT_R4(sp) |
| ldw r5, PT_R5(sp) |
| |
| local_restart: |
| /* Check that the requested system call is within limits */ |
| movui r1, __NR_syscalls |
| bgeu r2, r1, ret_invsyscall |
| slli r1, r2, 2 |
| movhi r11, %hiadj(sys_call_table) |
| add r1, r1, r11 |
| ldw r1, %lo(sys_call_table)(r1) |
| beq r1, r0, ret_invsyscall |
| |
| /* Check if we are being traced */ |
| GET_THREAD_INFO r11 |
| ldw r11,TI_FLAGS(r11) |
| BTBNZ r11,r11,TIF_SYSCALL_TRACE,traced_system_call |
| |
| /* Execute the system call */ |
| callr r1 |
| |
| /* If the syscall returns a negative result: |
| * Set r7 to 1 to indicate error, |
| * Negate r2 to get a positive error code |
| * If the syscall returns zero or a positive value: |
| * Set r7 to 0. |
| * The sigreturn system calls will skip the code below by |
| * adding to register ra. To avoid destroying registers |
| */ |
| translate_rc_and_ret: |
| movi r1, 0 |
| bge r2, zero, 3f |
| sub r2, zero, r2 |
| movi r1, 1 |
| 3: |
| stw r2, PT_R2(sp) |
| stw r1, PT_R7(sp) |
| end_translate_rc_and_ret: |
| |
| ret_from_exception: |
| ldw r1, PT_ESTATUS(sp) |
| /* if so, skip resched, signals */ |
| TSTBNZ r1, r1, ESTATUS_EU, Luser_return |
| |
| restore_all: |
| rdctl r10, status /* disable intrs */ |
| andi r10, r10, %lo(~STATUS_PIE) |
| wrctl status, r10 |
| RESTORE_ALL |
| eret |
| |
| /* If the syscall number was invalid return ENOSYS */ |
| ret_invsyscall: |
| movi r2, -ENOSYS |
| br translate_rc_and_ret |
| |
| /* This implements the same as above, except it calls |
| * do_syscall_trace_enter and do_syscall_trace_exit before and after the |
| * syscall in order for utilities like strace and gdb to work. |
| */ |
| traced_system_call: |
| SAVE_SWITCH_STACK |
| call do_syscall_trace_enter |
| RESTORE_SWITCH_STACK |
| |
| /* Create system call register arguments. The 5th and 6th |
| arguments on stack are already in place at the beginning |
| of pt_regs. */ |
| ldw r2, PT_R2(sp) |
| ldw r4, PT_R4(sp) |
| ldw r5, PT_R5(sp) |
| ldw r6, PT_R6(sp) |
| ldw r7, PT_R7(sp) |
| |
| /* Fetch the syscall function, we don't need to check the boundaries |
| * since this is already done. |
| */ |
| slli r1, r2, 2 |
| movhi r11,%hiadj(sys_call_table) |
| add r1, r1, r11 |
| ldw r1, %lo(sys_call_table)(r1) |
| |
| callr r1 |
| |
| /* If the syscall returns a negative result: |
| * Set r7 to 1 to indicate error, |
| * Negate r2 to get a positive error code |
| * If the syscall returns zero or a positive value: |
| * Set r7 to 0. |
| * The sigreturn system calls will skip the code below by |
| * adding to register ra. To avoid destroying registers |
| */ |
| translate_rc_and_ret2: |
| movi r1, 0 |
| bge r2, zero, 4f |
| sub r2, zero, r2 |
| movi r1, 1 |
| 4: |
| stw r2, PT_R2(sp) |
| stw r1, PT_R7(sp) |
| end_translate_rc_and_ret2: |
| SAVE_SWITCH_STACK |
| call do_syscall_trace_exit |
| RESTORE_SWITCH_STACK |
| br ret_from_exception |
| |
| Luser_return: |
| GET_THREAD_INFO r11 /* get thread_info pointer */ |
| ldw r10, TI_FLAGS(r11) /* get thread_info->flags */ |
| ANDI32 r11, r10, _TIF_WORK_MASK |
| beq r11, r0, restore_all /* Nothing to do */ |
| BTBZ r1, r10, TIF_NEED_RESCHED, Lsignal_return |
| |
| /* Reschedule work */ |
| call schedule |
| br ret_from_exception |
| |
| Lsignal_return: |
| ANDI32 r1, r10, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME |
| beq r1, r0, restore_all |
| mov r4, sp /* pt_regs */ |
| SAVE_SWITCH_STACK |
| call do_notify_resume |
| beq r2, r0, no_work_pending |
| RESTORE_SWITCH_STACK |
| /* prepare restart syscall here without leaving kernel */ |
| ldw r2, PT_R2(sp) /* reload syscall number in r2 */ |
| ldw r4, PT_R4(sp) /* reload syscall arguments r4-r9 */ |
| ldw r5, PT_R5(sp) |
| ldw r6, PT_R6(sp) |
| ldw r7, PT_R7(sp) |
| ldw r8, PT_R8(sp) |
| ldw r9, PT_R9(sp) |
| br local_restart /* restart syscall */ |
| |
| no_work_pending: |
| RESTORE_SWITCH_STACK |
| br ret_from_exception |
| |
| /*********************************************************************** |
| * Handle external interrupts. |
| *********************************************************************** |
| */ |
| /* |
| * This is the generic interrupt handler (for all hardware interrupt |
| * sources). It figures out the vector number and calls the appropriate |
| * interrupt service routine directly. |
| */ |
| external_interrupt: |
| rdctl r12, ipending |
| rdctl r9, ienable |
| and r12, r12, r9 |
| /* skip if no interrupt is pending */ |
| beq r12, r0, ret_from_interrupt |
| |
| movi r24, -1 |
| stw r24, PT_ORIG_R2(sp) |
| |
| /* |
| * Process an external hardware interrupt. |
| */ |
| |
| addi ea, ea, -4 /* re-issue the interrupted instruction */ |
| stw ea, PT_EA(sp) |
| 2: movi r4, %lo(-1) /* Start from bit position 0, |
| highest priority */ |
| /* This is the IRQ # for handler call */ |
| 1: andi r10, r12, 1 /* Isolate bit we are interested in */ |
| srli r12, r12, 1 /* shift count is costly without hardware |
| multiplier */ |
| addi r4, r4, 1 |
| beq r10, r0, 1b |
| mov r5, sp /* Setup pt_regs pointer for handler call */ |
| call do_IRQ |
| rdctl r12, ipending /* check again if irq still pending */ |
| rdctl r9, ienable /* Isolate possible interrupts */ |
| and r12, r12, r9 |
| bne r12, r0, 2b |
| /* br ret_from_interrupt */ /* fall through to ret_from_interrupt */ |
| |
| ENTRY(ret_from_interrupt) |
| ldw r1, PT_ESTATUS(sp) /* check if returning to kernel */ |
| TSTBNZ r1, r1, ESTATUS_EU, Luser_return |
| |
| #ifdef CONFIG_PREEMPTION |
| GET_THREAD_INFO r1 |
| ldw r4, TI_PREEMPT_COUNT(r1) |
| bne r4, r0, restore_all |
| ldw r4, TI_FLAGS(r1) /* ? Need resched set */ |
| BTBZ r10, r4, TIF_NEED_RESCHED, restore_all |
| ldw r4, PT_ESTATUS(sp) /* ? Interrupts off */ |
| andi r10, r4, ESTATUS_EPIE |
| beq r10, r0, restore_all |
| call preempt_schedule_irq |
| #endif |
| br restore_all |
| |
| /*********************************************************************** |
| * A few syscall wrappers |
| *********************************************************************** |
| */ |
| /* |
| * int clone(unsigned long clone_flags, unsigned long newsp, |
| * int __user * parent_tidptr, int __user * child_tidptr, |
| * int tls_val) |
| */ |
| ENTRY(sys_clone) |
| SAVE_SWITCH_STACK |
| call nios2_clone |
| RESTORE_SWITCH_STACK |
| ret |
| |
| ENTRY(sys_rt_sigreturn) |
| SAVE_SWITCH_STACK |
| mov r4, sp |
| call do_rt_sigreturn |
| RESTORE_SWITCH_STACK |
| addi ra, ra, (end_translate_rc_and_ret - translate_rc_and_ret) |
| ret |
| |
| /*********************************************************************** |
| * A few other wrappers and stubs |
| *********************************************************************** |
| */ |
| protection_exception_pte: |
| rdctl r6, pteaddr |
| slli r6, r6, 10 |
| call do_page_fault |
| br ret_from_exception |
| |
| protection_exception_ba: |
| rdctl r6, badaddr |
| call do_page_fault |
| br ret_from_exception |
| |
| protection_exception_instr: |
| call handle_supervisor_instr |
| br ret_from_exception |
| |
| handle_breakpoint: |
| call breakpoint_c |
| br ret_from_exception |
| |
| #ifdef CONFIG_NIOS2_ALIGNMENT_TRAP |
| handle_unaligned: |
| SAVE_SWITCH_STACK |
| call handle_unaligned_c |
| RESTORE_SWITCH_STACK |
| br ret_from_exception |
| #else |
| handle_unaligned: |
| call handle_unaligned_c |
| br ret_from_exception |
| #endif |
| |
| handle_illegal: |
| call handle_illegal_c |
| br ret_from_exception |
| |
| handle_diverror: |
| call handle_diverror_c |
| br ret_from_exception |
| |
| #ifdef CONFIG_KGDB |
| handle_kgdb_breakpoint: |
| call kgdb_breakpoint_c |
| br ret_from_exception |
| #endif |
| |
| handle_trap_1: |
| call handle_trap_1_c |
| br ret_from_exception |
| |
| handle_trap_2: |
| call handle_trap_2_c |
| br ret_from_exception |
| |
| handle_trap_3: |
| handle_trap_reserved: |
| call handle_trap_3_c |
| br ret_from_exception |
| |
| /* |
| * Beware - when entering resume, prev (the current task) is |
| * in r4, next (the new task) is in r5, don't change these |
| * registers. |
| */ |
| ENTRY(resume) |
| |
| rdctl r7, status /* save thread status reg */ |
| stw r7, TASK_THREAD + THREAD_KPSR(r4) |
| |
| andi r7, r7, %lo(~STATUS_PIE) /* disable interrupts */ |
| wrctl status, r7 |
| |
| SAVE_SWITCH_STACK |
| stw sp, TASK_THREAD + THREAD_KSP(r4)/* save kernel stack pointer */ |
| ldw sp, TASK_THREAD + THREAD_KSP(r5)/* restore new thread stack */ |
| movia r24, _current_thread /* save thread */ |
| GET_THREAD_INFO r1 |
| stw r1, 0(r24) |
| RESTORE_SWITCH_STACK |
| |
| ldw r7, TASK_THREAD + THREAD_KPSR(r5)/* restore thread status reg */ |
| wrctl status, r7 |
| ret |
| |
| ENTRY(ret_from_fork) |
| call schedule_tail |
| br ret_from_exception |
| |
| ENTRY(ret_from_kernel_thread) |
| call schedule_tail |
| mov r4,r17 /* arg */ |
| callr r16 /* function */ |
| br ret_from_exception |
| |
| /* |
| * Kernel user helpers. |
| * |
| * 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: |
