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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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, et1:.endm
.section .rodata.align 4exception_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: stw r2, PT_ORIG_R2(sp) /* 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)
/* 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 ldw r1, PT_ORIG_R2(sp) addi r1, r1, 1 beq r1, zero, 3f sub r2, zero, r2 movi r1, 13: 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. */ movui r1, __NR_syscalls bgeu r2, r1, traced_invsyscall 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 ldw r1, PT_ORIG_R2(sp) addi r1, r1, 1 beq r1, zero, 4f sub r2, zero, r2 movi r1, 14: 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
/* If the syscall number was invalid return ENOSYS */traced_invsyscall: movi r2, -ENOSYS br translate_rc_and_ret2
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
/* * 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 subi sp, sp, 4 /* make space for tls pointer */ stw r8, 0(sp) /* pass tls pointer (r8) via stack (5th argument) */ call nios2_clone addi sp, sp, 4 RESTORE_SWITCH_STACK ret/* long syscall(SYS_clone3, struct clone_args *cl_args, size_t size); */ENTRY(__sys_clone3) SAVE_SWITCH_STACK call sys_clone3 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_TRAPhandle_unaligned: SAVE_SWITCH_STACK call handle_unaligned_c RESTORE_SWITCH_STACK br ret_from_exception#elsehandle_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_KGDBhandle_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: