376 строки
10 KiB
ArmAsm
376 строки
10 KiB
ArmAsm
/*
|
|
* Common Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC
|
|
* (included from entry-<isa>.S
|
|
*
|
|
* Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
/*------------------------------------------------------------------
|
|
* Function ABI
|
|
*------------------------------------------------------------------
|
|
*
|
|
* Arguments r0 - r7
|
|
* Caller Saved Registers r0 - r12
|
|
* Callee Saved Registers r13- r25
|
|
* Global Pointer (gp) r26
|
|
* Frame Pointer (fp) r27
|
|
* Stack Pointer (sp) r28
|
|
* Branch link register (blink) r31
|
|
*------------------------------------------------------------------
|
|
*/
|
|
|
|
;################### Special Sys Call Wrappers ##########################
|
|
|
|
ENTRY(sys_clone_wrapper)
|
|
SAVE_CALLEE_SAVED_USER
|
|
bl @sys_clone
|
|
DISCARD_CALLEE_SAVED_USER
|
|
|
|
GET_CURR_THR_INFO_FLAGS r10
|
|
btst r10, TIF_SYSCALL_TRACE
|
|
bnz tracesys_exit
|
|
|
|
b ret_from_system_call
|
|
END(sys_clone_wrapper)
|
|
|
|
ENTRY(ret_from_fork)
|
|
; when the forked child comes here from the __switch_to function
|
|
; r0 has the last task pointer.
|
|
; put last task in scheduler queue
|
|
jl @schedule_tail
|
|
|
|
ld r9, [sp, PT_status32]
|
|
brne r9, 0, 1f
|
|
|
|
jl.d [r14] ; kernel thread entry point
|
|
mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
|
|
|
|
1:
|
|
; Return to user space
|
|
; 1. Any forked task (Reach here via BRne above)
|
|
; 2. First ever init task (Reach here via return from JL above)
|
|
; This is the historic "kernel_execve" use-case, to return to init
|
|
; user mode, in a round about way since that is always done from
|
|
; a kernel thread which is executed via JL above but always returns
|
|
; out whenever kernel_execve (now inline do_fork()) is involved
|
|
b ret_from_exception
|
|
END(ret_from_fork)
|
|
|
|
#ifdef CONFIG_ARC_DW2_UNWIND
|
|
; Workaround for bug 94179 (STAR ):
|
|
; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
|
|
; section (.debug_frame) as loadable. So we force it here.
|
|
; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
|
|
; would not work after a clean build due to kernel build system dependencies.
|
|
.section .debug_frame, "wa",@progbits
|
|
|
|
; Reset to .text as this file is included in entry-<isa>.S
|
|
.section .text, "ax",@progbits
|
|
#endif
|
|
|
|
;################### Non TLB Exception Handling #############################
|
|
|
|
; ---------------------------------------------
|
|
; Instruction Error Exception Handler
|
|
; ---------------------------------------------
|
|
|
|
ENTRY(instr_service)
|
|
|
|
EXCEPTION_PROLOGUE
|
|
|
|
lr r0, [efa]
|
|
mov r1, sp
|
|
|
|
FAKE_RET_FROM_EXCPN
|
|
|
|
bl do_insterror_or_kprobe
|
|
b ret_from_exception
|
|
END(instr_service)
|
|
|
|
; ---------------------------------------------
|
|
; Machine Check Exception Handler
|
|
; ---------------------------------------------
|
|
|
|
ENTRY(EV_MachineCheck)
|
|
|
|
EXCEPTION_PROLOGUE
|
|
|
|
lr r2, [ecr]
|
|
lr r0, [efa]
|
|
mov r1, sp
|
|
|
|
lsr r3, r2, 8
|
|
bmsk r3, r3, 7
|
|
brne r3, ECR_C_MCHK_DUP_TLB, 1f
|
|
|
|
bl do_tlb_overlap_fault
|
|
b ret_from_exception
|
|
|
|
1:
|
|
; DEAD END: can't do much, display Regs and HALT
|
|
SAVE_CALLEE_SAVED_USER
|
|
|
|
GET_CURR_TASK_FIELD_PTR TASK_THREAD, r10
|
|
st sp, [r10, THREAD_CALLEE_REG]
|
|
|
|
j do_machine_check_fault
|
|
|
|
END(EV_MachineCheck)
|
|
|
|
; ---------------------------------------------
|
|
; Privilege Violation Exception Handler
|
|
; ---------------------------------------------
|
|
ENTRY(EV_PrivilegeV)
|
|
|
|
EXCEPTION_PROLOGUE
|
|
|
|
lr r0, [efa]
|
|
mov r1, sp
|
|
|
|
FAKE_RET_FROM_EXCPN
|
|
|
|
bl do_privilege_fault
|
|
b ret_from_exception
|
|
END(EV_PrivilegeV)
|
|
|
|
; ---------------------------------------------
|
|
; Extension Instruction Exception Handler
|
|
; ---------------------------------------------
|
|
ENTRY(EV_Extension)
|
|
|
|
EXCEPTION_PROLOGUE
|
|
|
|
lr r0, [efa]
|
|
mov r1, sp
|
|
|
|
FAKE_RET_FROM_EXCPN
|
|
|
|
bl do_extension_fault
|
|
b ret_from_exception
|
|
END(EV_Extension)
|
|
|
|
;################ Trap Handling (Syscall, Breakpoint) ##################
|
|
|
|
; ---------------------------------------------
|
|
; syscall Tracing
|
|
; ---------------------------------------------
|
|
tracesys:
|
|
; save EFA in case tracer wants the PC of traced task
|
|
; using ERET won't work since next-PC has already committed
|
|
lr r12, [efa]
|
|
GET_CURR_TASK_FIELD_PTR TASK_THREAD, r11
|
|
st r12, [r11, THREAD_FAULT_ADDR] ; thread.fault_address
|
|
|
|
; PRE Sys Call Ptrace hook
|
|
mov r0, sp ; pt_regs needed
|
|
bl @syscall_trace_entry
|
|
|
|
; Tracing code now returns the syscall num (orig or modif)
|
|
mov r8, r0
|
|
|
|
; Do the Sys Call as we normally would.
|
|
; Validate the Sys Call number
|
|
cmp r8, NR_syscalls
|
|
mov.hi r0, -ENOSYS
|
|
bhi tracesys_exit
|
|
|
|
; Restore the sys-call args. Mere invocation of the hook abv could have
|
|
; clobbered them (since they are in scratch regs). The tracer could also
|
|
; have deliberately changed the syscall args: r0-r7
|
|
ld r0, [sp, PT_r0]
|
|
ld r1, [sp, PT_r1]
|
|
ld r2, [sp, PT_r2]
|
|
ld r3, [sp, PT_r3]
|
|
ld r4, [sp, PT_r4]
|
|
ld r5, [sp, PT_r5]
|
|
ld r6, [sp, PT_r6]
|
|
ld r7, [sp, PT_r7]
|
|
ld.as r9, [sys_call_table, r8]
|
|
jl [r9] ; Entry into Sys Call Handler
|
|
|
|
tracesys_exit:
|
|
st r0, [sp, PT_r0] ; sys call return value in pt_regs
|
|
|
|
;POST Sys Call Ptrace Hook
|
|
bl @syscall_trace_exit
|
|
b ret_from_exception ; NOT ret_from_system_call at is saves r0 which
|
|
; we'd done before calling post hook above
|
|
|
|
; ---------------------------------------------
|
|
; Breakpoint TRAP
|
|
; ---------------------------------------------
|
|
trap_with_param:
|
|
|
|
; stop_pc info by gdb needs this info
|
|
lr r0, [efa]
|
|
mov r1, sp
|
|
|
|
; Now that we have read EFA, it is safe to do "fake" rtie
|
|
; and get out of CPU exception mode
|
|
FAKE_RET_FROM_EXCPN
|
|
|
|
; Save callee regs in case gdb wants to have a look
|
|
; SP will grow up by size of CALLEE Reg-File
|
|
; NOTE: clobbers r12
|
|
SAVE_CALLEE_SAVED_USER
|
|
|
|
; save location of saved Callee Regs @ thread_struct->pc
|
|
GET_CURR_TASK_FIELD_PTR TASK_THREAD, r10
|
|
st sp, [r10, THREAD_CALLEE_REG]
|
|
|
|
; Call the trap handler
|
|
bl do_non_swi_trap
|
|
|
|
; unwind stack to discard Callee saved Regs
|
|
DISCARD_CALLEE_SAVED_USER
|
|
|
|
b ret_from_exception
|
|
|
|
; ---------------------------------------------
|
|
; syscall TRAP
|
|
; ABI: (r0-r7) upto 8 args, (r8) syscall number
|
|
; ---------------------------------------------
|
|
|
|
ENTRY(EV_Trap)
|
|
|
|
EXCEPTION_PROLOGUE
|
|
|
|
;============ TRAP 1 :breakpoints
|
|
; Check ECR for trap with arg (PROLOGUE ensures r9 has ECR)
|
|
bmsk.f 0, r9, 7
|
|
bnz trap_with_param
|
|
|
|
;============ TRAP (no param): syscall top level
|
|
|
|
; First return from Exception to pure K mode (Exception/IRQs renabled)
|
|
FAKE_RET_FROM_EXCPN
|
|
|
|
; If syscall tracing ongoing, invoke pre-post-hooks
|
|
GET_CURR_THR_INFO_FLAGS r10
|
|
btst r10, TIF_SYSCALL_TRACE
|
|
bnz tracesys ; this never comes back
|
|
|
|
;============ Normal syscall case
|
|
|
|
; syscall num shd not exceed the total system calls avail
|
|
cmp r8, NR_syscalls
|
|
mov.hi r0, -ENOSYS
|
|
bhi ret_from_system_call
|
|
|
|
; Offset into the syscall_table and call handler
|
|
ld.as r9,[sys_call_table, r8]
|
|
jl [r9] ; Entry into Sys Call Handler
|
|
|
|
; fall through to ret_from_system_call
|
|
END(EV_Trap)
|
|
|
|
ENTRY(ret_from_system_call)
|
|
|
|
st r0, [sp, PT_r0] ; sys call return value in pt_regs
|
|
|
|
; fall through yet again to ret_from_exception
|
|
|
|
;############# Return from Intr/Excp/Trap (Linux Specifics) ##############
|
|
;
|
|
; If ret to user mode do we need to handle signals, schedule() et al.
|
|
|
|
ENTRY(ret_from_exception)
|
|
|
|
; Pre-{IRQ,Trap,Exception} K/U mode from pt_regs->status32
|
|
ld r8, [sp, PT_status32] ; returning to User/Kernel Mode
|
|
|
|
bbit0 r8, STATUS_U_BIT, resume_kernel_mode
|
|
|
|
; Before returning to User mode check-for-and-complete any pending work
|
|
; such as rescheduling/signal-delivery etc.
|
|
resume_user_mode_begin:
|
|
|
|
; Disable IRQs to ensures that chk for pending work itself is atomic
|
|
; (and we don't end up missing a NEED_RESCHED/SIGPENDING due to an
|
|
; interim IRQ).
|
|
IRQ_DISABLE r10
|
|
|
|
; Fast Path return to user mode if no pending work
|
|
GET_CURR_THR_INFO_FLAGS r9
|
|
and.f 0, r9, _TIF_WORK_MASK
|
|
bz .Lrestore_regs
|
|
|
|
; --- (Slow Path #1) task preemption ---
|
|
bbit0 r9, TIF_NEED_RESCHED, .Lchk_pend_signals
|
|
mov blink, resume_user_mode_begin ; tail-call to U mode ret chks
|
|
j @schedule ; BTST+Bnz causes relo error in link
|
|
|
|
.Lchk_pend_signals:
|
|
IRQ_ENABLE r10
|
|
|
|
; --- (Slow Path #2) pending signal ---
|
|
mov r0, sp ; pt_regs for arg to do_signal()/do_notify_resume()
|
|
|
|
GET_CURR_THR_INFO_FLAGS r9
|
|
bbit0 r9, TIF_SIGPENDING, .Lchk_notify_resume
|
|
|
|
; Normal Trap/IRQ entry only saves Scratch (caller-saved) regs
|
|
; in pt_reg since the "C" ABI (kernel code) will automatically
|
|
; save/restore callee-saved regs.
|
|
;
|
|
; However, here we need to explicitly save callee regs because
|
|
; (i) If this signal causes coredump - full regfile needed
|
|
; (ii) If signal is SIGTRAP/SIGSTOP, task is being traced thus
|
|
; tracer might call PEEKUSR(CALLEE reg)
|
|
;
|
|
; NOTE: SP will grow up by size of CALLEE Reg-File
|
|
SAVE_CALLEE_SAVED_USER ; clobbers r12
|
|
|
|
; save location of saved Callee Regs @ thread_struct->callee
|
|
GET_CURR_TASK_FIELD_PTR TASK_THREAD, r10
|
|
st sp, [r10, THREAD_CALLEE_REG]
|
|
|
|
bl @do_signal
|
|
|
|
; Ideally we want to discard the Callee reg above, however if this was
|
|
; a tracing signal, tracer could have done a POKEUSR(CALLEE reg)
|
|
RESTORE_CALLEE_SAVED_USER
|
|
|
|
b resume_user_mode_begin ; loop back to start of U mode ret
|
|
|
|
; --- (Slow Path #3) notify_resume ---
|
|
.Lchk_notify_resume:
|
|
btst r9, TIF_NOTIFY_RESUME
|
|
blnz @do_notify_resume
|
|
b resume_user_mode_begin ; unconditionally back to U mode ret chks
|
|
; for single exit point from this block
|
|
|
|
resume_kernel_mode:
|
|
|
|
; Disable Interrupts from this point on
|
|
; CONFIG_PREEMPT: This is a must for preempt_schedule_irq()
|
|
; !CONFIG_PREEMPT: To ensure restore_regs is intr safe
|
|
IRQ_DISABLE r9
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
|
|
; Can't preempt if preemption disabled
|
|
GET_CURR_THR_INFO_FROM_SP r10
|
|
ld r8, [r10, THREAD_INFO_PREEMPT_COUNT]
|
|
brne r8, 0, .Lrestore_regs
|
|
|
|
; check if this task's NEED_RESCHED flag set
|
|
ld r9, [r10, THREAD_INFO_FLAGS]
|
|
bbit0 r9, TIF_NEED_RESCHED, .Lrestore_regs
|
|
|
|
; Invoke PREEMPTION
|
|
jl preempt_schedule_irq
|
|
|
|
; preempt_schedule_irq() always returns with IRQ disabled
|
|
#endif
|
|
|
|
b .Lrestore_regs
|
|
|
|
##### DONT ADD CODE HERE - .Lrestore_regs actually follows in entry-<isa>.S
|
|
|