diff options
Diffstat (limited to 'arch/arc/kernel/entry.S')
| -rw-r--r-- | arch/arc/kernel/entry.S | 45 |
1 files changed, 20 insertions, 25 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index cd26e0fa5044..f291fc8476d7 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -160,20 +160,19 @@ END(EV_Extension) ; 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 + ; safekeep EFA (r12) if syscall tracer wanted PC + ; for traps, ERET is pre-commit so points to next-PC 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 + ; PRE syscall trace hook + mov r0, sp ; pt_regs + bl @syscall_trace_enter ; 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 - 1 mov.hi r0, -ENOSYS bhi tracesys_exit @@ -190,36 +189,36 @@ tracesys: ld r6, [sp, PT_r6] ld r7, [sp, PT_r7] ld.as r9, [sys_call_table, r8] - jl [r9] ; Entry into Sys Call Handler + jl [r9] tracesys_exit: - st r0, [sp, PT_r0] ; sys call return value in pt_regs + st r0, [sp, PT_r0] - ;POST Sys Call Ptrace Hook + ; POST syscall trace hook mov r0, sp ; pt_regs needed 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 + + ; don't call ret_from_system_call as it saves r0, already done above + b ret_from_exception ; --------------------------------------------- ; Breakpoint TRAP ; --------------------------------------------- trap_with_param: mov r0, r12 ; EFA in case ptracer/gdb wants stop_pc - mov r1, sp + mov r1, sp ; pt_regs - ; Save callee regs in case gdb wants to have a look - ; SP will grow up by size of CALLEE Reg-File + ; save callee regs in case tracer/gdb wants to peek SAVE_CALLEE_SAVED_USER - ; save location of saved Callee Regs @ thread_struct->pc + ; safekeep ref to callee regs GET_CURR_TASK_FIELD_PTR TASK_THREAD, r10 st sp, [r10, THREAD_CALLEE_REG] - ; Call the trap handler + ; call the non syscall trap handler bl do_non_swi_trap - ; unwind stack to discard Callee saved Regs + ; unwind stack to discard callee regs DISCARD_CALLEE_SAVED_USER b ret_from_exception @@ -237,31 +236,27 @@ ENTRY(EV_Trap) FAKE_RET_FROM_EXCPN - ;============ TRAP 1 :breakpoints - ; Check ECR for trap with arg (PROLOGUE ensures r10 has ECR) + ;============ TRAP N : breakpoints, kprobes etc bmsk.f 0, r10, 7 bnz trap_with_param - ;============ TRAP (no param): syscall top level + ;============ TRAP 0 (no param): syscall - ; If syscall tracing ongoing, invoke pre-post-hooks + ; syscall tracing ongoing, invoke pre-post-hooks around syscall GET_CURR_THR_INFO_FLAGS r10 and.f 0, r10, _TIF_SYSCALL_WORK bnz tracesys ; this never comes back ;============ Normal syscall case - ; syscall num shd not exceed the total system calls avail cmp r8, NR_syscalls - 1 mov.hi r0, -ENOSYS bhi .Lret_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 + jl [r9] .Lret_from_system_call: - st r0, [sp, PT_r0] ; sys call return value in pt_regs ; fall through to ret_from_exception |