Commit 4bf4564b authored by Vineet Gupta's avatar Vineet Gupta

ARC: entry.S: comments cleanup

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent a8717d28
......@@ -322,13 +322,8 @@ ENTRY(EV_TLBProtV)
EXCEPTION_PROLOGUE
;---------(3) Save some more regs-----------------
; vineetg: Mar 6th: Random Seg Fault issue #1
; ecr and efa were not saved in case an Intr sneaks in
; after fake rtie
lr r2, [ecr]
lr r0, [efa] ; Faulting Data address
lr r0, [efa] ; Faulting Data addr (not part of pt_regs saved above)
; Exception auto-disables further Intr/exceptions.
; Re-enable them by pretending to return from exception
......@@ -336,7 +331,7 @@ ENTRY(EV_TLBProtV)
FAKE_RET_FROM_EXCPN
mov r1, sp
mov r1, sp ; Handle to pt_regs
;------ (5) Type of Protection Violation? ----------
;
......@@ -415,8 +410,11 @@ ENTRY(EV_Extension)
b ret_from_exception
END(EV_Extension)
;######################### System Call Tracing #########################
;################ 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
......@@ -459,10 +457,9 @@ tracesys_exit:
b ret_from_exception ; NOT ret_from_system_call at is saves r0 which
; we'd done before calling post hook above
;################### Break Point TRAP ##########################
; ======= (5b) Trap is due to Break-Point =========
; ---------------------------------------------
; Breakpoint TRAP
; ---------------------------------------------
trap_with_param:
; stop_pc info by gdb needs this info
......@@ -490,36 +487,33 @@ trap_with_param:
b ret_from_exception
;##################### Trap Handling ##############################
;
; EV_Trap caused by TRAP_S and TRAP0 instructions.
;------------------------------------------------------------------
; (1) System Calls
; :parameters in r0-r7.
; :r8 has the system call number
; (2) Break Points
;------------------------------------------------------------------
; ---------------------------------------------
; syscall TRAP
; ABI: (r0-r7) upto 8 args, (r8) syscall number
; ---------------------------------------------
ENTRY(EV_Trap)
EXCEPTION_PROLOGUE
;------- (4) What caused the Trap --------------
;============ TRAP 1 :breakpoints
lr r10, [ecr]
bmsk.f 0, r10, 7
bnz trap_with_param
; ======= (5a) Trap is due to System Call ========
;============ 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-pos-hooks
; 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
;============ This is normal System Call case ==========
; Sys-call num shd not exceed the total system calls avail
;============ 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
......
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