diff options
Diffstat (limited to 'arch/arc/kernel/entry.S')
| -rw-r--r-- | arch/arc/kernel/entry.S | 274 |
1 files changed, 104 insertions, 170 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index ef6800ba2f0..83a046a7cd0 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -141,8 +141,8 @@ VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26) VECTOR reserved ; Reserved Exceptions .endr -#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */ -#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */ +#include <linux/linkage.h> /* {EXTRY,EXIT} */ +#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,SYS...} */ #include <asm/errno.h> #include <asm/arcregs.h> #include <asm/irqflags.h> @@ -156,7 +156,7 @@ ARCFP_DATA int1_saved_reg int1_saved_reg: .zero 4 -/* Each Interrupt level needs it's own scratch */ +/* Each Interrupt level needs its own scratch */ #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS ARCFP_DATA int2_saved_reg @@ -184,7 +184,7 @@ reserved: ; processor restart ; --------------------------------------------- ; Level 2 ISR: Can interrupt a Level 1 ISR ; --------------------------------------------- -ARC_ENTRY handle_interrupt_level2 +ENTRY(handle_interrupt_level2) ; TODO-vineetg for SMP this wont work ; free up r9 as scratchpad @@ -225,14 +225,14 @@ ARC_ENTRY handle_interrupt_level2 b ret_from_exception -ARC_EXIT handle_interrupt_level2 +END(handle_interrupt_level2) #endif ; --------------------------------------------- ; Level 1 ISR ; --------------------------------------------- -ARC_ENTRY handle_interrupt_level1 +ENTRY(handle_interrupt_level1) /* free up r9 as scratchpad */ #ifdef CONFIG_SMP @@ -250,6 +250,14 @@ ARC_ENTRY handle_interrupt_level1 lr r0, [icause1] and r0, r0, 0x1f +#ifdef CONFIG_TRACE_IRQFLAGS + ; icause1 needs to be read early, before calling tracing, which + ; can clobber scratch regs, hence use of stack to stash it + push r0 + TRACE_ASM_IRQ_DISABLE + pop r0 +#endif + bl.d @arch_do_IRQ mov r1, sp @@ -257,7 +265,7 @@ ARC_ENTRY handle_interrupt_level1 sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg b ret_from_exception -ARC_EXIT handle_interrupt_level1 +END(handle_interrupt_level1) ;################### Non TLB Exception Handling ############################# @@ -265,63 +273,52 @@ ARC_EXIT handle_interrupt_level1 ; Instruction Error Exception Handler ; --------------------------------------------- -ARC_ENTRY instr_service - - EXCPN_PROLOG_FREEUP_REG r9 - - lr r9, [erstatus] - - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS +ENTRY(instr_service) - lr r0, [ecr] - lr r1, [efa] + EXCEPTION_PROLOGUE - mov r2, sp + lr r0, [efa] + mov r1, sp FAKE_RET_FROM_EXCPN r9 bl do_insterror_or_kprobe b ret_from_exception -ARC_EXIT instr_service +END(instr_service) ; --------------------------------------------- ; Memory Error Exception Handler ; --------------------------------------------- -ARC_ENTRY mem_service +ENTRY(mem_service) - EXCPN_PROLOG_FREEUP_REG r9 + EXCEPTION_PROLOGUE - lr r9, [erstatus] + lr r0, [efa] + mov r1, sp - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS + FAKE_RET_FROM_EXCPN r9 - lr r0, [ecr] - lr r1, [efa] - mov r2, sp bl do_memory_error b ret_from_exception -ARC_EXIT mem_service +END(mem_service) ; --------------------------------------------- ; Machine Check Exception Handler ; --------------------------------------------- -ARC_ENTRY EV_MachineCheck +ENTRY(EV_MachineCheck) - EXCPN_PROLOG_FREEUP_REG r9 - lr r9, [erstatus] + EXCEPTION_PROLOGUE - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS + lr r2, [ecr] + lr r0, [efa] + mov r1, sp - lr r0, [ecr] - lr r1, [efa] - mov r2, sp + lsr r3, r2, 8 + bmsk r3, r3, 7 + brne r3, ECR_C_MCHK_DUP_TLB, 1f - brne r0, 0x200100, 1f bl do_tlb_overlap_fault b ret_from_exception @@ -334,29 +331,23 @@ ARC_ENTRY EV_MachineCheck j do_machine_check_fault -ARC_EXIT EV_MachineCheck +END(EV_MachineCheck) ; --------------------------------------------- ; Protection Violation Exception Handler ; --------------------------------------------- -ARC_ENTRY EV_TLBProtV - - EXCPN_PROLOG_FREEUP_REG r9 +ENTRY(EV_TLBProtV) - ;Which mode (user/kernel) was the system in when Exception occured - lr r9, [erstatus] - - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS + 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 r3, [ecr] - lr r4, [efa] + + lr r2, [ecr] + lr r0, [efa] ; Faulting Data address ; --------(4) Return from CPU Exception Mode --------- ; Fake a rtie, but rtie to next label @@ -365,85 +356,68 @@ ARC_ENTRY EV_TLBProtV FAKE_RET_FROM_EXCPN r9 + mov r1, sp + ;------ (5) Type of Protection Violation? ---------- ; ; ProtV Hardware Exception is triggered for Access Faults of 2 types - ; -Access Violaton (WRITE to READ ONLY Page) - for linux COW - ; -Unaligned Access (READ/WRITE on odd boundary) + ; -Access Violaton : 00_23_(00|01|02|03)_00 + ; x r w r+w + ; -Unaligned Access : 00_23_04_00 ; - cmp r3, 0x230400 ; Misaligned data access ? - beq 4f + bbit1 r2, ECR_C_BIT_PROTV_MISALIG_DATA, 4f ;========= (6a) Access Violation Processing ======== - cmp r3, 0x230100 - mov r1, 0x0 ; if LD exception ? write = 0 - mov.ne r1, 0x1 ; else write = 1 - - mov r2, r4 ; faulting address - mov r0, sp ; pt_regs bl do_page_fault b ret_from_exception ;========== (6b) Non aligned access ============ 4: - mov r0, r3 ; cause code - mov r1, r4 ; faulting address - mov r2, sp ; pt_regs -#ifdef CONFIG_ARC_MISALIGN_ACCESS SAVE_CALLEE_SAVED_USER - mov r3, sp ; callee_regs -#endif + mov r2, sp ; callee_regs bl do_misaligned_access -#ifdef CONFIG_ARC_MISALIGN_ACCESS - DISCARD_CALLEE_SAVED_USER -#endif + ; TBD: optimize - do this only if a callee reg was involved + ; either a dst of emulated LD/ST or src with address-writeback + RESTORE_CALLEE_SAVED_USER b ret_from_exception -ARC_EXIT EV_TLBProtV +END(EV_TLBProtV) ; --------------------------------------------- ; Privilege Violation Exception Handler ; --------------------------------------------- -ARC_ENTRY EV_PrivilegeV - - EXCPN_PROLOG_FREEUP_REG r9 +ENTRY(EV_PrivilegeV) - lr r9, [erstatus] + EXCEPTION_PROLOGUE - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS - - lr r0, [ecr] - lr r1, [efa] - mov r2, sp + lr r0, [efa] + mov r1, sp FAKE_RET_FROM_EXCPN r9 bl do_privilege_fault b ret_from_exception -ARC_EXIT EV_PrivilegeV +END(EV_PrivilegeV) ; --------------------------------------------- ; Extension Instruction Exception Handler ; --------------------------------------------- -ARC_ENTRY EV_Extension +ENTRY(EV_Extension) - EXCPN_PROLOG_FREEUP_REG r9 - lr r9, [erstatus] + EXCEPTION_PROLOGUE - SWITCH_TO_KERNEL_STK - SAVE_ALL_SYS + lr r0, [efa] + mov r1, sp + + FAKE_RET_FROM_EXCPN r9 - lr r0, [ecr] - lr r1, [efa] - mov r2, sp bl do_extension_fault b ret_from_exception -ARC_EXIT EV_Extension +END(EV_Extension) ;######################### System Call Tracing ######################### @@ -452,7 +426,7 @@ tracesys: ; 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] + st r12, [r11, THREAD_FAULT_ADDR] ; thread.fault_address ; PRE Sys Call Ptrace hook mov r0, sp ; pt_regs needed @@ -496,13 +470,10 @@ tracesys_exit: trap_with_param: ; stop_pc info by gdb needs this info - stw orig_r8_IS_BRKPT, [sp, PT_orig_r8] - - mov r0, r12 - lr r1, [efa] - mov r2, sp + lr r0, [efa] + mov r1, sp - ; Now that we have read EFA, its safe to do "fake" rtie + ; Now that we have read EFA, it is safe to do "fake" rtie ; and get out of CPU exception mode FAKE_RET_FROM_EXCPN r11 @@ -533,20 +504,13 @@ trap_with_param: ; (2) Break Points ;------------------------------------------------------------------ -ARC_ENTRY EV_Trap +ENTRY(EV_Trap) - ; Need at least 1 reg to code the early exception prolog - EXCPN_PROLOG_FREEUP_REG r9 - - ;Which mode (user/kernel) was the system in when intr occured - lr r9, [erstatus] - - SWITCH_TO_KERNEL_STK - SAVE_ALL_TRAP + EXCEPTION_PROLOGUE ;------- (4) What caused the Trap -------------- lr r12, [ecr] - and.f 0, r12, ECR_PARAM_MASK + bmsk.f 0, r12, 7 bnz trap_with_param ; ======= (5a) Trap is due to System Call ======== @@ -570,9 +534,9 @@ ARC_ENTRY EV_Trap jl [r9] ; Entry into Sys Call Handler ; fall through to ret_from_system_call -ARC_EXIT EV_Trap +END(EV_Trap) -ARC_ENTRY ret_from_system_call +ENTRY(ret_from_system_call) st r0, [sp, PT_r0] ; sys call return value in pt_regs @@ -582,16 +546,12 @@ ARC_ENTRY ret_from_system_call ; ; If ret to user mode do we need to handle signals, schedule() et al. -ARC_ENTRY ret_from_exception +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 -#ifdef CONFIG_PREEMPT bbit0 r8, STATUS_U_BIT, resume_kernel_mode -#else - bbit0 r8, STATUS_U_BIT, restore_regs -#endif ; Before returning to User mode check-for-and-complete any pending work ; such as rescheduling/signal-delivery etc. @@ -618,6 +578,7 @@ resume_user_mode_begin: ; --- (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 @@ -651,10 +612,15 @@ resume_user_mode_begin: b resume_user_mode_begin ; unconditionally back to U mode ret chks ; for single exit point from this block -#ifdef CONFIG_PREEMPT - 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] @@ -664,8 +630,6 @@ resume_kernel_mode: ld r9, [r10, THREAD_INFO_FLAGS] bbit0 r9, TIF_NEED_RESCHED, restore_regs - IRQ_DISABLE r9 - ; Invoke PREEMPTION bl preempt_schedule_irq @@ -678,23 +642,13 @@ resume_kernel_mode: ; ; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap) ; IRQ shd definitely not happen between now and rtie +; All 2 entry points to here already disable interrupts restore_regs : - ; Disable Interrupts while restoring reg-file back - ; XXX can this be optimised out - IRQ_DISABLE_SAVE r9, r10 ;@r10 has prisitine (pre-disable) copy - -#ifdef CONFIG_ARC_CURR_IN_REG - ; Restore User R25 - ; Earlier this used to be only for returning to user mode - ; However with 2 levels of IRQ this can also happen even if - ; in kernel mode - ld r9, [sp, PT_sp] - brhs r9, VMALLOC_START, 8f - RESTORE_USER_R25 -8: -#endif + TRACE_ASM_IRQ_ENABLE + + lr r10, [status32] ; Restore REG File. In case multiple Events outstanding, ; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None @@ -712,28 +666,33 @@ not_exception: #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS + ; Level 2 interrupt return Path - from hardware standpoint bbit0 r10, STATUS_A2_BIT, not_level2_interrupt ;------------------------------------------------------------------ - ; if L2 IRQ interrupted a L1 ISR, we'd disbaled preemption earlier - ; so that sched doesnt move to new task, causing L1 to be delayed - ; undeterministically. Now that we've achieved that, lets reset + ; However the context returning might not have taken L2 intr itself + ; e.g. Task'A' user-code -> L2 intr -> schedule -> 'B' user-code ret + ; Special considerations needed for the context which took L2 intr + + ld r9, [sp, PT_event] ; Ensure this is L2 intr context + brne r9, event_IRQ2, 149f + + ;------------------------------------------------------------------ + ; if L2 IRQ interrupted an L1 ISR, we'd disabled preemption earlier + ; so that sched doesn't move to new task, causing L1 to be delayed + ; undeterministically. Now that we've achieved that, let's reset ; things to what they were, before returning from L2 context ;---------------------------------------------------------------- - ldw r9, [sp, PT_orig_r8] ; get orig_r8 to make sure it is - brne r9, orig_r8_IS_IRQ2, 149f ; infact a L2 ISR ret path - ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs) bbit0 r9, STATUS_A1_BIT, 149f ; L1 not active when L2 IRQ, so normal - ; A1 is set in status32_l2 ; decrement thread_info->preempt_count (re-enable preemption) GET_CURR_THR_INFO_FROM_SP r10 ld r9, [r10, THREAD_INFO_PREEMPT_COUNT] ; paranoid check, given A1 was active when A2 happened, preempt count - ; must not be 0 beccause we would have incremented it. + ; must not be 0 because we would have incremented it. ; If this does happen we simply HALT as it means a BUG !!! cmp r9, 0 bnz 2f @@ -769,15 +728,15 @@ not_level1_interrupt: debug_marker_syscall: rtie -ARC_EXIT ret_from_exception +END(ret_from_exception) -ARC_ENTRY ret_from_fork +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 bl @schedule_tail - ; If kernel thread, jump to it's entry-point + ; If kernel thread, jump to its entry-point ld r9, [sp, PT_status32] brne r9, 0, 1f @@ -788,36 +747,11 @@ ARC_ENTRY ret_from_fork ; special case of kernel_thread entry point returning back due to ; kernel_execve() - pretend return from syscall to ret to userland b ret_from_exception -ARC_EXIT ret_from_fork +END(ret_from_fork) ;################### Special Sys Call Wrappers ########################## -; TBD: call do_fork directly from here -ARC_ENTRY sys_fork_wrapper - SAVE_CALLEE_SAVED_USER - bl @sys_fork - DISCARD_CALLEE_SAVED_USER - - GET_CURR_THR_INFO_FLAGS r10 - btst r10, TIF_SYSCALL_TRACE - bnz tracesys_exit - - b ret_from_system_call -ARC_EXIT sys_fork_wrapper - -ARC_ENTRY sys_vfork_wrapper - SAVE_CALLEE_SAVED_USER - bl @sys_vfork - DISCARD_CALLEE_SAVED_USER - - GET_CURR_THR_INFO_FLAGS r10 - btst r10, TIF_SYSCALL_TRACE - bnz tracesys_exit - - b ret_from_system_call -ARC_EXIT sys_vfork_wrapper - -ARC_ENTRY sys_clone_wrapper +ENTRY(sys_clone_wrapper) SAVE_CALLEE_SAVED_USER bl @sys_clone DISCARD_CALLEE_SAVED_USER @@ -827,7 +761,7 @@ ARC_ENTRY sys_clone_wrapper bnz tracesys_exit b ret_from_system_call -ARC_EXIT sys_clone_wrapper +END(sys_clone_wrapper) #ifdef CONFIG_ARC_DW2_UNWIND ; Workaround for bug 94179 (STAR ): |