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Diffstat (limited to 'arch/arc/kernel/entry.S')
| -rw-r--r-- | arch/arc/kernel/entry.S | 839 |
1 files changed, 839 insertions, 0 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S new file mode 100644 index 00000000000..ef6800ba2f0 --- /dev/null +++ b/arch/arc/kernel/entry.S @@ -0,0 +1,839 @@ +/* + * Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC + * + * 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. + * + * vineetg: May 2011 + * -Userspace unaligned access emulation + * + * vineetg: Feb 2011 (ptrace low level code fixes) + * -traced syscall return code (r0) was not saved into pt_regs for restoring + * into user reg-file when traded task rets to user space. + * -syscalls needing arch-wrappers (mainly for passing sp as pt_regs) + * were not invoking post-syscall trace hook (jumping directly into + * ret_from_system_call) + * + * vineetg: Nov 2010: + * -Vector table jumps (@8 bytes) converted into branches (@4 bytes) + * -To maintain the slot size of 8 bytes/vector, added nop, which is + * not executed at runtime. + * + * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK) + * -do_signal()invoked upon TIF_RESTORE_SIGMASK as well + * -Wrappers for sys_{,rt_}sigsuspend() nolonger needed as they don't + * need ptregs anymore + * + * Vineetg: Oct 2009 + * -In a rare scenario, Process gets a Priv-V exception and gets scheduled + * out. Since we don't do FAKE RTIE for Priv-V, CPU excpetion state remains + * active (AE bit enabled). This causes a double fault for a subseq valid + * exception. Thus FAKE RTIE needed in low level Priv-Violation handler. + * Instr Error could also cause similar scenario, so same there as well. + * + * Vineetg: March 2009 (Supporting 2 levels of Interrupts) + * + * Vineetg: Aug 28th 2008: Bug #94984 + * -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap + * Normally CPU does this automatically, however when doing FAKE rtie, + * we need to explicitly do this. The problem in macros + * FAKE_RET_FROM_EXCPN and FAKE_RET_FROM_EXCPN_LOCK_IRQ was that this bit + * was being "CLEARED" rather then "SET". Since it is Loop INHIBIT Bit, + * setting it and not clearing it clears ZOL context + * + * Vineetg: May 16th, 2008 + * - r25 now contains the Current Task when in kernel + * + * Vineetg: Dec 22, 2007 + * Minor Surgery of Low Level ISR to make it SMP safe + * - MMU_SCRATCH0 Reg used for freeing up r9 in Level 1 ISR + * - _current_task is made an array of NR_CPUS + * - Access of _current_task wrapped inside a macro so that if hardware + * team agrees for a dedicated reg, no other code is touched + * + * Amit Bhor, Rahul Trivedi, Kanika Nema, Sameer Dhavale : Codito Tech 2004 + */ + +/*------------------------------------------------------------------ + * 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 + * Interrupt link register (ilink1) r29 + * Interrupt link register (ilink2) r30 + * Branch link register (blink) r31 + *------------------------------------------------------------------ + */ + + .cpu A7 + +;############################ Vector Table ################################# + +.macro VECTOR lbl +#if 1 /* Just in case, build breaks */ + j \lbl +#else + b \lbl + nop +#endif +.endm + + .section .vector, "ax",@progbits + .align 4 + +/* Each entry in the vector table must occupy 2 words. Since it is a jump + * across sections (.vector to .text) we are gauranteed that 'j somewhere' + * will use the 'j limm' form of the intrsuction as long as somewhere is in + * a section other than .vector. + */ + +; ********* Critical System Events ********************** +VECTOR res_service ; 0x0, Restart Vector (0x0) +VECTOR mem_service ; 0x8, Mem exception (0x1) +VECTOR instr_service ; 0x10, Instrn Error (0x2) + +; ******************** Device ISRs ********************** +#ifdef CONFIG_ARC_IRQ3_LV2 +VECTOR handle_interrupt_level2 +#else +VECTOR handle_interrupt_level1 +#endif + +VECTOR handle_interrupt_level1 + +#ifdef CONFIG_ARC_IRQ5_LV2 +VECTOR handle_interrupt_level2 +#else +VECTOR handle_interrupt_level1 +#endif + +#ifdef CONFIG_ARC_IRQ6_LV2 +VECTOR handle_interrupt_level2 +#else +VECTOR handle_interrupt_level1 +#endif + +.rept 25 +VECTOR handle_interrupt_level1 ; Other devices +.endr + +/* FOR ARC600: timer = 0x3, uart = 0x8, emac = 0x10 */ + +; ******************** Exceptions ********************** +VECTOR EV_MachineCheck ; 0x100, Fatal Machine check (0x20) +VECTOR EV_TLBMissI ; 0x108, Intruction TLB miss (0x21) +VECTOR EV_TLBMissD ; 0x110, Data TLB miss (0x22) +VECTOR EV_TLBProtV ; 0x118, Protection Violation (0x23) + ; or Misaligned Access +VECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24) +VECTOR EV_Trap ; 0x128, Trap exception (0x25) +VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26) + +.rept 24 +VECTOR reserved ; Reserved Exceptions +.endr + +#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */ +#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */ +#include <asm/errno.h> +#include <asm/arcregs.h> +#include <asm/irqflags.h> + +;##################### Scratch Mem for IRQ stack switching ############# + +ARCFP_DATA int1_saved_reg + .align 32 + .type int1_saved_reg, @object + .size int1_saved_reg, 4 +int1_saved_reg: + .zero 4 + +/* Each Interrupt level needs it's own scratch */ +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS + +ARCFP_DATA int2_saved_reg + .type int2_saved_reg, @object + .size int2_saved_reg, 4 +int2_saved_reg: + .zero 4 + +#endif + +; --------------------------------------------- + .section .text, "ax",@progbits + +res_service: ; processor restart + flag 0x1 ; not implemented + nop + nop + +reserved: ; processor restart + rtie ; jump to processor initializations + +;##################### Interrupt Handling ############################## + +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS +; --------------------------------------------- +; Level 2 ISR: Can interrupt a Level 1 ISR +; --------------------------------------------- +ARC_ENTRY handle_interrupt_level2 + + ; TODO-vineetg for SMP this wont work + ; free up r9 as scratchpad + st r9, [@int2_saved_reg] + + ;Which mode (user/kernel) was the system in when intr occured + lr r9, [status32_l2] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_INT2 + + ;------------------------------------------------------ + ; if L2 IRQ interrupted a L1 ISR, disable preemption + ;------------------------------------------------------ + + ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs) + bbit0 r9, STATUS_A1_BIT, 1f ; L1 not active when L2 IRQ, so normal + + ; A1 is set in status32_l2 + ; bump thread_info->preempt_count (Disable preemption) + GET_CURR_THR_INFO_FROM_SP r10 + ld r9, [r10, THREAD_INFO_PREEMPT_COUNT] + add r9, r9, 1 + st r9, [r10, THREAD_INFO_PREEMPT_COUNT] + +1: + ;------------------------------------------------------ + ; setup params for Linux common ISR and invoke it + ;------------------------------------------------------ + lr r0, [icause2] + and r0, r0, 0x1f + + bl.d @arch_do_IRQ + mov r1, sp + + mov r8,0x2 + sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg + + b ret_from_exception + +ARC_EXIT handle_interrupt_level2 + +#endif + +; --------------------------------------------- +; Level 1 ISR +; --------------------------------------------- +ARC_ENTRY handle_interrupt_level1 + + /* free up r9 as scratchpad */ +#ifdef CONFIG_SMP + sr r9, [ARC_REG_SCRATCH_DATA0] +#else + st r9, [@int1_saved_reg] +#endif + + ;Which mode (user/kernel) was the system in when intr occured + lr r9, [status32_l1] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_INT1 + + lr r0, [icause1] + and r0, r0, 0x1f + + bl.d @arch_do_IRQ + mov r1, sp + + mov r8,0x1 + sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg + + b ret_from_exception +ARC_EXIT handle_interrupt_level1 + +;################### Non TLB Exception Handling ############################# + +; --------------------------------------------- +; Instruction Error Exception Handler +; --------------------------------------------- + +ARC_ENTRY instr_service + + EXCPN_PROLOG_FREEUP_REG r9 + + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + lr r0, [ecr] + lr r1, [efa] + + mov r2, sp + + FAKE_RET_FROM_EXCPN r9 + + bl do_insterror_or_kprobe + b ret_from_exception +ARC_EXIT instr_service + +; --------------------------------------------- +; Memory Error Exception Handler +; --------------------------------------------- + +ARC_ENTRY mem_service + + EXCPN_PROLOG_FREEUP_REG r9 + + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + lr r0, [ecr] + lr r1, [efa] + mov r2, sp + bl do_memory_error + b ret_from_exception +ARC_EXIT mem_service + +; --------------------------------------------- +; Machine Check Exception Handler +; --------------------------------------------- + +ARC_ENTRY EV_MachineCheck + + EXCPN_PROLOG_FREEUP_REG r9 + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + lr r0, [ecr] + lr r1, [efa] + mov r2, sp + + brne r0, 0x200100, 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 + +ARC_EXIT EV_MachineCheck + +; --------------------------------------------- +; Protection Violation Exception Handler +; --------------------------------------------- + +ARC_ENTRY EV_TLBProtV + + EXCPN_PROLOG_FREEUP_REG r9 + + ;Which mode (user/kernel) was the system in when Exception occured + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + ;---------(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] + + ; --------(4) Return from CPU Exception Mode --------- + ; Fake a rtie, but rtie to next label + ; That way, subsequently, do_page_fault ( ) executes in pure kernel + ; mode with further Exceptions enabled + + FAKE_RET_FROM_EXCPN r9 + + ;------ (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) + ; + cmp r3, 0x230400 ; Misaligned data access ? + beq 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 + + bl do_misaligned_access + +#ifdef CONFIG_ARC_MISALIGN_ACCESS + DISCARD_CALLEE_SAVED_USER +#endif + + b ret_from_exception + +ARC_EXIT EV_TLBProtV + +; --------------------------------------------- +; Privilege Violation Exception Handler +; --------------------------------------------- +ARC_ENTRY EV_PrivilegeV + + EXCPN_PROLOG_FREEUP_REG r9 + + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + lr r0, [ecr] + lr r1, [efa] + mov r2, sp + + FAKE_RET_FROM_EXCPN r9 + + bl do_privilege_fault + b ret_from_exception +ARC_EXIT EV_PrivilegeV + +; --------------------------------------------- +; Extension Instruction Exception Handler +; --------------------------------------------- +ARC_ENTRY EV_Extension + + EXCPN_PROLOG_FREEUP_REG r9 + lr r9, [erstatus] + + SWITCH_TO_KERNEL_STK + SAVE_ALL_SYS + + lr r0, [ecr] + lr r1, [efa] + mov r2, sp + bl do_extension_fault + b ret_from_exception +ARC_EXIT EV_Extension + +;######################### System Call 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] + + ; 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 + +;################### Break Point TRAP ########################## + + ; ======= (5b) Trap is due to Break-Point ========= + +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 + + ; Now that we have read EFA, its safe to do "fake" rtie + ; and get out of CPU exception mode + FAKE_RET_FROM_EXCPN r11 + + ; 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 + +;##################### 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 +;------------------------------------------------------------------ + +ARC_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 + + ;------- (4) What caused the Trap -------------- + lr r12, [ecr] + and.f 0, r12, ECR_PARAM_MASK + bnz trap_with_param + + ; ======= (5a) Trap is due to System Call ======== + + ; Before doing anything, return from CPU Exception Mode + FAKE_RET_FROM_EXCPN r11 + + ; If syscall tracing ongoing, invoke pre-pos-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 + 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 +ARC_EXIT EV_Trap + +ARC_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. + +ARC_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. +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 restore_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 + b @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() + + 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 + +#ifdef CONFIG_PREEMPT + +resume_kernel_mode: + + ; Can't preempt if preemption disabled + GET_CURR_THR_INFO_FROM_SP r10 + ld r8, [r10, THREAD_INFO_PREEMPT_COUNT] + brne r8, 0, restore_regs + + ; check if this task's NEED_RESCHED flag set + ld r9, [r10, THREAD_INFO_FLAGS] + bbit0 r9, TIF_NEED_RESCHED, restore_regs + + IRQ_DISABLE r9 + + ; Invoke PREEMPTION + bl preempt_schedule_irq + + ; preempt_schedule_irq() always returns with IRQ disabled +#endif + + ; fall through + +;############# Return from Intr/Excp/Trap (ARC Specifics) ############## +; +; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap) +; IRQ shd definitely not happen between now and rtie + +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 + + ; Restore REG File. In case multiple Events outstanding, + ; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None + ; Note that we use realtime STATUS32 (not pt_regs->status32) to + ; decide that. + + ; if Returning from Exception + bbit0 r10, STATUS_AE_BIT, not_exception + RESTORE_ALL_SYS + rtie + + ; Not Exception so maybe Interrupts (Level 1 or 2) + +not_exception: + +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS + + 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 + ; 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. + ; If this does happen we simply HALT as it means a BUG !!! + cmp r9, 0 + bnz 2f + flag 1 + +2: + sub r9, r9, 1 + st r9, [r10, THREAD_INFO_PREEMPT_COUNT] + +149: + ;return from level 2 + RESTORE_ALL_INT2 +debug_marker_l2: + rtie + +not_level2_interrupt: + +#endif + + bbit0 r10, STATUS_A1_BIT, not_level1_interrupt + + ;return from level 1 + + RESTORE_ALL_INT1 +debug_marker_l1: + rtie + +not_level1_interrupt: + + ;this case is for syscalls or Exceptions (with fake rtie) + + RESTORE_ALL_SYS +debug_marker_syscall: + rtie + +ARC_EXIT ret_from_exception + +ARC_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 + ld r9, [sp, PT_status32] + brne r9, 0, 1f + + jl.d [r14] + mov r0, r13 ; arg to payload + +1: + ; 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 + +;################### 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 + 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 +ARC_EXIT sys_clone_wrapper + +#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 +#endif |