/* * 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_LV2VECTOR handle_interrupt_level2#elseVECTOR handle_interrupt_level1#endif VECTOR handle_interrupt_level1 #ifdef CONFIG_ARC_IRQ5_LV2VECTOR handle_interrupt_level2#elseVECTOR handle_interrupt_level1#endif #ifdef CONFIG_ARC_IRQ6_LV2VECTOR handle_interrupt_level2#elseVECTOR handle_interrupt_level1#endif .rept 25VECTOR 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 AccessVECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24)VECTOR EV_Trap ; 0x128, Trap exception (0x25)VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26) .rept 24VECTOR 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, 4int1_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, 4int2_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_exceptionARC_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_exceptionARC_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_exceptionARC_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_exceptionARC_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_exceptionARC_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] ; 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 ;################### 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] Lines 1–500 of 814. Load more
/* * 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] ; 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 ;################### 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]