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-rw-r--r--arch/arc/kernel/entry.S157
1 files changed, 53 insertions, 104 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 0c6d664..b908dde 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -142,7 +142,7 @@ VECTOR reserved ; Reserved Exceptions
.endr
#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */
-#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */
+#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,SYS...} */
#include <asm/errno.h>
#include <asm/arcregs.h>
#include <asm/irqflags.h>
@@ -267,17 +267,10 @@ ARC_EXIT handle_interrupt_level1
ARC_ENTRY instr_service
- EXCPN_PROLOG_FREEUP_REG r9
+ EXCEPTION_PROLOGUE
- lr r9, [erstatus]
-
- 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
@@ -291,16 +284,13 @@ ARC_EXIT instr_service
ARC_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
@@ -311,17 +301,16 @@ ARC_EXIT mem_service
ARC_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
@@ -342,21 +331,15 @@ ARC_EXIT EV_MachineCheck
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
+ 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 r1, [efa] ; Faulting Data address
; --------(4) Return from CPU Exception Mode ---------
; Fake a rtie, but rtie to next label
@@ -368,31 +351,25 @@ ARC_ENTRY EV_TLBProtV
;------ (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
+ mov r0, r1
+ mov r1, sp ; pt_regs
#ifdef CONFIG_ARC_MISALIGN_ACCESS
SAVE_CALLEE_SAVED_USER
- mov r3, sp ; callee_regs
+ mov r2, sp ; callee_regs
bl do_misaligned_access
@@ -412,16 +389,10 @@ ARC_EXIT EV_TLBProtV
; ---------------------------------------------
ARC_ENTRY EV_PrivilegeV
- EXCPN_PROLOG_FREEUP_REG r9
-
- lr r9, [erstatus]
-
- SWITCH_TO_KERNEL_STK
- SAVE_ALL_SYS
+ EXCEPTION_PROLOGUE
- lr r0, [ecr]
- lr r1, [efa]
- mov r2, sp
+ lr r0, [efa]
+ mov r1, sp
FAKE_RET_FROM_EXCPN r9
@@ -434,15 +405,13 @@ ARC_EXIT EV_PrivilegeV
; ---------------------------------------------
ARC_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
@@ -498,11 +467,8 @@ 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
; and get out of CPU exception mode
@@ -537,18 +503,11 @@ trap_with_param:
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
+ 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 ========
@@ -589,11 +548,7 @@ 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.
@@ -653,9 +608,12 @@ resume_user_mode_begin:
b resume_user_mode_begin ; unconditionally back to U mode ret chks
; for single exit point from this block
+resume_kernel_mode:
+
#ifdef CONFIG_PREEMPT
-resume_kernel_mode:
+ ; This is a must for preempt_schedule_irq()
+ IRQ_DISABLE r9
; Can't preempt if preemption disabled
GET_CURR_THR_INFO_FROM_SP r10
@@ -666,8 +624,6 @@ 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
@@ -680,23 +636,11 @@ 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
+ lr r10, [status32]
; Restore REG File. In case multiple Events outstanding,
; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None
@@ -714,28 +658,33 @@ not_exception:
#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
+ ; Level 2 interrupt return Path - from hardware standpoint
bbit0 r10, STATUS_A2_BIT, not_level2_interrupt
;------------------------------------------------------------------
+ ; 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 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.
+ ; 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
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