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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * ARCv2 ISA based core Low Level Intr/Traps/Exceptions(non-TLB) Handling
4 *
5 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
6 */
7
8#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */
9#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */
10#include <asm/errno.h>
11#include <asm/arcregs.h>
12#include <asm/irqflags.h>
13
14; A maximum number of supported interrupts in the core interrupt controller.
15; This number is not equal to the maximum interrupt number (256) because
16; first 16 lines are reserved for exceptions and are not configurable.
17#define NR_CPU_IRQS 240
18
19 .cpu HS
20
21#define VECTOR .word
22
23;############################ Vector Table #################################
24
25 .section .vector,"a",@progbits
26 .align 4
27
28# Initial 16 slots are Exception Vectors
29VECTOR res_service ; Reset Vector
30VECTOR mem_service ; Mem exception
31VECTOR instr_service ; Instrn Error
32VECTOR EV_MachineCheck ; Fatal Machine check
33VECTOR EV_TLBMissI ; Intruction TLB miss
34VECTOR EV_TLBMissD ; Data TLB miss
35VECTOR EV_TLBProtV ; Protection Violation
36VECTOR EV_PrivilegeV ; Privilege Violation
37VECTOR EV_SWI ; Software Breakpoint
38VECTOR EV_Trap ; Trap exception
39VECTOR EV_Extension ; Extn Instruction Exception
40VECTOR EV_DivZero ; Divide by Zero
41VECTOR EV_DCError ; Data Cache Error
42VECTOR EV_Misaligned ; Misaligned Data Access
43VECTOR reserved ; Reserved slots
44VECTOR reserved ; Reserved slots
45
46# Begin Interrupt Vectors
47VECTOR handle_interrupt ; (16) Timer0
48VECTOR handle_interrupt ; unused (Timer1)
49VECTOR handle_interrupt ; unused (WDT)
50VECTOR handle_interrupt ; (19) Inter core Interrupt (IPI)
51VECTOR handle_interrupt ; (20) perf Interrupt
52VECTOR handle_interrupt ; (21) Software Triggered Intr (Self IPI)
53VECTOR handle_interrupt ; unused
54VECTOR handle_interrupt ; (23) unused
55# End of fixed IRQs
56
57.rept NR_CPU_IRQS - 8
58 VECTOR handle_interrupt
59.endr
60
61 .section .text, "ax",@progbits
62
63reserved:
64 flag 1 ; Unexpected event, halt
65
66;##################### Interrupt Handling ##############################
67
68ENTRY(handle_interrupt)
69
70 INTERRUPT_PROLOGUE
71
72 # irq control APIs local_irq_save/restore/disable/enable fiddle with
73 # global interrupt enable bits in STATUS32 (.IE for 1 prio, .E[] for 2 prio)
74 # However a taken interrupt doesn't clear these bits. Thus irqs_disabled()
75 # query in hard ISR path would return false (since .IE is set) which would
76 # trips genirq interrupt handling asserts.
77 #
78 # So do a "soft" disable of interrutps here.
79 #
80 # Note this disable is only for consistent book-keeping as further interrupts
81 # will be disabled anyways even w/o this. Hardware tracks active interrupts
82 # seperately in AUX_IRQ_ACT.active and will not take new interrupts
83 # unless this one returns (or higher prio becomes pending in 2-prio scheme)
84
85 IRQ_DISABLE
86
87 ; icause is banked: one per priority level
88 ; so a higher prio interrupt taken here won't clobber prev prio icause
89 lr r0, [ICAUSE]
90 mov blink, ret_from_exception
91
92 b.d arch_do_IRQ
93 mov r1, sp
94
95END(handle_interrupt)
96
97;################### Non TLB Exception Handling #############################
98
99ENTRY(EV_SWI)
100 ; TODO: implement this
101 EXCEPTION_PROLOGUE
102 b ret_from_exception
103END(EV_SWI)
104
105ENTRY(EV_DivZero)
106 ; TODO: implement this
107 EXCEPTION_PROLOGUE
108 b ret_from_exception
109END(EV_DivZero)
110
111ENTRY(EV_DCError)
112 ; TODO: implement this
113 EXCEPTION_PROLOGUE
114 b ret_from_exception
115END(EV_DCError)
116
117; ---------------------------------------------
118; Memory Error Exception Handler
119; - Unlike ARCompact, handles Bus errors for both User/Kernel mode,
120; Instruction fetch or Data access, under a single Exception Vector
121; ---------------------------------------------
122
123ENTRY(mem_service)
124
125 EXCEPTION_PROLOGUE
126
127 lr r0, [efa]
128 mov r1, sp
129
130 FAKE_RET_FROM_EXCPN
131
132 bl do_memory_error
133 b ret_from_exception
134END(mem_service)
135
136ENTRY(EV_Misaligned)
137
138 EXCEPTION_PROLOGUE
139
140 lr r0, [efa] ; Faulting Data address
141 mov r1, sp
142
143 FAKE_RET_FROM_EXCPN
144
145 SAVE_CALLEE_SAVED_USER
146 mov r2, sp ; callee_regs
147
148 bl do_misaligned_access
149
150 ; TBD: optimize - do this only if a callee reg was involved
151 ; either a dst of emulated LD/ST or src with address-writeback
152 RESTORE_CALLEE_SAVED_USER
153
154 b ret_from_exception
155END(EV_Misaligned)
156
157; ---------------------------------------------
158; Protection Violation Exception Handler
159; ---------------------------------------------
160
161ENTRY(EV_TLBProtV)
162
163 EXCEPTION_PROLOGUE
164
165 lr r0, [efa] ; Faulting Data address
166 mov r1, sp ; pt_regs
167
168 FAKE_RET_FROM_EXCPN
169
170 mov blink, ret_from_exception
171 b do_page_fault
172
173END(EV_TLBProtV)
174
175; From Linux standpoint Slow Path I/D TLB Miss is same a ProtV as they
176; need to call do_page_fault().
177; ECR in pt_regs provides whether access was R/W/X
178
179.global call_do_page_fault
180.set call_do_page_fault, EV_TLBProtV
181
182;############# Common Handlers for ARCompact and ARCv2 ##############
183
184#include "entry.S"
185
186;############# Return from Intr/Excp/Trap (ARCv2 ISA Specifics) ##############
187;
188; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
189; IRQ shd definitely not happen between now and rtie
190; All 2 entry points to here already disable interrupts
191
192.Lrestore_regs:
193restore_regs:
194
195 # Interrpts are actually disabled from this point on, but will get
196 # reenabled after we return from interrupt/exception.
197 # But irq tracer needs to be told now...
198 TRACE_ASM_IRQ_ENABLE
199
200 ld r0, [sp, PT_status32] ; U/K mode at time of entry
201 lr r10, [AUX_IRQ_ACT]
202
203 bmsk r11, r10, 15 ; extract AUX_IRQ_ACT.active
204 breq r11, 0, .Lexcept_ret ; No intr active, ret from Exception
205
206;####### Return from Intr #######
207
208.Lisr_ret:
209
210debug_marker_l1:
211 ; bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot
212 btst r0, STATUS_DE_BIT ; Z flag set if bit clear
213 bnz .Lintr_ret_to_delay_slot ; branch if STATUS_DE_BIT set
214
215 ; Handle special case #1: (Entry via Exception, Return via IRQ)
216 ;
217 ; Exception in U mode, preempted in kernel, Intr taken (K mode), orig
218 ; task now returning to U mode (riding the Intr)
219 ; AUX_IRQ_ACTIVE won't have U bit set (since intr in K mode), hence SP
220 ; won't be switched to correct U mode value (from AUX_SP)
221 ; So force AUX_IRQ_ACT.U for such a case
222
223 btst r0, STATUS_U_BIT ; Z flag set if K (Z clear for U)
224 bset.nz r11, r11, AUX_IRQ_ACT_BIT_U ; NZ means U
225 sr r11, [AUX_IRQ_ACT]
226
227 INTERRUPT_EPILOGUE
228 rtie
229
230;####### Return from Exception / pure kernel mode #######
231
232.Lexcept_ret: ; Expects r0 has PT_status32
233
234debug_marker_syscall:
235 EXCEPTION_EPILOGUE
236 rtie
237
238;####### Return from Intr to insn in delay slot #######
239
240; Handle special case #2: (Entry via Exception in Delay Slot, Return via IRQ)
241;
242; Intr returning to a Delay Slot (DS) insn
243; (since IRQ NOT allowed in DS in ARCv2, this can only happen if orig
244; entry was via Exception in DS which got preempted in kernel).
245;
246; IRQ RTIE won't reliably restore DE bit and/or BTA, needs workaround
247;
248; Solution is to drop out of interrupt context into pure kernel mode
249; and return from pure kernel mode which does right things for delay slot
250
251.Lintr_ret_to_delay_slot:
252debug_marker_ds:
253
254 ld r2, [@intr_to_DE_cnt]
255 add r2, r2, 1
256 st r2, [@intr_to_DE_cnt]
257
258 ; drop out of interrupt context (clear AUX_IRQ_ACT.active)
259 bmskn r11, r10, 15
260 sr r11, [AUX_IRQ_ACT]
261 b .Lexcept_ret
262
263END(ret_from_exception)
1/*
2 * ARCv2 ISA based core Low Level Intr/Traps/Exceptions(non-TLB) Handling
3 *
4 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */
12#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */
13#include <asm/errno.h>
14#include <asm/arcregs.h>
15#include <asm/irqflags.h>
16
17 .cpu HS
18
19#define VECTOR .word
20
21;############################ Vector Table #################################
22
23 .section .vector,"a",@progbits
24 .align 4
25
26# Initial 16 slots are Exception Vectors
27VECTOR res_service ; Reset Vector
28VECTOR mem_service ; Mem exception
29VECTOR instr_service ; Instrn Error
30VECTOR EV_MachineCheck ; Fatal Machine check
31VECTOR EV_TLBMissI ; Intruction TLB miss
32VECTOR EV_TLBMissD ; Data TLB miss
33VECTOR EV_TLBProtV ; Protection Violation
34VECTOR EV_PrivilegeV ; Privilege Violation
35VECTOR EV_SWI ; Software Breakpoint
36VECTOR EV_Trap ; Trap exception
37VECTOR EV_Extension ; Extn Instruction Exception
38VECTOR EV_DivZero ; Divide by Zero
39VECTOR EV_DCError ; Data Cache Error
40VECTOR EV_Misaligned ; Misaligned Data Access
41VECTOR reserved ; Reserved slots
42VECTOR reserved ; Reserved slots
43
44# Begin Interrupt Vectors
45VECTOR handle_interrupt ; (16) Timer0
46VECTOR handle_interrupt ; unused (Timer1)
47VECTOR handle_interrupt ; unused (WDT)
48VECTOR handle_interrupt ; (19) Inter core Interrupt (IPI)
49VECTOR handle_interrupt ; (20) perf Interrupt
50VECTOR handle_interrupt ; (21) Software Triggered Intr (Self IPI)
51VECTOR handle_interrupt ; unused
52VECTOR handle_interrupt ; (23) unused
53# End of fixed IRQs
54
55.rept CONFIG_ARC_NUMBER_OF_INTERRUPTS - 8
56 VECTOR handle_interrupt
57.endr
58
59 .section .text, "ax",@progbits
60
61reserved:
62 flag 1 ; Unexpected event, halt
63
64;##################### Interrupt Handling ##############################
65
66ENTRY(handle_interrupt)
67
68 INTERRUPT_PROLOGUE irq
69
70 clri ; To make status32.IE agree with CPU internal state
71
72#ifdef CONFIG_TRACE_IRQFLAGS
73 TRACE_ASM_IRQ_DISABLE
74#endif
75
76 lr r0, [ICAUSE]
77 mov blink, ret_from_exception
78
79 b.d arch_do_IRQ
80 mov r1, sp
81
82END(handle_interrupt)
83
84;################### Non TLB Exception Handling #############################
85
86ENTRY(EV_SWI)
87 flag 1
88END(EV_SWI)
89
90ENTRY(EV_DivZero)
91 flag 1
92END(EV_DivZero)
93
94ENTRY(EV_DCError)
95 flag 1
96END(EV_DCError)
97
98; ---------------------------------------------
99; Memory Error Exception Handler
100; - Unlike ARCompact, handles Bus errors for both User/Kernel mode,
101; Instruction fetch or Data access, under a single Exception Vector
102; ---------------------------------------------
103
104ENTRY(mem_service)
105
106 EXCEPTION_PROLOGUE
107
108 lr r0, [efa]
109 mov r1, sp
110
111 FAKE_RET_FROM_EXCPN
112
113 bl do_memory_error
114 b ret_from_exception
115END(mem_service)
116
117ENTRY(EV_Misaligned)
118
119 EXCEPTION_PROLOGUE
120
121 lr r0, [efa] ; Faulting Data address
122 mov r1, sp
123
124 FAKE_RET_FROM_EXCPN
125
126 SAVE_CALLEE_SAVED_USER
127 mov r2, sp ; callee_regs
128
129 bl do_misaligned_access
130
131 ; TBD: optimize - do this only if a callee reg was involved
132 ; either a dst of emulated LD/ST or src with address-writeback
133 RESTORE_CALLEE_SAVED_USER
134
135 b ret_from_exception
136END(EV_Misaligned)
137
138; ---------------------------------------------
139; Protection Violation Exception Handler
140; ---------------------------------------------
141
142ENTRY(EV_TLBProtV)
143
144 EXCEPTION_PROLOGUE
145
146 lr r0, [efa] ; Faulting Data address
147 mov r1, sp ; pt_regs
148
149 FAKE_RET_FROM_EXCPN
150
151 mov blink, ret_from_exception
152 b do_page_fault
153
154END(EV_TLBProtV)
155
156; From Linux standpoint Slow Path I/D TLB Miss is same a ProtV as they
157; need to call do_page_fault().
158; ECR in pt_regs provides whether access was R/W/X
159
160.global call_do_page_fault
161.set call_do_page_fault, EV_TLBProtV
162
163;############# Common Handlers for ARCompact and ARCv2 ##############
164
165#include "entry.S"
166
167;############# Return from Intr/Excp/Trap (ARCv2 ISA Specifics) ##############
168;
169; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
170; IRQ shd definitely not happen between now and rtie
171; All 2 entry points to here already disable interrupts
172
173.Lrestore_regs:
174
175 # Interrpts are actually disabled from this point on, but will get
176 # reenabled after we return from interrupt/exception.
177 # But irq tracer needs to be told now...
178 TRACE_ASM_IRQ_ENABLE
179
180 ld r0, [sp, PT_status32] ; U/K mode at time of entry
181 lr r10, [AUX_IRQ_ACT]
182
183 bmsk r11, r10, 15 ; AUX_IRQ_ACT.ACTIVE
184 breq r11, 0, .Lexcept_ret ; No intr active, ret from Exception
185
186;####### Return from Intr #######
187
188debug_marker_l1:
189 bbit1.nt r0, STATUS_DE_BIT, .Lintr_ret_to_delay_slot
190
191.Lisr_ret_fast_path:
192 ; Handle special case #1: (Entry via Exception, Return via IRQ)
193 ;
194 ; Exception in U mode, preempted in kernel, Intr taken (K mode), orig
195 ; task now returning to U mode (riding the Intr)
196 ; AUX_IRQ_ACTIVE won't have U bit set (since intr in K mode), hence SP
197 ; won't be switched to correct U mode value (from AUX_SP)
198 ; So force AUX_IRQ_ACT.U for such a case
199
200 btst r0, STATUS_U_BIT ; Z flag set if K (Z clear for U)
201 bset.nz r11, r11, AUX_IRQ_ACT_BIT_U ; NZ means U
202 sr r11, [AUX_IRQ_ACT]
203
204 INTERRUPT_EPILOGUE irq
205 rtie
206
207;####### Return from Exception / pure kernel mode #######
208
209.Lexcept_ret: ; Expects r0 has PT_status32
210
211debug_marker_syscall:
212 EXCEPTION_EPILOGUE
213 rtie
214
215;####### Return from Intr to insn in delay slot #######
216
217; Handle special case #2: (Entry via Exception in Delay Slot, Return via IRQ)
218;
219; Intr returning to a Delay Slot (DS) insn
220; (since IRQ NOT allowed in DS in ARCv2, this can only happen if orig
221; entry was via Exception in DS which got preempted in kernel).
222;
223; IRQ RTIE won't reliably restore DE bit and/or BTA, needs workaround
224;
225; Solution is return from Intr w/o any delay slot quirks into a kernel trampoline
226; and from pure kernel mode return to delay slot which handles DS bit/BTA correctly
227
228.Lintr_ret_to_delay_slot:
229debug_marker_ds:
230
231 ld r2, [@intr_to_DE_cnt]
232 add r2, r2, 1
233 st r2, [@intr_to_DE_cnt]
234
235 ld r2, [sp, PT_ret]
236 ld r3, [sp, PT_status32]
237
238 ; STAT32 for Int return created from scratch
239 ; (No delay dlot, disable Further intr in trampoline)
240
241 bic r0, r3, STATUS_U_MASK|STATUS_DE_MASK|STATUS_IE_MASK|STATUS_L_MASK
242 st r0, [sp, PT_status32]
243
244 mov r1, .Lintr_ret_to_delay_slot_2
245 st r1, [sp, PT_ret]
246
247 ; Orig exception PC/STAT32 safekept @orig_r0 and @event stack slots
248 st r2, [sp, 0]
249 st r3, [sp, 4]
250
251 b .Lisr_ret_fast_path
252
253.Lintr_ret_to_delay_slot_2:
254 ; Trampoline to restore orig exception PC/STAT32/BTA/AUX_USER_SP
255 sub sp, sp, SZ_PT_REGS
256 st r9, [sp, -4]
257
258 ld r9, [sp, 0]
259 sr r9, [eret]
260
261 ld r9, [sp, 4]
262 sr r9, [erstatus]
263
264 ; restore AUX_USER_SP if returning to U mode
265 bbit0 r9, STATUS_U_BIT, 1f
266 ld r9, [sp, PT_sp]
267 sr r9, [AUX_USER_SP]
268
2691:
270 ld r9, [sp, 8]
271 sr r9, [erbta]
272
273 ld r9, [sp, -4]
274 add sp, sp, SZ_PT_REGS
275
276 ; return from pure kernel mode to delay slot
277 rtie
278
279END(ret_from_exception)