1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Common Low Level Interrupts/Traps/Exception !! 2 * This file is subject to the terms and conditions of the GNU General Public
4 * (included from entry-<isa>.S !! 3 * License. See the file "COPYING" in the main directory of this archive
>> 4 * for more details.
5 * 5 *
6 * Copyright (C) 2014-15 Synopsys, Inc. (www.s !! 6 * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
7 * Copyright (C) 2004, 2007-2010, 2011-2012 Sy !! 7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
>> 8 * Copyright (C) 2001 MIPS Technologies, Inc.
8 */ 9 */
9 10
10 /*-------------------------------------------- !! 11 #include <asm/asm.h>
11 * Function ABI !! 12 #include <asm/asmmacro.h>
12 *-------------------------------------------- !! 13 #include <asm/compiler.h>
13 * !! 14 #include <asm/irqflags.h>
14 * Arguments r0 - r !! 15 #include <asm/regdef.h>
15 * Caller Saved Registers r0 - r !! 16 #include <asm/mipsregs.h>
16 * Callee Saved Registers r13- r !! 17 #include <asm/stackframe.h>
17 * Global Pointer (gp) r26 !! 18 #include <asm/isadep.h>
18 * Frame Pointer (fp) r27 !! 19 #include <asm/thread_info.h>
19 * Stack Pointer (sp) r28 !! 20
20 * Branch link register (blink) r31 !! 21 #ifndef CONFIG_PREEMPTION
21 *-------------------------------------------- !! 22 #define resume_kernel restore_all
22 */ !! 23 #else
23 !! 24 #define __ret_from_irq ret_from_exception
24 ;################### Special Sys Call Wrappers !! 25 #endif
25 <<
26 ENTRY(sys_clone_wrapper) <<
27 SAVE_CALLEE_SAVED_USER <<
28 bl @sys_clone <<
29 DISCARD_CALLEE_SAVED_USER <<
30 <<
31 GET_CURR_THR_INFO_FLAGS r10 <<
32 and.f 0, r10, _TIF_SYSCALL_WORK <<
33 bnz tracesys_exit <<
34 <<
35 b .Lret_from_system_call <<
36 END(sys_clone_wrapper) <<
37 <<
38 ENTRY(sys_clone3_wrapper) <<
39 SAVE_CALLEE_SAVED_USER <<
40 bl @sys_clone3 <<
41 DISCARD_CALLEE_SAVED_USER <<
42 <<
43 GET_CURR_THR_INFO_FLAGS r10 <<
44 and.f 0, r10, _TIF_SYSCALL_WORK <<
45 bnz tracesys_exit <<
46 <<
47 b .Lret_from_system_call <<
48 END(sys_clone3_wrapper) <<
49 <<
50 ENTRY(ret_from_fork) <<
51 ; when the forked child comes here fro <<
52 ; r0 has the last task pointer. <<
53 ; put last task in scheduler queue <<
54 jl @schedule_tail <<
55 <<
56 ld r9, [sp, PT_status32] <<
57 brne r9, 0, 1f <<
58 <<
59 jl.d [r14] ; kernel threa <<
60 mov r0, r13 ; (see PF_KTHR <<
61 <<
62 1: <<
63 ; Return to user space <<
64 ; 1. Any forked task (Reach here via B <<
65 ; 2. First ever init task (Reach here <<
66 ; This is the historic "kernel_exec <<
67 ; user mode, in a round about way s <<
68 ; a kernel thread which is executed <<
69 ; out whenever kernel_execve (now i <<
70 b ret_from_exception <<
71 END(ret_from_fork) <<
72 <<
73 ;################### Non TLB Exception Handlin <<
74 <<
75 ; -------------------------------------------- <<
76 ; Instruction Error Exception Handler <<
77 ; -------------------------------------------- <<
78 <<
79 ENTRY(instr_service) <<
80 <<
81 EXCEPTION_PROLOGUE <<
82 <<
83 bl do_insterror_or_kprobe <<
84 b ret_from_exception <<
85 END(instr_service) <<
86 <<
87 ; -------------------------------------------- <<
88 ; Machine Check Exception Handler <<
89 ; -------------------------------------------- <<
90 <<
91 ENTRY(EV_MachineCheck) <<
92 <<
93 EXCEPTION_PROLOGUE_KEEP_AE ; ECR <<
94 <<
95 lr r0, [efa] <<
96 mov r1, sp <<
97 <<
98 ; MC exceptions disable MMU <<
99 ARC_MMU_REENABLE r3 <<
100 <<
101 lsr r3, r10, 8 <<
102 bmsk r3, r3, 7 <<
103 brne r3, ECR_C_MCHK_DUP_TLB, 1f <<
104 <<
105 bl do_tlb_overlap_fault <<
106 b ret_from_exception <<
107 <<
108 1: <<
109 ; DEAD END: can't do much, display Reg <<
110 SAVE_CALLEE_SAVED_USER <<
111 <<
112 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
113 st sp, [r10, THREAD_CALLEE_REG] <<
114 <<
115 j do_machine_check_fault <<
116 <<
117 END(EV_MachineCheck) <<
118 <<
119 ; -------------------------------------------- <<
120 ; Privilege Violation Exception Handler <<
121 ; -------------------------------------------- <<
122 ENTRY(EV_PrivilegeV) <<
123 <<
124 EXCEPTION_PROLOGUE <<
125 <<
126 bl do_privilege_fault <<
127 b ret_from_exception <<
128 END(EV_PrivilegeV) <<
129 <<
130 ; -------------------------------------------- <<
131 ; Extension Instruction Exception Handler <<
132 ; -------------------------------------------- <<
133 ENTRY(EV_Extension) <<
134 <<
135 EXCEPTION_PROLOGUE <<
136 <<
137 bl do_extension_fault <<
138 b ret_from_exception <<
139 END(EV_Extension) <<
140 <<
141 ;################ Trap Handling (Syscall, Brea <<
142 <<
143 ; -------------------------------------------- <<
144 ; syscall Tracing <<
145 ; -------------------------------------------- <<
146 tracesys: <<
147 ; safekeep EFA (r12) if syscall tracer <<
148 ; for traps, ERET is pre-commit so poi <<
149 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
150 st r12, [r11, THREAD_FAULT_ADDR] <<
151 <<
152 ; PRE syscall trace hook <<
153 mov r0, sp <<
154 bl @syscall_trace_enter <<
155 <<
156 ; Tracing code now returns the syscall <<
157 mov r8, r0 <<
158 <<
159 ; Do the Sys Call as we normally would <<
160 cmp r8, NR_syscalls - 1 <<
161 mov.hi r0, -ENOSYS <<
162 bhi tracesys_exit <<
163 <<
164 ; Restore the sys-call args. Mere invo <<
165 ; clobbered them (since they are in sc <<
166 ; have deliberately changed the syscal <<
167 ld r0, [sp, PT_r0] <<
168 ld r1, [sp, PT_r1] <<
169 ld r2, [sp, PT_r2] <<
170 ld r3, [sp, PT_r3] <<
171 ld r4, [sp, PT_r4] <<
172 ld r5, [sp, PT_r5] <<
173 ld r6, [sp, PT_r6] <<
174 ld r7, [sp, PT_r7] <<
175 ld.as r9, [sys_call_table, r8] <<
176 jl [r9] <<
177 <<
178 tracesys_exit: <<
179 st r0, [sp, PT_r0] <<
180 <<
181 ; POST syscall trace hook <<
182 mov r0, sp ; pt_regs need <<
183 bl @syscall_trace_exit <<
184 <<
185 ; don't call ret_from_system_call as i <<
186 b ret_from_exception <<
187 <<
188 ; -------------------------------------------- <<
189 ; Breakpoint TRAP <<
190 ; -------------------------------------------- <<
191 trap_with_param: <<
192 mov r0, r12 ; EFA in case ptracer/ <<
193 mov r1, sp ; pt_regs <<
194 <<
195 ; save callee regs in case tracer/gdb <<
196 SAVE_CALLEE_SAVED_USER <<
197 <<
198 ; safekeep ref to callee regs <<
199 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
200 st sp, [r10, THREAD_CALLEE_REG] <<
201 <<
202 ; call the non syscall trap handler <<
203 bl do_non_swi_trap <<
204 <<
205 ; unwind stack to discard callee regs <<
206 DISCARD_CALLEE_SAVED_USER <<
207 <<
208 b ret_from_exception <<
209 <<
210 ; -------------------------------------------- <<
211 ; syscall TRAP <<
212 ; ABI: (r0-r7) up to 8 args, (r8) syscall numb <<
213 ; -------------------------------------------- <<
214 <<
215 ENTRY(EV_Trap) <<
216 <<
217 EXCEPTION_PROLOGUE_KEEP_AE <<
218 <<
219 lr r12, [efa] <<
220 <<
221 FAKE_RET_FROM_EXCPN <<
222 <<
223 ;============ TRAP N : breakpoints, kp <<
224 bmsk.f 0, r10, 7 <<
225 bnz trap_with_param <<
226 <<
227 ;============ TRAP 0 (no param): sysca <<
228 <<
229 ; syscall tracing ongoing, invoke pre- <<
230 GET_CURR_THR_INFO_FLAGS r10 <<
231 and.f 0, r10, _TIF_SYSCALL_WORK <<
232 bnz tracesys ; this never comes bac <<
233 <<
234 ;============ Normal syscall case <<
235 <<
236 cmp r8, NR_syscalls - 1 <<
237 mov.hi r0, -ENOSYS <<
238 bhi .Lret_from_system_call <<
239 <<
240 ld.as r9,[sys_call_table, r8] <<
241 jl [r9] <<
242 <<
243 .Lret_from_system_call: <<
244 st r0, [sp, PT_r0] ; sys call ret <<
245 <<
246 ; fall through to ret_from_exception <<
247 END(EV_Trap) <<
248 <<
249 ;############# Return from Intr/Excp/Trap (Lin <<
250 ; <<
251 ; If ret to user mode do we need to handle sig <<
252 <<
253 ENTRY(ret_from_exception) <<
254 <<
255 ; Pre-{IRQ,Trap,Exception} K/U mode fr <<
256 ld r8, [sp, PT_status32] ; returnin <<
257 <<
258 bbit0 r8, STATUS_U_BIT, resume_kernel <<
259 <<
260 ; Before returning to User mode check- <<
261 ; such as rescheduling/signal-delivery <<
262 resume_user_mode_begin: <<
263 <<
264 ; Disable IRQs to ensures that chk for <<
265 ; (and we don't end up missing a NEED_ <<
266 ; interim IRQ). <<
267 IRQ_DISABLE r10 <<
268 <<
269 ; Fast Path return to user mode if no <<
270 GET_CURR_THR_INFO_FLAGS r9 <<
271 and.f 0, r9, _TIF_WORK_MASK <<
272 bz .Lrestore_regs <<
273 <<
274 ; --- (Slow Path #1) task preemption - <<
275 bbit0 r9, TIF_NEED_RESCHED, .Lchk_pen <<
276 mov blink, resume_user_mode_begin <<
277 j @schedule ; BTST+Bnz cau <<
278 <<
279 .Lchk_pend_signals: <<
280 IRQ_ENABLE r10 <<
281 <<
282 ; --- (Slow Path #2) pending signal - <<
283 mov r0, sp ; pt_regs for arg to d <<
284 <<
285 GET_CURR_THR_INFO_FLAGS r9 <<
286 and.f 0, r9, _TIF_SIGPENDING|_TIF_NO <<
287 bz .Lchk_notify_resume <<
288 <<
289 ; Normal Trap/IRQ entry only saves Scr <<
290 ; in pt_reg since the "C" ABI (kernel <<
291 ; save/restore callee-saved regs. <<
292 ; <<
293 ; However, here we need to explicitly <<
294 ; (i) If this signal causes coredump <<
295 ; (ii) If signal is SIGTRAP/SIGSTOP, t <<
296 ; tracer might call PEEKUSR(CALLE <<
297 ; <<
298 ; NOTE: SP will grow up by size of CAL <<
299 SAVE_CALLEE_SAVED_USER <<
300 <<
301 ; save location of saved Callee Regs @ <<
302 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
303 st sp, [r10, THREAD_CALLEE_REG] <<
304 <<
305 bl @do_signal <<
306 <<
307 ; Ideally we want to discard the Calle <<
308 ; a tracing signal, tracer could have <<
309 RESTORE_CALLEE_SAVED_USER <<
310 <<
311 b resume_user_mode_begin ; loop <<
312 <<
313 ; --- (Slow Path #3) notify_resume --- <<
314 .Lchk_notify_resume: <<
315 btst r9, TIF_NOTIFY_RESUME <<
316 blnz @do_notify_resume <<
317 b resume_user_mode_begin ; unco <<
318 ; for <<
319 <<
320 resume_kernel_mode: <<
321 26
322 ; Disable Interrupts from this point o !! 27 .text
323 ; CONFIG_PREEMPTION: This is a must fo !! 28 .align 5
324 ; !CONFIG_PREEMPTION: To ensure restor !! 29 #ifndef CONFIG_PREEMPTION
325 IRQ_DISABLE r9 !! 30 FEXPORT(ret_from_exception)
>> 31 local_irq_disable # preempt stop
>> 32 b __ret_from_irq
>> 33 #endif
>> 34 FEXPORT(ret_from_irq)
>> 35 LONG_S s0, TI_REGS($28)
>> 36 FEXPORT(__ret_from_irq)
>> 37 /*
>> 38 * We can be coming here from a syscall done in the kernel space,
>> 39 * e.g. a failed kernel_execve().
>> 40 */
>> 41 resume_userspace_check:
>> 42 LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
>> 43 andi t0, t0, KU_USER
>> 44 beqz t0, resume_kernel
>> 45
>> 46 resume_userspace:
>> 47 local_irq_disable # make sure we dont miss an
>> 48 # interrupt setting need_resched
>> 49 # between sampling and return
>> 50 LONG_L a2, TI_FLAGS($28) # current->work
>> 51 andi t0, a2, _TIF_WORK_MASK # (ignoring syscall_trace)
>> 52 bnez t0, work_pending
>> 53 j restore_all
326 54
327 #ifdef CONFIG_PREEMPTION 55 #ifdef CONFIG_PREEMPTION
>> 56 resume_kernel:
>> 57 local_irq_disable
>> 58 lw t0, TI_PRE_COUNT($28)
>> 59 bnez t0, restore_all
>> 60 LONG_L t0, TI_FLAGS($28)
>> 61 andi t1, t0, _TIF_NEED_RESCHED
>> 62 beqz t1, restore_all
>> 63 LONG_L t0, PT_STATUS(sp) # Interrupts off?
>> 64 andi t0, 1
>> 65 beqz t0, restore_all
>> 66 PTR_LA ra, restore_all
>> 67 j preempt_schedule_irq
>> 68 #endif
328 69
329 ; Can't preempt if preemption disabled !! 70 FEXPORT(ret_from_kernel_thread)
330 GET_CURR_THR_INFO_FROM_SP r10 !! 71 jal schedule_tail # a0 = struct task_struct *prev
331 ld r8, [r10, THREAD_INFO_PREEMPT_COUN !! 72 move a0, s1
332 brne r8, 0, .Lrestore_regs !! 73 jal s0
333 !! 74 j syscall_exit
334 ; check if this task's NEED_RESCHED fl !! 75
335 ld r9, [r10, THREAD_INFO_FLAGS] !! 76 FEXPORT(ret_from_fork)
336 bbit0 r9, TIF_NEED_RESCHED, .Lrestore !! 77 jal schedule_tail # a0 = struct task_struct *prev
337 !! 78
338 ; Invoke PREEMPTION !! 79 FEXPORT(syscall_exit)
339 jl preempt_schedule_irq !! 80 #ifdef CONFIG_DEBUG_RSEQ
340 !! 81 move a0, sp
341 ; preempt_schedule_irq() always return !! 82 jal rseq_syscall
>> 83 #endif
>> 84 local_irq_disable # make sure need_resched and
>> 85 # signals dont change between
>> 86 # sampling and return
>> 87 LONG_L a2, TI_FLAGS($28) # current->work
>> 88 li t0, _TIF_ALLWORK_MASK
>> 89 and t0, a2, t0
>> 90 bnez t0, syscall_exit_work
>> 91
>> 92 restore_all: # restore full frame
>> 93 .set noat
>> 94 RESTORE_TEMP
>> 95 RESTORE_AT
>> 96 RESTORE_STATIC
>> 97 restore_partial: # restore partial frame
>> 98 #ifdef CONFIG_TRACE_IRQFLAGS
>> 99 SAVE_STATIC
>> 100 SAVE_AT
>> 101 SAVE_TEMP
>> 102 LONG_L v0, PT_STATUS(sp)
>> 103 #if defined(CONFIG_CPU_R3000)
>> 104 and v0, ST0_IEP
>> 105 #else
>> 106 and v0, ST0_IE
342 #endif 107 #endif
>> 108 beqz v0, 1f
>> 109 jal trace_hardirqs_on
>> 110 b 2f
>> 111 1: jal trace_hardirqs_off
>> 112 2:
>> 113 RESTORE_TEMP
>> 114 RESTORE_AT
>> 115 RESTORE_STATIC
>> 116 #endif
>> 117 RESTORE_SOME
>> 118 RESTORE_SP_AND_RET
>> 119 .set at
>> 120
>> 121 work_pending:
>> 122 andi t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
>> 123 beqz t0, work_notifysig
>> 124 work_resched:
>> 125 TRACE_IRQS_OFF
>> 126 jal schedule
>> 127
>> 128 local_irq_disable # make sure need_resched and
>> 129 # signals dont change between
>> 130 # sampling and return
>> 131 LONG_L a2, TI_FLAGS($28)
>> 132 andi t0, a2, _TIF_WORK_MASK # is there any work to be done
>> 133 # other than syscall tracing?
>> 134 beqz t0, restore_all
>> 135 andi t0, a2, _TIF_NEED_RESCHED
>> 136 bnez t0, work_resched
>> 137
>> 138 work_notifysig: # deal with pending signals and
>> 139 # notify-resume requests
>> 140 move a0, sp
>> 141 li a1, 0
>> 142 jal do_notify_resume # a2 already loaded
>> 143 j resume_userspace_check
>> 144
>> 145 FEXPORT(syscall_exit_partial)
>> 146 #ifdef CONFIG_DEBUG_RSEQ
>> 147 move a0, sp
>> 148 jal rseq_syscall
>> 149 #endif
>> 150 local_irq_disable # make sure need_resched doesn't
>> 151 # change between and return
>> 152 LONG_L a2, TI_FLAGS($28) # current->work
>> 153 li t0, _TIF_ALLWORK_MASK
>> 154 and t0, a2
>> 155 beqz t0, restore_partial
>> 156 SAVE_STATIC
>> 157 syscall_exit_work:
>> 158 LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
>> 159 andi t0, t0, KU_USER
>> 160 beqz t0, resume_kernel
>> 161 li t0, _TIF_WORK_SYSCALL_EXIT
>> 162 and t0, a2 # a2 is preloaded with TI_FLAGS
>> 163 beqz t0, work_pending # trace bit set?
>> 164 local_irq_enable # could let syscall_trace_leave()
>> 165 # call schedule() instead
>> 166 TRACE_IRQS_ON
>> 167 move a0, sp
>> 168 jal syscall_trace_leave
>> 169 b resume_userspace
343 170
344 b .Lrestore_regs !! 171 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
>> 172 defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
345 173
346 ##### DONT ADD CODE HERE - .Lrestore_regs actu !! 174 /*
>> 175 * MIPS32R2 Instruction Hazard Barrier - must be called
>> 176 *
>> 177 * For C code use the inline version named instruction_hazard().
>> 178 */
>> 179 LEAF(mips_ihb)
>> 180 .set MIPS_ISA_LEVEL_RAW
>> 181 jr.hb ra
>> 182 nop
>> 183 END(mips_ihb)
347 184
>> 185 #endif /* CONFIG_CPU_MIPSR2 - CONFIG_CPU_MIPSR6 or CONFIG_MIPS_MT */
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