1 /* SPDX-License-Identifier: GPL-2.0 */
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3
4 #include <linux/linkage.h>
5 #include <abi/entry.h>
6 #include <abi/pgtable-bits.h>
7 #include <asm/errno.h>
8 #include <asm/setup.h>
9 #include <asm/unistd.h>
10 #include <asm/asm-offsets.h>
11 #include <linux/threads.h>
12 #include <asm/page.h>
13 #include <asm/thread_info.h>
14
15 .macro zero_fp
16 #ifdef CONFIG_STACKTRACE
17 movi r8, 0
18 #endif
19 .endm
20
21 .macro context_tracking
22 #ifdef CONFIG_CONTEXT_TRACKING_USER
23 mfcr a0, epsr
24 btsti a0, 31
25 bt 1f
26 jbsr user_exit_callable
27 ldw a0, (sp, LSAVE_A0)
28 ldw a1, (sp, LSAVE_A1)
29 ldw a2, (sp, LSAVE_A2)
30 ldw a3, (sp, LSAVE_A3)
31 #if defined(__CSKYABIV1__)
32 ldw r6, (sp, LSAVE_A4)
33 ldw r7, (sp, LSAVE_A5)
34 #endif
35 1:
36 #endif
37 .endm
38
39 .text
40 ENTRY(csky_pagefault)
41 SAVE_ALL 0
42 zero_fp
43 context_tracking
44 psrset ee
45 mov a0, sp
46 jbsr do_page_fault
47 jmpi ret_from_exception
48
49 ENTRY(csky_systemcall)
50 SAVE_ALL TRAP0_SIZE
51 zero_fp
52 context_tracking
53 psrset ee, ie
54
55 lrw r9, __NR_syscalls
56 cmphs syscallid, r9 /* Check nr of syscall */
57 bt ret_from_exception
58
59 lrw r9, sys_call_table
60 ixw r9, syscallid
61 ldw syscallid, (r9)
62 cmpnei syscallid, 0
63 bf ret_from_exception
64
65 mov r9, sp
66 bmaski r10, THREAD_SHIFT
67 andn r9, r10
68 ldw r10, (r9, TINFO_FLAGS)
69 lrw r9, _TIF_SYSCALL_WORK
70 and r10, r9
71 cmpnei r10, 0
72 bt csky_syscall_trace
73 #if defined(__CSKYABIV2__)
74 subi sp, 8
75 stw r5, (sp, 0x4)
76 stw r4, (sp, 0x0)
77 jsr syscallid /* Do system call */
78 addi sp, 8
79 #else
80 jsr syscallid
81 #endif
82 stw a0, (sp, LSAVE_A0) /* Save return value */
83 jmpi ret_from_exception
84
85 csky_syscall_trace:
86 mov a0, sp /* sp = pt_regs pointer */
87 jbsr syscall_trace_enter
88 cmpnei a0, 0
89 bt 1f
90 /* Prepare args before do system call */
91 ldw a0, (sp, LSAVE_A0)
92 ldw a1, (sp, LSAVE_A1)
93 ldw a2, (sp, LSAVE_A2)
94 ldw a3, (sp, LSAVE_A3)
95 #if defined(__CSKYABIV2__)
96 subi sp, 8
97 ldw r9, (sp, LSAVE_A4)
98 stw r9, (sp, 0x0)
99 ldw r9, (sp, LSAVE_A5)
100 stw r9, (sp, 0x4)
101 jsr syscallid /* Do system call */
102 addi sp, 8
103 #else
104 ldw r6, (sp, LSAVE_A4)
105 ldw r7, (sp, LSAVE_A5)
106 jsr syscallid /* Do system call */
107 #endif
108 stw a0, (sp, LSAVE_A0) /* Save return value */
109
110 1:
111 mov a0, sp /* right now, sp --> pt_regs */
112 jbsr syscall_trace_exit
113 br ret_from_exception
114
115 ENTRY(ret_from_kernel_thread)
116 jbsr schedule_tail
117 mov a0, r10
118 jsr r9
119 jbsr ret_from_exception
120
121 ENTRY(ret_from_fork)
122 jbsr schedule_tail
123 mov r9, sp
124 bmaski r10, THREAD_SHIFT
125 andn r9, r10
126 ldw r10, (r9, TINFO_FLAGS)
127 lrw r9, _TIF_SYSCALL_WORK
128 and r10, r9
129 cmpnei r10, 0
130 bf ret_from_exception
131 mov a0, sp /* sp = pt_regs pointer */
132 jbsr syscall_trace_exit
133
134 ret_from_exception:
135 psrclr ie
136 ld r9, (sp, LSAVE_PSR)
137 btsti r9, 31
138
139 bt 1f
140 /*
141 * Load address of current->thread_info, Then get address of task_struct
142 * Get task_needreshed in task_struct
143 */
144 mov r9, sp
145 bmaski r10, THREAD_SHIFT
146 andn r9, r10
147
148 ldw r10, (r9, TINFO_FLAGS)
149 lrw r9, _TIF_WORK_MASK
150 and r10, r9
151 cmpnei r10, 0
152 bt exit_work
153 #ifdef CONFIG_CONTEXT_TRACKING_USER
154 jbsr user_enter_callable
155 #endif
156 1:
157 #ifdef CONFIG_PREEMPTION
158 mov r9, sp
159 bmaski r10, THREAD_SHIFT
160 andn r9, r10
161
162 ldw r10, (r9, TINFO_PREEMPT)
163 cmpnei r10, 0
164 bt 2f
165 jbsr preempt_schedule_irq /* irq en/disable is done inside */
166 2:
167 #endif
168
169 #ifdef CONFIG_TRACE_IRQFLAGS
170 ld r10, (sp, LSAVE_PSR)
171 btsti r10, 6
172 bf 2f
173 jbsr trace_hardirqs_on
174 2:
175 #endif
176 RESTORE_ALL
177
178 exit_work:
179 lrw r9, ret_from_exception
180 mov lr, r9
181
182 btsti r10, TIF_NEED_RESCHED
183 bt work_resched
184
185 psrset ie
186 mov a0, sp
187 mov a1, r10
188 jmpi do_notify_resume
189
190 work_resched:
191 jmpi schedule
192
193 ENTRY(csky_trap)
194 SAVE_ALL 0
195 zero_fp
196 context_tracking
197 psrset ee
198 mov a0, sp /* Push Stack pointer arg */
199 jbsr trap_c /* Call C-level trap handler */
200 jmpi ret_from_exception
201
202 /*
203 * Prototype from libc for abiv1:
204 * register unsigned int __result asm("a0");
205 * asm( "trap 3" :"=r"(__result)::);
206 */
207 ENTRY(csky_get_tls)
208 USPTOKSP
209
210 RD_MEH a0
211 WR_MEH a0
212
213 /* increase epc for continue */
214 mfcr a0, epc
215 addi a0, TRAP0_SIZE
216 mtcr a0, epc
217
218 /* get current task thread_info with kernel 8K stack */
219 bmaski a0, THREAD_SHIFT
220 not a0
221 subi sp, 1
222 and a0, sp
223 addi sp, 1
224
225 /* get tls */
226 ldw a0, (a0, TINFO_TP_VALUE)
227
228 KSPTOUSP
229 rte
230
231 ENTRY(csky_irq)
232 SAVE_ALL 0
233 zero_fp
234 context_tracking
235 psrset ee
236
237 #ifdef CONFIG_TRACE_IRQFLAGS
238 jbsr trace_hardirqs_off
239 #endif
240
241
242 mov a0, sp
243 jbsr generic_handle_arch_irq
244
245 jmpi ret_from_exception
246
247 /*
248 * a0 = prev task_struct *
249 * a1 = next task_struct *
250 * a0 = return next
251 */
252 ENTRY(__switch_to)
253 lrw a3, TASK_THREAD
254 addu a3, a0
255
256 SAVE_SWITCH_STACK
257
258 stw sp, (a3, THREAD_KSP)
259
260 /* Set up next process to run */
261 lrw a3, TASK_THREAD
262 addu a3, a1
263
264 ldw sp, (a3, THREAD_KSP) /* Set next kernel sp */
265
266 #if defined(__CSKYABIV2__)
267 addi a3, a1, TASK_THREAD_INFO
268 ldw tls, (a3, TINFO_TP_VALUE)
269 #endif
270
271 RESTORE_SWITCH_STACK
272
273 rts
274 ENDPROC(__switch_to)
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