1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
4  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5  */
6 
7 #ifndef __ASM_ARC_ENTRY_H
8 #define __ASM_ARC_ENTRY_H
9 
10 #include <asm/unistd.h>		/* For NR_syscalls defination */
11 #include <asm/arcregs.h>
12 #include <asm/ptrace.h>
13 #include <asm/processor.h>	/* For VMALLOC_START */
14 #include <asm/mmu.h>
15 
16 #ifdef CONFIG_ISA_ARCOMPACT
17 #include <asm/entry-compact.h>	/* ISA specific bits */
18 #else
19 #include <asm/entry-arcv2.h>
20 #endif
21 
22 /* Note on the LD/ST addr modes with addr reg wback
23  *
24  * LD.a same as LD.aw
25  *
26  * LD.a    reg1, [reg2, x]  => Pre Incr
27  *      Eff Addr for load = [reg2 + x]
28  *
29  * LD.ab   reg1, [reg2, x]  => Post Incr
30  *      Eff Addr for load = [reg2]
31  */
32 
33 .macro PUSH reg
34 	st.a	\reg, [sp, -4]
35 .endm
36 
37 .macro PUSHAX aux
38 	lr	r9, [\aux]
39 	PUSH	r9
40 .endm
41 
42 .macro POP reg
43 	ld.ab	\reg, [sp, 4]
44 .endm
45 
46 .macro POPAX aux
47 	POP	r9
48 	sr	r9, [\aux]
49 .endm
50 
51 /*--------------------------------------------------------------
52  * Helpers to save/restore Scratch Regs:
53  * used by Interrupt/Exception Prologue/Epilogue
54  *-------------------------------------------------------------*/
55 .macro  SAVE_R0_TO_R12
56 	PUSH	r0
57 	PUSH	r1
58 	PUSH	r2
59 	PUSH	r3
60 	PUSH	r4
61 	PUSH	r5
62 	PUSH	r6
63 	PUSH	r7
64 	PUSH	r8
65 	PUSH	r9
66 	PUSH	r10
67 	PUSH	r11
68 	PUSH	r12
69 .endm
70 
71 .macro RESTORE_R12_TO_R0
72 	POP	r12
73 	POP	r11
74 	POP	r10
75 	POP	r9
76 	POP	r8
77 	POP	r7
78 	POP	r6
79 	POP	r5
80 	POP	r4
81 	POP	r3
82 	POP	r2
83 	POP	r1
84 	POP	r0
85 
86 .endm
87 
88 /*--------------------------------------------------------------
89  * Helpers to save/restore callee-saved regs:
90  * used by several macros below
91  *-------------------------------------------------------------*/
92 .macro SAVE_R13_TO_R24
93 	PUSH	r13
94 	PUSH	r14
95 	PUSH	r15
96 	PUSH	r16
97 	PUSH	r17
98 	PUSH	r18
99 	PUSH	r19
100 	PUSH	r20
101 	PUSH	r21
102 	PUSH	r22
103 	PUSH	r23
104 	PUSH	r24
105 .endm
106 
107 .macro RESTORE_R24_TO_R13
108 	POP	r24
109 	POP	r23
110 	POP	r22
111 	POP	r21
112 	POP	r20
113 	POP	r19
114 	POP	r18
115 	POP	r17
116 	POP	r16
117 	POP	r15
118 	POP	r14
119 	POP	r13
120 .endm
121 
122 /*--------------------------------------------------------------
123  * Collect User Mode callee regs as struct callee_regs - needed by
124  * fork/do_signal/unaligned-access-emulation.
125  * (By default only scratch regs are saved on entry to kernel)
126  *
127  * Special handling for r25 if used for caching Task Pointer.
128  * It would have been saved in task->thread.user_r25 already, but to keep
129  * the interface same it is copied into regular r25 placeholder in
130  * struct callee_regs.
131  *-------------------------------------------------------------*/
132 .macro SAVE_CALLEE_SAVED_USER
133 
134 	mov	r12, sp		; save SP as ref to pt_regs
135 	SAVE_R13_TO_R24
136 
137 #ifdef CONFIG_ARC_CURR_IN_REG
138 	; Retrieve orig r25 and save it with rest of callee_regs
139 	ld	r12, [r12, PT_user_r25]
140 	PUSH	r12
141 #else
142 	PUSH	r25
143 #endif
144 
145 .endm
146 
147 /*--------------------------------------------------------------
148  * Save kernel Mode callee regs at the time of Contect Switch.
149  *
150  * Special handling for r25 if used for caching Task Pointer.
151  * Kernel simply skips saving it since it will be loaded with
152  * incoming task pointer anyways
153  *-------------------------------------------------------------*/
154 .macro SAVE_CALLEE_SAVED_KERNEL
155 
156 	SAVE_R13_TO_R24
157 
158 #ifdef CONFIG_ARC_CURR_IN_REG
159 	sub     sp, sp, 4
160 #else
161 	PUSH	r25
162 #endif
163 .endm
164 
165 /*--------------------------------------------------------------
166  * Opposite of SAVE_CALLEE_SAVED_KERNEL
167  *-------------------------------------------------------------*/
168 .macro RESTORE_CALLEE_SAVED_KERNEL
169 
170 #ifdef CONFIG_ARC_CURR_IN_REG
171 	add     sp, sp, 4  /* skip usual r25 placeholder */
172 #else
173 	POP	r25
174 #endif
175 	RESTORE_R24_TO_R13
176 .endm
177 
178 /*--------------------------------------------------------------
179  * Opposite of SAVE_CALLEE_SAVED_USER
180  *
181  * ptrace tracer or unaligned-access fixup might have changed a user mode
182  * callee reg which is saved back to usual r25 storage location
183  *-------------------------------------------------------------*/
184 .macro RESTORE_CALLEE_SAVED_USER
185 
186 #ifdef CONFIG_ARC_CURR_IN_REG
187 	POP	r12
188 #else
189 	POP	r25
190 #endif
191 	RESTORE_R24_TO_R13
192 
193 	; SP is back to start of pt_regs
194 #ifdef CONFIG_ARC_CURR_IN_REG
195 	st	r12, [sp, PT_user_r25]
196 #endif
197 .endm
198 
199 /*--------------------------------------------------------------
200  * Super FAST Restore callee saved regs by simply re-adjusting SP
201  *-------------------------------------------------------------*/
202 .macro DISCARD_CALLEE_SAVED_USER
203 	add     sp, sp, SZ_CALLEE_REGS
204 .endm
205 
206 /*-------------------------------------------------------------
207  * given a tsk struct, get to the base of it's kernel mode stack
208  * tsk->thread_info is really a PAGE, whose bottom hoists stack
209  * which grows upwards towards thread_info
210  *------------------------------------------------------------*/
211 
212 .macro GET_TSK_STACK_BASE tsk, out
213 
214 	/* Get task->thread_info (this is essentially start of a PAGE) */
215 	ld  \out, [\tsk, TASK_THREAD_INFO]
216 
217 	/* Go to end of page where stack begins (grows upwards) */
218 	add2 \out, \out, (THREAD_SIZE)/4
219 
220 .endm
221 
222 /*
223  * @reg [OUT] thread_info->flags of "current"
224  */
225 .macro GET_CURR_THR_INFO_FLAGS  reg
226 	GET_CURR_THR_INFO_FROM_SP  \reg
227 	ld  \reg, [\reg, THREAD_INFO_FLAGS]
228 .endm
229 
230 #ifdef CONFIG_SMP
231 
232 /*-------------------------------------------------
233  * Retrieve the current running task on this CPU
234  * 1. Determine curr CPU id.
235  * 2. Use it to index into _current_task[ ]
236  */
237 .macro  GET_CURR_TASK_ON_CPU   reg
238 	GET_CPU_ID  \reg
239 	ld.as  \reg, [@_current_task, \reg]
240 .endm
241 
242 /*-------------------------------------------------
243  * Save a new task as the "current" task on this CPU
244  * 1. Determine curr CPU id.
245  * 2. Use it to index into _current_task[ ]
246  *
247  * Coded differently than GET_CURR_TASK_ON_CPU (which uses LD.AS)
248  * because ST r0, [r1, offset] can ONLY have s9 @offset
249  * while   LD can take s9 (4 byte insn) or LIMM (8 byte insn)
250  */
251 
252 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
253 	GET_CPU_ID  \tmp
254 	add2 \tmp, @_current_task, \tmp
255 	st   \tsk, [\tmp]
256 #ifdef CONFIG_ARC_CURR_IN_REG
257 	mov r25, \tsk
258 #endif
259 
260 .endm
261 
262 
263 #else   /* Uniprocessor implementation of macros */
264 
265 .macro  GET_CURR_TASK_ON_CPU    reg
266 	ld  \reg, [@_current_task]
267 .endm
268 
269 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
270 	st  \tsk, [@_current_task]
271 #ifdef CONFIG_ARC_CURR_IN_REG
272 	mov r25, \tsk
273 #endif
274 .endm
275 
276 #endif /* SMP / UNI */
277 
278 /* ------------------------------------------------------------------
279  * Get the ptr to some field of Current Task at @off in task struct
280  *  -Uses r25 for Current task ptr if that is enabled
281  */
282 
283 #ifdef CONFIG_ARC_CURR_IN_REG
284 
285 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
286 	add \reg, r25, \off
287 .endm
288 
289 #else
290 
291 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
292 	GET_CURR_TASK_ON_CPU  \reg
293 	add \reg, \reg, \off
294 .endm
295 
296 #endif	/* CONFIG_ARC_CURR_IN_REG */
297 
298 #endif  /* __ASM_ARC_ENTRY_H */
299