xref: /openbmc/linux/arch/csky/kernel/entry.S (revision 15e3ae36) 
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/setup.h>
13#include <asm/page.h>
14#include <asm/thread_info.h>
15
16#define PTE_INDX_MSK    0xffc
17#define PTE_INDX_SHIFT  10
18#define _PGDIR_SHIFT    22
19
20.macro	zero_fp
21#ifdef CONFIG_STACKTRACE
22	movi	r8, 0
23#endif
24.endm
25
26.macro tlbop_begin name, val0, val1, val2
27ENTRY(csky_\name)
28	mtcr    a3, ss2
29	mtcr    r6, ss3
30	mtcr    a2, ss4
31
32	RD_PGDR	r6
33	RD_MEH	a3
34#ifdef CONFIG_CPU_HAS_TLBI
35	tlbi.vaas a3
36	sync.is
37
38	btsti	a3, 31
39	bf	1f
40	RD_PGDR_K r6
411:
42#else
43	bgeni	a2, 31
44	WR_MCIR	a2
45	bgeni	a2, 25
46	WR_MCIR	a2
47#endif
48	bclri   r6, 0
49	lrw	a2, va_pa_offset
50	ld.w	a2, (a2, 0)
51	subu	r6, a2
52	bseti	r6, 31
53
54	mov     a2, a3
55	lsri    a2, _PGDIR_SHIFT
56	lsli    a2, 2
57	addu    r6, a2
58	ldw     r6, (r6)
59
60	lrw	a2, va_pa_offset
61	ld.w	a2, (a2, 0)
62	subu	r6, a2
63	bseti	r6, 31
64
65	lsri    a3, PTE_INDX_SHIFT
66	lrw     a2, PTE_INDX_MSK
67	and     a3, a2
68	addu    r6, a3
69	ldw     a3, (r6)
70
71	movi	a2, (_PAGE_PRESENT | \val0)
72	and     a3, a2
73	cmpne   a3, a2
74	bt	\name
75
76	/* First read/write the page, just update the flags */
77	ldw     a3, (r6)
78	bgeni   a2, PAGE_VALID_BIT
79	bseti   a2, PAGE_ACCESSED_BIT
80	bseti   a2, \val1
81	bseti   a2, \val2
82	or      a3, a2
83	stw     a3, (r6)
84
85	/* Some cpu tlb-hardrefill bypass the cache */
86#ifdef CONFIG_CPU_NEED_TLBSYNC
87	movi	a2, 0x22
88	bseti	a2, 6
89	mtcr	r6, cr22
90	mtcr	a2, cr17
91	sync
92#endif
93
94	mfcr    a3, ss2
95	mfcr    r6, ss3
96	mfcr    a2, ss4
97	rte
98\name:
99	mfcr    a3, ss2
100	mfcr    r6, ss3
101	mfcr    a2, ss4
102	SAVE_ALL 0
103.endm
104.macro tlbop_end is_write
105	zero_fp
106	RD_MEH	a2
107	psrset  ee, ie
108	mov     a0, sp
109	movi    a1, \is_write
110	jbsr    do_page_fault
111	jmpi    ret_from_exception
112.endm
113
114.text
115
116tlbop_begin tlbinvalidl, _PAGE_READ, PAGE_VALID_BIT, PAGE_ACCESSED_BIT
117tlbop_end 0
118
119tlbop_begin tlbinvalids, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
120tlbop_end 1
121
122tlbop_begin tlbmodified, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
123#ifndef CONFIG_CPU_HAS_LDSTEX
124jbsr csky_cmpxchg_fixup
125#endif
126tlbop_end 1
127
128ENTRY(csky_systemcall)
129	SAVE_ALL TRAP0_SIZE
130	zero_fp
131#ifdef CONFIG_RSEQ_DEBUG
132	mov	a0, sp
133	jbsr	rseq_syscall
134#endif
135	psrset  ee, ie
136
137	lrw     r11, __NR_syscalls
138	cmphs   syscallid, r11		/* Check nr of syscall */
139	bt      ret_from_exception
140
141	lrw     r13, sys_call_table
142	ixw     r13, syscallid
143	ldw     r11, (r13)
144	cmpnei  r11, 0
145	bf      ret_from_exception
146
147	mov     r9, sp
148	bmaski  r10, THREAD_SHIFT
149	andn    r9, r10
150	ldw     r12, (r9, TINFO_FLAGS)
151	ANDI_R3	r12, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
152	cmpnei	r12, 0
153	bt      csky_syscall_trace
154#if defined(__CSKYABIV2__)
155	subi    sp, 8
156	stw  	r5, (sp, 0x4)
157	stw  	r4, (sp, 0x0)
158	jsr     r11                      /* Do system call */
159	addi 	sp, 8
160#else
161	jsr     r11
162#endif
163	stw     a0, (sp, LSAVE_A0)      /* Save return value */
164	jmpi    ret_from_exception
165
166csky_syscall_trace:
167	mov	a0, sp                  /* sp = pt_regs pointer */
168	jbsr	syscall_trace_enter
169	/* Prepare args before do system call */
170	ldw	a0, (sp, LSAVE_A0)
171	ldw	a1, (sp, LSAVE_A1)
172	ldw	a2, (sp, LSAVE_A2)
173	ldw	a3, (sp, LSAVE_A3)
174#if defined(__CSKYABIV2__)
175	subi	sp, 8
176	stw	r5, (sp, 0x4)
177	stw	r4, (sp, 0x0)
178#else
179	ldw	r6, (sp, LSAVE_A4)
180	ldw	r7, (sp, LSAVE_A5)
181#endif
182	jsr	r11                     /* Do system call */
183#if defined(__CSKYABIV2__)
184	addi	sp, 8
185#endif
186	stw	a0, (sp, LSAVE_A0)	/* Save return value */
187
188	mov     a0, sp                  /* right now, sp --> pt_regs */
189	jbsr    syscall_trace_exit
190	br	ret_from_exception
191
192ENTRY(ret_from_kernel_thread)
193	jbsr	schedule_tail
194	mov	a0, r10
195	jsr	r9
196	jbsr	ret_from_exception
197
198ENTRY(ret_from_fork)
199	jbsr	schedule_tail
200	mov	r9, sp
201	bmaski	r10, THREAD_SHIFT
202	andn	r9, r10
203	ldw	r12, (r9, TINFO_FLAGS)
204	ANDI_R3	r12, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
205	cmpnei	r12, 0
206	bf	ret_from_exception
207	mov	a0, sp			/* sp = pt_regs pointer */
208	jbsr	syscall_trace_exit
209
210ret_from_exception:
211	ld	syscallid, (sp, LSAVE_PSR)
212	btsti	syscallid, 31
213	bt	1f
214
215	/*
216	 * Load address of current->thread_info, Then get address of task_struct
217	 * Get task_needreshed in task_struct
218	 */
219	mov	r9, sp
220	bmaski	r10, THREAD_SHIFT
221	andn	r9, r10
222
223	ldw	r12, (r9, TINFO_FLAGS)
224	andi	r12, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | _TIF_UPROBE)
225	cmpnei	r12, 0
226	bt	exit_work
2271:
228#ifdef CONFIG_TRACE_IRQFLAGS
229	ld	r10, (sp, LSAVE_PSR)
230	btsti	r10, 6
231	bf	2f
232	jbsr	trace_hardirqs_on
2332:
234#endif
235	RESTORE_ALL
236
237exit_work:
238	lrw	syscallid, ret_from_exception
239	mov	lr, syscallid
240
241	btsti	r12, TIF_NEED_RESCHED
242	bt	work_resched
243
244	mov	a0, sp
245	mov	a1, r12
246	jmpi	do_notify_resume
247
248work_resched:
249	jmpi	schedule
250
251ENTRY(csky_trap)
252	SAVE_ALL 0
253	zero_fp
254	psrset	ee
255	mov	a0, sp                 /* Push Stack pointer arg */
256	jbsr	trap_c                 /* Call C-level trap handler */
257	jmpi	ret_from_exception
258
259/*
260 * Prototype from libc for abiv1:
261 * register unsigned int __result asm("a0");
262 * asm( "trap 3" :"=r"(__result)::);
263 */
264ENTRY(csky_get_tls)
265	USPTOKSP
266
267	/* increase epc for continue */
268	mfcr	a0, epc
269	addi	a0, TRAP0_SIZE
270	mtcr	a0, epc
271
272	/* get current task thread_info with kernel 8K stack */
273	bmaski	a0, THREAD_SHIFT
274	not	a0
275	subi	sp, 1
276	and	a0, sp
277	addi	sp, 1
278
279	/* get tls */
280	ldw	a0, (a0, TINFO_TP_VALUE)
281
282	KSPTOUSP
283	rte
284
285ENTRY(csky_irq)
286	SAVE_ALL 0
287	zero_fp
288	psrset	ee
289
290#ifdef CONFIG_TRACE_IRQFLAGS
291	jbsr	trace_hardirqs_off
292#endif
293
294#ifdef CONFIG_PREEMPTION
295	mov	r9, sp			/* Get current stack  pointer */
296	bmaski	r10, THREAD_SHIFT
297	andn	r9, r10			/* Get thread_info */
298
299	/*
300	 * Get task_struct->stack.preempt_count for current,
301	 * and increase 1.
302	 */
303	ldw	r12, (r9, TINFO_PREEMPT)
304	addi	r12, 1
305	stw	r12, (r9, TINFO_PREEMPT)
306#endif
307
308	mov	a0, sp
309	jbsr	csky_do_IRQ
310
311#ifdef CONFIG_PREEMPTION
312	subi	r12, 1
313	stw	r12, (r9, TINFO_PREEMPT)
314	cmpnei	r12, 0
315	bt	2f
316	ldw	r12, (r9, TINFO_FLAGS)
317	btsti	r12, TIF_NEED_RESCHED
318	bf	2f
319	jbsr	preempt_schedule_irq	/* irq en/disable is done inside */
320#endif
3212:
322	jmpi	ret_from_exception
323
324/*
325 * a0 =  prev task_struct *
326 * a1 =  next task_struct *
327 * a0 =  return next
328 */
329ENTRY(__switch_to)
330	lrw	a3, TASK_THREAD
331	addu	a3, a0
332
333	mfcr	a2, psr			/* Save PSR value */
334	stw	a2, (a3, THREAD_SR)	/* Save PSR in task struct */
335	bclri	a2, 6			/* Disable interrupts */
336	mtcr	a2, psr
337
338	SAVE_SWITCH_STACK
339
340	stw	sp, (a3, THREAD_KSP)
341
342	/* Set up next process to run */
343	lrw	a3, TASK_THREAD
344	addu	a3, a1
345
346	ldw	sp, (a3, THREAD_KSP)	/* Set next kernel sp */
347
348	ldw	a2, (a3, THREAD_SR)	/* Set next PSR */
349	mtcr	a2, psr
350
351#if  defined(__CSKYABIV2__)
352	addi	r7, a1, TASK_THREAD_INFO
353	ldw	tls, (r7, TINFO_TP_VALUE)
354#endif
355
356	RESTORE_SWITCH_STACK
357
358	rts
359ENDPROC(__switch_to)
360