1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * S390 64-bit swsusp implementation
  4 *
  5 * Copyright IBM Corp. 2009
  6 *
  7 * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
  8 *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
  9 */
 10
 11#include <linux/linkage.h>
 12#include <asm/page.h>
 13#include <asm/ptrace.h>
 14#include <asm/thread_info.h>
 15#include <asm/asm-offsets.h>
 16#include <asm/nospec-insn.h>
 17#include <asm/sigp.h>
 18
 19/*
 20 * Save register context in absolute 0 lowcore and call swsusp_save() to
 21 * create in-memory kernel image. The context is saved in the designated
 22 * "store status" memory locations (see POP).
 23 * We return from this function twice. The first time during the suspend to
 24 * disk process. The second time via the swsusp_arch_resume() function
 25 * (see below) in the resume process.
 26 * This function runs with disabled interrupts.
 27 */
 28	GEN_BR_THUNK %r14
 29
 30	.section .text
 31ENTRY(swsusp_arch_suspend)
 32	lg	%r1,__LC_NODAT_STACK
 33	stmg	%r6,%r15,__SF_GPRS(%r1)
 34	aghi	%r1,-STACK_FRAME_OVERHEAD
 35	stg	%r15,__SF_BACKCHAIN(%r1)
 36	lgr	%r15,%r1
 37
 38	/* Store FPU registers */
 39	brasl	%r14,save_fpu_regs
 40
 41	/* Deactivate DAT */
 42	stnsm	__SF_EMPTY(%r15),0xfb
 43
 44	/* Store prefix register on stack */
 45	stpx	__SF_EMPTY(%r15)
 46
 47	/* Save prefix register contents for lowcore copy */
 48	llgf	%r10,__SF_EMPTY(%r15)
 49
 50	/* Get pointer to save area */
 51	lghi	%r1,0x1000
 52
 53	/* Save CPU address */
 54	stap	__LC_EXT_CPU_ADDR(%r0)
 55
 56	/* Store registers */
 57	mvc	0x318(4,%r1),__SF_EMPTY(%r15)	/* move prefix to lowcore */
 58	stam	%a0,%a15,0x340(%r1)		/* store access registers */
 59	stctg	%c0,%c15,0x380(%r1)		/* store control registers */
 60	stmg	%r0,%r15,0x280(%r1)		/* store general registers */
 61
 62	stpt	0x328(%r1)			/* store timer */
 63	stck	__SF_EMPTY(%r15)		/* store clock */
 64	stckc	0x330(%r1)			/* store clock comparator */
 65
 66	/* Update cputime accounting before going to sleep */
 67	lg	%r0,__LC_LAST_UPDATE_TIMER
 68	slg	%r0,0x328(%r1)
 69	alg	%r0,__LC_SYSTEM_TIMER
 70	stg	%r0,__LC_SYSTEM_TIMER
 71	mvc	__LC_LAST_UPDATE_TIMER(8),0x328(%r1)
 72	lg	%r0,__LC_LAST_UPDATE_CLOCK
 73	slg	%r0,__SF_EMPTY(%r15)
 74	alg	%r0,__LC_STEAL_TIMER
 75	stg	%r0,__LC_STEAL_TIMER
 76	mvc	__LC_LAST_UPDATE_CLOCK(8),__SF_EMPTY(%r15)
 77
 78	/* Activate DAT */
 79	stosm	__SF_EMPTY(%r15),0x04
 80
 81	/* Set prefix page to zero */
 82	xc	__SF_EMPTY(4,%r15),__SF_EMPTY(%r15)
 83	spx	__SF_EMPTY(%r15)
 84
 85	/* Save absolute zero pages */
 86	larl	%r2,suspend_zero_pages
 87	lg	%r2,0(%r2)
 88	lghi	%r4,0
 89	lghi	%r3,2*PAGE_SIZE
 90	lghi	%r5,2*PAGE_SIZE
 911:	mvcle	%r2,%r4,0
 92	jo	1b
 93
 94	/* Copy lowcore to absolute zero lowcore */
 95	lghi	%r2,0
 96	lgr	%r4,%r10
 97	lghi	%r3,2*PAGE_SIZE
 98	lghi	%r5,2*PAGE_SIZE
 991:	mvcle	%r2,%r4,0
100	jo	1b
101
102	/* Save image */
103	brasl	%r14,swsusp_save
104
105	/* Restore prefix register and return */
106	lghi	%r1,0x1000
107	spx	0x318(%r1)
108	lmg	%r6,%r15,STACK_FRAME_OVERHEAD + __SF_GPRS(%r15)
109	lghi	%r2,0
110	BR_EX	%r14
111ENDPROC(swsusp_arch_suspend)
112
113/*
114 * Restore saved memory image to correct place and restore register context.
115 * Then we return to the function that called swsusp_arch_suspend().
116 * swsusp_arch_resume() runs with disabled interrupts.
117 */
118ENTRY(swsusp_arch_resume)
119	stmg	%r6,%r15,__SF_GPRS(%r15)
120	lgr	%r1,%r15
121	aghi	%r15,-STACK_FRAME_OVERHEAD
122	stg	%r1,__SF_BACKCHAIN(%r15)
123
124	/* Make all free pages stable */
125	lghi	%r2,1
126	brasl	%r14,arch_set_page_states
127
128	/* Set prefix page to zero */
129	xc	__SF_EMPTY(4,%r15),__SF_EMPTY(%r15)
130	spx	__SF_EMPTY(%r15)
131
132	/* Deactivate DAT */
133	stnsm	__SF_EMPTY(%r15),0xfb
134
135	/* Restore saved image */
136	larl	%r1,restore_pblist
137	lg	%r1,0(%r1)
138	ltgr	%r1,%r1
139	jz	2f
1400:
141	lg	%r2,8(%r1)
142	lg	%r4,0(%r1)
143	iske	%r0,%r4
144	lghi	%r3,PAGE_SIZE
145	lghi	%r5,PAGE_SIZE
1461:
147	mvcle	%r2,%r4,0
148	jo	1b
149	lg	%r2,8(%r1)
150	sske	%r0,%r2
151	lg	%r1,16(%r1)
152	ltgr	%r1,%r1
153	jnz	0b
1542:
155	ptlb				/* flush tlb */
156
157	/* Reset System */
158	larl	%r1,.Lnew_pgm_check_psw
159	epsw	%r2,%r3
160	stm	%r2,%r3,0(%r1)
161	mvc	__LC_PGM_NEW_PSW(16,%r0),0(%r1)
162	larl	%r1,__swsusp_reset_dma
163	lg	%r1,0(%r1)
164	BASR_EX	%r14,%r1
165	larl	%r1,smp_cpu_mt_shift
166	icm	%r1,15,0(%r1)
167	jz	smt_done
168	llgfr	%r1,%r1
169smt_loop:
170	sigp	%r1,%r0,SIGP_SET_MULTI_THREADING
171	brc	8,smt_done			/* accepted */
172	brc	2,smt_loop			/* busy, try again */
173smt_done:
174	larl	%r1,.Lnew_pgm_check_psw
175	lpswe	0(%r1)
176pgm_check_entry:
177
178	/* Switch to original suspend CPU */
179	larl	%r1,.Lresume_cpu		/* Resume CPU address: r2 */
180	stap	0(%r1)
181	llgh	%r2,0(%r1)
182	llgh	%r1,__LC_EXT_CPU_ADDR(%r0)	/* Suspend CPU address: r1 */
183	cgr	%r1,%r2
184	je	restore_registers		/* r1 = r2 -> nothing to do */
185	larl	%r4,.Lrestart_suspend_psw	/* Set new restart PSW */
186	mvc	__LC_RST_NEW_PSW(16,%r0),0(%r4)
1873:
188	sigp	%r9,%r1,SIGP_INITIAL_CPU_RESET	/* sigp initial cpu reset */
189	brc	8,4f				/* accepted */
190	brc	2,3b				/* busy, try again */
191
192	/* Suspend CPU not available -> panic */
193	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD
194	larl	%r2,.Lpanic_string
195	brasl	%r14,sclp_early_printk_force
196	larl	%r3,.Ldisabled_wait_31
197	lpsw	0(%r3)
1984:
199	/* Switch to suspend CPU */
200	sigp	%r9,%r1,SIGP_RESTART	/* sigp restart to suspend CPU */
201	brc	2,4b			/* busy, try again */
2025:
203	sigp	%r9,%r2,SIGP_STOP	/* sigp stop to current resume CPU */
204	brc	2,5b			/* busy, try again */
2056:	j	6b
206
207restart_suspend:
208	larl	%r1,.Lresume_cpu
209	llgh	%r2,0(%r1)
2107:
211	sigp	%r9,%r2,SIGP_SENSE	/* sigp sense, wait for resume CPU */
212	brc	8,7b			/* accepted, status 0, still running */
213	brc	2,7b			/* busy, try again */
214	tmll	%r9,0x40		/* Test if resume CPU is stopped */
215	jz	7b
216
217restore_registers:
218	/* Restore registers */
219	lghi	%r13,0x1000		/* %r1 = pointer to save area */
220
221	/* Ignore time spent in suspended state. */
222	llgf	%r1,0x318(%r13)
223	stck	__LC_LAST_UPDATE_CLOCK(%r1)
224	spt	0x328(%r13)		/* reprogram timer */
225	//sckc	0x330(%r13)		/* set clock comparator */
226
227	lctlg	%c0,%c15,0x380(%r13)	/* load control registers */
228	lam	%a0,%a15,0x340(%r13)	/* load access registers */
229
230	/* Load old stack */
231	lg	%r15,0x2f8(%r13)
232
233	/* Save prefix register */
234	mvc __SF_EMPTY(4,%r15),0x318(%r13)
235
236	/* Restore absolute zero pages */
237	lghi	%r2,0
238	larl	%r4,suspend_zero_pages
239	lg	%r4,0(%r4)
240	lghi	%r3,2*PAGE_SIZE
241	lghi	%r5,2*PAGE_SIZE
2421:	mvcle	%r2,%r4,0
243	jo	1b
244
245	/* Restore prefix register */
246	spx	__SF_EMPTY(%r15)
247
248	/* Activate DAT */
249	stosm	__SF_EMPTY(%r15),0x04
250
251	/* Make all free pages unstable */
252	lghi	%r2,0
253	brasl	%r14,arch_set_page_states
254
255	/* Call arch specific early resume code */
256	brasl	%r14,s390_early_resume
257
258	/* Return 0 */
259	lmg	%r6,%r15,STACK_FRAME_OVERHEAD + __SF_GPRS(%r15)
260	lghi	%r2,0
261	BR_EX	%r14
262ENDPROC(swsusp_arch_resume)
263
264	.section .data..nosave,"aw",@progbits
265	.align	8
266.Ldisabled_wait_31:
267	.long  0x000a0000,0x00000000
268.Lpanic_string:
269	.asciz	"Resume not possible because suspend CPU is no longer available\n"
270	.align	8
271.Lrestart_suspend_psw:
272	.quad	0x0000000180000000,restart_suspend
273.Lnew_pgm_check_psw:
274	.quad	0,pgm_check_entry
275.Lresume_cpu:
276	.byte	0,0