1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * rtrap.S: Preparing for return from trap on Sparc V9.
4 *
5 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
7 */
8
9
10#include <asm/asi.h>
11#include <asm/pstate.h>
12#include <asm/ptrace.h>
13#include <asm/spitfire.h>
14#include <asm/head.h>
15#include <asm/visasm.h>
16#include <asm/processor.h>
17
18#ifdef CONFIG_CONTEXT_TRACKING
19# define SCHEDULE_USER schedule_user
20#else
21# define SCHEDULE_USER schedule
22#endif
23
24		.text
25		.align			32
26__handle_preemption:
27		call			SCHEDULE_USER
28661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
29		/* If userspace is using ADI, it could potentially pass
30		 * a pointer with version tag embedded in it. To maintain
31		 * the ADI security, we must re-enable PSTATE.mcde before
32		 * we continue execution in the kernel for another thread.
33		 */
34		.section .sun_m7_1insn_patch, "ax"
35		.word	661b
36		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
37		.previous
38		ba,pt			%xcc, __handle_preemption_continue
39		 wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
40
41__handle_user_windows:
42		add			%sp, PTREGS_OFF, %o0
43		call			fault_in_user_windows
44661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
45		/* If userspace is using ADI, it could potentially pass
46		 * a pointer with version tag embedded in it. To maintain
47		 * the ADI security, we must re-enable PSTATE.mcde before
48		 * we continue execution in the kernel for another thread.
49		 */
50		.section .sun_m7_1insn_patch, "ax"
51		.word	661b
52		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
53		.previous
54		ba,pt			%xcc, __handle_preemption_continue
55		 wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
56
57__handle_userfpu:
58		rd			%fprs, %l5
59		andcc			%l5, FPRS_FEF, %g0
60		sethi			%hi(TSTATE_PEF), %o0
61		be,a,pn			%icc, __handle_userfpu_continue
62		 andn			%l1, %o0, %l1
63		ba,a,pt			%xcc, __handle_userfpu_continue
64
65__handle_signal:
66		mov			%l5, %o1
67		add			%sp, PTREGS_OFF, %o0
68		mov			%l0, %o2
69		call			do_notify_resume
70661:		 wrpr			%g0, RTRAP_PSTATE, %pstate
71		/* If userspace is using ADI, it could potentially pass
72		 * a pointer with version tag embedded in it. To maintain
73		 * the ADI security, we must re-enable PSTATE.mcde before
74		 * we continue execution in the kernel for another thread.
75		 */
76		.section .sun_m7_1insn_patch, "ax"
77		.word	661b
78		 wrpr			%g0, RTRAP_PSTATE|PSTATE_MCDE, %pstate
79		.previous
80		wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
81
82		/* Signal delivery can modify pt_regs tstate, so we must
83		 * reload it.
84		 */
85		ldx			[%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
86		sethi			%hi(0xf << 20), %l4
87		and			%l1, %l4, %l4
88		andn			%l1, %l4, %l1
89		ba,pt			%xcc, __handle_preemption_continue
90		 srl			%l4, 20, %l4
91
92		/* When returning from a NMI (%pil==15) interrupt we want to
93		 * avoid running softirqs, doing IRQ tracing, preempting, etc.
94		 */
95		.globl			rtrap_nmi
96rtrap_nmi:	ldx			[%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
97		sethi			%hi(0xf << 20), %l4
98		and			%l1, %l4, %l4
99		andn			%l1, %l4, %l1
100		srl			%l4, 20, %l4
101		ba,pt			%xcc, rtrap_no_irq_enable
102		nop
103		/* Do not actually set the %pil here.  We will do that
104		 * below after we clear PSTATE_IE in the %pstate register.
105		 * If we re-enable interrupts here, we can recurse down
106		 * the hardirq stack potentially endlessly, causing a
107		 * stack overflow.
108		 */
109
110		.align			64
111		.globl			rtrap_irq, rtrap, irqsz_patchme, rtrap_xcall
112rtrap_irq:
113rtrap:
114		/* mm/ultra.S:xcall_report_regs KNOWS about this load. */
115		ldx			[%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
116rtrap_xcall:
117		sethi			%hi(0xf << 20), %l4
118		and			%l1, %l4, %l4
119		andn			%l1, %l4, %l1
120		srl			%l4, 20, %l4
121#ifdef CONFIG_TRACE_IRQFLAGS
122		brnz,pn			%l4, rtrap_no_irq_enable
123		 nop
124		call			trace_hardirqs_on
125		 nop
126		/* Do not actually set the %pil here.  We will do that
127		 * below after we clear PSTATE_IE in the %pstate register.
128		 * If we re-enable interrupts here, we can recurse down
129		 * the hardirq stack potentially endlessly, causing a
130		 * stack overflow.
131		 *
132		 * It is tempting to put this test and trace_hardirqs_on
133		 * call at the 'rt_continue' label, but that will not work
134		 * as that path hits unconditionally and we do not want to
135		 * execute this in NMI return paths, for example.
136		 */
137#endif
138rtrap_no_irq_enable:
139		andcc			%l1, TSTATE_PRIV, %l3
140		bne,pn			%icc, to_kernel
141		 nop
142
143		/* We must hold IRQs off and atomically test schedule+signal
144		 * state, then hold them off all the way back to userspace.
145		 * If we are returning to kernel, none of this matters.  Note
146		 * that we are disabling interrupts via PSTATE_IE, not using
147		 * %pil.
148		 *
149		 * If we do not do this, there is a window where we would do
150		 * the tests, later the signal/resched event arrives but we do
151		 * not process it since we are still in kernel mode.  It would
152		 * take until the next local IRQ before the signal/resched
153		 * event would be handled.
154		 *
155		 * This also means that if we have to deal with user
156		 * windows, we have to redo all of these sched+signal checks
157		 * with IRQs disabled.
158		 */
159to_user:	wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
160		wrpr			0, %pil
161__handle_preemption_continue:
162		ldx			[%g6 + TI_FLAGS], %l0
163		sethi			%hi(_TIF_USER_WORK_MASK), %o0
164		or			%o0, %lo(_TIF_USER_WORK_MASK), %o0
165		andcc			%l0, %o0, %g0
166		sethi			%hi(TSTATE_PEF), %o0
167		be,pt			%xcc, user_nowork
168		 andcc			%l1, %o0, %g0
169		andcc			%l0, _TIF_NEED_RESCHED, %g0
170		bne,pn			%xcc, __handle_preemption
171		 andcc			%l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
172		bne,pn			%xcc, __handle_signal
173		 ldub			[%g6 + TI_WSAVED], %o2
174		brnz,pn			%o2, __handle_user_windows
175		 nop
176		sethi			%hi(TSTATE_PEF), %o0
177		andcc			%l1, %o0, %g0
178
179		/* This fpdepth clear is necessary for non-syscall rtraps only */
180user_nowork:
181		bne,pn			%xcc, __handle_userfpu
182		 stb			%g0, [%g6 + TI_FPDEPTH]
183__handle_userfpu_continue:
184
185rt_continue:	ldx			[%sp + PTREGS_OFF + PT_V9_G1], %g1
186		ldx			[%sp + PTREGS_OFF + PT_V9_G2], %g2
187
188		ldx			[%sp + PTREGS_OFF + PT_V9_G3], %g3
189		ldx			[%sp + PTREGS_OFF + PT_V9_G4], %g4
190		ldx			[%sp + PTREGS_OFF + PT_V9_G5], %g5
191		brz,pt			%l3, 1f
192		mov			%g6, %l2
193
194		/* Must do this before thread reg is clobbered below.  */
195		LOAD_PER_CPU_BASE(%g5, %g6, %i0, %i1, %i2)
1961:
197		ldx			[%sp + PTREGS_OFF + PT_V9_G6], %g6
198		ldx			[%sp + PTREGS_OFF + PT_V9_G7], %g7
199
200		/* Normal globals are restored, go to trap globals.  */
201661:		wrpr			%g0, RTRAP_PSTATE_AG_IRQOFF, %pstate
202		nop
203		.section		.sun4v_2insn_patch, "ax"
204		.word			661b
205		wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
206		SET_GL(1)
207		.previous
208
209		mov			%l2, %g6
210
211		ldx			[%sp + PTREGS_OFF + PT_V9_I0], %i0
212		ldx			[%sp + PTREGS_OFF + PT_V9_I1], %i1
213
214		ldx			[%sp + PTREGS_OFF + PT_V9_I2], %i2
215		ldx			[%sp + PTREGS_OFF + PT_V9_I3], %i3
216		ldx			[%sp + PTREGS_OFF + PT_V9_I4], %i4
217		ldx			[%sp + PTREGS_OFF + PT_V9_I5], %i5
218		ldx			[%sp + PTREGS_OFF + PT_V9_I6], %i6
219		ldx			[%sp + PTREGS_OFF + PT_V9_I7], %i7
220		ldx			[%sp + PTREGS_OFF + PT_V9_TPC], %l2
221		ldx			[%sp + PTREGS_OFF + PT_V9_TNPC], %o2
222
223		ld			[%sp + PTREGS_OFF + PT_V9_Y], %o3
224		wr			%o3, %g0, %y
225		wrpr			%l4, 0x0, %pil
226		wrpr			%g0, 0x1, %tl
227		andn			%l1, TSTATE_SYSCALL, %l1
228		wrpr			%l1, %g0, %tstate
229		wrpr			%l2, %g0, %tpc
230		wrpr			%o2, %g0, %tnpc
231
232		brnz,pn			%l3, kern_rtt
233		 mov			PRIMARY_CONTEXT, %l7
234
235661:		ldxa			[%l7 + %l7] ASI_DMMU, %l0
236		.section		.sun4v_1insn_patch, "ax"
237		.word			661b
238		ldxa			[%l7 + %l7] ASI_MMU, %l0
239		.previous
240
241		sethi			%hi(sparc64_kern_pri_nuc_bits), %l1
242		ldx			[%l1 + %lo(sparc64_kern_pri_nuc_bits)], %l1
243		or			%l0, %l1, %l0
244
245661:		stxa			%l0, [%l7] ASI_DMMU
246		.section		.sun4v_1insn_patch, "ax"
247		.word			661b
248		stxa			%l0, [%l7] ASI_MMU
249		.previous
250
251		sethi			%hi(KERNBASE), %l7
252		flush			%l7
253		rdpr			%wstate, %l1
254		rdpr			%otherwin, %l2
255		srl			%l1, 3, %l1
256
257661:		wrpr			%l2, %g0, %canrestore
258		.section		.fast_win_ctrl_1insn_patch, "ax"
259		.word			661b
260		.word			0x89880000	! normalw
261		.previous
262
263		wrpr			%l1, %g0, %wstate
264		brnz,pt			%l2, user_rtt_restore
265661:		 wrpr			%g0, %g0, %otherwin
266		.section		.fast_win_ctrl_1insn_patch, "ax"
267		.word			661b
268		 nop
269		.previous
270
271		ldx			[%g6 + TI_FLAGS], %g3
272		wr			%g0, ASI_AIUP, %asi
273		rdpr			%cwp, %g1
274		andcc			%g3, _TIF_32BIT, %g0
275		sub			%g1, 1, %g1
276		bne,pt			%xcc, user_rtt_fill_32bit
277		 wrpr			%g1, %cwp
278		ba,a,pt			%xcc, user_rtt_fill_64bit
279		 nop
280
281user_rtt_fill_fixup_dax:
282		ba,pt	%xcc, user_rtt_fill_fixup_common
283		 mov	1, %g3
284
285user_rtt_fill_fixup_mna:
286		ba,pt	%xcc, user_rtt_fill_fixup_common
287		 mov	2, %g3
288
289user_rtt_fill_fixup:
290		ba,pt	%xcc, user_rtt_fill_fixup_common
291		 clr	%g3
292
293user_rtt_pre_restore:
294		add			%g1, 1, %g1
295		wrpr			%g1, 0x0, %cwp
296
297user_rtt_restore:
298		restore
299		rdpr			%canrestore, %g1
300		wrpr			%g1, 0x0, %cleanwin
301		retry
302		nop
303
304kern_rtt:	rdpr			%canrestore, %g1
305		brz,pn			%g1, kern_rtt_fill
306		 nop
307kern_rtt_restore:
308		stw			%g0, [%sp + PTREGS_OFF + PT_V9_MAGIC]
309		restore
310		retry
311
312to_kernel:
313#ifdef CONFIG_PREEMPTION
314		ldsw			[%g6 + TI_PRE_COUNT], %l5
315		brnz			%l5, kern_fpucheck
316		 ldx			[%g6 + TI_FLAGS], %l5
317		andcc			%l5, _TIF_NEED_RESCHED, %g0
318		be,pt			%xcc, kern_fpucheck
319		 nop
320		cmp			%l4, 0
321		bne,pn			%xcc, kern_fpucheck
322		 nop
323		call			preempt_schedule_irq
324		 nop
325		ba,pt			%xcc, rtrap
326#endif
327kern_fpucheck:	ldub			[%g6 + TI_FPDEPTH], %l5
328		brz,pt			%l5, rt_continue
329		 srl			%l5, 1, %o0
330		add			%g6, TI_FPSAVED, %l6
331		ldub			[%l6 + %o0], %l2
332		sub			%l5, 2, %l5
333
334		add			%g6, TI_GSR, %o1
335		andcc			%l2, (FPRS_FEF|FPRS_DU), %g0
336		be,pt			%icc, 2f
337		 and			%l2, FPRS_DL, %l6
338		andcc			%l2, FPRS_FEF, %g0
339		be,pn			%icc, 5f
340		 sll			%o0, 3, %o5
341		rd			%fprs, %g1
342
343		wr			%g1, FPRS_FEF, %fprs
344		ldx			[%o1 + %o5], %g1
345		add			%g6, TI_XFSR, %o1
346		sll			%o0, 8, %o2
347		add			%g6, TI_FPREGS, %o3
348		brz,pn			%l6, 1f
349		 add			%g6, TI_FPREGS+0x40, %o4
350
351		membar			#Sync
352		ldda			[%o3 + %o2] ASI_BLK_P, %f0
353		ldda			[%o4 + %o2] ASI_BLK_P, %f16
354		membar			#Sync
3551:		andcc			%l2, FPRS_DU, %g0
356		be,pn			%icc, 1f
357		 wr			%g1, 0, %gsr
358		add			%o2, 0x80, %o2
359		membar			#Sync
360		ldda			[%o3 + %o2] ASI_BLK_P, %f32
361		ldda			[%o4 + %o2] ASI_BLK_P, %f48
3621:		membar			#Sync
363		ldx			[%o1 + %o5], %fsr
3642:		stb			%l5, [%g6 + TI_FPDEPTH]
365		ba,pt			%xcc, rt_continue
366		 nop
3675:		wr			%g0, FPRS_FEF, %fprs
368		sll			%o0, 8, %o2
369
370		add			%g6, TI_FPREGS+0x80, %o3
371		add			%g6, TI_FPREGS+0xc0, %o4
372		membar			#Sync
373		ldda			[%o3 + %o2] ASI_BLK_P, %f32
374		ldda			[%o4 + %o2] ASI_BLK_P, %f48
375		membar			#Sync
376		wr			%g0, FPRS_DU, %fprs
377		ba,pt			%xcc, rt_continue
378		 stb			%l5, [%g6 + TI_FPDEPTH]
379