summaryrefslogtreecommitdiff
path: root/arch/arm64/include/asm/assembler.h
blob: 4feb6119c3c94840c459ceb3c328e67e60351688 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
/*
 * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S
 *
 * Copyright (C) 1996-2000 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASSEMBLY__
#error "Only include this from assembly code"
#endif

#ifndef __ASM_ASSEMBLER_H
#define __ASM_ASSEMBLER_H

#include <asm-generic/export.h>

#include <asm/asm-offsets.h>
#include <asm/cpufeature.h>
#include <asm/debug-monitors.h>
#include <asm/page.h>
#include <asm/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>

	.macro save_and_disable_daif, flags
	mrs	\flags, daif
	msr	daifset, #0xf
	.endm

	.macro disable_daif
	msr	daifset, #0xf
	.endm

	.macro enable_daif
	msr	daifclr, #0xf
	.endm

	.macro	restore_daif, flags:req
	msr	daif, \flags
	.endm

	/* Only on aarch64 pstate, PSR_D_BIT is different for aarch32 */
	.macro	inherit_daif, pstate:req, tmp:req
	and	\tmp, \pstate, #(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
	msr	daif, \tmp
	.endm

	/* IRQ is the lowest priority flag, unconditionally unmask the rest. */
	.macro enable_da_f
	msr	daifclr, #(8 | 4 | 1)
	.endm

/*
 * Enable and disable interrupts.
 */
	.macro	disable_irq
	msr	daifset, #2
	.endm

	.macro	enable_irq
	msr	daifclr, #2
	.endm

	.macro	save_and_disable_irq, flags
	mrs	\flags, daif
	msr	daifset, #2
	.endm

	.macro	restore_irq, flags
	msr	daif, \flags
	.endm

	.macro	enable_dbg
	msr	daifclr, #8
	.endm

	.macro	disable_step_tsk, flgs, tmp
	tbz	\flgs, #TIF_SINGLESTEP, 9990f
	mrs	\tmp, mdscr_el1
	bic	\tmp, \tmp, #DBG_MDSCR_SS
	msr	mdscr_el1, \tmp
	isb	// Synchronise with enable_dbg
9990:
	.endm

	/* call with daif masked */
	.macro	enable_step_tsk, flgs, tmp
	tbz	\flgs, #TIF_SINGLESTEP, 9990f
	mrs	\tmp, mdscr_el1
	orr	\tmp, \tmp, #DBG_MDSCR_SS
	msr	mdscr_el1, \tmp
9990:
	.endm

/*
 * SMP data memory barrier
 */
	.macro	smp_dmb, opt
	dmb	\opt
	.endm

/*
 * RAS Error Synchronization barrier
 */
	.macro  esb
	hint    #16
	.endm

/*
 * Value prediction barrier
 */
	.macro	csdb
	hint	#20
	.endm

/*
 * Speculation barrier
 */
	.macro	sb
alternative_if_not ARM64_HAS_SB
	dsb	nsh
	isb
alternative_else
	SB_BARRIER_INSN
	nop
alternative_endif
	.endm

/*
 * Sanitise a 64-bit bounded index wrt speculation, returning zero if out
 * of bounds.
 */
	.macro	mask_nospec64, idx, limit, tmp
	sub	\tmp, \idx, \limit
	bic	\tmp, \tmp, \idx
	and	\idx, \idx, \tmp, asr #63
	csdb
	.endm

/*
 * NOP sequence
 */
	.macro	nops, num
	.rept	\num
	nop
	.endr
	.endm

/*
 * Emit an entry into the exception table
 */
	.macro		_asm_extable, from, to
	.pushsection	__ex_table, "a"
	.align		3
	.long		(\from - .), (\to - .)
	.popsection
	.endm

#define USER(l, x...)				\
9999:	x;					\
	_asm_extable	9999b, l

/*
 * Register aliases.
 */
lr	.req	x30		// link register

/*
 * Vector entry
 */
	 .macro	ventry	label
	.align	7
	b	\label
	.endm

/*
 * Select code when configured for BE.
 */
#ifdef CONFIG_CPU_BIG_ENDIAN
#define CPU_BE(code...) code
#else
#define CPU_BE(code...)
#endif

/*
 * Select code when configured for LE.
 */
#ifdef CONFIG_CPU_BIG_ENDIAN
#define CPU_LE(code...)
#else
#define CPU_LE(code...) code
#endif

/*
 * Define a macro that constructs a 64-bit value by concatenating two
 * 32-bit registers. Note that on big endian systems the order of the
 * registers is swapped.
 */
#ifndef CONFIG_CPU_BIG_ENDIAN
	.macro	regs_to_64, rd, lbits, hbits
#else
	.macro	regs_to_64, rd, hbits, lbits
#endif
	orr	\rd, \lbits, \hbits, lsl #32
	.endm

/*
 * Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where
 * <symbol> is within the range +/- 4 GB of the PC.
 */
	/*
	 * @dst: destination register (64 bit wide)
	 * @sym: name of the symbol
	 */
	.macro	adr_l, dst, sym
	adrp	\dst, \sym
	add	\dst, \dst, :lo12:\sym
	.endm

	/*
	 * @dst: destination register (32 or 64 bit wide)
	 * @sym: name of the symbol
	 * @tmp: optional 64-bit scratch register to be used if <dst> is a
	 *       32-bit wide register, in which case it cannot be used to hold
	 *       the address
	 */
	.macro	ldr_l, dst, sym, tmp=
	.ifb	\tmp
	adrp	\dst, \sym
	ldr	\dst, [\dst, :lo12:\sym]
	.else
	adrp	\tmp, \sym
	ldr	\dst, [\tmp, :lo12:\sym]
	.endif
	.endm

	/*
	 * @src: source register (32 or 64 bit wide)
	 * @sym: name of the symbol
	 * @tmp: mandatory 64-bit scratch register to calculate the address
	 *       while <src> needs to be preserved.
	 */
	.macro	str_l, src, sym, tmp
	adrp	\tmp, \sym
	str	\src, [\tmp, :lo12:\sym]
	.endm

	/*
	 * @dst: Result of per_cpu(sym, smp_processor_id()) (can be SP)
	 * @sym: The name of the per-cpu variable
	 * @tmp: scratch register
	 */
	.macro adr_this_cpu, dst, sym, tmp
	adrp	\tmp, \sym
	add	\dst, \tmp, #:lo12:\sym
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
	mrs	\tmp, tpidr_el1
alternative_else
	mrs	\tmp, tpidr_el2
alternative_endif
	add	\dst, \dst, \tmp
	.endm

	/*
	 * @dst: Result of READ_ONCE(per_cpu(sym, smp_processor_id()))
	 * @sym: The name of the per-cpu variable
	 * @tmp: scratch register
	 */
	.macro ldr_this_cpu dst, sym, tmp
	adr_l	\dst, \sym
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
	mrs	\tmp, tpidr_el1
alternative_else
	mrs	\tmp, tpidr_el2
alternative_endif
	ldr	\dst, [\dst, \tmp]
	.endm

/*
 * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
 */
	.macro	vma_vm_mm, rd, rn
	ldr	\rd, [\rn, #VMA_VM_MM]
	.endm

/*
 * mmid - get context id from mm pointer (mm->context.id)
 */
	.macro	mmid, rd, rn
	ldr	\rd, [\rn, #MM_CONTEXT_ID]
	.endm
/*
 * read_ctr - read CTR_EL0. If the system has mismatched register fields,
 * provide the system wide safe value from arm64_ftr_reg_ctrel0.sys_val
 */
	.macro	read_ctr, reg
alternative_if_not ARM64_MISMATCHED_CACHE_TYPE
	mrs	\reg, ctr_el0			// read CTR
	nop
alternative_else
	ldr_l	\reg, arm64_ftr_reg_ctrel0 + ARM64_FTR_SYSVAL
alternative_endif
	.endm


/*
 * raw_dcache_line_size - get the minimum D-cache line size on this CPU
 * from the CTR register.
 */
	.macro	raw_dcache_line_size, reg, tmp
	mrs	\tmp, ctr_el0			// read CTR
	ubfm	\tmp, \tmp, #16, #19		// cache line size encoding
	mov	\reg, #4			// bytes per word
	lsl	\reg, \reg, \tmp		// actual cache line size
	.endm

/*
 * dcache_line_size - get the safe D-cache line size across all CPUs
 */
	.macro	dcache_line_size, reg, tmp
	read_ctr	\tmp
	ubfm		\tmp, \tmp, #16, #19	// cache line size encoding
	mov		\reg, #4		// bytes per word
	lsl		\reg, \reg, \tmp	// actual cache line size
	.endm

/*
 * raw_icache_line_size - get the minimum I-cache line size on this CPU
 * from the CTR register.
 */
	.macro	raw_icache_line_size, reg, tmp
	mrs	\tmp, ctr_el0			// read CTR
	and	\tmp, \tmp, #0xf		// cache line size encoding
	mov	\reg, #4			// bytes per word
	lsl	\reg, \reg, \tmp		// actual cache line size
	.endm

/*
 * icache_line_size - get the safe I-cache line size across all CPUs
 */
	.macro	icache_line_size, reg, tmp
	read_ctr	\tmp
	and		\tmp, \tmp, #0xf	// cache line size encoding
	mov		\reg, #4		// bytes per word
	lsl		\reg, \reg, \tmp	// actual cache line size
	.endm

/*
 * tcr_set_t0sz - update TCR.T0SZ so that we can load the ID map
 */
	.macro	tcr_set_t0sz, valreg, t0sz
	bfi	\valreg, \t0sz, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
	.endm

/*
 * tcr_compute_pa_size - set TCR.(I)PS to the highest supported
 * ID_AA64MMFR0_EL1.PARange value
 *
 *	tcr:		register with the TCR_ELx value to be updated
 *	pos:		IPS or PS bitfield position
 *	tmp{0,1}:	temporary registers
 */
	.macro	tcr_compute_pa_size, tcr, pos, tmp0, tmp1
	mrs	\tmp0, ID_AA64MMFR0_EL1
	// Narrow PARange to fit the PS field in TCR_ELx
	ubfx	\tmp0, \tmp0, #ID_AA64MMFR0_PARANGE_SHIFT, #3
	mov	\tmp1, #ID_AA64MMFR0_PARANGE_MAX
	cmp	\tmp0, \tmp1
	csel	\tmp0, \tmp1, \tmp0, hi
	bfi	\tcr, \tmp0, \pos, #3
	.endm

/*
 * Macro to perform a data cache maintenance for the interval
 * [kaddr, kaddr + size)
 *
 * 	op:		operation passed to dc instruction
 * 	domain:		domain used in dsb instruciton
 * 	kaddr:		starting virtual address of the region
 * 	size:		size of the region
 * 	Corrupts:	kaddr, size, tmp1, tmp2
 */
	.macro __dcache_op_workaround_clean_cache, op, kaddr
alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
	dc	\op, \kaddr
alternative_else
	dc	civac, \kaddr
alternative_endif
	.endm

	.macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
	dcache_line_size \tmp1, \tmp2
	add	\size, \kaddr, \size
	sub	\tmp2, \tmp1, #1
	bic	\kaddr, \kaddr, \tmp2
9998:
	.ifc	\op, cvau
	__dcache_op_workaround_clean_cache \op, \kaddr
	.else
	.ifc	\op, cvac
	__dcache_op_workaround_clean_cache \op, \kaddr
	.else
	.ifc	\op, cvap
	sys	3, c7, c12, 1, \kaddr	// dc cvap
	.else
	dc	\op, \kaddr
	.endif
	.endif
	.endif
	add	\kaddr, \kaddr, \tmp1
	cmp	\kaddr, \size
	b.lo	9998b
	dsb	\domain
	.endm

/*
 * Macro to perform an instruction cache maintenance for the interval
 * [start, end)
 *
 * 	start, end:	virtual addresses describing the region
 *	label:		A label to branch to on user fault.
 * 	Corrupts:	tmp1, tmp2
 */
	.macro invalidate_icache_by_line start, end, tmp1, tmp2, label
	icache_line_size \tmp1, \tmp2
	sub	\tmp2, \tmp1, #1
	bic	\tmp2, \start, \tmp2
9997:
USER(\label, ic	ivau, \tmp2)			// invalidate I line PoU
	add	\tmp2, \tmp2, \tmp1
	cmp	\tmp2, \end
	b.lo	9997b
	dsb	ish
	isb
	.endm

/*
 * reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present
 */
	.macro	reset_pmuserenr_el0, tmpreg
	mrs	\tmpreg, id_aa64dfr0_el1	// Check ID_AA64DFR0_EL1 PMUVer
	sbfx	\tmpreg, \tmpreg, #8, #4
	cmp	\tmpreg, #1			// Skip if no PMU present
	b.lt	9000f
	msr	pmuserenr_el0, xzr		// Disable PMU access from EL0
9000:
	.endm

/*
 * copy_page - copy src to dest using temp registers t1-t8
 */
	.macro copy_page dest:req src:req t1:req t2:req t3:req t4:req t5:req t6:req t7:req t8:req
9998:	ldp	\t1, \t2, [\src]
	ldp	\t3, \t4, [\src, #16]
	ldp	\t5, \t6, [\src, #32]
	ldp	\t7, \t8, [\src, #48]
	add	\src, \src, #64
	stnp	\t1, \t2, [\dest]
	stnp	\t3, \t4, [\dest, #16]
	stnp	\t5, \t6, [\dest, #32]
	stnp	\t7, \t8, [\dest, #48]
	add	\dest, \dest, #64
	tst	\src, #(PAGE_SIZE - 1)
	b.ne	9998b
	.endm

/*
 * Annotate a function as position independent, i.e., safe to be called before
 * the kernel virtual mapping is activated.
 */
#define ENDPIPROC(x)			\
	.globl	__pi_##x;		\
	.type 	__pi_##x, %function;	\
	.set	__pi_##x, x;		\
	.size	__pi_##x, . - x;	\
	ENDPROC(x)

/*
 * Annotate a function as being unsuitable for kprobes.
 */
#ifdef CONFIG_KPROBES
#define NOKPROBE(x)				\
	.pushsection "_kprobe_blacklist", "aw";	\
	.quad	x;				\
	.popsection;
#else
#define NOKPROBE(x)
#endif

#ifdef CONFIG_KASAN
#define EXPORT_SYMBOL_NOKASAN(name)
#else
#define EXPORT_SYMBOL_NOKASAN(name)	EXPORT_SYMBOL(name)
#endif

	/*
	 * Emit a 64-bit absolute little endian symbol reference in a way that
	 * ensures that it will be resolved at build time, even when building a
	 * PIE binary. This requires cooperation from the linker script, which
	 * must emit the lo32/hi32 halves individually.
	 */
	.macro	le64sym, sym
	.long	\sym\()_lo32
	.long	\sym\()_hi32
	.endm

	/*
	 * mov_q - move an immediate constant into a 64-bit register using
	 *         between 2 and 4 movz/movk instructions (depending on the
	 *         magnitude and sign of the operand)
	 */
	.macro	mov_q, reg, val
	.if (((\val) >> 31) == 0 || ((\val) >> 31) == 0x1ffffffff)
	movz	\reg, :abs_g1_s:\val
	.else
	.if (((\val) >> 47) == 0 || ((\val) >> 47) == 0x1ffff)
	movz	\reg, :abs_g2_s:\val
	.else
	movz	\reg, :abs_g3:\val
	movk	\reg, :abs_g2_nc:\val
	.endif
	movk	\reg, :abs_g1_nc:\val
	.endif
	movk	\reg, :abs_g0_nc:\val
	.endm

/*
 * Return the current thread_info.
 */
	.macro	get_thread_info, rd
	mrs	\rd, sp_el0
	.endm

/*
 * Offset ttbr1 to allow for 48-bit kernel VAs set with 52-bit PTRS_PER_PGD.
 * orr is used as it can cover the immediate value (and is idempotent).
 * In future this may be nop'ed out when dealing with 52-bit kernel VAs.
 * 	ttbr: Value of ttbr to set, modified.
 */
	.macro	offset_ttbr1, ttbr
#ifdef CONFIG_ARM64_USER_VA_BITS_52
	orr	\ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET
#endif
	.endm

/*
 * Perform the reverse of offset_ttbr1.
 * bic is used as it can cover the immediate value and, in future, won't need
 * to be nop'ed out when dealing with 52-bit kernel VAs.
 */
	.macro	restore_ttbr1, ttbr
#ifdef CONFIG_ARM64_USER_VA_BITS_52
	bic	\ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET
#endif
	.endm

/*
 * Arrange a physical address in a TTBR register, taking care of 52-bit
 * addresses.
 *
 * 	phys:	physical address, preserved
 * 	ttbr:	returns the TTBR value
 */
	.macro	phys_to_ttbr, ttbr, phys
#ifdef CONFIG_ARM64_PA_BITS_52
	orr	\ttbr, \phys, \phys, lsr #46
	and	\ttbr, \ttbr, #TTBR_BADDR_MASK_52
#else
	mov	\ttbr, \phys
#endif
	.endm

	.macro	phys_to_pte, pte, phys
#ifdef CONFIG_ARM64_PA_BITS_52
	/*
	 * We assume \phys is 64K aligned and this is guaranteed by only
	 * supporting this configuration with 64K pages.
	 */
	orr	\pte, \phys, \phys, lsr #36
	and	\pte, \pte, #PTE_ADDR_MASK
#else
	mov	\pte, \phys
#endif
	.endm

	.macro	pte_to_phys, phys, pte
#ifdef CONFIG_ARM64_PA_BITS_52
	ubfiz	\phys, \pte, #(48 - 16 - 12), #16
	bfxil	\phys, \pte, #16, #32
	lsl	\phys, \phys, #16
#else
	and	\phys, \pte, #PTE_ADDR_MASK
#endif
	.endm

/**
 * Errata workaround prior to disable MMU. Insert an ISB immediately prior
 * to executing the MSR that will change SCTLR_ELn[M] from a value of 1 to 0.
 */
	.macro pre_disable_mmu_workaround
#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041
	isb
#endif
	.endm

	/*
	 * frame_push - Push @regcount callee saved registers to the stack,
	 *              starting at x19, as well as x29/x30, and set x29 to
	 *              the new value of sp. Add @extra bytes of stack space
	 *              for locals.
	 */
	.macro		frame_push, regcount:req, extra
	__frame		st, \regcount, \extra
	.endm

	/*
	 * frame_pop  - Pop the callee saved registers from the stack that were
	 *              pushed in the most recent call to frame_push, as well
	 *              as x29/x30 and any extra stack space that may have been
	 *              allocated.
	 */
	.macro		frame_pop
	__frame		ld
	.endm

	.macro		__frame_regs, reg1, reg2, op, num
	.if		.Lframe_regcount == \num
	\op\()r		\reg1, [sp, #(\num + 1) * 8]
	.elseif		.Lframe_regcount > \num
	\op\()p		\reg1, \reg2, [sp, #(\num + 1) * 8]
	.endif
	.endm

	.macro		__frame, op, regcount, extra=0
	.ifc		\op, st
	.if		(\regcount) < 0 || (\regcount) > 10
	.error		"regcount should be in the range [0 ... 10]"
	.endif
	.if		((\extra) % 16) != 0
	.error		"extra should be a multiple of 16 bytes"
	.endif
	.ifdef		.Lframe_regcount
	.if		.Lframe_regcount != -1
	.error		"frame_push/frame_pop may not be nested"
	.endif
	.endif
	.set		.Lframe_regcount, \regcount
	.set		.Lframe_extra, \extra
	.set		.Lframe_local_offset, ((\regcount + 3) / 2) * 16
	stp		x29, x30, [sp, #-.Lframe_local_offset - .Lframe_extra]!
	mov		x29, sp
	.endif

	__frame_regs	x19, x20, \op, 1
	__frame_regs	x21, x22, \op, 3
	__frame_regs	x23, x24, \op, 5
	__frame_regs	x25, x26, \op, 7
	__frame_regs	x27, x28, \op, 9

	.ifc		\op, ld
	.if		.Lframe_regcount == -1
	.error		"frame_push/frame_pop may not be nested"
	.endif
	ldp		x29, x30, [sp], #.Lframe_local_offset + .Lframe_extra
	.set		.Lframe_regcount, -1
	.endif
	.endm

/*
 * Check whether to yield to another runnable task from kernel mode NEON code
 * (which runs with preemption disabled).
 *
 * if_will_cond_yield_neon
 *        // pre-yield patchup code
 * do_cond_yield_neon
 *        // post-yield patchup code
 * endif_yield_neon    <label>
 *
 * where <label> is optional, and marks the point where execution will resume
 * after a yield has been performed. If omitted, execution resumes right after
 * the endif_yield_neon invocation. Note that the entire sequence, including
 * the provided patchup code, will be omitted from the image if CONFIG_PREEMPT
 * is not defined.
 *
 * As a convenience, in the case where no patchup code is required, the above
 * sequence may be abbreviated to
 *
 * cond_yield_neon <label>
 *
 * Note that the patchup code does not support assembler directives that change
 * the output section, any use of such directives is undefined.
 *
 * The yield itself consists of the following:
 * - Check whether the preempt count is exactly 1, in which case disabling
 *   preemption once will make the task preemptible. If this is not the case,
 *   yielding is pointless.
 * - Check whether TIF_NEED_RESCHED is set, and if so, disable and re-enable
 *   kernel mode NEON (which will trigger a reschedule), and branch to the
 *   yield fixup code.
 *
 * This macro sequence may clobber all CPU state that is not guaranteed by the
 * AAPCS to be preserved across an ordinary function call.
 */

	.macro		cond_yield_neon, lbl
	if_will_cond_yield_neon
	do_cond_yield_neon
	endif_yield_neon	\lbl
	.endm

	.macro		if_will_cond_yield_neon
#ifdef CONFIG_PREEMPT
	get_thread_info	x0
	ldr		x0, [x0, #TSK_TI_PREEMPT]
	sub		x0, x0, #PREEMPT_DISABLE_OFFSET
	cbz		x0, .Lyield_\@
	/* fall through to endif_yield_neon */
	.subsection	1
.Lyield_\@ :
#else
	.section	".discard.cond_yield_neon", "ax"
#endif
	.endm

	.macro		do_cond_yield_neon
	bl		kernel_neon_end
	bl		kernel_neon_begin
	.endm

	.macro		endif_yield_neon, lbl
	.ifnb		\lbl
	b		\lbl
	.else
	b		.Lyield_out_\@
	.endif
	.previous
.Lyield_out_\@ :
	.endm

#endif	/* __ASM_ASSEMBLER_H */