xref: /openbmc/linux/arch/arm/include/asm/assembler.h (revision 8ec90bfd) 
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  *  arch/arm/include/asm/assembler.h
4  *
5  *  Copyright (C) 1996-2000 Russell King
6  *
7  *  This file contains arm architecture specific defines
8  *  for the different processors.
9  *
10  *  Do not include any C declarations in this file - it is included by
11  *  assembler source.
12  */
13 #ifndef __ASM_ASSEMBLER_H__
14 #define __ASM_ASSEMBLER_H__
15 
16 #ifndef __ASSEMBLY__
17 #error "Only include this from assembly code"
18 #endif
19 
20 #include <asm/ptrace.h>
21 #include <asm/opcodes-virt.h>
22 #include <asm/asm-offsets.h>
23 #include <asm/page.h>
24 #include <asm/thread_info.h>
25 #include <asm/uaccess-asm.h>
26 
27 #define IOMEM(x)	(x)
28 
29 /*
30  * Endian independent macros for shifting bytes within registers.
31  */
32 #ifndef __ARMEB__
33 #define lspull          lsr
34 #define lspush          lsl
35 #define get_byte_0      lsl #0
36 #define get_byte_1	lsr #8
37 #define get_byte_2	lsr #16
38 #define get_byte_3	lsr #24
39 #define put_byte_0      lsl #0
40 #define put_byte_1	lsl #8
41 #define put_byte_2	lsl #16
42 #define put_byte_3	lsl #24
43 #else
44 #define lspull          lsl
45 #define lspush          lsr
46 #define get_byte_0	lsr #24
47 #define get_byte_1	lsr #16
48 #define get_byte_2	lsr #8
49 #define get_byte_3      lsl #0
50 #define put_byte_0	lsl #24
51 #define put_byte_1	lsl #16
52 #define put_byte_2	lsl #8
53 #define put_byte_3      lsl #0
54 #endif
55 
56 /* Select code for any configuration running in BE8 mode */
57 #ifdef CONFIG_CPU_ENDIAN_BE8
58 #define ARM_BE8(code...) code
59 #else
60 #define ARM_BE8(code...)
61 #endif
62 
63 /*
64  * Data preload for architectures that support it
65  */
66 #if __LINUX_ARM_ARCH__ >= 5
67 #define PLD(code...)	code
68 #else
69 #define PLD(code...)
70 #endif
71 
72 /*
73  * This can be used to enable code to cacheline align the destination
74  * pointer when bulk writing to memory.  Experiments on StrongARM and
75  * XScale didn't show this a worthwhile thing to do when the cache is not
76  * set to write-allocate (this would need further testing on XScale when WA
77  * is used).
78  *
79  * On Feroceon there is much to gain however, regardless of cache mode.
80  */
81 #ifdef CONFIG_CPU_FEROCEON
82 #define CALGN(code...) code
83 #else
84 #define CALGN(code...)
85 #endif
86 
87 #define IMM12_MASK 0xfff
88 
89 /*
90  * Enable and disable interrupts
91  */
92 #if __LINUX_ARM_ARCH__ >= 6
93 	.macro	disable_irq_notrace
94 	cpsid	i
95 	.endm
96 
97 	.macro	enable_irq_notrace
98 	cpsie	i
99 	.endm
100 #else
101 	.macro	disable_irq_notrace
102 	msr	cpsr_c, #PSR_I_BIT | SVC_MODE
103 	.endm
104 
105 	.macro	enable_irq_notrace
106 	msr	cpsr_c, #SVC_MODE
107 	.endm
108 #endif
109 
110 	.macro asm_trace_hardirqs_off, save=1
111 #if defined(CONFIG_TRACE_IRQFLAGS)
112 	.if \save
113 	stmdb   sp!, {r0-r3, ip, lr}
114 	.endif
115 	bl	trace_hardirqs_off
116 	.if \save
117 	ldmia	sp!, {r0-r3, ip, lr}
118 	.endif
119 #endif
120 	.endm
121 
122 	.macro asm_trace_hardirqs_on, cond=al, save=1
123 #if defined(CONFIG_TRACE_IRQFLAGS)
124 	/*
125 	 * actually the registers should be pushed and pop'd conditionally, but
126 	 * after bl the flags are certainly clobbered
127 	 */
128 	.if \save
129 	stmdb   sp!, {r0-r3, ip, lr}
130 	.endif
131 	bl\cond	trace_hardirqs_on
132 	.if \save
133 	ldmia	sp!, {r0-r3, ip, lr}
134 	.endif
135 #endif
136 	.endm
137 
138 	.macro disable_irq, save=1
139 	disable_irq_notrace
140 	asm_trace_hardirqs_off \save
141 	.endm
142 
143 	.macro enable_irq
144 	asm_trace_hardirqs_on
145 	enable_irq_notrace
146 	.endm
147 /*
148  * Save the current IRQ state and disable IRQs.  Note that this macro
149  * assumes FIQs are enabled, and that the processor is in SVC mode.
150  */
151 	.macro	save_and_disable_irqs, oldcpsr
152 #ifdef CONFIG_CPU_V7M
153 	mrs	\oldcpsr, primask
154 #else
155 	mrs	\oldcpsr, cpsr
156 #endif
157 	disable_irq
158 	.endm
159 
160 	.macro	save_and_disable_irqs_notrace, oldcpsr
161 #ifdef CONFIG_CPU_V7M
162 	mrs	\oldcpsr, primask
163 #else
164 	mrs	\oldcpsr, cpsr
165 #endif
166 	disable_irq_notrace
167 	.endm
168 
169 /*
170  * Restore interrupt state previously stored in a register.  We don't
171  * guarantee that this will preserve the flags.
172  */
173 	.macro	restore_irqs_notrace, oldcpsr
174 #ifdef CONFIG_CPU_V7M
175 	msr	primask, \oldcpsr
176 #else
177 	msr	cpsr_c, \oldcpsr
178 #endif
179 	.endm
180 
181 	.macro restore_irqs, oldcpsr
182 	tst	\oldcpsr, #PSR_I_BIT
183 	asm_trace_hardirqs_on cond=eq
184 	restore_irqs_notrace \oldcpsr
185 	.endm
186 
187 /*
188  * Assembly version of "adr rd, BSYM(sym)".  This should only be used to
189  * reference local symbols in the same assembly file which are to be
190  * resolved by the assembler.  Other usage is undefined.
191  */
192 	.irp	c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo
193 	.macro	badr\c, rd, sym
194 #ifdef CONFIG_THUMB2_KERNEL
195 	adr\c	\rd, \sym + 1
196 #else
197 	adr\c	\rd, \sym
198 #endif
199 	.endm
200 	.endr
201 
202 /*
203  * Get current thread_info.
204  */
205 	.macro	get_thread_info, rd
206  ARM(	mov	\rd, sp, lsr #THREAD_SIZE_ORDER + PAGE_SHIFT	)
207  THUMB(	mov	\rd, sp			)
208  THUMB(	lsr	\rd, \rd, #THREAD_SIZE_ORDER + PAGE_SHIFT	)
209 	mov	\rd, \rd, lsl #THREAD_SIZE_ORDER + PAGE_SHIFT
210 	.endm
211 
212 /*
213  * Increment/decrement the preempt count.
214  */
215 #ifdef CONFIG_PREEMPT_COUNT
216 	.macro	inc_preempt_count, ti, tmp
217 	ldr	\tmp, [\ti, #TI_PREEMPT]	@ get preempt count
218 	add	\tmp, \tmp, #1			@ increment it
219 	str	\tmp, [\ti, #TI_PREEMPT]
220 	.endm
221 
222 	.macro	dec_preempt_count, ti, tmp
223 	ldr	\tmp, [\ti, #TI_PREEMPT]	@ get preempt count
224 	sub	\tmp, \tmp, #1			@ decrement it
225 	str	\tmp, [\ti, #TI_PREEMPT]
226 	.endm
227 
228 	.macro	dec_preempt_count_ti, ti, tmp
229 	get_thread_info \ti
230 	dec_preempt_count \ti, \tmp
231 	.endm
232 #else
233 	.macro	inc_preempt_count, ti, tmp
234 	.endm
235 
236 	.macro	dec_preempt_count, ti, tmp
237 	.endm
238 
239 	.macro	dec_preempt_count_ti, ti, tmp
240 	.endm
241 #endif
242 
243 #define USERL(l, x...)				\
244 9999:	x;					\
245 	.pushsection __ex_table,"a";		\
246 	.align	3;				\
247 	.long	9999b,l;			\
248 	.popsection
249 
250 #define USER(x...)	USERL(9001f, x)
251 
252 #ifdef CONFIG_SMP
253 #define ALT_SMP(instr...)					\
254 9998:	instr
255 /*
256  * Note: if you get assembler errors from ALT_UP() when building with
257  * CONFIG_THUMB2_KERNEL, you almost certainly need to use
258  * ALT_SMP( W(instr) ... )
259  */
260 #define ALT_UP(instr...)					\
261 	.pushsection ".alt.smp.init", "a"			;\
262 	.long	9998b						;\
263 9997:	instr							;\
264 	.if . - 9997b == 2					;\
265 		nop						;\
266 	.endif							;\
267 	.if . - 9997b != 4					;\
268 		.error "ALT_UP() content must assemble to exactly 4 bytes";\
269 	.endif							;\
270 	.popsection
271 #define ALT_UP_B(label)					\
272 	.pushsection ".alt.smp.init", "a"			;\
273 	.long	9998b						;\
274 	W(b)	. + (label - 9998b)					;\
275 	.popsection
276 #else
277 #define ALT_SMP(instr...)
278 #define ALT_UP(instr...) instr
279 #define ALT_UP_B(label) b label
280 #endif
281 
282 /*
283  * Instruction barrier
284  */
285 	.macro	instr_sync
286 #if __LINUX_ARM_ARCH__ >= 7
287 	isb
288 #elif __LINUX_ARM_ARCH__ == 6
289 	mcr	p15, 0, r0, c7, c5, 4
290 #endif
291 	.endm
292 
293 /*
294  * SMP data memory barrier
295  */
296 	.macro	smp_dmb mode
297 #ifdef CONFIG_SMP
298 #if __LINUX_ARM_ARCH__ >= 7
299 	.ifeqs "\mode","arm"
300 	ALT_SMP(dmb	ish)
301 	.else
302 	ALT_SMP(W(dmb)	ish)
303 	.endif
304 #elif __LINUX_ARM_ARCH__ == 6
305 	ALT_SMP(mcr	p15, 0, r0, c7, c10, 5)	@ dmb
306 #else
307 #error Incompatible SMP platform
308 #endif
309 	.ifeqs "\mode","arm"
310 	ALT_UP(nop)
311 	.else
312 	ALT_UP(W(nop))
313 	.endif
314 #endif
315 	.endm
316 
317 #if defined(CONFIG_CPU_V7M)
318 	/*
319 	 * setmode is used to assert to be in svc mode during boot. For v7-M
320 	 * this is done in __v7m_setup, so setmode can be empty here.
321 	 */
322 	.macro	setmode, mode, reg
323 	.endm
324 #elif defined(CONFIG_THUMB2_KERNEL)
325 	.macro	setmode, mode, reg
326 	mov	\reg, #\mode
327 	msr	cpsr_c, \reg
328 	.endm
329 #else
330 	.macro	setmode, mode, reg
331 	msr	cpsr_c, #\mode
332 	.endm
333 #endif
334 
335 /*
336  * Helper macro to enter SVC mode cleanly and mask interrupts. reg is
337  * a scratch register for the macro to overwrite.
338  *
339  * This macro is intended for forcing the CPU into SVC mode at boot time.
340  * you cannot return to the original mode.
341  */
342 .macro safe_svcmode_maskall reg:req
343 #if __LINUX_ARM_ARCH__ >= 6 && !defined(CONFIG_CPU_V7M)
344 	mrs	\reg , cpsr
345 	eor	\reg, \reg, #HYP_MODE
346 	tst	\reg, #MODE_MASK
347 	bic	\reg , \reg , #MODE_MASK
348 	orr	\reg , \reg , #PSR_I_BIT | PSR_F_BIT | SVC_MODE
349 THUMB(	orr	\reg , \reg , #PSR_T_BIT	)
350 	bne	1f
351 	orr	\reg, \reg, #PSR_A_BIT
352 	badr	lr, 2f
353 	msr	spsr_cxsf, \reg
354 	__MSR_ELR_HYP(14)
355 	__ERET
356 1:	msr	cpsr_c, \reg
357 2:
358 #else
359 /*
360  * workaround for possibly broken pre-v6 hardware
361  * (akita, Sharp Zaurus C-1000, PXA270-based)
362  */
363 	setmode	PSR_F_BIT | PSR_I_BIT | SVC_MODE, \reg
364 #endif
365 .endm
366 
367 /*
368  * STRT/LDRT access macros with ARM and Thumb-2 variants
369  */
370 #ifdef CONFIG_THUMB2_KERNEL
371 
372 	.macro	usraccoff, instr, reg, ptr, inc, off, cond, abort, t=TUSER()
373 9999:
374 	.if	\inc == 1
375 	\instr\()b\t\cond\().w \reg, [\ptr, #\off]
376 	.elseif	\inc == 4
377 	\instr\t\cond\().w \reg, [\ptr, #\off]
378 	.else
379 	.error	"Unsupported inc macro argument"
380 	.endif
381 
382 	.pushsection __ex_table,"a"
383 	.align	3
384 	.long	9999b, \abort
385 	.popsection
386 	.endm
387 
388 	.macro	usracc, instr, reg, ptr, inc, cond, rept, abort
389 	@ explicit IT instruction needed because of the label
390 	@ introduced by the USER macro
391 	.ifnc	\cond,al
392 	.if	\rept == 1
393 	itt	\cond
394 	.elseif	\rept == 2
395 	ittt	\cond
396 	.else
397 	.error	"Unsupported rept macro argument"
398 	.endif
399 	.endif
400 
401 	@ Slightly optimised to avoid incrementing the pointer twice
402 	usraccoff \instr, \reg, \ptr, \inc, 0, \cond, \abort
403 	.if	\rept == 2
404 	usraccoff \instr, \reg, \ptr, \inc, \inc, \cond, \abort
405 	.endif
406 
407 	add\cond \ptr, #\rept * \inc
408 	.endm
409 
410 #else	/* !CONFIG_THUMB2_KERNEL */
411 
412 	.macro	usracc, instr, reg, ptr, inc, cond, rept, abort, t=TUSER()
413 	.rept	\rept
414 9999:
415 	.if	\inc == 1
416 	\instr\()b\t\cond \reg, [\ptr], #\inc
417 	.elseif	\inc == 4
418 	\instr\t\cond \reg, [\ptr], #\inc
419 	.else
420 	.error	"Unsupported inc macro argument"
421 	.endif
422 
423 	.pushsection __ex_table,"a"
424 	.align	3
425 	.long	9999b, \abort
426 	.popsection
427 	.endr
428 	.endm
429 
430 #endif	/* CONFIG_THUMB2_KERNEL */
431 
432 	.macro	strusr, reg, ptr, inc, cond=al, rept=1, abort=9001f
433 	usracc	str, \reg, \ptr, \inc, \cond, \rept, \abort
434 	.endm
435 
436 	.macro	ldrusr, reg, ptr, inc, cond=al, rept=1, abort=9001f
437 	usracc	ldr, \reg, \ptr, \inc, \cond, \rept, \abort
438 	.endm
439 
440 /* Utility macro for declaring string literals */
441 	.macro	string name:req, string
442 	.type \name , #object
443 \name:
444 	.asciz "\string"
445 	.size \name , . - \name
446 	.endm
447 
448 	.irp	c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo
449 	.macro	ret\c, reg
450 #if __LINUX_ARM_ARCH__ < 6
451 	mov\c	pc, \reg
452 #else
453 	.ifeqs	"\reg", "lr"
454 	bx\c	\reg
455 	.else
456 	mov\c	pc, \reg
457 	.endif
458 #endif
459 	.endm
460 	.endr
461 
462 	.macro	ret.w, reg
463 	ret	\reg
464 #ifdef CONFIG_THUMB2_KERNEL
465 	nop
466 #endif
467 	.endm
468 
469 	.macro	bug, msg, line
470 #ifdef CONFIG_THUMB2_KERNEL
471 1:	.inst	0xde02
472 #else
473 1:	.inst	0xe7f001f2
474 #endif
475 #ifdef CONFIG_DEBUG_BUGVERBOSE
476 	.pushsection .rodata.str, "aMS", %progbits, 1
477 2:	.asciz	"\msg"
478 	.popsection
479 	.pushsection __bug_table, "aw"
480 	.align	2
481 	.word	1b, 2b
482 	.hword	\line
483 	.popsection
484 #endif
485 	.endm
486 
487 #ifdef CONFIG_KPROBES
488 #define _ASM_NOKPROBE(entry)				\
489 	.pushsection "_kprobe_blacklist", "aw" ;	\
490 	.balign 4 ;					\
491 	.long entry;					\
492 	.popsection
493 #else
494 #define _ASM_NOKPROBE(entry)
495 #endif
496 
497 #endif /* __ASM_ASSEMBLER_H__ */
498