xref: /minix3/sys/arch/arm/include/arm32/frame.h (revision b5e2faaaaf60a8b9a02f8d72f64caa56a87eb312)
1 /*	$NetBSD: frame.h,v 1.36 2013/08/18 06:37:02 matt Exp $	*/
2 
3 /*
4  * Copyright (c) 1994-1997 Mark Brinicombe.
5  * Copyright (c) 1994 Brini.
6  * All rights reserved.
7  *
8  * This code is derived from software written for Brini by Mark Brinicombe
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by Brini.
21  * 4. The name of the company nor the name of the author may be used to
22  *    endorse or promote products derived from this software without specific
23  *    prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
26  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
29  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
30  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
31  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * RiscBSD kernel project
38  *
39  * frame.h
40  *
41  * Stack frames structures
42  *
43  * Created      : 30/09/94
44  */
45 
46 #ifndef _ARM32_FRAME_H_
47 #define _ARM32_FRAME_H_
48 
49 #include <arm/frame.h>		/* Common ARM stack frames */
50 
51 #ifndef _LOCORE
52 
53 /*
54  * Switch frame.
55  *
56  * Should be a multiple of 8 bytes for dumpsys.
57  */
58 
59 struct switchframe {
60 	u_int	sf_r4;
61 	u_int	sf_r5;
62 	u_int	sf_r6;
63 	u_int	sf_r7;
64 	u_int	sf_sp;
65 	u_int	sf_pc;
66 };
67 
68 /*
69  * System stack frames.
70  */
71 
72 struct clockframe {
73 	struct trapframe cf_tf;
74 };
75 
76 /*
77  * Stack frame. Used during stack traces (db_trace.c)
78  */
79 struct frame {
80 	u_int	fr_fp;
81 	u_int	fr_sp;
82 	u_int	fr_lr;
83 	u_int	fr_pc;
84 };
85 
86 #ifdef _KERNEL
87 void validate_trapframe(trapframe_t *, int);
88 #endif /* _KERNEL */
89 
90 #else /* _LOCORE */
91 
92 #include "opt_compat_netbsd.h"
93 #include "opt_execfmt.h"
94 #include "opt_multiprocessor.h"
95 #include "opt_cpuoptions.h"
96 #include "opt_arm_debug.h"
97 #include "opt_cputypes.h"
98 
99 #include <arm/locore.h>
100 
101 /*
102  * This macro is used by DO_AST_AND_RESTORE_ALIGNMENT_FAULTS to process
103  * any pending softints.
104  */
105 #ifdef _ARM_ARCH_4T
106 #define	B_CF_CONTROL(rX)						;\
107 	ldr	ip, [rX, #CF_CONTROL]	/* get function addr */		;\
108 	bx	ip			/* branch to cpu_control */
109 #else
110 #define	B_CF_CONTROL(rX)						;\
111 	ldr	pc, [rX, #CF_CONTROL]	/* branch to cpu_control */
112 #endif
113 #ifdef _ARM_ARCH_5T
114 #define	BL_CF_CONTROL(rX)						;\
115 	ldr	ip, [rX, #CF_CONTROL]	/* get function addr */		;\
116 	blx	ip			/* call cpu_control */
117 #else
118 #define	BL_CF_CONTROL(rX)						;\
119 	mov	lr, pc							;\
120 	ldr	pc, [rX, #CF_CONTROL]	/* call cpu_control */
121 #endif
122 #if defined(__HAVE_FAST_SOFTINTS) && !defined(__HAVE_PIC_FAST_SOFTINTS)
123 #define	DO_PENDING_SOFTINTS						\
124 	ldr	r0, [r4, #CI_INTR_DEPTH]/* Get current intr depth */	;\
125 	cmp	r0, #0			/* Test for 0. */		;\
126 	bne	10f			/*   skip softints if != 0 */	;\
127 	ldr	r0, [r4, #CI_CPL]	/* Get current priority level */;\
128 	ldr	r1, [r4, #CI_SOFTINTS]	/* Get pending softint mask */	;\
129 	lsrs	r0, r1, r0		/* shift mask by cpl */		;\
130 	blne	_C_LABEL(dosoftints)	/* dosoftints(void) */		;\
131 10:
132 #else
133 #define	DO_PENDING_SOFTINTS		/* nothing */
134 #endif
135 
136 #ifdef MULTIPROCESSOR
137 #define	KERNEL_LOCK							\
138 	mov	r0, #1							;\
139 	mov	r1, #0							;\
140 	bl	_C_LABEL(_kernel_lock)
141 
142 #define	KERNEL_UNLOCK							\
143 	mov	r0, #1							;\
144 	mov	r1, #0							;\
145 	mov	r2, #0							;\
146 	bl	_C_LABEL(_kernel_unlock)
147 #else
148 #define	KERNEL_LOCK			/* nothing */
149 #define	KERNEL_UNLOCK			/* nothing */
150 #endif
151 
152 #ifdef _ARM_ARCH_6
153 #define	GET_CPSR(rb)			/* nothing */
154 #define	CPSID_I(ra,rb)			cpsid	i
155 #define	CPSIE_I(ra,rb)			cpsie	i
156 #else
157 #define	GET_CPSR(rb)							\
158 	mrs	rb, cpsr		/* fetch CPSR */
159 
160 #define	CPSID_I(ra,rb)							\
161 	orr	ra, rb, #(IF32_bits)					;\
162 	msr	cpsr_c, ra		/* Disable interrupts */
163 
164 #define	CPSIE_I(ra,rb)							\
165 	bic	ra, rb, #(IF32_bits)					;\
166 	msr	cpsr_c, ra		/* Restore interrupts */
167 #endif
168 
169 /*
170  * AST_ALIGNMENT_FAULT_LOCALS and ENABLE_ALIGNMENT_FAULTS
171  * These are used in order to support dynamic enabling/disabling of
172  * alignment faults when executing old a.out ARM binaries.
173  *
174  * Note that when ENABLE_ALIGNMENTS_FAULTS finishes r4 will contain
175  * pointer to the cpu's cpu_info.  DO_AST_AND_RESTORE_ALIGNMENT_FAULTS
176  * relies on r4 being preserved.
177  */
178 #ifdef EXEC_AOUT
179 #define	AST_ALIGNMENT_FAULT_LOCALS					\
180 .Laflt_cpufuncs:							;\
181 	.word	_C_LABEL(cpufuncs)
182 
183 /*
184  * This macro must be invoked following PUSHFRAMEINSVC or PUSHFRAME at
185  * the top of interrupt/exception handlers.
186  *
187  * When invoked, r0 *must* contain the value of SPSR on the current
188  * trap/interrupt frame. This is always the case if ENABLE_ALIGNMENT_FAULTS
189  * is invoked immediately after PUSHFRAMEINSVC or PUSHFRAME.
190  */
191 #define	ENABLE_ALIGNMENT_FAULTS						\
192 	and	r7, r0, #(PSR_MODE)	/* Test for USR32 mode */	;\
193 	teq	r7, #(PSR_USR32_MODE)					;\
194 	GET_CURCPU(r4)			/* r4 = cpuinfo */		;\
195 	bne	1f			/* Not USR mode skip AFLT */	;\
196 	ldr	r1, [r4, #CI_CURLWP]	/* get curlwp from cpu_info */	;\
197 	ldr	r1, [r1, #L_MD_FLAGS]	/* Fetch l_md.md_flags */	;\
198 	tst	r1, #MDLWP_NOALIGNFLT					;\
199 	beq	1f			/* AFLTs already enabled */	;\
200 	ldr	r2, .Laflt_cpufuncs					;\
201 	ldr	r1, [r4, #CI_CTRL]	/* Fetch control register */	;\
202 	mov	r0, #-1							;\
203 	BL_CF_CONTROL(r2)		/* Enable alignment faults */	;\
204 1:	KERNEL_LOCK
205 
206 /*
207  * This macro must be invoked just before PULLFRAMEFROMSVCANDEXIT or
208  * PULLFRAME at the end of interrupt/exception handlers.  We know that
209  * r4 points to cpu_info since that is what ENABLE_ALIGNMENT_FAULTS did
210  * for use.
211  */
212 #define	DO_AST_AND_RESTORE_ALIGNMENT_FAULTS				\
213 	DO_PENDING_SOFTINTS						;\
214 	GET_CPSR(r5)			/* save CPSR */			;\
215 	CPSID_I(r1, r5)			/* Disable interrupts */	;\
216 	teq	r7, #(PSR_USR32_MODE)	/* Returning to USR mode? */	;\
217 	bne	3f			/* Nope, get out now */		;\
218 1:	ldr	r1, [r4, #CI_ASTPENDING] /* Pending AST? */		;\
219 	teq	r1, #0x00000000						;\
220 	bne	2f			/* Yup. Go deal with it */	;\
221 	ldr	r1, [r4, #CI_CURLWP]	/* get curlwp from cpu_info */	;\
222 	ldr	r0, [r1, #L_MD_FLAGS]	/* get md_flags from lwp */	;\
223 	tst	r0, #MDLWP_NOALIGNFLT					;\
224 	beq	3f			/* Keep AFLTs enabled */	;\
225 	ldr	r1, [r4, #CI_CTRL]	/* Fetch control register */	;\
226 	ldr	r2, .Laflt_cpufuncs					;\
227 	mov	r0, #-1							;\
228 	bic	r1, r1, #CPU_CONTROL_AFLT_ENABLE  /* Disable AFLTs */	;\
229 	adr	lr, 3f							;\
230 	B_CF_CONTROL(r2)		/* Set new CTRL reg value */	;\
231 	/* NOTREACHED */						\
232 2:	mov	r1, #0x00000000						;\
233 	str	r1, [r4, #CI_ASTPENDING] /* Clear astpending */		;\
234 	CPSIE_I(r5, r5)			/* Restore interrupts */	;\
235 	mov	r0, sp							;\
236 	bl	_C_LABEL(ast)		/* ast(frame) */		;\
237 	CPSID_I(r0, r5)			/* Disable interrupts */	;\
238 	b	1b			/* Back around again */		;\
239 3:	KERNEL_UNLOCK
240 
241 #else	/* !EXEC_AOUT */
242 
243 #define	AST_ALIGNMENT_FAULT_LOCALS
244 
245 #define	ENABLE_ALIGNMENT_FAULTS						\
246 	and	r7, r0, #(PSR_MODE)	/* Test for USR32 mode */	;\
247 	GET_CURCPU(r4)			/* r4 = cpuinfo */		;\
248 	KERNEL_LOCK
249 
250 #define	DO_AST_AND_RESTORE_ALIGNMENT_FAULTS				\
251 	DO_PENDING_SOFTINTS						;\
252 	GET_CPSR(r5)			/* save CPSR */			;\
253 	CPSID_I(r1, r5)			/* Disable interrupts */	;\
254 	teq	r7, #(PSR_USR32_MODE)					;\
255 	bne	2f			/* Nope, get out now */		;\
256 1:	ldr	r1, [r4, #CI_ASTPENDING] /* Pending AST? */		;\
257 	teq	r1, #0x00000000						;\
258 	beq	2f			/* Nope. Just bail */		;\
259 	mov	r1, #0x00000000						;\
260 	str	r1, [r4, #CI_ASTPENDING] /* Clear astpending */		;\
261 	CPSIE_I(r5, r5)			/* Restore interrupts */	;\
262 	mov	r0, sp							;\
263 	bl	_C_LABEL(ast)		/* ast(frame) */		;\
264 	CPSID_I(r0, r5)			/* Disable interrupts */	;\
265 	b	1b							;\
266 2:	KERNEL_UNLOCK			/* unlock the kernel */
267 #endif /* EXEC_AOUT */
268 
269 #ifndef _ARM_ARCH_6
270 #ifdef ARM_LOCK_CAS_DEBUG
271 #define	LOCK_CAS_DEBUG_LOCALS						 \
272 .L_lock_cas_restart:							;\
273 	.word	_C_LABEL(_lock_cas_restart)
274 
275 #if defined(__ARMEB__)
276 #define	LOCK_CAS_DEBUG_COUNT_RESTART					 \
277 	ble	99f							;\
278 	ldr	r0, .L_lock_cas_restart					;\
279 	ldmia	r0, {r1-r2}		/* load ev_count */		;\
280 	adds	r2, r2, #1		/* 64-bit incr (lo) */		;\
281 	adc	r1, r1, #0		/* 64-bit incr (hi) */		;\
282 	stmia	r0, {r1-r2}		/* store ev_count */
283 #else /* __ARMEB__ */
284 #define	LOCK_CAS_DEBUG_COUNT_RESTART					 \
285 	ble	99f							;\
286 	ldr	r0, .L_lock_cas_restart					;\
287 	ldmia	r0, {r1-r2}		/* load ev_count */		;\
288 	adds	r1, r1, #1		/* 64-bit incr (lo) */		;\
289 	adc	r2, r2, #0		/* 64-bit incr (hi) */		;\
290 	stmia	r0, {r1-r2}		/* store ev_count */
291 #endif /* __ARMEB__ */
292 #else /* ARM_LOCK_CAS_DEBUG */
293 #define	LOCK_CAS_DEBUG_LOCALS		/* nothing */
294 #define	LOCK_CAS_DEBUG_COUNT_RESTART	/* nothing */
295 #endif /* ARM_LOCK_CAS_DEBUG */
296 
297 #define	LOCK_CAS_CHECK_LOCALS						 \
298 .L_lock_cas:								;\
299 	.word	_C_LABEL(_lock_cas)					;\
300 .L_lock_cas_end:							;\
301 	.word	_C_LABEL(_lock_cas_end)					;\
302 LOCK_CAS_DEBUG_LOCALS
303 
304 #define	LOCK_CAS_CHECK							 \
305 	ldr	r0, [sp]		/* get saved PSR */		;\
306 	and	r0, r0, #(PSR_MODE)	/* check for SVC32 mode */	;\
307 	teq	r0, #(PSR_SVC32_MODE)					;\
308 	bne	99f			/* nope, get out now */		;\
309 	ldr	r0, [sp, #(TF_PC)]					;\
310 	ldr	r1, .L_lock_cas_end					;\
311 	cmp	r0, r1							;\
312 	bge	99f							;\
313 	ldr	r1, .L_lock_cas						;\
314 	cmp	r0, r1							;\
315 	strgt	r1, [sp, #(TF_PC)]					;\
316 	LOCK_CAS_DEBUG_COUNT_RESTART					;\
317 99:
318 
319 #else
320 #define	LOCK_CAS_CHECK			/* nothing */
321 #define	LOCK_CAS_CHECK_LOCALS		/* nothing */
322 #endif
323 
324 /*
325  * ASM macros for pushing and pulling trapframes from the stack
326  *
327  * These macros are used to handle the trapframe structure defined above.
328  */
329 
330 /*
331  * PUSHFRAME - macro to push a trap frame on the stack in the current mode
332  * Since the current mode is used, the SVC lr field is not defined.
333  */
334 
335 #ifdef CPU_SA110
336 /*
337  * NOTE: r13 and r14 are stored separately as a work around for the
338  * SA110 rev 2 STM^ bug
339  */
340 #define	PUSHUSERREGS							   \
341 	stmia	sp, {r0-r12};		/* Push the user mode registers */ \
342 	add	r0, sp, #(TF_USR_SP-TF_R0); /* Adjust the stack pointer */ \
343 	stmia	r0, {r13-r14}^		/* Push the user mode registers */
344 #else
345 #define	PUSHUSERREGS							   \
346 	stmia	sp, {r0-r14}^		/* Push the user mode registers */
347 #endif
348 
349 #define PUSHFRAME							   \
350 	str	lr, [sp, #-4]!;		/* Push the return address */	   \
351 	sub	sp, sp, #(TF_PC-TF_R0);	/* Adjust the stack pointer */	   \
352 	PUSHUSERREGS;			/* Push the user mode registers */ \
353 	mov     r0, r0;                 /* NOP for previous instruction */ \
354 	mrs	r0, spsr_all;		/* Get the SPSR */		   \
355 	str	r0, [sp, #-TF_R0]!	/* Push the SPSR on the stack */
356 
357 /*
358  * Push a minimal trapframe so we can dispatch an interrupt from the
359  * idle loop.  The only reason the idle loop wakes up is to dispatch
360  * interrupts so why take the avoid of a full exception when we can do
361  * something minimal.
362  */
363 #define PUSHIDLEFRAME							   \
364 	str	lr, [sp, #-4]!;		/* save SVC32 lr */		   \
365 	str	r6, [sp, #(TF_R6-TF_PC)]!; /* save callee-saved r6 */	   \
366 	str	r4, [sp, #(TF_R4-TF_R6)]!; /* save callee-saved r4 */	   \
367 	mrs	r0, cpsr_all;		/* Get the CPSR */		   \
368 	str	r0, [sp, #(-TF_R4)]!	/* Push the CPSR on the stack */
369 
370 /*
371  * Push a trapframe to be used by cpu_switchto
372  */
373 #define PUSHSWITCHFRAME(rX)						\
374 	mov	ip, sp;							\
375 	sub	sp, sp, #(TRAPFRAMESIZE-TF_R12); /* Adjust the stack pointer */ \
376 	push	{r4-r11};		/* Push the callee saved registers */ \
377 	sub	sp, sp, #TF_R4;		/* reserve rest of trapframe */	\
378 	str	ip, [sp, #TF_SVC_SP];					\
379 	str	lr, [sp, #TF_SVC_LR];					\
380 	str	lr, [sp, #TF_PC];					\
381 	mrs	rX, cpsr_all;		/* Get the CPSR */		\
382 	str	rX, [sp, #TF_SPSR]	/* save in trapframe */
383 
384 #define PUSHSWITCHFRAME1						   \
385 	mov	ip, sp;							   \
386 	sub	sp, sp, #(TRAPFRAMESIZE-TF_R8); /* Adjust the stack pointer */ \
387 	push	{r4-r7};		/* Push some of the callee saved registers */ \
388 	sub	sp, sp, #TF_R4;		/* reserve rest of trapframe */	\
389 	str	ip, [sp, #TF_SVC_SP];					\
390 	str	lr, [sp, #TF_SVC_LR];					\
391 	str	lr, [sp, #TF_PC]
392 
393 #if defined(_ARM_ARCH_DWORD_OK) && __ARM_EABI__
394 #define	PUSHSWITCHFRAME2						\
395 	strd	r10, [sp, #TF_R10];	/* save r10 & r11 */		\
396 	strd	r8, [sp, #TF_R8];	/* save r8 & r9 */		\
397 	mrs	r0, cpsr_all;		/* Get the CPSR */		\
398 	str	r0, [sp, #TF_SPSR]	/* save in trapframe */
399 #else
400 #define	PUSHSWITCHFRAME2						\
401 	add	r0, sp, #TF_R8;		/* get ptr to r8 and above */	\
402 	stmia	r0, {r8-r11};		/* save rest of registers */	\
403 	mrs	r0, cpsr_all;		/* Get the CPSR */		\
404 	str	r0, [sp, #TF_SPSR]	/* save in trapframe */
405 #endif
406 
407 /*
408  * PULLFRAME - macro to pull a trap frame from the stack in the current mode
409  * Since the current mode is used, the SVC lr field is ignored.
410  */
411 
412 #define PULLFRAME							   \
413 	ldr     r0, [sp], #TF_R0;	/* Pop the SPSR from stack */	   \
414 	msr     spsr_all, r0;						   \
415 	ldmia   sp, {r0-r14}^;		/* Restore registers (usr mode) */ \
416 	mov     r0, r0;                 /* NOP for previous instruction */ \
417 	add	sp, sp, #(TF_PC-TF_R0);	/* Adjust the stack pointer */	   \
418  	ldr	lr, [sp], #0x0004	/* Pop the return address */
419 
420 #define PULLIDLEFRAME							   \
421 	add	sp, sp, #TF_R4;		/* Adjust the stack pointer */	   \
422 	ldr	r4, [sp], #(TF_R6-TF_R4); /* restore callee-saved r4 */	   \
423 	ldr	r6, [sp], #(TF_PC-TF_R6); /* restore callee-saved r6 */	   \
424  	ldr	lr, [sp], #4		/* Pop the return address */
425 
426 /*
427  * Pop a trapframe to be used by cpu_switchto (don't touch r0 & r1).
428  */
429 #define PULLSWITCHFRAME							\
430 	add	sp, sp, #TF_R4;		/* Adjust the stack pointer */	\
431 	pop	{r4-r11};		/* pop the callee saved registers */ \
432 	add	sp, sp, #(TF_PC-TF_R12); /* Adjust the stack pointer */	\
433 	ldr	lr, [sp], #4;		/* pop the return address */
434 
435 /*
436  * PUSHFRAMEINSVC - macro to push a trap frame on the stack in SVC32 mode
437  * This should only be used if the processor is not currently in SVC32
438  * mode. The processor mode is switched to SVC mode and the trap frame is
439  * stored. The SVC lr field is used to store the previous value of
440  * lr in SVC mode.
441  *
442  * NOTE: r13 and r14 are stored separately as a work around for the
443  * SA110 rev 2 STM^ bug
444  */
445 
446 #ifdef _ARM_ARCH_6
447 #define	SET_CPSR_MODE(tmp, mode)	\
448 	cps	#(mode)
449 #else
450 #define	SET_CPSR_MODE(tmp, mode)	\
451 	mrs     tmp, cpsr; 		/* Get the CPSR */		   \
452 	bic     tmp, tmp, #(PSR_MODE);	/* Fix for SVC mode */		   \
453 	orr     tmp, tmp, #(mode);					   \
454 	msr     cpsr_c, tmp		/* Punch into SVC mode */
455 #endif
456 
457 #define PUSHFRAMEINSVC							   \
458 	stmdb	sp, {r0-r3};		/* Save 4 registers */		   \
459 	mov	r0, lr;			/* Save xxx32 r14 */		   \
460 	mov	r1, sp;			/* Save xxx32 sp */		   \
461 	mrs	r3, spsr;		/* Save xxx32 spsr */		   \
462 	SET_CPSR_MODE(r2, PSR_SVC32_MODE);				   \
463 	bic	r2, sp, #7;		/* Align new SVC sp */		   \
464 	str	r0, [r2, #-4]!;		/* Push return address */	   \
465 	stmdb	r2!, {sp, lr};		/* Push SVC sp, lr */		   \
466 	mov	sp, r2;			/* Keep stack aligned */	   \
467 	msr     spsr_all, r3;		/* Restore correct spsr */	   \
468 	ldmdb	r1, {r0-r3};		/* Restore 4 regs from xxx mode */ \
469 	sub	sp, sp, #(TF_SVC_SP-TF_R0); /* Adjust the stack pointer */ \
470 	PUSHUSERREGS;			/* Push the user mode registers */ \
471 	mov     r0, r0;                 /* NOP for previous instruction */ \
472 	mrs	r0, spsr_all;		/* Get the SPSR */		   \
473 	str	r0, [sp, #-TF_R0]!	/* Push the SPSR onto the stack */
474 
475 /*
476  * PULLFRAMEFROMSVCANDEXIT - macro to pull a trap frame from the stack
477  * in SVC32 mode and restore the saved processor mode and PC.
478  * This should be used when the SVC lr register needs to be restored on
479  * exit.
480  */
481 
482 #define PULLFRAMEFROMSVCANDEXIT						   \
483 	ldr     r0, [sp], #0x0008;	/* Pop the SPSR from stack */	   \
484 	msr     spsr_all, r0;		/* restore SPSR */		   \
485 	ldmia   sp, {r0-r14}^;		/* Restore registers (usr mode) */ \
486 	mov     r0, r0;	  		/* NOP for previous instruction */ \
487 	add	sp, sp, #(TF_SVC_SP-TF_R0); /* Adjust the stack pointer */ \
488 	ldmia	sp, {sp, lr, pc}^	/* Restore lr and exit */
489 
490 #endif /* _LOCORE */
491 
492 #endif /* _ARM32_FRAME_H_ */
493