1#ifndef __M68KNOMMU_ENTRY_H
  2#define __M68KNOMMU_ENTRY_H
  3
  4#include <asm/setup.h>
  5#include <asm/page.h>
  6
  7/*
  8 * Stack layout in 'ret_from_exception':
  9 *
 10 * This allows access to the syscall arguments in registers d1-d5
 11 *
 12 *	 0(sp) - d1
 13 *	 4(sp) - d2
 14 *	 8(sp) - d3
 15 *	 C(sp) - d4
 16 *	10(sp) - d5
 17 *	14(sp) - a0
 18 *	18(sp) - a1
 19 *	1C(sp) - a2
 20 *	20(sp) - d0
 21 *	24(sp) - orig_d0
 22 *	28(sp) - stack adjustment
 23 *	2C(sp) - [ sr              ] [ format & vector ]
 24 *	2E(sp) - [ pc-hiword       ] [ sr              ]
 25 *	30(sp) - [ pc-loword       ] [ pc-hiword       ]
 26 *	32(sp) - [ format & vector ] [ pc-loword       ]
 27 *		  ^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^^^
 28 *			M68K		  COLDFIRE
 29 */
 30
 31#define ALLOWINT (~0x700)
 32
 33#ifdef __ASSEMBLY__
 34
 35#define SWITCH_STACK_SIZE (6*4+4)	/* Includes return address */
 36
 37/*
 38 * This defines the normal kernel pt-regs layout.
 39 *
 40 * regs are a2-a6 and d6-d7 preserved by C code
 41 * the kernel doesn't mess with usp unless it needs to
 42 */
 43
 44#ifdef CONFIG_COLDFIRE
 45#ifdef CONFIG_COLDFIRE_SW_A7
 46/*
 47 * This is made a little more tricky on older ColdFires. There is no
 48 * separate supervisor and user stack pointers. Need to artificially
 49 * construct a usp in software... When doing this we need to disable
 50 * interrupts, otherwise bad things will happen.
 51 */
 52.globl sw_usp
 53.globl sw_ksp
 54
 55.macro SAVE_ALL
 56	move	#0x2700,%sr		/* disable intrs */
 57	btst	#5,%sp@(2)		/* from user? */
 58	bnes	6f			/* no, skip */
 59	movel	%sp,sw_usp		/* save user sp */
 60	addql	#8,sw_usp		/* remove exception */
 61	movel	sw_ksp,%sp		/* kernel sp */
 62	subql	#8,%sp			/* room for exception */
 63	clrl	%sp@-			/* stkadj */
 64	movel	%d0,%sp@-		/* orig d0 */
 65	movel	%d0,%sp@-		/* d0 */
 66	lea	%sp@(-32),%sp		/* space for 8 regs */
 67	moveml	%d1-%d5/%a0-%a2,%sp@
 68	movel	sw_usp,%a0		/* get usp */
 69	movel	%a0@-,%sp@(PT_OFF_PC)	/* copy exception program counter */
 70	movel	%a0@-,%sp@(PT_OFF_FORMATVEC)/*copy exception format/vector/sr */
 71	bra	7f
 72	6:
 73	clrl	%sp@-			/* stkadj */
 74	movel	%d0,%sp@-		/* orig d0 */
 75	movel	%d0,%sp@-		/* d0 */
 76	lea	%sp@(-32),%sp		/* space for 8 regs */
 77	moveml	%d1-%d5/%a0-%a2,%sp@
 78	7:
 79.endm
 80
 81.macro RESTORE_USER
 82	move	#0x2700,%sr		/* disable intrs */
 83	movel	sw_usp,%a0		/* get usp */
 84	movel	%sp@(PT_OFF_PC),%a0@-	/* copy exception program counter */
 85	movel	%sp@(PT_OFF_FORMATVEC),%a0@-/*copy exception format/vector/sr */
 86	moveml	%sp@,%d1-%d5/%a0-%a2
 87	lea	%sp@(32),%sp		/* space for 8 regs */
 88	movel	%sp@+,%d0
 89	addql	#4,%sp			/* orig d0 */
 90	addl	%sp@+,%sp		/* stkadj */
 91	addql	#8,%sp			/* remove exception */
 92	movel	%sp,sw_ksp		/* save ksp */
 93	subql	#8,sw_usp		/* set exception */
 94	movel	sw_usp,%sp		/* restore usp */
 95	rte
 96.endm
 97
 98.macro RDUSP
 99	movel	sw_usp,%a3
100.endm
101
102.macro WRUSP
103	movel	%a3,sw_usp
104.endm
105
106#else /* !CONFIG_COLDFIRE_SW_A7 */
107/*
108 * Modern ColdFire parts have separate supervisor and user stack
109 * pointers. Simple load and restore macros for this case.
110 */
111.macro SAVE_ALL
112	move	#0x2700,%sr		/* disable intrs */
113	clrl	%sp@-			/* stkadj */
114	movel	%d0,%sp@-		/* orig d0 */
115	movel	%d0,%sp@-		/* d0 */
116	lea	%sp@(-32),%sp		/* space for 8 regs */
117	moveml	%d1-%d5/%a0-%a2,%sp@
118.endm
119
120.macro RESTORE_USER
121	moveml	%sp@,%d1-%d5/%a0-%a2
122	lea	%sp@(32),%sp		/* space for 8 regs */
123	movel	%sp@+,%d0
124	addql	#4,%sp			/* orig d0 */
125	addl	%sp@+,%sp		/* stkadj */
126	rte
127.endm
128
129.macro RDUSP
130	/*move	%usp,%a3*/
131	.word	0x4e6b
132.endm
133
134.macro WRUSP
135	/*move	%a3,%usp*/
136	.word	0x4e63
137.endm
138
139#endif /* !CONFIG_COLDFIRE_SW_A7 */
140
141.macro SAVE_SWITCH_STACK
142	lea	%sp@(-24),%sp		/* 6 regs */
143	moveml	%a3-%a6/%d6-%d7,%sp@
144.endm
145
146.macro RESTORE_SWITCH_STACK
147	moveml	%sp@,%a3-%a6/%d6-%d7
148	lea	%sp@(24),%sp		/* 6 regs */
149.endm
150
151#else /* !CONFIG_COLDFIRE */
152
153/*
154 * Standard 68k interrupt entry and exit macros.
155 */
156.macro SAVE_ALL
157	clrl	%sp@-			/* stkadj */
158	movel	%d0,%sp@-		/* orig d0 */
159	movel	%d0,%sp@-		/* d0 */
160	moveml	%d1-%d5/%a0-%a2,%sp@-
161.endm
162
163.macro RESTORE_ALL
164	moveml	%sp@+,%a0-%a2/%d1-%d5
165	movel	%sp@+,%d0
166	addql	#4,%sp			/* orig d0 */
167	addl	%sp@+,%sp		/* stkadj */
168	rte
169.endm
170
171.macro SAVE_SWITCH_STACK
172	moveml	%a3-%a6/%d6-%d7,%sp@-
173.endm
174
175.macro RESTORE_SWITCH_STACK
176	moveml	%sp@+,%a3-%a6/%d6-%d7
177.endm
178
179#endif /* !COLDFIRE_SW_A7 */
180#endif /* __ASSEMBLY__ */
181#endif /* __M68KNOMMU_ENTRY_H */