[mirror_ubuntu-zesty-kernel.git] / arch / arm / kernel / head-common.S

/*
 *  linux/arch/arm/kernel/head-common.S
 *
 *  Copyright (C) 1994-2002 Russell King
 *  Copyright (c) 2003 ARM Limited
 *  All Rights Reserved
 *
 * 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.
 *
 */

#define ATAG_CORE 0x54410001
#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
#define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)

	.align	2
	.type	__switch_data, %object
__switch_data:
	.long	__mmap_switched
	.long	__data_loc			@ r4
	.long	_sdata				@ r5
	.long	__bss_start			@ r6
	.long	_end				@ r7
	.long	processor_id			@ r4
	.long	__machine_arch_type		@ r5
	.long	__atags_pointer			@ r6
	.long	cr_alignment			@ r7
	.long	init_thread_union + THREAD_START_SP @ sp

/*
 * The following fragment of code is executed with the MMU on in MMU mode,
 * and uses absolute addresses; this is not position independent.
 *
 *  r0  = cp#15 control register
 *  r1  = machine ID
 *  r2  = atags pointer
 *  r9  = processor ID
 */
__mmap_switched:
	adr	r3, __switch_data + 4

	ldmia	r3!, {r4, r5, r6, r7}
	cmp	r4, r5				@ Copy data segment if needed
1:	cmpne	r5, r6
	ldrne	fp, [r4], #4
	strne	fp, [r5], #4
	bne	1b

	mov	fp, #0				@ Clear BSS (and zero fp)
1:	cmp	r6, r7
	strcc	fp, [r6],#4
	bcc	1b

 ARM(	ldmia	r3, {r4, r5, r6, r7, sp})
 THUMB(	ldmia	r3, {r4, r5, r6, r7}	)
 THUMB(	ldr	sp, [r3, #16]		)
	str	r9, [r4]			@ Save processor ID
	str	r1, [r5]			@ Save machine type
	str	r2, [r6]			@ Save atags pointer
	bic	r4, r0, #CR_A			@ Clear 'A' bit
	stmia	r7, {r0, r4}			@ Save control register values
	b	start_kernel
ENDPROC(__mmap_switched)

/*
 * Exception handling.  Something went wrong and we can't proceed.  We
 * ought to tell the user, but since we don't have any guarantee that
 * we're even running on the right architecture, we do virtually nothing.
 *
 * If CONFIG_DEBUG_LL is set we try to print out something about the error
 * and hope for the best (useful if bootloader fails to pass a proper
 * machine ID for example).
 */
__error_p:
#ifdef CONFIG_DEBUG_LL
	adr	r0, str_p1
	bl	printascii
	mov	r0, r9
	bl	printhex8
	adr	r0, str_p2
	bl	printascii
	b	__error
str_p1:	.asciz	"\nError: unrecognized/unsupported processor variant (0x"
str_p2:	.asciz	").\n"
	.align
#endif
ENDPROC(__error_p)

__error_a:
#ifdef CONFIG_DEBUG_LL
	mov	r4, r1				@ preserve machine ID
	adr	r0, str_a1
	bl	printascii
	mov	r0, r4
	bl	printhex8
	adr	r0, str_a2
	bl	printascii
	adr	r3, 4f
	ldmia	r3, {r4, r5, r6}		@ get machine desc list
	sub	r4, r3, r4			@ get offset between virt&phys
	add	r5, r5, r4			@ convert virt addresses to
	add	r6, r6, r4			@ physical address space
1:	ldr	r0, [r5, #MACHINFO_TYPE]	@ get machine type
	bl	printhex8
	mov	r0, #'\t'
	bl	printch
	ldr     r0, [r5, #MACHINFO_NAME]	@ get machine name
	add	r0, r0, r4
	bl	printascii
	mov	r0, #'\n'
	bl	printch
	add	r5, r5, #SIZEOF_MACHINE_DESC	@ next machine_desc
	cmp	r5, r6
	blo	1b
	adr	r0, str_a3
	bl	printascii
	b	__error
ENDPROC(__error_a)

str_a1:	.asciz	"\nError: unrecognized/unsupported machine ID (r1 = 0x"
str_a2:	.asciz	").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
str_a3:	.asciz	"\nPlease check your kernel config and/or bootloader.\n"
	.align
#endif

__error:
#ifdef CONFIG_ARCH_RPC
/*
 * Turn the screen red on a error - RiscPC only.
 */
	mov	r0, #0x02000000
	mov	r3, #0x11
	orr	r3, r3, r3, lsl #8
	orr	r3, r3, r3, lsl #16
	str	r3, [r0], #4
	str	r3, [r0], #4
	str	r3, [r0], #4
	str	r3, [r0], #4
#endif
1:	mov	r0, r0
	b	1b
ENDPROC(__error)


/*
 * Read processor ID register (CP#15, CR0), and look up in the linker-built
 * supported processor list.  Note that we can't use the absolute addresses
 * for the __proc_info lists since we aren't running with the MMU on
 * (and therefore, we are not in the correct address space).  We have to
 * calculate the offset.
 *
 *	r9 = cpuid
 * Returns:
 *	r3, r4, r6 corrupted
 *	r5 = proc_info pointer in physical address space
 *	r9 = cpuid (preserved)
 */
__lookup_processor_type:
	adr	r3, 3f
	ldmia	r3, {r5 - r7}
	add	r3, r3, #8
	sub	r3, r3, r7			@ get offset between virt&phys
	add	r5, r5, r3			@ convert virt addresses to
	add	r6, r6, r3			@ physical address space
1:	ldmia	r5, {r3, r4}			@ value, mask
	and	r4, r4, r9			@ mask wanted bits
	teq	r3, r4
	beq	2f
	add	r5, r5, #PROC_INFO_SZ		@ sizeof(proc_info_list)
	cmp	r5, r6
	blo	1b
	mov	r5, #0				@ unknown processor
2:	mov	pc, lr
ENDPROC(__lookup_processor_type)

/*
 * This provides a C-API version of the above function.
 */
ENTRY(lookup_processor_type)
	stmfd	sp!, {r4 - r7, r9, lr}
	mov	r9, r0
	bl	__lookup_processor_type
	mov	r0, r5
	ldmfd	sp!, {r4 - r7, r9, pc}
ENDPROC(lookup_processor_type)

/*
 * Look in <asm/procinfo.h> and arch/arm/kernel/arch.[ch] for
 * more information about the __proc_info and __arch_info structures.
 */
	.align	2
3:	.long	__proc_info_begin
	.long	__proc_info_end
4:	.long	.
	.long	__arch_info_begin
	.long	__arch_info_end

/*
 * Lookup machine architecture in the linker-build list of architectures.
 * Note that we can't use the absolute addresses for the __arch_info
 * lists since we aren't running with the MMU on (and therefore, we are
 * not in the correct address space).  We have to calculate the offset.
 *
 *  r1 = machine architecture number
 * Returns:
 *  r3, r4, r6 corrupted
 *  r5 = mach_info pointer in physical address space
 */
__lookup_machine_type:
	adr	r3, 4b
	ldmia	r3, {r4, r5, r6}
	sub	r3, r3, r4			@ get offset between virt&phys
	add	r5, r5, r3			@ convert virt addresses to
	add	r6, r6, r3			@ physical address space
1:	ldr	r3, [r5, #MACHINFO_TYPE]	@ get machine type
	teq	r3, r1				@ matches loader number?
	beq	2f				@ found
	add	r5, r5, #SIZEOF_MACHINE_DESC	@ next machine_desc
	cmp	r5, r6
	blo	1b
	mov	r5, #0				@ unknown machine
2:	mov	pc, lr
ENDPROC(__lookup_machine_type)

/*
 * This provides a C-API version of the above function.
 */
ENTRY(lookup_machine_type)
	stmfd	sp!, {r4 - r6, lr}
	mov	r1, r0
	bl	__lookup_machine_type
	mov	r0, r5
	ldmfd	sp!, {r4 - r6, pc}
ENDPROC(lookup_machine_type)

/* Determine validity of the r2 atags pointer.  The heuristic requires
 * that the pointer be aligned, in the first 16k of physical RAM and
 * that the ATAG_CORE marker is first and present.  Future revisions
 * of this function may be more lenient with the physical address and
 * may also be able to move the ATAGS block if necessary.
 *
 * r8  = machinfo
 *
 * Returns:
 *  r2 either valid atags pointer, or zero
 *  r5, r6 corrupted
 */
__vet_atags:
	tst	r2, #0x3			@ aligned?
	bne	1f

	ldr	r5, [r2, #0]			@ is first tag ATAG_CORE?
	cmp	r5, #ATAG_CORE_SIZE
	cmpne	r5, #ATAG_CORE_SIZE_EMPTY
	bne	1f
	ldr	r5, [r2, #4]
	ldr	r6, =ATAG_CORE
	cmp	r5, r6
	bne	1f

	mov	pc, lr				@ atag pointer is ok

1:	mov	r2, #0
	mov	pc, lr
ENDPROC(__vet_atags)
Commit	Line	Data
75d90832 HC	1	/*
	2	* linux/arch/arm/kernel/head-common.S
	3	*
	4	* Copyright (C) 1994-2002 Russell King
	5	* Copyright (c) 2003 ARM Limited
	6	* All Rights Reserved
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
9c4c9f38 GU	14	#define ATAG_CORE 0x54410001
9c4c9f38 GU	15	#define ATAG_CORE_SIZE ((24 + 34) >> 2)
31abdb74	16	#define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)
9c4c9f38	17
88987ef9	18	.align 2
75d90832 HC	19	.type __switch_data, %object
	20	__switch_data:
	21	.long __mmap_switched
	22	.long __data_loc @ r4
842eab40	23	.long _sdata @ r5
75d90832 HC	24	.long __bss_start @ r6
	25	.long _end @ r7
	26	.long processor_id @ r4
	27	.long __machine_arch_type @ r5
9d20fdd5 BG	28	.long __atags_pointer @ r6
9d20fdd5 BG	29	.long cr_alignment @ r7
75d90832 HC	30	.long init_thread_union + THREAD_START_SP @ sp
	31
	32	/*
	33	* The following fragment of code is executed with the MMU on in MMU mode,
	34	* and uses absolute addresses; this is not position independent.
	35	*
	36	* r0 = cp#15 control register
	37	* r1 = machine ID
9d20fdd5	38	* r2 = atags pointer
75d90832 HC	39	* r9 = processor ID
75d90832 HC	40	*/
75d90832 HC	41	__mmap_switched:
	42	adr r3, __switch_data + 4
	43
	44	ldmia r3!, {r4, r5, r6, r7}
	45	cmp r4, r5 @ Copy data segment if needed
	46	1: cmpne r5, r6
	47	ldrne fp, [r4], #4
	48	strne fp, [r5], #4
	49	bne 1b
	50
	51	mov fp, #0 @ Clear BSS (and zero fp)
	52	1: cmp r6, r7
	53	strcc fp, [r6],#4
	54	bcc 1b
	55
b86040a5 CM	56	ARM( ldmia r3, {r4, r5, r6, r7, sp})
	57	THUMB( ldmia r3, {r4, r5, r6, r7} )
	58	THUMB( ldr sp, [r3, #16] )
75d90832 HC	59	str r9, [r4] @ Save processor ID
75d90832 HC	60	str r1, [r5] @ Save machine type
9d20fdd5	61	str r2, [r6] @ Save atags pointer
75d90832	62	bic r4, r0, #CR_A @ Clear 'A' bit
9d20fdd5	63	stmia r7, {r0, r4} @ Save control register values
75d90832	64	b start_kernel
93ed3970	65	ENDPROC(__mmap_switched)
75d90832 HC	66
	67	/*
	68	* Exception handling. Something went wrong and we can't proceed. We
	69	* ought to tell the user, but since we don't have any guarantee that
	70	* we're even running on the right architecture, we do virtually nothing.
	71	*
	72	* If CONFIG_DEBUG_LL is set we try to print out something about the error
	73	* and hope for the best (useful if bootloader fails to pass a proper
	74	* machine ID for example).
	75	*/
75d90832 HC	76	__error_p:
	77	#ifdef CONFIG_DEBUG_LL
	78	adr r0, str_p1
	79	bl printascii
84081bd2 LB	80	mov r0, r9
	81	bl printhex8
	82	adr r0, str_p2
	83	bl printascii
75d90832	84	b __error
84081bd2 LB	85	str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x"
84081bd2 LB	86	str_p2: .asciz ").\n"
75d90832 HC	87	.align
75d90832 HC	88	#endif
93ed3970	89	ENDPROC(__error_p)
75d90832	90
75d90832 HC	91	__error_a:
	92	#ifdef CONFIG_DEBUG_LL
	93	mov r4, r1 @ preserve machine ID
	94	adr r0, str_a1
	95	bl printascii
	96	mov r0, r4
	97	bl printhex8
	98	adr r0, str_a2
	99	bl printascii
158bc5af	100	adr r3, 4f
75d90832 HC	101	ldmia r3, {r4, r5, r6} @ get machine desc list
	102	sub r4, r3, r4 @ get offset between virt&phys
	103	add r5, r5, r4 @ convert virt addresses to
	104	add r6, r6, r4 @ physical address space
	105	1: ldr r0, [r5, #MACHINFO_TYPE] @ get machine type
	106	bl printhex8
	107	mov r0, #'\t'
	108	bl printch
	109	ldr r0, [r5, #MACHINFO_NAME] @ get machine name
	110	add r0, r0, r4
	111	bl printascii
	112	mov r0, #'\n'
	113	bl printch
	114	add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
	115	cmp r5, r6
	116	blo 1b
	117	adr r0, str_a3
	118	bl printascii
	119	b __error
93ed3970 CM	120	ENDPROC(__error_a)
93ed3970 CM	121
75d90832 HC	122	str_a1: .asciz "\nError: unrecognized/unsupported machine ID (r1 = 0x"
	123	str_a2: .asciz ").\n\nAvailable machine support:\n\nID (hex)\tNAME\n"
	124	str_a3: .asciz "\nPlease check your kernel config and/or bootloader.\n"
	125	.align
	126	#endif
	127
75d90832 HC	128	__error:
	129	#ifdef CONFIG_ARCH_RPC
	130	/*
	131	* Turn the screen red on a error - RiscPC only.
	132	*/
	133	mov r0, #0x02000000
	134	mov r3, #0x11
	135	orr r3, r3, r3, lsl #8
	136	orr r3, r3, r3, lsl #16
	137	str r3, [r0], #4
	138	str r3, [r0], #4
	139	str r3, [r0], #4
	140	str r3, [r0], #4
	141	#endif
	142	1: mov r0, r0
	143	b 1b
93ed3970	144	ENDPROC(__error)
75d90832 HC	145
	146
	147	/*
	148	* Read processor ID register (CP#15, CR0), and look up in the linker-built
	149	* supported processor list. Note that we can't use the absolute addresses
	150	* for the __proc_info lists since we aren't running with the MMU on
	151	* (and therefore, we are not in the correct address space). We have to
	152	* calculate the offset.
	153	*
	154	* r9 = cpuid
	155	* Returns:
	156	* r3, r4, r6 corrupted
	157	* r5 = proc_info pointer in physical address space
	158	* r9 = cpuid (preserved)
	159	*/
75d90832 HC	160	__lookup_processor_type:
75d90832 HC	161	adr r3, 3f
b86040a5 CM	162	ldmia r3, {r5 - r7}
b86040a5 CM	163	add r3, r3, #8
75d90832 HC	164	sub r3, r3, r7 @ get offset between virt&phys
	165	add r5, r5, r3 @ convert virt addresses to
	166	add r6, r6, r3 @ physical address space
	167	1: ldmia r5, {r3, r4} @ value, mask
	168	and r4, r4, r9 @ mask wanted bits
	169	teq r3, r4
	170	beq 2f
	171	add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list)
	172	cmp r5, r6
	173	blo 1b
	174	mov r5, #0 @ unknown processor
	175	2: mov pc, lr
93ed3970	176	ENDPROC(__lookup_processor_type)
75d90832 HC	177
	178	/*
	179	* This provides a C-API version of the above function.
	180	*/
	181	ENTRY(lookup_processor_type)
	182	stmfd sp!, {r4 - r7, r9, lr}
	183	mov r9, r0
	184	bl __lookup_processor_type
	185	mov r0, r5
	186	ldmfd sp!, {r4 - r7, r9, pc}
93ed3970	187	ENDPROC(lookup_processor_type)
75d90832 HC	188
75d90832 HC	189	/*
4baa9922	190	* Look in <asm/procinfo.h> and arch/arm/kernel/arch.[ch] for
75d90832 HC	191	* more information about the __proc_info and __arch_info structures.
75d90832 HC	192	*/
88987ef9	193	.align 2
b86040a5	194	3: .long __proc_info_begin
75d90832	195	.long __proc_info_end
b86040a5	196	4: .long .
75d90832 HC	197	.long __arch_info_begin
	198	.long __arch_info_end
	199
	200	/*
	201	* Lookup machine architecture in the linker-build list of architectures.
	202	* Note that we can't use the absolute addresses for the __arch_info
	203	* lists since we aren't running with the MMU on (and therefore, we are
	204	* not in the correct address space). We have to calculate the offset.
	205	*
	206	* r1 = machine architecture number
	207	* Returns:
	208	* r3, r4, r6 corrupted
	209	* r5 = mach_info pointer in physical address space
	210	*/
75d90832	211	__lookup_machine_type:
b86040a5	212	adr r3, 4b
75d90832 HC	213	ldmia r3, {r4, r5, r6}
	214	sub r3, r3, r4 @ get offset between virt&phys
	215	add r5, r5, r3 @ convert virt addresses to
	216	add r6, r6, r3 @ physical address space
	217	1: ldr r3, [r5, #MACHINFO_TYPE] @ get machine type
	218	teq r3, r1 @ matches loader number?
	219	beq 2f @ found
	220	add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc
	221	cmp r5, r6
	222	blo 1b
	223	mov r5, #0 @ unknown machine
	224	2: mov pc, lr
93ed3970	225	ENDPROC(__lookup_machine_type)
75d90832 HC	226
	227	/*
	228	* This provides a C-API version of the above function.
	229	*/
	230	ENTRY(lookup_machine_type)
	231	stmfd sp!, {r4 - r6, lr}
	232	mov r1, r0
	233	bl __lookup_machine_type
	234	mov r0, r5
	235	ldmfd sp!, {r4 - r6, pc}
93ed3970	236	ENDPROC(lookup_machine_type)
9d20fdd5 BG	237
	238	/* Determine validity of the r2 atags pointer. The heuristic requires
	239	* that the pointer be aligned, in the first 16k of physical RAM and
	240	* that the ATAG_CORE marker is first and present. Future revisions
	241	* of this function may be more lenient with the physical address and
	242	* may also be able to move the ATAGS block if necessary.
	243	*
	244	* r8 = machinfo
	245	*
	246	* Returns:
	247	* r2 either valid atags pointer, or zero
	248	* r5, r6 corrupted
	249	*/
9d20fdd5 BG	250	__vet_atags:
	251	tst r2, #0x3 @ aligned?
	252	bne 1f
	253
	254	ldr r5, [r2, #0] @ is first tag ATAG_CORE?
31abdb74 DB	255	cmp r5, #ATAG_CORE_SIZE
31abdb74 DB	256	cmpne r5, #ATAG_CORE_SIZE_EMPTY
9d20fdd5 BG	257	bne 1f
	258	ldr r5, [r2, #4]
	259	ldr r6, =ATAG_CORE
	260	cmp r5, r6
	261	bne 1f
	262
	263	mov pc, lr @ atag pointer is ok
	264
	265	1: mov r2, #0
	266	mov pc, lr
93ed3970	267	ENDPROC(__vet_atags)