blob: 21e17dc94cb56757f6f25f05b61ba4c2d6e095ca [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/kernel/head.S
3 *
4 * Copyright (C) 1994-2002 Russell King
Russell Kinge65f38e2005-06-18 09:33:31 +01005 * Copyright (c) 2003 ARM Limited
6 * All Rights Reserved
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
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 * Kernel startup code for all 32-bit CPUs
13 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/linkage.h>
15#include <linux/init.h>
16
17#include <asm/assembler.h>
18#include <asm/domain.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <asm/ptrace.h>
Sam Ravnborge6ae7442005-09-09 21:08:59 +020020#include <asm/asm-offsets.h>
Nicolas Pitref09b9972005-10-29 21:44:55 +010021#include <asm/memory.h>
Russell King4f7a1812005-05-05 13:11:00 +010022#include <asm/thread_info.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <asm/system.h>
24
Linus Walleijd4e1c882007-01-21 20:08:33 +010025#if (PHYS_OFFSET & 0x001fffff)
26#error "PHYS_OFFSET must be at an even 2MiB boundary!"
27#endif
28
Russell Kingf06b97f2006-12-11 22:29:16 +000029#define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)
30#define KERNEL_RAM_PADDR (PHYS_OFFSET + TEXT_OFFSET)
Russell King9d4f13e2006-01-03 17:28:33 +000031
Bill Gatliff9d20fdd2007-05-31 22:02:22 +010032
Linus Torvalds1da177e2005-04-16 15:20:36 -070033/*
Nicolas Pitre37d07b72005-10-29 21:44:56 +010034 * swapper_pg_dir is the virtual address of the initial page table.
Russell Kingf06b97f2006-12-11 22:29:16 +000035 * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
36 * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect
Nicolas Pitre37d07b72005-10-29 21:44:56 +010037 * the least significant 16 bits to be 0x8000, but we could probably
Russell Kingf06b97f2006-12-11 22:29:16 +000038 * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 */
Russell Kingf06b97f2006-12-11 22:29:16 +000040#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
41#error KERNEL_RAM_VADDR must start at 0xXXXX8000
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#endif
43
44 .globl swapper_pg_dir
Russell Kingf06b97f2006-12-11 22:29:16 +000045 .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Nicolas Pitre37d07b72005-10-29 21:44:56 +010047 .macro pgtbl, rd
Russell Kingf06b97f2006-12-11 22:29:16 +000048 ldr \rd, =(KERNEL_RAM_PADDR - 0x4000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 .endm
Nicolas Pitre37d07b72005-10-29 21:44:56 +010050
51#ifdef CONFIG_XIP_KERNEL
Nicolas Pitree98ff7f2007-02-22 16:18:09 +010052#define KERNEL_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
53#define KERNEL_END _edata_loc
Linus Torvalds1da177e2005-04-16 15:20:36 -070054#else
Nicolas Pitree98ff7f2007-02-22 16:18:09 +010055#define KERNEL_START KERNEL_RAM_VADDR
56#define KERNEL_END _end
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#endif
58
59/*
60 * Kernel startup entry point.
61 * ---------------------------
62 *
63 * This is normally called from the decompressor code. The requirements
64 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
Bill Gatliff9d20fdd2007-05-31 22:02:22 +010065 * r1 = machine nr, r2 = atags pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 *
67 * This code is mostly position independent, so if you link the kernel at
68 * 0xc0008000, you call this at __pa(0xc0008000).
69 *
70 * See linux/arch/arm/tools/mach-types for the complete list of machine
71 * numbers for r1.
72 *
73 * We're trying to keep crap to a minimum; DO NOT add any machine specific
74 * crap here - that's what the boot loader (or in extreme, well justified
75 * circumstances, zImage) is for.
76 */
Russell King08fdffd2007-05-08 15:15:45 +010077 .section ".text.head", "ax"
Linus Torvalds1da177e2005-04-16 15:20:36 -070078ENTRY(stext)
Russell King801194e2006-06-25 12:01:48 +010079 msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | SVC_MODE @ ensure svc mode
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 @ and irqs disabled
Russell King0f44ba12006-02-24 21:04:56 +000081 mrc p15, 0, r9, c0, c0 @ get processor id
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 bl __lookup_processor_type @ r5=procinfo r9=cpuid
83 movs r10, r5 @ invalid processor (r5=0)?
Russell King3c0bdac2005-11-25 15:43:22 +000084 beq __error_p @ yes, error 'p'
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 bl __lookup_machine_type @ r5=machinfo
86 movs r8, r5 @ invalid machine (r5=0)?
87 beq __error_a @ yes, error 'a'
Bill Gatliff9d20fdd2007-05-31 22:02:22 +010088 bl __vet_atags
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 bl __create_page_tables
90
91 /*
92 * The following calls CPU specific code in a position independent
93 * manner. See arch/arm/mm/proc-*.S for details. r10 = base of
94 * xxx_proc_info structure selected by __lookup_machine_type
95 * above. On return, the CPU will be ready for the MMU to be
96 * turned on, and r0 will hold the CPU control register value.
97 */
98 ldr r13, __switch_data @ address to jump to after
99 @ mmu has been enabled
100 adr lr, __enable_mmu @ return (PIC) address
101 add pc, r10, #PROCINFO_INITFUNC
Catalin Marinas93ed3972008-08-28 11:22:32 +0100102ENDPROC(stext)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Russell Kinge65f38e2005-06-18 09:33:31 +0100104#if defined(CONFIG_SMP)
Russell Kinge65f38e2005-06-18 09:33:31 +0100105ENTRY(secondary_startup)
106 /*
107 * Common entry point for secondary CPUs.
108 *
109 * Ensure that we're in SVC mode, and IRQs are disabled. Lookup
110 * the processor type - there is no need to check the machine type
111 * as it has already been validated by the primary processor.
112 */
Russell King801194e2006-06-25 12:01:48 +0100113 msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | SVC_MODE
Russell King0f44ba12006-02-24 21:04:56 +0000114 mrc p15, 0, r9, c0, c0 @ get processor id
Russell Kinge65f38e2005-06-18 09:33:31 +0100115 bl __lookup_processor_type
116 movs r10, r5 @ invalid processor?
117 moveq r0, #'p' @ yes, error 'p'
118 beq __error
119
120 /*
121 * Use the page tables supplied from __cpu_up.
122 */
123 adr r4, __secondary_data
Russell King34d92622006-07-26 18:57:40 +0100124 ldmia r4, {r5, r7, r13} @ address to jump to after
Russell Kinge65f38e2005-06-18 09:33:31 +0100125 sub r4, r4, r5 @ mmu has been enabled
Russell King34d92622006-07-26 18:57:40 +0100126 ldr r4, [r7, r4] @ get secondary_data.pgdir
Russell Kinge65f38e2005-06-18 09:33:31 +0100127 adr lr, __enable_mmu @ return address
Catalin Marinas90af7742006-08-18 15:34:46 +0100128 add pc, r10, #PROCINFO_INITFUNC @ initialise processor
Russell Kinge65f38e2005-06-18 09:33:31 +0100129 @ (return control reg)
Catalin Marinas93ed3972008-08-28 11:22:32 +0100130ENDPROC(secondary_startup)
Russell Kinge65f38e2005-06-18 09:33:31 +0100131
132 /*
133 * r6 = &secondary_data
134 */
135ENTRY(__secondary_switched)
Russell King34d92622006-07-26 18:57:40 +0100136 ldr sp, [r7, #4] @ get secondary_data.stack
Russell Kinge65f38e2005-06-18 09:33:31 +0100137 mov fp, #0
138 b secondary_start_kernel
Catalin Marinas93ed3972008-08-28 11:22:32 +0100139ENDPROC(__secondary_switched)
Russell Kinge65f38e2005-06-18 09:33:31 +0100140
141 .type __secondary_data, %object
142__secondary_data:
143 .long .
144 .long secondary_data
145 .long __secondary_switched
146#endif /* defined(CONFIG_SMP) */
147
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149
150/*
151 * Setup common bits before finally enabling the MMU. Essentially
152 * this is just loading the page table pointer and domain access
153 * registers.
154 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155__enable_mmu:
156#ifdef CONFIG_ALIGNMENT_TRAP
157 orr r0, r0, #CR_A
158#else
159 bic r0, r0, #CR_A
160#endif
161#ifdef CONFIG_CPU_DCACHE_DISABLE
162 bic r0, r0, #CR_C
163#endif
164#ifdef CONFIG_CPU_BPREDICT_DISABLE
165 bic r0, r0, #CR_Z
166#endif
167#ifdef CONFIG_CPU_ICACHE_DISABLE
168 bic r0, r0, #CR_I
169#endif
170 mov r5, #(domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \
171 domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
172 domain_val(DOMAIN_TABLE, DOMAIN_MANAGER) | \
173 domain_val(DOMAIN_IO, DOMAIN_CLIENT))
174 mcr p15, 0, r5, c3, c0, 0 @ load domain access register
175 mcr p15, 0, r4, c2, c0, 0 @ load page table pointer
176 b __turn_mmu_on
Catalin Marinas93ed3972008-08-28 11:22:32 +0100177ENDPROC(__enable_mmu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179/*
180 * Enable the MMU. This completely changes the structure of the visible
181 * memory space. You will not be able to trace execution through this.
182 * If you have an enquiry about this, *please* check the linux-arm-kernel
183 * mailing list archives BEFORE sending another post to the list.
184 *
185 * r0 = cp#15 control register
186 * r13 = *virtual* address to jump to upon completion
187 *
188 * other registers depend on the function called upon completion
189 */
190 .align 5
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191__turn_mmu_on:
192 mov r0, r0
193 mcr p15, 0, r0, c1, c0, 0 @ write control reg
194 mrc p15, 0, r3, c0, c0, 0 @ read id reg
195 mov r3, r3
196 mov r3, r3
197 mov pc, r13
Catalin Marinas93ed3972008-08-28 11:22:32 +0100198ENDPROC(__turn_mmu_on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
200
201/*
202 * Setup the initial page tables. We only setup the barest
203 * amount which are required to get the kernel running, which
204 * generally means mapping in the kernel code.
205 *
206 * r8 = machinfo
207 * r9 = cpuid
208 * r10 = procinfo
209 *
210 * Returns:
Nicolas Pitre2df96b32006-01-13 20:51:46 +0000211 * r0, r3, r6, r7 corrupted
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 * r4 = physical page table address
213 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214__create_page_tables:
Nicolas Pitre37d07b72005-10-29 21:44:56 +0100215 pgtbl r4 @ page table address
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
217 /*
218 * Clear the 16K level 1 swapper page table
219 */
220 mov r0, r4
221 mov r3, #0
222 add r6, r0, #0x4000
2231: str r3, [r0], #4
224 str r3, [r0], #4
225 str r3, [r0], #4
226 str r3, [r0], #4
227 teq r0, r6
228 bne 1b
229
Russell King8799ee92006-06-29 18:24:21 +0100230 ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
232 /*
233 * Create identity mapping for first MB of kernel to
234 * cater for the MMU enable. This identity mapping
235 * will be removed by paging_init(). We use our current program
236 * counter to determine corresponding section base address.
237 */
238 mov r6, pc, lsr #20 @ start of kernel section
239 orr r3, r7, r6, lsl #20 @ flags + kernel base
240 str r3, [r4, r6, lsl #2] @ identity mapping
241
242 /*
243 * Now setup the pagetables for our kernel direct
Lennert Buytenhek2552fc22006-09-29 21:14:05 +0100244 * mapped region.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 */
Nicolas Pitree98ff7f2007-02-22 16:18:09 +0100246 add r0, r4, #(KERNEL_START & 0xff000000) >> 18
247 str r3, [r0, #(KERNEL_START & 0x00f00000) >> 18]!
248 ldr r6, =(KERNEL_END - 1)
249 add r0, r0, #4
250 add r6, r4, r6, lsr #18
2511: cmp r0, r6
252 add r3, r3, #1 << 20
253 strls r3, [r0], #4
254 bls 1b
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
Nicolas Pitreec3622d2007-02-21 15:32:28 +0100256#ifdef CONFIG_XIP_KERNEL
257 /*
258 * Map some ram to cover our .data and .bss areas.
259 */
260 orr r3, r7, #(KERNEL_RAM_PADDR & 0xff000000)
Nicolas Pitre40435792007-02-21 15:58:13 +0100261 .if (KERNEL_RAM_PADDR & 0x00f00000)
Nicolas Pitreec3622d2007-02-21 15:32:28 +0100262 orr r3, r3, #(KERNEL_RAM_PADDR & 0x00f00000)
Nicolas Pitre40435792007-02-21 15:58:13 +0100263 .endif
Nicolas Pitreec3622d2007-02-21 15:32:28 +0100264 add r0, r4, #(KERNEL_RAM_VADDR & 0xff000000) >> 18
265 str r3, [r0, #(KERNEL_RAM_VADDR & 0x00f00000) >> 18]!
266 ldr r6, =(_end - 1)
267 add r0, r0, #4
268 add r6, r4, r6, lsr #18
2691: cmp r0, r6
270 add r3, r3, #1 << 20
271 strls r3, [r0], #4
272 bls 1b
273#endif
274
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 /*
276 * Then map first 1MB of ram in case it contains our boot params.
277 */
Nicolas Pitref09b9972005-10-29 21:44:55 +0100278 add r0, r4, #PAGE_OFFSET >> 18
Linus Walleijd4e1c882007-01-21 20:08:33 +0100279 orr r6, r7, #(PHYS_OFFSET & 0xff000000)
Nicolas Pitre40435792007-02-21 15:58:13 +0100280 .if (PHYS_OFFSET & 0x00f00000)
281 orr r6, r6, #(PHYS_OFFSET & 0x00f00000)
282 .endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 str r6, [r0]
284
Russell Kingc77b0422005-07-01 11:56:55 +0100285#ifdef CONFIG_DEBUG_LL
Russell King8799ee92006-06-29 18:24:21 +0100286 ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 /*
288 * Map in IO space for serial debugging.
289 * This allows debug messages to be output
290 * via a serial console before paging_init.
291 */
292 ldr r3, [r8, #MACHINFO_PGOFFIO]
293 add r0, r4, r3
294 rsb r3, r3, #0x4000 @ PTRS_PER_PGD*sizeof(long)
295 cmp r3, #0x0800 @ limit to 512MB
296 movhi r3, #0x0800
297 add r6, r0, r3
298 ldr r3, [r8, #MACHINFO_PHYSIO]
299 orr r3, r3, r7
3001: str r3, [r0], #4
301 add r3, r3, #1 << 20
302 teq r0, r6
303 bne 1b
304#if defined(CONFIG_ARCH_NETWINDER) || defined(CONFIG_ARCH_CATS)
305 /*
Russell King3c0bdac2005-11-25 15:43:22 +0000306 * If we're using the NetWinder or CATS, we also need to map
307 * in the 16550-type serial port for the debug messages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 */
Russell Kingc77b0422005-07-01 11:56:55 +0100309 add r0, r4, #0xff000000 >> 18
310 orr r3, r7, #0x7c000000
311 str r3, [r0]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313#ifdef CONFIG_ARCH_RPC
314 /*
315 * Map in screen at 0x02000000 & SCREEN2_BASE
316 * Similar reasons here - for debug. This is
317 * only for Acorn RiscPC architectures.
318 */
Russell Kingc77b0422005-07-01 11:56:55 +0100319 add r0, r4, #0x02000000 >> 18
320 orr r3, r7, #0x02000000
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 str r3, [r0]
Russell Kingc77b0422005-07-01 11:56:55 +0100322 add r0, r4, #0xd8000000 >> 18
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 str r3, [r0]
324#endif
Russell Kingc77b0422005-07-01 11:56:55 +0100325#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +0100327ENDPROC(__create_page_tables)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 .ltorg
329
Hyok S. Choi75d90832006-03-27 14:58:25 +0100330#include "head-common.S"