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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/kernel/head.S
4 *
5 * Copyright (C) 1994-2002 Russell King
6 * Copyright (c) 2003 ARM Limited
7 * All Rights Reserved
8 *
9 * Kernel startup code for all 32-bit CPUs
10 */
11#include <linux/linkage.h>
12#include <linux/init.h>
13#include <linux/pgtable.h>
14
15#include <asm/assembler.h>
16#include <asm/cp15.h>
17#include <asm/domain.h>
18#include <asm/ptrace.h>
19#include <asm/asm-offsets.h>
20#include <asm/memory.h>
21#include <asm/thread_info.h>
22
23#if defined(CONFIG_DEBUG_LL) && !defined(CONFIG_DEBUG_SEMIHOSTING)
24#include CONFIG_DEBUG_LL_INCLUDE
25#endif
26
27/*
28 * swapper_pg_dir is the virtual address of the initial page table.
29 * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
30 * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect
31 * the least significant 16 bits to be 0x8000, but we could probably
32 * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
33 */
34#define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)
35#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
36#error KERNEL_RAM_VADDR must start at 0xXXXX8000
37#endif
38
39#ifdef CONFIG_ARM_LPAE
40 /* LPAE requires an additional page for the PGD */
41#define PG_DIR_SIZE 0x5000
42#define PMD_ORDER 3
43#else
44#define PG_DIR_SIZE 0x4000
45#define PMD_ORDER 2
46#endif
47
48 .globl swapper_pg_dir
49 .equ swapper_pg_dir, KERNEL_RAM_VADDR - PG_DIR_SIZE
50
51 .macro pgtbl, rd, phys
52 add \rd, \phys, #TEXT_OFFSET
53 sub \rd, \rd, #PG_DIR_SIZE
54 .endm
55
56/*
57 * Kernel startup entry point.
58 * ---------------------------
59 *
60 * This is normally called from the decompressor code. The requirements
61 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
62 * r1 = machine nr, r2 = atags or dtb pointer.
63 *
64 * This code is mostly position independent, so if you link the kernel at
65 * 0xc0008000, you call this at __pa(0xc0008000).
66 *
67 * See linux/arch/arm/tools/mach-types for the complete list of machine
68 * numbers for r1.
69 *
70 * We're trying to keep crap to a minimum; DO NOT add any machine specific
71 * crap here - that's what the boot loader (or in extreme, well justified
72 * circumstances, zImage) is for.
73 */
74 .arm
75
76 __HEAD
77ENTRY(stext)
78 ARM_BE8(setend be ) @ ensure we are in BE8 mode
79
80 THUMB( badr r9, 1f ) @ Kernel is always entered in ARM.
81 THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
82 THUMB( .thumb ) @ switch to Thumb now.
83 THUMB(1: )
84
85#ifdef CONFIG_ARM_VIRT_EXT
86 bl __hyp_stub_install
87#endif
88 @ ensure svc mode and all interrupts masked
89 safe_svcmode_maskall r9
90
91 mrc p15, 0, r9, c0, c0 @ get processor id
92 bl __lookup_processor_type @ r5=procinfo r9=cpuid
93 movs r10, r5 @ invalid processor (r5=0)?
94 THUMB( it eq ) @ force fixup-able long branch encoding
95 beq __error_p @ yes, error 'p'
96
97#ifdef CONFIG_ARM_LPAE
98 mrc p15, 0, r3, c0, c1, 4 @ read ID_MMFR0
99 and r3, r3, #0xf @ extract VMSA support
100 cmp r3, #5 @ long-descriptor translation table format?
101 THUMB( it lo ) @ force fixup-able long branch encoding
102 blo __error_lpae @ only classic page table format
103#endif
104
105#ifndef CONFIG_XIP_KERNEL
106 adr r3, 2f
107 ldmia r3, {r4, r8}
108 sub r4, r3, r4 @ (PHYS_OFFSET - PAGE_OFFSET)
109 add r8, r8, r4 @ PHYS_OFFSET
110#else
111 ldr r8, =PLAT_PHYS_OFFSET @ always constant in this case
112#endif
113
114 /*
115 * r1 = machine no, r2 = atags or dtb,
116 * r8 = phys_offset, r9 = cpuid, r10 = procinfo
117 */
118 bl __vet_atags
119#ifdef CONFIG_SMP_ON_UP
120 bl __fixup_smp
121#endif
122#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
123 bl __fixup_pv_table
124#endif
125 bl __create_page_tables
126
127 /*
128 * The following calls CPU specific code in a position independent
129 * manner. See arch/arm/mm/proc-*.S for details. r10 = base of
130 * xxx_proc_info structure selected by __lookup_processor_type
131 * above.
132 *
133 * The processor init function will be called with:
134 * r1 - machine type
135 * r2 - boot data (atags/dt) pointer
136 * r4 - translation table base (low word)
137 * r5 - translation table base (high word, if LPAE)
138 * r8 - translation table base 1 (pfn if LPAE)
139 * r9 - cpuid
140 * r13 - virtual address for __enable_mmu -> __turn_mmu_on
141 *
142 * On return, the CPU will be ready for the MMU to be turned on,
143 * r0 will hold the CPU control register value, r1, r2, r4, and
144 * r9 will be preserved. r5 will also be preserved if LPAE.
145 */
146 ldr r13, =__mmap_switched @ address to jump to after
147 @ mmu has been enabled
148 badr lr, 1f @ return (PIC) address
149#ifdef CONFIG_ARM_LPAE
150 mov r5, #0 @ high TTBR0
151 mov r8, r4, lsr #12 @ TTBR1 is swapper_pg_dir pfn
152#else
153 mov r8, r4 @ set TTBR1 to swapper_pg_dir
154#endif
155 ldr r12, [r10, #PROCINFO_INITFUNC]
156 add r12, r12, r10
157 ret r12
1581: b __enable_mmu
159ENDPROC(stext)
160 .ltorg
161#ifndef CONFIG_XIP_KERNEL
1622: .long .
163 .long PAGE_OFFSET
164#endif
165
166/*
167 * Setup the initial page tables. We only setup the barest
168 * amount which are required to get the kernel running, which
169 * generally means mapping in the kernel code.
170 *
171 * r8 = phys_offset, r9 = cpuid, r10 = procinfo
172 *
173 * Returns:
174 * r0, r3, r5-r7 corrupted
175 * r4 = physical page table address
176 */
177__create_page_tables:
178 pgtbl r4, r8 @ page table address
179
180 /*
181 * Clear the swapper page table
182 */
183 mov r0, r4
184 mov r3, #0
185 add r6, r0, #PG_DIR_SIZE
1861: str r3, [r0], #4
187 str r3, [r0], #4
188 str r3, [r0], #4
189 str r3, [r0], #4
190 teq r0, r6
191 bne 1b
192
193#ifdef CONFIG_ARM_LPAE
194 /*
195 * Build the PGD table (first level) to point to the PMD table. A PGD
196 * entry is 64-bit wide.
197 */
198 mov r0, r4
199 add r3, r4, #0x1000 @ first PMD table address
200 orr r3, r3, #3 @ PGD block type
201 mov r6, #4 @ PTRS_PER_PGD
202 mov r7, #1 << (55 - 32) @ L_PGD_SWAPPER
2031:
204#ifdef CONFIG_CPU_ENDIAN_BE8
205 str r7, [r0], #4 @ set top PGD entry bits
206 str r3, [r0], #4 @ set bottom PGD entry bits
207#else
208 str r3, [r0], #4 @ set bottom PGD entry bits
209 str r7, [r0], #4 @ set top PGD entry bits
210#endif
211 add r3, r3, #0x1000 @ next PMD table
212 subs r6, r6, #1
213 bne 1b
214
215 add r4, r4, #0x1000 @ point to the PMD tables
216#ifdef CONFIG_CPU_ENDIAN_BE8
217 add r4, r4, #4 @ we only write the bottom word
218#endif
219#endif
220
221 ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
222
223 /*
224 * Create identity mapping to cater for __enable_mmu.
225 * This identity mapping will be removed by paging_init().
226 */
227 adr r0, __turn_mmu_on_loc
228 ldmia r0, {r3, r5, r6}
229 sub r0, r0, r3 @ virt->phys offset
230 add r5, r5, r0 @ phys __turn_mmu_on
231 add r6, r6, r0 @ phys __turn_mmu_on_end
232 mov r5, r5, lsr #SECTION_SHIFT
233 mov r6, r6, lsr #SECTION_SHIFT
234
2351: orr r3, r7, r5, lsl #SECTION_SHIFT @ flags + kernel base
236 str r3, [r4, r5, lsl #PMD_ORDER] @ identity mapping
237 cmp r5, r6
238 addlo r5, r5, #1 @ next section
239 blo 1b
240
241 /*
242 * Map our RAM from the start to the end of the kernel .bss section.
243 */
244 add r0, r4, #PAGE_OFFSET >> (SECTION_SHIFT - PMD_ORDER)
245 ldr r6, =(_end - 1)
246 orr r3, r8, r7
247 add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
2481: str r3, [r0], #1 << PMD_ORDER
249 add r3, r3, #1 << SECTION_SHIFT
250 cmp r0, r6
251 bls 1b
252
253#ifdef CONFIG_XIP_KERNEL
254 /*
255 * Map the kernel image separately as it is not located in RAM.
256 */
257#define XIP_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
258 mov r3, pc
259 mov r3, r3, lsr #SECTION_SHIFT
260 orr r3, r7, r3, lsl #SECTION_SHIFT
261 add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER)
262 str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]!
263 ldr r6, =(_edata_loc - 1)
264 add r0, r0, #1 << PMD_ORDER
265 add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER)
2661: cmp r0, r6
267 add r3, r3, #1 << SECTION_SHIFT
268 strls r3, [r0], #1 << PMD_ORDER
269 bls 1b
270#endif
271
272 /*
273 * Then map boot params address in r2 if specified.
274 * We map 2 sections in case the ATAGs/DTB crosses a section boundary.
275 */
276 mov r0, r2, lsr #SECTION_SHIFT
277 movs r0, r0, lsl #SECTION_SHIFT
278 subne r3, r0, r8
279 addne r3, r3, #PAGE_OFFSET
280 addne r3, r4, r3, lsr #(SECTION_SHIFT - PMD_ORDER)
281 orrne r6, r7, r0
282 strne r6, [r3], #1 << PMD_ORDER
283 addne r6, r6, #1 << SECTION_SHIFT
284 strne r6, [r3]
285
286#if defined(CONFIG_ARM_LPAE) && defined(CONFIG_CPU_ENDIAN_BE8)
287 sub r4, r4, #4 @ Fixup page table pointer
288 @ for 64-bit descriptors
289#endif
290
291#ifdef CONFIG_DEBUG_LL
292#if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)
293 /*
294 * Map in IO space for serial debugging.
295 * This allows debug messages to be output
296 * via a serial console before paging_init.
297 */
298 addruart r7, r3, r0
299
300 mov r3, r3, lsr #SECTION_SHIFT
301 mov r3, r3, lsl #PMD_ORDER
302
303 add r0, r4, r3
304 mov r3, r7, lsr #SECTION_SHIFT
305 ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
306 orr r3, r7, r3, lsl #SECTION_SHIFT
307#ifdef CONFIG_ARM_LPAE
308 mov r7, #1 << (54 - 32) @ XN
309#ifdef CONFIG_CPU_ENDIAN_BE8
310 str r7, [r0], #4
311 str r3, [r0], #4
312#else
313 str r3, [r0], #4
314 str r7, [r0], #4
315#endif
316#else
317 orr r3, r3, #PMD_SECT_XN
318 str r3, [r0], #4
319#endif
320
321#else /* CONFIG_DEBUG_ICEDCC || CONFIG_DEBUG_SEMIHOSTING */
322 /* we don't need any serial debugging mappings */
323 ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
324#endif
325
326#if defined(CONFIG_ARCH_NETWINDER) || defined(CONFIG_ARCH_CATS)
327 /*
328 * If we're using the NetWinder or CATS, we also need to map
329 * in the 16550-type serial port for the debug messages
330 */
331 add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ORDER)
332 orr r3, r7, #0x7c000000
333 str r3, [r0]
334#endif
335#ifdef CONFIG_ARCH_RPC
336 /*
337 * Map in screen at 0x02000000 & SCREEN2_BASE
338 * Similar reasons here - for debug. This is
339 * only for Acorn RiscPC architectures.
340 */
341 add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ORDER)
342 orr r3, r7, #0x02000000
343 str r3, [r0]
344 add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ORDER)
345 str r3, [r0]
346#endif
347#endif
348#ifdef CONFIG_ARM_LPAE
349 sub r4, r4, #0x1000 @ point to the PGD table
350#endif
351 ret lr
352ENDPROC(__create_page_tables)
353 .ltorg
354 .align
355__turn_mmu_on_loc:
356 .long .
357 .long __turn_mmu_on
358 .long __turn_mmu_on_end
359
360#if defined(CONFIG_SMP)
361 .text
362 .arm
363ENTRY(secondary_startup_arm)
364 THUMB( badr r9, 1f ) @ Kernel is entered in ARM.
365 THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
366 THUMB( .thumb ) @ switch to Thumb now.
367 THUMB(1: )
368ENTRY(secondary_startup)
369 /*
370 * Common entry point for secondary CPUs.
371 *
372 * Ensure that we're in SVC mode, and IRQs are disabled. Lookup
373 * the processor type - there is no need to check the machine type
374 * as it has already been validated by the primary processor.
375 */
376
377 ARM_BE8(setend be) @ ensure we are in BE8 mode
378
379#ifdef CONFIG_ARM_VIRT_EXT
380 bl __hyp_stub_install_secondary
381#endif
382 safe_svcmode_maskall r9
383
384 mrc p15, 0, r9, c0, c0 @ get processor id
385 bl __lookup_processor_type
386 movs r10, r5 @ invalid processor?
387 moveq r0, #'p' @ yes, error 'p'
388 THUMB( it eq ) @ force fixup-able long branch encoding
389 beq __error_p
390
391 /*
392 * Use the page tables supplied from __cpu_up.
393 */
394 adr r4, __secondary_data
395 ldmia r4, {r5, r7, r12} @ address to jump to after
396 sub lr, r4, r5 @ mmu has been enabled
397 add r3, r7, lr
398 ldrd r4, r5, [r3, #0] @ get secondary_data.pgdir
399ARM_BE8(eor r4, r4, r5) @ Swap r5 and r4 in BE:
400ARM_BE8(eor r5, r4, r5) @ it can be done in 3 steps
401ARM_BE8(eor r4, r4, r5) @ without using a temp reg.
402 ldr r8, [r3, #8] @ get secondary_data.swapper_pg_dir
403 badr lr, __enable_mmu @ return address
404 mov r13, r12 @ __secondary_switched address
405 ldr r12, [r10, #PROCINFO_INITFUNC]
406 add r12, r12, r10 @ initialise processor
407 @ (return control reg)
408 ret r12
409ENDPROC(secondary_startup)
410ENDPROC(secondary_startup_arm)
411
412 /*
413 * r6 = &secondary_data
414 */
415ENTRY(__secondary_switched)
416 ldr sp, [r7, #12] @ get secondary_data.stack
417 mov fp, #0
418 b secondary_start_kernel
419ENDPROC(__secondary_switched)
420
421 .align
422
423 .type __secondary_data, %object
424__secondary_data:
425 .long .
426 .long secondary_data
427 .long __secondary_switched
428#endif /* defined(CONFIG_SMP) */
429
430
431
432/*
433 * Setup common bits before finally enabling the MMU. Essentially
434 * this is just loading the page table pointer and domain access
435 * registers. All these registers need to be preserved by the
436 * processor setup function (or set in the case of r0)
437 *
438 * r0 = cp#15 control register
439 * r1 = machine ID
440 * r2 = atags or dtb pointer
441 * r4 = TTBR pointer (low word)
442 * r5 = TTBR pointer (high word if LPAE)
443 * r9 = processor ID
444 * r13 = *virtual* address to jump to upon completion
445 */
446__enable_mmu:
447#if defined(CONFIG_ALIGNMENT_TRAP) && __LINUX_ARM_ARCH__ < 6
448 orr r0, r0, #CR_A
449#else
450 bic r0, r0, #CR_A
451#endif
452#ifdef CONFIG_CPU_DCACHE_DISABLE
453 bic r0, r0, #CR_C
454#endif
455#ifdef CONFIG_CPU_BPREDICT_DISABLE
456 bic r0, r0, #CR_Z
457#endif
458#ifdef CONFIG_CPU_ICACHE_DISABLE
459 bic r0, r0, #CR_I
460#endif
461#ifdef CONFIG_ARM_LPAE
462 mcrr p15, 0, r4, r5, c2 @ load TTBR0
463#else
464 mov r5, #DACR_INIT
465 mcr p15, 0, r5, c3, c0, 0 @ load domain access register
466 mcr p15, 0, r4, c2, c0, 0 @ load page table pointer
467#endif
468 b __turn_mmu_on
469ENDPROC(__enable_mmu)
470
471/*
472 * Enable the MMU. This completely changes the structure of the visible
473 * memory space. You will not be able to trace execution through this.
474 * If you have an enquiry about this, *please* check the linux-arm-kernel
475 * mailing list archives BEFORE sending another post to the list.
476 *
477 * r0 = cp#15 control register
478 * r1 = machine ID
479 * r2 = atags or dtb pointer
480 * r9 = processor ID
481 * r13 = *virtual* address to jump to upon completion
482 *
483 * other registers depend on the function called upon completion
484 */
485 .align 5
486 .pushsection .idmap.text, "ax"
487ENTRY(__turn_mmu_on)
488 mov r0, r0
489 instr_sync
490 mcr p15, 0, r0, c1, c0, 0 @ write control reg
491 mrc p15, 0, r3, c0, c0, 0 @ read id reg
492 instr_sync
493 mov r3, r3
494 mov r3, r13
495 ret r3
496__turn_mmu_on_end:
497ENDPROC(__turn_mmu_on)
498 .popsection
499
500
501#ifdef CONFIG_SMP_ON_UP
502 __HEAD
503__fixup_smp:
504 and r3, r9, #0x000f0000 @ architecture version
505 teq r3, #0x000f0000 @ CPU ID supported?
506 bne __fixup_smp_on_up @ no, assume UP
507
508 bic r3, r9, #0x00ff0000
509 bic r3, r3, #0x0000000f @ mask 0xff00fff0
510 mov r4, #0x41000000
511 orr r4, r4, #0x0000b000
512 orr r4, r4, #0x00000020 @ val 0x4100b020
513 teq r3, r4 @ ARM 11MPCore?
514 reteq lr @ yes, assume SMP
515
516 mrc p15, 0, r0, c0, c0, 5 @ read MPIDR
517 and r0, r0, #0xc0000000 @ multiprocessing extensions and
518 teq r0, #0x80000000 @ not part of a uniprocessor system?
519 bne __fixup_smp_on_up @ no, assume UP
520
521 @ Core indicates it is SMP. Check for Aegis SOC where a single
522 @ Cortex-A9 CPU is present but SMP operations fault.
523 mov r4, #0x41000000
524 orr r4, r4, #0x0000c000
525 orr r4, r4, #0x00000090
526 teq r3, r4 @ Check for ARM Cortex-A9
527 retne lr @ Not ARM Cortex-A9,
528
529 @ If a future SoC *does* use 0x0 as the PERIPH_BASE, then the
530 @ below address check will need to be #ifdef'd or equivalent
531 @ for the Aegis platform.
532 mrc p15, 4, r0, c15, c0 @ get SCU base address
533 teq r0, #0x0 @ '0' on actual UP A9 hardware
534 beq __fixup_smp_on_up @ So its an A9 UP
535 ldr r0, [r0, #4] @ read SCU Config
536ARM_BE8(rev r0, r0) @ byteswap if big endian
537 and r0, r0, #0x3 @ number of CPUs
538 teq r0, #0x0 @ is 1?
539 retne lr
540
541__fixup_smp_on_up:
542 adr r0, 1f
543 ldmia r0, {r3 - r5}
544 sub r3, r0, r3
545 add r4, r4, r3
546 add r5, r5, r3
547 b __do_fixup_smp_on_up
548ENDPROC(__fixup_smp)
549
550 .align
5511: .word .
552 .word __smpalt_begin
553 .word __smpalt_end
554
555 .pushsection .data
556 .align 2
557 .globl smp_on_up
558smp_on_up:
559 ALT_SMP(.long 1)
560 ALT_UP(.long 0)
561 .popsection
562#endif
563
564 .text
565__do_fixup_smp_on_up:
566 cmp r4, r5
567 reths lr
568 ldmia r4!, {r0, r6}
569 ARM( str r6, [r0, r3] )
570 THUMB( add r0, r0, r3 )
571#ifdef __ARMEB__
572 THUMB( mov r6, r6, ror #16 ) @ Convert word order for big-endian.
573#endif
574 THUMB( strh r6, [r0], #2 ) @ For Thumb-2, store as two halfwords
575 THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r3.
576 THUMB( strh r6, [r0] )
577 b __do_fixup_smp_on_up
578ENDPROC(__do_fixup_smp_on_up)
579
580ENTRY(fixup_smp)
581 stmfd sp!, {r4 - r6, lr}
582 mov r4, r0
583 add r5, r0, r1
584 mov r3, #0
585 bl __do_fixup_smp_on_up
586 ldmfd sp!, {r4 - r6, pc}
587ENDPROC(fixup_smp)
588
589#ifdef __ARMEB__
590#define LOW_OFFSET 0x4
591#define HIGH_OFFSET 0x0
592#else
593#define LOW_OFFSET 0x0
594#define HIGH_OFFSET 0x4
595#endif
596
597#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
598
599/* __fixup_pv_table - patch the stub instructions with the delta between
600 * PHYS_OFFSET and PAGE_OFFSET, which is assumed to be 16MiB aligned and
601 * can be expressed by an immediate shifter operand. The stub instruction
602 * has a form of '(add|sub) rd, rn, #imm'.
603 */
604 __HEAD
605__fixup_pv_table:
606 adr r0, 1f
607 ldmia r0, {r3-r7}
608 mvn ip, #0
609 subs r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET
610 add r4, r4, r3 @ adjust table start address
611 add r5, r5, r3 @ adjust table end address
612 add r6, r6, r3 @ adjust __pv_phys_pfn_offset address
613 add r7, r7, r3 @ adjust __pv_offset address
614 mov r0, r8, lsr #PAGE_SHIFT @ convert to PFN
615 str r0, [r6] @ save computed PHYS_OFFSET to __pv_phys_pfn_offset
616 strcc ip, [r7, #HIGH_OFFSET] @ save to __pv_offset high bits
617 mov r6, r3, lsr #24 @ constant for add/sub instructions
618 teq r3, r6, lsl #24 @ must be 16MiB aligned
619THUMB( it ne @ cross section branch )
620 bne __error
621 str r3, [r7, #LOW_OFFSET] @ save to __pv_offset low bits
622 b __fixup_a_pv_table
623ENDPROC(__fixup_pv_table)
624
625 .align
6261: .long .
627 .long __pv_table_begin
628 .long __pv_table_end
6292: .long __pv_phys_pfn_offset
630 .long __pv_offset
631
632 .text
633__fixup_a_pv_table:
634 adr r0, 3f
635 ldr r6, [r0]
636 add r6, r6, r3
637 ldr r0, [r6, #HIGH_OFFSET] @ pv_offset high word
638 ldr r6, [r6, #LOW_OFFSET] @ pv_offset low word
639 mov r6, r6, lsr #24
640 cmn r0, #1
641#ifdef CONFIG_THUMB2_KERNEL
642 moveq r0, #0x200000 @ set bit 21, mov to mvn instruction
643 lsls r6, #24
644 beq 2f
645 clz r7, r6
646 lsr r6, #24
647 lsl r6, r7
648 bic r6, #0x0080
649 lsrs r7, #1
650 orrcs r6, #0x0080
651 orr r6, r6, r7, lsl #12
652 orr r6, #0x4000
653 b 2f
6541: add r7, r3
655 ldrh ip, [r7, #2]
656ARM_BE8(rev16 ip, ip)
657 tst ip, #0x4000
658 and ip, #0x8f00
659 orrne ip, r6 @ mask in offset bits 31-24
660 orreq ip, r0 @ mask in offset bits 7-0
661ARM_BE8(rev16 ip, ip)
662 strh ip, [r7, #2]
663 bne 2f
664 ldrh ip, [r7]
665ARM_BE8(rev16 ip, ip)
666 bic ip, #0x20
667 orr ip, ip, r0, lsr #16
668ARM_BE8(rev16 ip, ip)
669 strh ip, [r7]
6702: cmp r4, r5
671 ldrcc r7, [r4], #4 @ use branch for delay slot
672 bcc 1b
673 bx lr
674#else
675#ifdef CONFIG_CPU_ENDIAN_BE8
676 moveq r0, #0x00004000 @ set bit 22, mov to mvn instruction
677#else
678 moveq r0, #0x400000 @ set bit 22, mov to mvn instruction
679#endif
680 b 2f
6811: ldr ip, [r7, r3]
682#ifdef CONFIG_CPU_ENDIAN_BE8
683 @ in BE8, we load data in BE, but instructions still in LE
684 bic ip, ip, #0xff000000
685 tst ip, #0x000f0000 @ check the rotation field
686 orrne ip, ip, r6, lsl #24 @ mask in offset bits 31-24
687 biceq ip, ip, #0x00004000 @ clear bit 22
688 orreq ip, ip, r0 @ mask in offset bits 7-0
689#else
690 bic ip, ip, #0x000000ff
691 tst ip, #0xf00 @ check the rotation field
692 orrne ip, ip, r6 @ mask in offset bits 31-24
693 biceq ip, ip, #0x400000 @ clear bit 22
694 orreq ip, ip, r0 @ mask in offset bits 7-0
695#endif
696 str ip, [r7, r3]
6972: cmp r4, r5
698 ldrcc r7, [r4], #4 @ use branch for delay slot
699 bcc 1b
700 ret lr
701#endif
702ENDPROC(__fixup_a_pv_table)
703
704 .align
7053: .long __pv_offset
706
707ENTRY(fixup_pv_table)
708 stmfd sp!, {r4 - r7, lr}
709 mov r3, #0 @ no offset
710 mov r4, r0 @ r0 = table start
711 add r5, r0, r1 @ r1 = table size
712 bl __fixup_a_pv_table
713 ldmfd sp!, {r4 - r7, pc}
714ENDPROC(fixup_pv_table)
715
716 .data
717 .align 2
718 .globl __pv_phys_pfn_offset
719 .type __pv_phys_pfn_offset, %object
720__pv_phys_pfn_offset:
721 .word 0
722 .size __pv_phys_pfn_offset, . -__pv_phys_pfn_offset
723
724 .globl __pv_offset
725 .type __pv_offset, %object
726__pv_offset:
727 .quad 0
728 .size __pv_offset, . -__pv_offset
729#endif
730
731#include "head-common.S"
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/arm/kernel/head.S
4 *
5 * Copyright (C) 1994-2002 Russell King
6 * Copyright (c) 2003 ARM Limited
7 * All Rights Reserved
8 *
9 * Kernel startup code for all 32-bit CPUs
10 */
11#include <linux/linkage.h>
12#include <linux/init.h>
13#include <linux/pgtable.h>
14
15#include <asm/assembler.h>
16#include <asm/cp15.h>
17#include <asm/domain.h>
18#include <asm/ptrace.h>
19#include <asm/asm-offsets.h>
20#include <asm/page.h>
21#include <asm/thread_info.h>
22
23#if defined(CONFIG_DEBUG_LL) && !defined(CONFIG_DEBUG_SEMIHOSTING)
24#include CONFIG_DEBUG_LL_INCLUDE
25#endif
26/*
27 * swapper_pg_dir is the virtual address of the initial page table.
28 * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
29 * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect
30 * the least significant 16 bits to be 0x8000, but we could probably
31 * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
32 */
33#define KERNEL_RAM_VADDR (KERNEL_OFFSET + TEXT_OFFSET)
34#if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
35#error KERNEL_RAM_VADDR must start at 0xXXXX8000
36#endif
37
38#ifdef CONFIG_ARM_LPAE
39 /* LPAE requires an additional page for the PGD */
40#define PG_DIR_SIZE 0x5000
41#define PMD_ENTRY_ORDER 3 /* PMD entry size is 2^PMD_ENTRY_ORDER */
42#else
43#define PG_DIR_SIZE 0x4000
44#define PMD_ENTRY_ORDER 2
45#endif
46
47 .globl swapper_pg_dir
48 .equ swapper_pg_dir, KERNEL_RAM_VADDR - PG_DIR_SIZE
49
50 /*
51 * This needs to be assigned at runtime when the linker symbols are
52 * resolved. These are unsigned 64bit really, but in this assembly code
53 * We store them as 32bit.
54 */
55 .pushsection .data
56 .align 2
57 .globl kernel_sec_start
58 .globl kernel_sec_end
59kernel_sec_start:
60 .long 0
61 .long 0
62kernel_sec_end:
63 .long 0
64 .long 0
65 .popsection
66
67 .macro pgtbl, rd, phys
68 add \rd, \phys, #TEXT_OFFSET
69 sub \rd, \rd, #PG_DIR_SIZE
70 .endm
71
72/*
73 * Kernel startup entry point.
74 * ---------------------------
75 *
76 * This is normally called from the decompressor code. The requirements
77 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
78 * r1 = machine nr, r2 = atags or dtb pointer.
79 *
80 * This code is mostly position independent, so if you link the kernel at
81 * 0xc0008000, you call this at __pa(0xc0008000).
82 *
83 * See linux/arch/arm/tools/mach-types for the complete list of machine
84 * numbers for r1.
85 *
86 * We're trying to keep crap to a minimum; DO NOT add any machine specific
87 * crap here - that's what the boot loader (or in extreme, well justified
88 * circumstances, zImage) is for.
89 */
90 .arm
91
92 __HEAD
93ENTRY(stext)
94 ARM_BE8(setend be ) @ ensure we are in BE8 mode
95
96 THUMB( badr r9, 1f ) @ Kernel is always entered in ARM.
97 THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
98 THUMB( .thumb ) @ switch to Thumb now.
99 THUMB(1: )
100
101#ifdef CONFIG_ARM_VIRT_EXT
102 bl __hyp_stub_install
103#endif
104 @ ensure svc mode and all interrupts masked
105 safe_svcmode_maskall r9
106
107 mrc p15, 0, r9, c0, c0 @ get processor id
108 bl __lookup_processor_type @ r5=procinfo r9=cpuid
109 movs r10, r5 @ invalid processor (r5=0)?
110 THUMB( it eq ) @ force fixup-able long branch encoding
111 beq __error_p @ yes, error 'p'
112
113#ifdef CONFIG_ARM_LPAE
114 mrc p15, 0, r3, c0, c1, 4 @ read ID_MMFR0
115 and r3, r3, #0xf @ extract VMSA support
116 cmp r3, #5 @ long-descriptor translation table format?
117 THUMB( it lo ) @ force fixup-able long branch encoding
118 blo __error_lpae @ only classic page table format
119#endif
120
121#ifndef CONFIG_XIP_KERNEL
122 adr_l r8, _text @ __pa(_text)
123 sub r8, r8, #TEXT_OFFSET @ PHYS_OFFSET
124#else
125 ldr r8, =PLAT_PHYS_OFFSET @ always constant in this case
126#endif
127
128 /*
129 * r1 = machine no, r2 = atags or dtb,
130 * r8 = phys_offset, r9 = cpuid, r10 = procinfo
131 */
132 bl __vet_atags
133#ifdef CONFIG_SMP_ON_UP
134 bl __fixup_smp
135#endif
136#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
137 bl __fixup_pv_table
138#endif
139 bl __create_page_tables
140
141 /*
142 * The following calls CPU specific code in a position independent
143 * manner. See arch/arm/mm/proc-*.S for details. r10 = base of
144 * xxx_proc_info structure selected by __lookup_processor_type
145 * above.
146 *
147 * The processor init function will be called with:
148 * r1 - machine type
149 * r2 - boot data (atags/dt) pointer
150 * r4 - translation table base (low word)
151 * r5 - translation table base (high word, if LPAE)
152 * r8 - translation table base 1 (pfn if LPAE)
153 * r9 - cpuid
154 * r13 - virtual address for __enable_mmu -> __turn_mmu_on
155 *
156 * On return, the CPU will be ready for the MMU to be turned on,
157 * r0 will hold the CPU control register value, r1, r2, r4, and
158 * r9 will be preserved. r5 will also be preserved if LPAE.
159 */
160 ldr r13, =__mmap_switched @ address to jump to after
161 @ mmu has been enabled
162 badr lr, 1f @ return (PIC) address
163#ifdef CONFIG_ARM_LPAE
164 mov r5, #0 @ high TTBR0
165 mov r8, r4, lsr #12 @ TTBR1 is swapper_pg_dir pfn
166#else
167 mov r8, r4 @ set TTBR1 to swapper_pg_dir
168#endif
169 ldr r12, [r10, #PROCINFO_INITFUNC]
170 add r12, r12, r10
171 ret r12
1721: b __enable_mmu
173ENDPROC(stext)
174 .ltorg
175
176/*
177 * Setup the initial page tables. We only setup the barest
178 * amount which are required to get the kernel running, which
179 * generally means mapping in the kernel code.
180 *
181 * r8 = phys_offset, r9 = cpuid, r10 = procinfo
182 *
183 * Returns:
184 * r0, r3, r5-r7 corrupted
185 * r4 = physical page table address
186 */
187__create_page_tables:
188 pgtbl r4, r8 @ page table address
189
190 /*
191 * Clear the swapper page table
192 */
193 mov r0, r4
194 mov r3, #0
195 add r6, r0, #PG_DIR_SIZE
1961: str r3, [r0], #4
197 str r3, [r0], #4
198 str r3, [r0], #4
199 str r3, [r0], #4
200 teq r0, r6
201 bne 1b
202
203#ifdef CONFIG_ARM_LPAE
204 /*
205 * Build the PGD table (first level) to point to the PMD table. A PGD
206 * entry is 64-bit wide.
207 */
208 mov r0, r4
209 add r3, r4, #0x1000 @ first PMD table address
210 orr r3, r3, #3 @ PGD block type
211 mov r6, #4 @ PTRS_PER_PGD
212 mov r7, #1 << (55 - 32) @ L_PGD_SWAPPER
2131:
214#ifdef CONFIG_CPU_ENDIAN_BE8
215 str r7, [r0], #4 @ set top PGD entry bits
216 str r3, [r0], #4 @ set bottom PGD entry bits
217#else
218 str r3, [r0], #4 @ set bottom PGD entry bits
219 str r7, [r0], #4 @ set top PGD entry bits
220#endif
221 add r3, r3, #0x1000 @ next PMD table
222 subs r6, r6, #1
223 bne 1b
224
225 add r4, r4, #0x1000 @ point to the PMD tables
226#ifdef CONFIG_CPU_ENDIAN_BE8
227 add r4, r4, #4 @ we only write the bottom word
228#endif
229#endif
230
231 ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
232
233 /*
234 * Create identity mapping to cater for __enable_mmu.
235 * This identity mapping will be removed by paging_init().
236 */
237 adr_l r5, __turn_mmu_on @ _pa(__turn_mmu_on)
238 adr_l r6, __turn_mmu_on_end @ _pa(__turn_mmu_on_end)
239 mov r5, r5, lsr #SECTION_SHIFT
240 mov r6, r6, lsr #SECTION_SHIFT
241
2421: orr r3, r7, r5, lsl #SECTION_SHIFT @ flags + kernel base
243 str r3, [r4, r5, lsl #PMD_ENTRY_ORDER] @ identity mapping
244 cmp r5, r6
245 addlo r5, r5, #1 @ next section
246 blo 1b
247
248 /*
249 * The main matter: map in the kernel using section mappings, and
250 * set two variables to indicate the physical start and end of the
251 * kernel.
252 */
253 add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
254 ldr r6, =(_end - 1)
255 adr_l r5, kernel_sec_start @ _pa(kernel_sec_start)
256#if defined CONFIG_CPU_ENDIAN_BE8 || defined CONFIG_CPU_ENDIAN_BE32
257 str r8, [r5, #4] @ Save physical start of kernel (BE)
258#else
259 str r8, [r5] @ Save physical start of kernel (LE)
260#endif
261 orr r3, r8, r7 @ Add the MMU flags
262 add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER)
2631: str r3, [r0], #1 << PMD_ENTRY_ORDER
264 add r3, r3, #1 << SECTION_SHIFT
265 cmp r0, r6
266 bls 1b
267 eor r3, r3, r7 @ Remove the MMU flags
268 adr_l r5, kernel_sec_end @ _pa(kernel_sec_end)
269#if defined CONFIG_CPU_ENDIAN_BE8 || defined CONFIG_CPU_ENDIAN_BE32
270 str r3, [r5, #4] @ Save physical end of kernel (BE)
271#else
272 str r3, [r5] @ Save physical end of kernel (LE)
273#endif
274
275#ifdef CONFIG_XIP_KERNEL
276 /*
277 * Map the kernel image separately as it is not located in RAM.
278 */
279#define XIP_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
280 mov r3, pc
281 mov r3, r3, lsr #SECTION_SHIFT
282 orr r3, r7, r3, lsl #SECTION_SHIFT
283 add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
284 str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ENTRY_ORDER]!
285 ldr r6, =(_edata_loc - 1)
286 add r0, r0, #1 << PMD_ENTRY_ORDER
287 add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER)
2881: cmp r0, r6
289 add r3, r3, #1 << SECTION_SHIFT
290 strls r3, [r0], #1 << PMD_ENTRY_ORDER
291 bls 1b
292#endif
293
294 /*
295 * Then map boot params address in r2 if specified.
296 * We map 2 sections in case the ATAGs/DTB crosses a section boundary.
297 */
298 mov r0, r2, lsr #SECTION_SHIFT
299 cmp r2, #0
300 ldrne r3, =FDT_FIXED_BASE >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
301 addne r3, r3, r4
302 orrne r6, r7, r0, lsl #SECTION_SHIFT
303 strne r6, [r3], #1 << PMD_ENTRY_ORDER
304 addne r6, r6, #1 << SECTION_SHIFT
305 strne r6, [r3]
306
307#if defined(CONFIG_ARM_LPAE) && defined(CONFIG_CPU_ENDIAN_BE8)
308 sub r4, r4, #4 @ Fixup page table pointer
309 @ for 64-bit descriptors
310#endif
311
312#ifdef CONFIG_DEBUG_LL
313#if !defined(CONFIG_DEBUG_ICEDCC) && !defined(CONFIG_DEBUG_SEMIHOSTING)
314 /*
315 * Map in IO space for serial debugging.
316 * This allows debug messages to be output
317 * via a serial console before paging_init.
318 */
319 addruart r7, r3, r0
320
321 mov r3, r3, lsr #SECTION_SHIFT
322 mov r3, r3, lsl #PMD_ENTRY_ORDER
323
324 add r0, r4, r3
325 mov r3, r7, lsr #SECTION_SHIFT
326 ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
327 orr r3, r7, r3, lsl #SECTION_SHIFT
328#ifdef CONFIG_ARM_LPAE
329 mov r7, #1 << (54 - 32) @ XN
330#ifdef CONFIG_CPU_ENDIAN_BE8
331 str r7, [r0], #4
332 str r3, [r0], #4
333#else
334 str r3, [r0], #4
335 str r7, [r0], #4
336#endif
337#else
338 orr r3, r3, #PMD_SECT_XN
339 str r3, [r0], #4
340#endif
341
342#else /* CONFIG_DEBUG_ICEDCC || CONFIG_DEBUG_SEMIHOSTING */
343 /* we don't need any serial debugging mappings */
344 ldr r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
345#endif
346
347#if defined(CONFIG_ARCH_NETWINDER)
348 /*
349 * If we're using the NetWinder or CATS, we also need to map
350 * in the 16550-type serial port for the debug messages
351 */
352 add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
353 orr r3, r7, #0x7c000000
354 str r3, [r0]
355#endif
356#ifdef CONFIG_ARCH_RPC
357 /*
358 * Map in screen at 0x02000000 & SCREEN2_BASE
359 * Similar reasons here - for debug. This is
360 * only for Acorn RiscPC architectures.
361 */
362 add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
363 orr r3, r7, #0x02000000
364 str r3, [r0]
365 add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER)
366 str r3, [r0]
367#endif
368#endif
369#ifdef CONFIG_ARM_LPAE
370 sub r4, r4, #0x1000 @ point to the PGD table
371#endif
372 ret lr
373ENDPROC(__create_page_tables)
374 .ltorg
375
376#if defined(CONFIG_SMP)
377 .text
378 .arm
379ENTRY(secondary_startup_arm)
380 THUMB( badr r9, 1f ) @ Kernel is entered in ARM.
381 THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
382 THUMB( .thumb ) @ switch to Thumb now.
383 THUMB(1: )
384ENTRY(secondary_startup)
385 /*
386 * Common entry point for secondary CPUs.
387 *
388 * Ensure that we're in SVC mode, and IRQs are disabled. Lookup
389 * the processor type - there is no need to check the machine type
390 * as it has already been validated by the primary processor.
391 */
392
393 ARM_BE8(setend be) @ ensure we are in BE8 mode
394
395#ifdef CONFIG_ARM_VIRT_EXT
396 bl __hyp_stub_install_secondary
397#endif
398 safe_svcmode_maskall r9
399
400 mrc p15, 0, r9, c0, c0 @ get processor id
401 bl __lookup_processor_type
402 movs r10, r5 @ invalid processor?
403 moveq r0, #'p' @ yes, error 'p'
404 THUMB( it eq ) @ force fixup-able long branch encoding
405 beq __error_p
406
407 /*
408 * Use the page tables supplied from __cpu_up.
409 */
410 adr_l r3, secondary_data
411 mov_l r12, __secondary_switched
412 ldrd r4, r5, [r3, #0] @ get secondary_data.pgdir
413ARM_BE8(eor r4, r4, r5) @ Swap r5 and r4 in BE:
414ARM_BE8(eor r5, r4, r5) @ it can be done in 3 steps
415ARM_BE8(eor r4, r4, r5) @ without using a temp reg.
416 ldr r8, [r3, #8] @ get secondary_data.swapper_pg_dir
417 badr lr, __enable_mmu @ return address
418 mov r13, r12 @ __secondary_switched address
419 ldr r12, [r10, #PROCINFO_INITFUNC]
420 add r12, r12, r10 @ initialise processor
421 @ (return control reg)
422 ret r12
423ENDPROC(secondary_startup)
424ENDPROC(secondary_startup_arm)
425
426ENTRY(__secondary_switched)
427#if defined(CONFIG_VMAP_STACK) && !defined(CONFIG_ARM_LPAE)
428 @ Before using the vmap'ed stack, we have to switch to swapper_pg_dir
429 @ as the ID map does not cover the vmalloc region.
430 mrc p15, 0, ip, c2, c0, 1 @ read TTBR1
431 mcr p15, 0, ip, c2, c0, 0 @ set TTBR0
432 instr_sync
433#endif
434 adr_l r7, secondary_data + 12 @ get secondary_data.stack
435 ldr sp, [r7]
436 ldr r0, [r7, #4] @ get secondary_data.task
437 mov fp, #0
438 b secondary_start_kernel
439ENDPROC(__secondary_switched)
440
441#endif /* defined(CONFIG_SMP) */
442
443
444
445/*
446 * Setup common bits before finally enabling the MMU. Essentially
447 * this is just loading the page table pointer and domain access
448 * registers. All these registers need to be preserved by the
449 * processor setup function (or set in the case of r0)
450 *
451 * r0 = cp#15 control register
452 * r1 = machine ID
453 * r2 = atags or dtb pointer
454 * r4 = TTBR pointer (low word)
455 * r5 = TTBR pointer (high word if LPAE)
456 * r9 = processor ID
457 * r13 = *virtual* address to jump to upon completion
458 */
459__enable_mmu:
460#if defined(CONFIG_ALIGNMENT_TRAP) && __LINUX_ARM_ARCH__ < 6
461 orr r0, r0, #CR_A
462#else
463 bic r0, r0, #CR_A
464#endif
465#ifdef CONFIG_CPU_DCACHE_DISABLE
466 bic r0, r0, #CR_C
467#endif
468#ifdef CONFIG_CPU_BPREDICT_DISABLE
469 bic r0, r0, #CR_Z
470#endif
471#ifdef CONFIG_CPU_ICACHE_DISABLE
472 bic r0, r0, #CR_I
473#endif
474#ifdef CONFIG_ARM_LPAE
475 mcrr p15, 0, r4, r5, c2 @ load TTBR0
476#else
477 mov r5, #DACR_INIT
478 mcr p15, 0, r5, c3, c0, 0 @ load domain access register
479 mcr p15, 0, r4, c2, c0, 0 @ load page table pointer
480#endif
481 b __turn_mmu_on
482ENDPROC(__enable_mmu)
483
484/*
485 * Enable the MMU. This completely changes the structure of the visible
486 * memory space. You will not be able to trace execution through this.
487 * If you have an enquiry about this, *please* check the linux-arm-kernel
488 * mailing list archives BEFORE sending another post to the list.
489 *
490 * r0 = cp#15 control register
491 * r1 = machine ID
492 * r2 = atags or dtb pointer
493 * r9 = processor ID
494 * r13 = *virtual* address to jump to upon completion
495 *
496 * other registers depend on the function called upon completion
497 */
498 .align 5
499 .pushsection .idmap.text, "ax"
500ENTRY(__turn_mmu_on)
501 mov r0, r0
502 instr_sync
503 mcr p15, 0, r0, c1, c0, 0 @ write control reg
504 mrc p15, 0, r3, c0, c0, 0 @ read id reg
505 instr_sync
506 mov r3, r3
507 mov r3, r13
508 ret r3
509__turn_mmu_on_end:
510ENDPROC(__turn_mmu_on)
511 .popsection
512
513
514#ifdef CONFIG_SMP_ON_UP
515 __HEAD
516__fixup_smp:
517 and r3, r9, #0x000f0000 @ architecture version
518 teq r3, #0x000f0000 @ CPU ID supported?
519 bne __fixup_smp_on_up @ no, assume UP
520
521 bic r3, r9, #0x00ff0000
522 bic r3, r3, #0x0000000f @ mask 0xff00fff0
523 mov r4, #0x41000000
524 orr r4, r4, #0x0000b000
525 orr r4, r4, #0x00000020 @ val 0x4100b020
526 teq r3, r4 @ ARM 11MPCore?
527 reteq lr @ yes, assume SMP
528
529 mrc p15, 0, r0, c0, c0, 5 @ read MPIDR
530 and r0, r0, #0xc0000000 @ multiprocessing extensions and
531 teq r0, #0x80000000 @ not part of a uniprocessor system?
532 bne __fixup_smp_on_up @ no, assume UP
533
534 @ Core indicates it is SMP. Check for Aegis SOC where a single
535 @ Cortex-A9 CPU is present but SMP operations fault.
536 mov r4, #0x41000000
537 orr r4, r4, #0x0000c000
538 orr r4, r4, #0x00000090
539 teq r3, r4 @ Check for ARM Cortex-A9
540 retne lr @ Not ARM Cortex-A9,
541
542 @ If a future SoC *does* use 0x0 as the PERIPH_BASE, then the
543 @ below address check will need to be #ifdef'd or equivalent
544 @ for the Aegis platform.
545 mrc p15, 4, r0, c15, c0 @ get SCU base address
546 teq r0, #0x0 @ '0' on actual UP A9 hardware
547 beq __fixup_smp_on_up @ So its an A9 UP
548 ldr r0, [r0, #4] @ read SCU Config
549ARM_BE8(rev r0, r0) @ byteswap if big endian
550 and r0, r0, #0x3 @ number of CPUs
551 teq r0, #0x0 @ is 1?
552 retne lr
553
554__fixup_smp_on_up:
555 adr_l r4, __smpalt_begin
556 adr_l r5, __smpalt_end
557 b __do_fixup_smp_on_up
558ENDPROC(__fixup_smp)
559
560 .pushsection .data
561 .align 2
562 .globl smp_on_up
563smp_on_up:
564 ALT_SMP(.long 1)
565 ALT_UP(.long 0)
566 .popsection
567#endif
568
569 .text
570__do_fixup_smp_on_up:
571 cmp r4, r5
572 reths lr
573 ldmia r4, {r0, r6}
574 ARM( str r6, [r0, r4] )
575 THUMB( add r0, r0, r4 )
576 add r4, r4, #8
577#ifdef __ARMEB__
578 THUMB( mov r6, r6, ror #16 ) @ Convert word order for big-endian.
579#endif
580 THUMB( strh r6, [r0], #2 ) @ For Thumb-2, store as two halfwords
581 THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r0.
582 THUMB( strh r6, [r0] )
583 b __do_fixup_smp_on_up
584ENDPROC(__do_fixup_smp_on_up)
585
586ENTRY(fixup_smp)
587 stmfd sp!, {r4 - r6, lr}
588 mov r4, r0
589 add r5, r0, r1
590 bl __do_fixup_smp_on_up
591 ldmfd sp!, {r4 - r6, pc}
592ENDPROC(fixup_smp)
593
594#include "head-common.S"