xref: /linux/arch/arm/kernel/setup.c (revision 8137a49e1567726eb10fcf55ad141ac19804ca6b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/arch/arm/kernel/setup.c
4  *
5  *  Copyright (C) 1995-2001 Russell King
6  */
7 #include <linux/efi.h>
8 #include <linux/export.h>
9 #include <linux/kernel.h>
10 #include <linux/stddef.h>
11 #include <linux/ioport.h>
12 #include <linux/delay.h>
13 #include <linux/utsname.h>
14 #include <linux/initrd.h>
15 #include <linux/console.h>
16 #include <linux/seq_file.h>
17 #include <linux/screen_info.h>
18 #include <linux/of_platform.h>
19 #include <linux/init.h>
20 #include <linux/kexec.h>
21 #include <linux/libfdt.h>
22 #include <linux/of_fdt.h>
23 #include <linux/cpu.h>
24 #include <linux/interrupt.h>
25 #include <linux/smp.h>
26 #include <linux/proc_fs.h>
27 #include <linux/memblock.h>
28 #include <linux/bug.h>
29 #include <linux/compiler.h>
30 #include <linux/sort.h>
31 #include <linux/psci.h>
32 
33 #include <asm/unified.h>
34 #include <asm/cp15.h>
35 #include <asm/cpu.h>
36 #include <asm/cputype.h>
37 #include <asm/efi.h>
38 #include <asm/elf.h>
39 #include <asm/early_ioremap.h>
40 #include <asm/fixmap.h>
41 #include <asm/procinfo.h>
42 #include <asm/psci.h>
43 #include <asm/sections.h>
44 #include <asm/setup.h>
45 #include <asm/smp_plat.h>
46 #include <asm/mach-types.h>
47 #include <asm/cacheflush.h>
48 #include <asm/cachetype.h>
49 #include <asm/tlbflush.h>
50 #include <asm/xen/hypervisor.h>
51 
52 #include <asm/prom.h>
53 #include <asm/mach/arch.h>
54 #include <asm/mach/irq.h>
55 #include <asm/mach/time.h>
56 #include <asm/system_info.h>
57 #include <asm/system_misc.h>
58 #include <asm/traps.h>
59 #include <asm/unwind.h>
60 #include <asm/memblock.h>
61 #include <asm/virt.h>
62 #include <asm/kasan.h>
63 
64 #include "atags.h"
65 
66 
67 #if defined(CONFIG_FPE_NWFPE) || defined(CONFIG_FPE_FASTFPE)
68 char fpe_type[8];
69 
70 static int __init fpe_setup(char *line)
71 {
72 	memcpy(fpe_type, line, 8);
73 	return 1;
74 }
75 
76 __setup("fpe=", fpe_setup);
77 #endif
78 
79 extern void init_default_cache_policy(unsigned long);
80 extern void paging_init(const struct machine_desc *desc);
81 extern void early_mm_init(const struct machine_desc *);
82 extern void adjust_lowmem_bounds(void);
83 extern enum reboot_mode reboot_mode;
84 extern void setup_dma_zone(const struct machine_desc *desc);
85 
86 unsigned int processor_id;
87 EXPORT_SYMBOL(processor_id);
88 unsigned int __machine_arch_type __read_mostly;
89 EXPORT_SYMBOL(__machine_arch_type);
90 unsigned int cacheid __read_mostly;
91 EXPORT_SYMBOL(cacheid);
92 
93 unsigned int __atags_pointer __initdata;
94 
95 unsigned int system_rev;
96 EXPORT_SYMBOL(system_rev);
97 
98 const char *system_serial;
99 EXPORT_SYMBOL(system_serial);
100 
101 unsigned int system_serial_low;
102 EXPORT_SYMBOL(system_serial_low);
103 
104 unsigned int system_serial_high;
105 EXPORT_SYMBOL(system_serial_high);
106 
107 unsigned int elf_hwcap __read_mostly;
108 EXPORT_SYMBOL(elf_hwcap);
109 
110 unsigned int elf_hwcap2 __read_mostly;
111 EXPORT_SYMBOL(elf_hwcap2);
112 
113 
114 #ifdef MULTI_CPU
115 struct processor processor __ro_after_init;
116 #if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
117 struct processor *cpu_vtable[NR_CPUS] = {
118 	[0] = &processor,
119 };
120 #endif
121 #endif
122 #ifdef MULTI_TLB
123 struct cpu_tlb_fns cpu_tlb __ro_after_init;
124 #endif
125 #ifdef MULTI_USER
126 struct cpu_user_fns cpu_user __ro_after_init;
127 #endif
128 #ifdef MULTI_CACHE
129 struct cpu_cache_fns cpu_cache __ro_after_init;
130 #endif
131 #ifdef CONFIG_OUTER_CACHE
132 struct outer_cache_fns outer_cache __ro_after_init;
133 EXPORT_SYMBOL(outer_cache);
134 #endif
135 
136 /*
137  * Cached cpu_architecture() result for use by assembler code.
138  * C code should use the cpu_architecture() function instead of accessing this
139  * variable directly.
140  */
141 int __cpu_architecture __read_mostly = CPU_ARCH_UNKNOWN;
142 
143 struct stack {
144 	u32 irq[3];
145 	u32 abt[3];
146 	u32 und[3];
147 	u32 fiq[3];
148 } ____cacheline_aligned;
149 
150 #ifndef CONFIG_CPU_V7M
151 static struct stack stacks[NR_CPUS];
152 #endif
153 
154 char elf_platform[ELF_PLATFORM_SIZE];
155 EXPORT_SYMBOL(elf_platform);
156 
157 static const char *cpu_name;
158 static const char *machine_name;
159 static char __initdata cmd_line[COMMAND_LINE_SIZE];
160 const struct machine_desc *machine_desc __initdata;
161 
162 static union { char c[4]; unsigned long l; } endian_test __initdata = { { 'l', '?', '?', 'b' } };
163 #define ENDIANNESS ((char)endian_test.l)
164 
165 DEFINE_PER_CPU(struct cpuinfo_arm, cpu_data);
166 
167 /*
168  * Standard memory resources
169  */
170 static struct resource mem_res[] = {
171 	{
172 		.name = "Video RAM",
173 		.start = 0,
174 		.end = 0,
175 		.flags = IORESOURCE_MEM
176 	},
177 	{
178 		.name = "Kernel code",
179 		.start = 0,
180 		.end = 0,
181 		.flags = IORESOURCE_SYSTEM_RAM
182 	},
183 	{
184 		.name = "Kernel data",
185 		.start = 0,
186 		.end = 0,
187 		.flags = IORESOURCE_SYSTEM_RAM
188 	}
189 };
190 
191 #define video_ram   mem_res[0]
192 #define kernel_code mem_res[1]
193 #define kernel_data mem_res[2]
194 
195 static struct resource io_res[] = {
196 	{
197 		.name = "reserved",
198 		.start = 0x3bc,
199 		.end = 0x3be,
200 		.flags = IORESOURCE_IO | IORESOURCE_BUSY
201 	},
202 	{
203 		.name = "reserved",
204 		.start = 0x378,
205 		.end = 0x37f,
206 		.flags = IORESOURCE_IO | IORESOURCE_BUSY
207 	},
208 	{
209 		.name = "reserved",
210 		.start = 0x278,
211 		.end = 0x27f,
212 		.flags = IORESOURCE_IO | IORESOURCE_BUSY
213 	}
214 };
215 
216 #define lp0 io_res[0]
217 #define lp1 io_res[1]
218 #define lp2 io_res[2]
219 
220 static const char *proc_arch[] = {
221 	"undefined/unknown",
222 	"3",
223 	"4",
224 	"4T",
225 	"5",
226 	"5T",
227 	"5TE",
228 	"5TEJ",
229 	"6TEJ",
230 	"7",
231 	"7M",
232 	"?(12)",
233 	"?(13)",
234 	"?(14)",
235 	"?(15)",
236 	"?(16)",
237 	"?(17)",
238 };
239 
240 #ifdef CONFIG_CPU_V7M
241 static int __get_cpu_architecture(void)
242 {
243 	return CPU_ARCH_ARMv7M;
244 }
245 #else
246 static int __get_cpu_architecture(void)
247 {
248 	int cpu_arch;
249 
250 	if ((read_cpuid_id() & 0x0008f000) == 0) {
251 		cpu_arch = CPU_ARCH_UNKNOWN;
252 	} else if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
253 		cpu_arch = (read_cpuid_id() & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
254 	} else if ((read_cpuid_id() & 0x00080000) == 0x00000000) {
255 		cpu_arch = (read_cpuid_id() >> 16) & 7;
256 		if (cpu_arch)
257 			cpu_arch += CPU_ARCH_ARMv3;
258 	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
259 		/* Revised CPUID format. Read the Memory Model Feature
260 		 * Register 0 and check for VMSAv7 or PMSAv7 */
261 		unsigned int mmfr0 = read_cpuid_ext(CPUID_EXT_MMFR0);
262 		if ((mmfr0 & 0x0000000f) >= 0x00000003 ||
263 		    (mmfr0 & 0x000000f0) >= 0x00000030)
264 			cpu_arch = CPU_ARCH_ARMv7;
265 		else if ((mmfr0 & 0x0000000f) == 0x00000002 ||
266 			 (mmfr0 & 0x000000f0) == 0x00000020)
267 			cpu_arch = CPU_ARCH_ARMv6;
268 		else
269 			cpu_arch = CPU_ARCH_UNKNOWN;
270 	} else
271 		cpu_arch = CPU_ARCH_UNKNOWN;
272 
273 	return cpu_arch;
274 }
275 #endif
276 
277 int __pure cpu_architecture(void)
278 {
279 	BUG_ON(__cpu_architecture == CPU_ARCH_UNKNOWN);
280 
281 	return __cpu_architecture;
282 }
283 
284 static int cpu_has_aliasing_icache(unsigned int arch)
285 {
286 	int aliasing_icache;
287 	unsigned int id_reg, num_sets, line_size;
288 
289 	/* PIPT caches never alias. */
290 	if (icache_is_pipt())
291 		return 0;
292 
293 	/* arch specifies the register format */
294 	switch (arch) {
295 	case CPU_ARCH_ARMv7:
296 		set_csselr(CSSELR_ICACHE | CSSELR_L1);
297 		isb();
298 		id_reg = read_ccsidr();
299 		line_size = 4 << ((id_reg & 0x7) + 2);
300 		num_sets = ((id_reg >> 13) & 0x7fff) + 1;
301 		aliasing_icache = (line_size * num_sets) > PAGE_SIZE;
302 		break;
303 	case CPU_ARCH_ARMv6:
304 		aliasing_icache = read_cpuid_cachetype() & (1 << 11);
305 		break;
306 	default:
307 		/* I-cache aliases will be handled by D-cache aliasing code */
308 		aliasing_icache = 0;
309 	}
310 
311 	return aliasing_icache;
312 }
313 
314 static void __init cacheid_init(void)
315 {
316 	unsigned int arch = cpu_architecture();
317 
318 	if (arch >= CPU_ARCH_ARMv6) {
319 		unsigned int cachetype = read_cpuid_cachetype();
320 
321 		if ((arch == CPU_ARCH_ARMv7M) && !(cachetype & 0xf000f)) {
322 			cacheid = 0;
323 		} else if ((cachetype & (7 << 29)) == 4 << 29) {
324 			/* ARMv7 register format */
325 			arch = CPU_ARCH_ARMv7;
326 			cacheid = CACHEID_VIPT_NONALIASING;
327 			switch (cachetype & (3 << 14)) {
328 			case (1 << 14):
329 				cacheid |= CACHEID_ASID_TAGGED;
330 				break;
331 			case (3 << 14):
332 				cacheid |= CACHEID_PIPT;
333 				break;
334 			}
335 		} else {
336 			arch = CPU_ARCH_ARMv6;
337 			if (cachetype & (1 << 23))
338 				cacheid = CACHEID_VIPT_ALIASING;
339 			else
340 				cacheid = CACHEID_VIPT_NONALIASING;
341 		}
342 		if (cpu_has_aliasing_icache(arch))
343 			cacheid |= CACHEID_VIPT_I_ALIASING;
344 	} else {
345 		cacheid = CACHEID_VIVT;
346 	}
347 
348 	pr_info("CPU: %s data cache, %s instruction cache\n",
349 		cache_is_vivt() ? "VIVT" :
350 		cache_is_vipt_aliasing() ? "VIPT aliasing" :
351 		cache_is_vipt_nonaliasing() ? "PIPT / VIPT nonaliasing" : "unknown",
352 		cache_is_vivt() ? "VIVT" :
353 		icache_is_vivt_asid_tagged() ? "VIVT ASID tagged" :
354 		icache_is_vipt_aliasing() ? "VIPT aliasing" :
355 		icache_is_pipt() ? "PIPT" :
356 		cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown");
357 }
358 
359 /*
360  * These functions re-use the assembly code in head.S, which
361  * already provide the required functionality.
362  */
363 extern struct proc_info_list *lookup_processor_type(unsigned int);
364 
365 void __init early_print(const char *str, ...)
366 {
367 	extern void printascii(const char *);
368 	char buf[256];
369 	va_list ap;
370 
371 	va_start(ap, str);
372 	vsnprintf(buf, sizeof(buf), str, ap);
373 	va_end(ap);
374 
375 #ifdef CONFIG_DEBUG_LL
376 	printascii(buf);
377 #endif
378 	printk("%s", buf);
379 }
380 
381 #ifdef CONFIG_ARM_PATCH_IDIV
382 
383 static inline u32 __attribute_const__ sdiv_instruction(void)
384 {
385 	if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
386 		/* "sdiv r0, r0, r1" */
387 		u32 insn = __opcode_thumb32_compose(0xfb90, 0xf0f1);
388 		return __opcode_to_mem_thumb32(insn);
389 	}
390 
391 	/* "sdiv r0, r0, r1" */
392 	return __opcode_to_mem_arm(0xe710f110);
393 }
394 
395 static inline u32 __attribute_const__ udiv_instruction(void)
396 {
397 	if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
398 		/* "udiv r0, r0, r1" */
399 		u32 insn = __opcode_thumb32_compose(0xfbb0, 0xf0f1);
400 		return __opcode_to_mem_thumb32(insn);
401 	}
402 
403 	/* "udiv r0, r0, r1" */
404 	return __opcode_to_mem_arm(0xe730f110);
405 }
406 
407 static inline u32 __attribute_const__ bx_lr_instruction(void)
408 {
409 	if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
410 		/* "bx lr; nop" */
411 		u32 insn = __opcode_thumb32_compose(0x4770, 0x46c0);
412 		return __opcode_to_mem_thumb32(insn);
413 	}
414 
415 	/* "bx lr" */
416 	return __opcode_to_mem_arm(0xe12fff1e);
417 }
418 
419 static void __init patch_aeabi_idiv(void)
420 {
421 	extern void __aeabi_uidiv(void);
422 	extern void __aeabi_idiv(void);
423 	uintptr_t fn_addr;
424 	unsigned int mask;
425 
426 	mask = IS_ENABLED(CONFIG_THUMB2_KERNEL) ? HWCAP_IDIVT : HWCAP_IDIVA;
427 	if (!(elf_hwcap & mask))
428 		return;
429 
430 	pr_info("CPU: div instructions available: patching division code\n");
431 
432 	fn_addr = ((uintptr_t)&__aeabi_uidiv) & ~1;
433 	asm ("" : "+g" (fn_addr));
434 	((u32 *)fn_addr)[0] = udiv_instruction();
435 	((u32 *)fn_addr)[1] = bx_lr_instruction();
436 	flush_icache_range(fn_addr, fn_addr + 8);
437 
438 	fn_addr = ((uintptr_t)&__aeabi_idiv) & ~1;
439 	asm ("" : "+g" (fn_addr));
440 	((u32 *)fn_addr)[0] = sdiv_instruction();
441 	((u32 *)fn_addr)[1] = bx_lr_instruction();
442 	flush_icache_range(fn_addr, fn_addr + 8);
443 }
444 
445 #else
446 static inline void patch_aeabi_idiv(void) { }
447 #endif
448 
449 static void __init cpuid_init_hwcaps(void)
450 {
451 	int block;
452 	u32 isar5;
453 
454 	if (cpu_architecture() < CPU_ARCH_ARMv7)
455 		return;
456 
457 	block = cpuid_feature_extract(CPUID_EXT_ISAR0, 24);
458 	if (block >= 2)
459 		elf_hwcap |= HWCAP_IDIVA;
460 	if (block >= 1)
461 		elf_hwcap |= HWCAP_IDIVT;
462 
463 	/* LPAE implies atomic ldrd/strd instructions */
464 	block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
465 	if (block >= 5)
466 		elf_hwcap |= HWCAP_LPAE;
467 
468 	/* check for supported v8 Crypto instructions */
469 	isar5 = read_cpuid_ext(CPUID_EXT_ISAR5);
470 
471 	block = cpuid_feature_extract_field(isar5, 4);
472 	if (block >= 2)
473 		elf_hwcap2 |= HWCAP2_PMULL;
474 	if (block >= 1)
475 		elf_hwcap2 |= HWCAP2_AES;
476 
477 	block = cpuid_feature_extract_field(isar5, 8);
478 	if (block >= 1)
479 		elf_hwcap2 |= HWCAP2_SHA1;
480 
481 	block = cpuid_feature_extract_field(isar5, 12);
482 	if (block >= 1)
483 		elf_hwcap2 |= HWCAP2_SHA2;
484 
485 	block = cpuid_feature_extract_field(isar5, 16);
486 	if (block >= 1)
487 		elf_hwcap2 |= HWCAP2_CRC32;
488 }
489 
490 static void __init elf_hwcap_fixup(void)
491 {
492 	unsigned id = read_cpuid_id();
493 
494 	/*
495 	 * HWCAP_TLS is available only on 1136 r1p0 and later,
496 	 * see also kuser_get_tls_init.
497 	 */
498 	if (read_cpuid_part() == ARM_CPU_PART_ARM1136 &&
499 	    ((id >> 20) & 3) == 0) {
500 		elf_hwcap &= ~HWCAP_TLS;
501 		return;
502 	}
503 
504 	/* Verify if CPUID scheme is implemented */
505 	if ((id & 0x000f0000) != 0x000f0000)
506 		return;
507 
508 	/*
509 	 * If the CPU supports LDREX/STREX and LDREXB/STREXB,
510 	 * avoid advertising SWP; it may not be atomic with
511 	 * multiprocessing cores.
512 	 */
513 	if (cpuid_feature_extract(CPUID_EXT_ISAR3, 12) > 1 ||
514 	    (cpuid_feature_extract(CPUID_EXT_ISAR3, 12) == 1 &&
515 	     cpuid_feature_extract(CPUID_EXT_ISAR4, 20) >= 3))
516 		elf_hwcap &= ~HWCAP_SWP;
517 }
518 
519 /*
520  * cpu_init - initialise one CPU.
521  *
522  * cpu_init sets up the per-CPU stacks.
523  */
524 void notrace cpu_init(void)
525 {
526 #ifndef CONFIG_CPU_V7M
527 	unsigned int cpu = smp_processor_id();
528 	struct stack *stk = &stacks[cpu];
529 
530 	if (cpu >= NR_CPUS) {
531 		pr_crit("CPU%u: bad primary CPU number\n", cpu);
532 		BUG();
533 	}
534 
535 	/*
536 	 * This only works on resume and secondary cores. For booting on the
537 	 * boot cpu, smp_prepare_boot_cpu is called after percpu area setup.
538 	 */
539 	set_my_cpu_offset(per_cpu_offset(cpu));
540 
541 	cpu_proc_init();
542 
543 	/*
544 	 * Define the placement constraint for the inline asm directive below.
545 	 * In Thumb-2, msr with an immediate value is not allowed.
546 	 */
547 #ifdef CONFIG_THUMB2_KERNEL
548 #define PLC_l	"l"
549 #define PLC_r	"r"
550 #else
551 #define PLC_l	"I"
552 #define PLC_r	"I"
553 #endif
554 
555 	/*
556 	 * setup stacks for re-entrant exception handlers
557 	 */
558 	__asm__ (
559 	"msr	cpsr_c, %1\n\t"
560 	"add	r14, %0, %2\n\t"
561 	"mov	sp, r14\n\t"
562 	"msr	cpsr_c, %3\n\t"
563 	"add	r14, %0, %4\n\t"
564 	"mov	sp, r14\n\t"
565 	"msr	cpsr_c, %5\n\t"
566 	"add	r14, %0, %6\n\t"
567 	"mov	sp, r14\n\t"
568 	"msr	cpsr_c, %7\n\t"
569 	"add	r14, %0, %8\n\t"
570 	"mov	sp, r14\n\t"
571 	"msr	cpsr_c, %9"
572 	    :
573 	    : "r" (stk),
574 	      PLC_r (PSR_F_BIT | PSR_I_BIT | IRQ_MODE),
575 	      "I" (offsetof(struct stack, irq[0])),
576 	      PLC_r (PSR_F_BIT | PSR_I_BIT | ABT_MODE),
577 	      "I" (offsetof(struct stack, abt[0])),
578 	      PLC_r (PSR_F_BIT | PSR_I_BIT | UND_MODE),
579 	      "I" (offsetof(struct stack, und[0])),
580 	      PLC_r (PSR_F_BIT | PSR_I_BIT | FIQ_MODE),
581 	      "I" (offsetof(struct stack, fiq[0])),
582 	      PLC_l (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
583 	    : "r14");
584 #endif
585 }
586 
587 u32 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
588 
589 void __init smp_setup_processor_id(void)
590 {
591 	int i;
592 	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
593 	u32 cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
594 
595 	cpu_logical_map(0) = cpu;
596 	for (i = 1; i < nr_cpu_ids; ++i)
597 		cpu_logical_map(i) = i == cpu ? 0 : i;
598 
599 	/*
600 	 * clear __my_cpu_offset on boot CPU to avoid hang caused by
601 	 * using percpu variable early, for example, lockdep will
602 	 * access percpu variable inside lock_release
603 	 */
604 	set_my_cpu_offset(0);
605 
606 	pr_info("Booting Linux on physical CPU 0x%x\n", mpidr);
607 }
608 
609 struct mpidr_hash mpidr_hash;
610 #ifdef CONFIG_SMP
611 /**
612  * smp_build_mpidr_hash - Pre-compute shifts required at each affinity
613  *			  level in order to build a linear index from an
614  *			  MPIDR value. Resulting algorithm is a collision
615  *			  free hash carried out through shifting and ORing
616  */
617 static void __init smp_build_mpidr_hash(void)
618 {
619 	u32 i, affinity;
620 	u32 fs[3], bits[3], ls, mask = 0;
621 	/*
622 	 * Pre-scan the list of MPIDRS and filter out bits that do
623 	 * not contribute to affinity levels, ie they never toggle.
624 	 */
625 	for_each_possible_cpu(i)
626 		mask |= (cpu_logical_map(i) ^ cpu_logical_map(0));
627 	pr_debug("mask of set bits 0x%x\n", mask);
628 	/*
629 	 * Find and stash the last and first bit set at all affinity levels to
630 	 * check how many bits are required to represent them.
631 	 */
632 	for (i = 0; i < 3; i++) {
633 		affinity = MPIDR_AFFINITY_LEVEL(mask, i);
634 		/*
635 		 * Find the MSB bit and LSB bits position
636 		 * to determine how many bits are required
637 		 * to express the affinity level.
638 		 */
639 		ls = fls(affinity);
640 		fs[i] = affinity ? ffs(affinity) - 1 : 0;
641 		bits[i] = ls - fs[i];
642 	}
643 	/*
644 	 * An index can be created from the MPIDR by isolating the
645 	 * significant bits at each affinity level and by shifting
646 	 * them in order to compress the 24 bits values space to a
647 	 * compressed set of values. This is equivalent to hashing
648 	 * the MPIDR through shifting and ORing. It is a collision free
649 	 * hash though not minimal since some levels might contain a number
650 	 * of CPUs that is not an exact power of 2 and their bit
651 	 * representation might contain holes, eg MPIDR[7:0] = {0x2, 0x80}.
652 	 */
653 	mpidr_hash.shift_aff[0] = fs[0];
654 	mpidr_hash.shift_aff[1] = MPIDR_LEVEL_BITS + fs[1] - bits[0];
655 	mpidr_hash.shift_aff[2] = 2*MPIDR_LEVEL_BITS + fs[2] -
656 						(bits[1] + bits[0]);
657 	mpidr_hash.mask = mask;
658 	mpidr_hash.bits = bits[2] + bits[1] + bits[0];
659 	pr_debug("MPIDR hash: aff0[%u] aff1[%u] aff2[%u] mask[0x%x] bits[%u]\n",
660 				mpidr_hash.shift_aff[0],
661 				mpidr_hash.shift_aff[1],
662 				mpidr_hash.shift_aff[2],
663 				mpidr_hash.mask,
664 				mpidr_hash.bits);
665 	/*
666 	 * 4x is an arbitrary value used to warn on a hash table much bigger
667 	 * than expected on most systems.
668 	 */
669 	if (mpidr_hash_size() > 4 * num_possible_cpus())
670 		pr_warn("Large number of MPIDR hash buckets detected\n");
671 	sync_cache_w(&mpidr_hash);
672 }
673 #endif
674 
675 /*
676  * locate processor in the list of supported processor types.  The linker
677  * builds this table for us from the entries in arch/arm/mm/proc-*.S
678  */
679 struct proc_info_list *lookup_processor(u32 midr)
680 {
681 	struct proc_info_list *list = lookup_processor_type(midr);
682 
683 	if (!list) {
684 		pr_err("CPU%u: configuration botched (ID %08x), CPU halted\n",
685 		       smp_processor_id(), midr);
686 		while (1)
687 		/* can't use cpu_relax() here as it may require MMU setup */;
688 	}
689 
690 	return list;
691 }
692 
693 static void __init setup_processor(void)
694 {
695 	unsigned int midr = read_cpuid_id();
696 	struct proc_info_list *list = lookup_processor(midr);
697 
698 	cpu_name = list->cpu_name;
699 	__cpu_architecture = __get_cpu_architecture();
700 
701 	init_proc_vtable(list->proc);
702 #ifdef MULTI_TLB
703 	cpu_tlb = *list->tlb;
704 #endif
705 #ifdef MULTI_USER
706 	cpu_user = *list->user;
707 #endif
708 #ifdef MULTI_CACHE
709 	cpu_cache = *list->cache;
710 #endif
711 
712 	pr_info("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n",
713 		list->cpu_name, midr, midr & 15,
714 		proc_arch[cpu_architecture()], get_cr());
715 
716 	snprintf(init_utsname()->machine, __NEW_UTS_LEN + 1, "%s%c",
717 		 list->arch_name, ENDIANNESS);
718 	snprintf(elf_platform, ELF_PLATFORM_SIZE, "%s%c",
719 		 list->elf_name, ENDIANNESS);
720 	elf_hwcap = list->elf_hwcap;
721 
722 	cpuid_init_hwcaps();
723 	patch_aeabi_idiv();
724 
725 #ifndef CONFIG_ARM_THUMB
726 	elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT);
727 #endif
728 #ifdef CONFIG_MMU
729 	init_default_cache_policy(list->__cpu_mm_mmu_flags);
730 #endif
731 	erratum_a15_798181_init();
732 
733 	elf_hwcap_fixup();
734 
735 	cacheid_init();
736 	cpu_init();
737 }
738 
739 void __init dump_machine_table(void)
740 {
741 	const struct machine_desc *p;
742 
743 	early_print("Available machine support:\n\nID (hex)\tNAME\n");
744 	for_each_machine_desc(p)
745 		early_print("%08x\t%s\n", p->nr, p->name);
746 
747 	early_print("\nPlease check your kernel config and/or bootloader.\n");
748 
749 	while (true)
750 		/* can't use cpu_relax() here as it may require MMU setup */;
751 }
752 
753 int __init arm_add_memory(u64 start, u64 size)
754 {
755 	u64 aligned_start;
756 
757 	/*
758 	 * Ensure that start/size are aligned to a page boundary.
759 	 * Size is rounded down, start is rounded up.
760 	 */
761 	aligned_start = PAGE_ALIGN(start);
762 	if (aligned_start > start + size)
763 		size = 0;
764 	else
765 		size -= aligned_start - start;
766 
767 #ifndef CONFIG_PHYS_ADDR_T_64BIT
768 	if (aligned_start > ULONG_MAX) {
769 		pr_crit("Ignoring memory at 0x%08llx outside 32-bit physical address space\n",
770 			start);
771 		return -EINVAL;
772 	}
773 
774 	if (aligned_start + size > ULONG_MAX) {
775 		pr_crit("Truncating memory at 0x%08llx to fit in 32-bit physical address space\n",
776 			(long long)start);
777 		/*
778 		 * To ensure bank->start + bank->size is representable in
779 		 * 32 bits, we use ULONG_MAX as the upper limit rather than 4GB.
780 		 * This means we lose a page after masking.
781 		 */
782 		size = ULONG_MAX - aligned_start;
783 	}
784 #endif
785 
786 	if (aligned_start < PHYS_OFFSET) {
787 		if (aligned_start + size <= PHYS_OFFSET) {
788 			pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
789 				aligned_start, aligned_start + size);
790 			return -EINVAL;
791 		}
792 
793 		pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
794 			aligned_start, (u64)PHYS_OFFSET);
795 
796 		size -= PHYS_OFFSET - aligned_start;
797 		aligned_start = PHYS_OFFSET;
798 	}
799 
800 	start = aligned_start;
801 	size = size & ~(phys_addr_t)(PAGE_SIZE - 1);
802 
803 	/*
804 	 * Check whether this memory region has non-zero size or
805 	 * invalid node number.
806 	 */
807 	if (size == 0)
808 		return -EINVAL;
809 
810 	memblock_add(start, size);
811 	return 0;
812 }
813 
814 /*
815  * Pick out the memory size.  We look for mem=size@start,
816  * where start and size are "size[KkMm]"
817  */
818 
819 static int __init early_mem(char *p)
820 {
821 	static int usermem __initdata = 0;
822 	u64 size;
823 	u64 start;
824 	char *endp;
825 
826 	/*
827 	 * If the user specifies memory size, we
828 	 * blow away any automatically generated
829 	 * size.
830 	 */
831 	if (usermem == 0) {
832 		usermem = 1;
833 		memblock_remove(memblock_start_of_DRAM(),
834 			memblock_end_of_DRAM() - memblock_start_of_DRAM());
835 	}
836 
837 	start = PHYS_OFFSET;
838 	size  = memparse(p, &endp);
839 	if (*endp == '@')
840 		start = memparse(endp + 1, NULL);
841 
842 	arm_add_memory(start, size);
843 
844 	return 0;
845 }
846 early_param("mem", early_mem);
847 
848 static void __init request_standard_resources(const struct machine_desc *mdesc)
849 {
850 	phys_addr_t start, end, res_end;
851 	struct resource *res;
852 	u64 i;
853 
854 	kernel_code.start   = virt_to_phys(_text);
855 	kernel_code.end     = virt_to_phys(__init_begin - 1);
856 	kernel_data.start   = virt_to_phys(_sdata);
857 	kernel_data.end     = virt_to_phys(_end - 1);
858 
859 	for_each_mem_range(i, &start, &end) {
860 		unsigned long boot_alias_start;
861 
862 		/*
863 		 * In memblock, end points to the first byte after the
864 		 * range while in resourses, end points to the last byte in
865 		 * the range.
866 		 */
867 		res_end = end - 1;
868 
869 		/*
870 		 * Some systems have a special memory alias which is only
871 		 * used for booting.  We need to advertise this region to
872 		 * kexec-tools so they know where bootable RAM is located.
873 		 */
874 		boot_alias_start = phys_to_idmap(start);
875 		if (arm_has_idmap_alias() && boot_alias_start != IDMAP_INVALID_ADDR) {
876 			res = memblock_alloc(sizeof(*res), SMP_CACHE_BYTES);
877 			if (!res)
878 				panic("%s: Failed to allocate %zu bytes\n",
879 				      __func__, sizeof(*res));
880 			res->name = "System RAM (boot alias)";
881 			res->start = boot_alias_start;
882 			res->end = phys_to_idmap(res_end);
883 			res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
884 			request_resource(&iomem_resource, res);
885 		}
886 
887 		res = memblock_alloc(sizeof(*res), SMP_CACHE_BYTES);
888 		if (!res)
889 			panic("%s: Failed to allocate %zu bytes\n", __func__,
890 			      sizeof(*res));
891 		res->name  = "System RAM";
892 		res->start = start;
893 		res->end = res_end;
894 		res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
895 
896 		request_resource(&iomem_resource, res);
897 
898 		if (kernel_code.start >= res->start &&
899 		    kernel_code.end <= res->end)
900 			request_resource(res, &kernel_code);
901 		if (kernel_data.start >= res->start &&
902 		    kernel_data.end <= res->end)
903 			request_resource(res, &kernel_data);
904 	}
905 
906 	if (mdesc->video_start) {
907 		video_ram.start = mdesc->video_start;
908 		video_ram.end   = mdesc->video_end;
909 		request_resource(&iomem_resource, &video_ram);
910 	}
911 
912 	/*
913 	 * Some machines don't have the possibility of ever
914 	 * possessing lp0, lp1 or lp2
915 	 */
916 	if (mdesc->reserve_lp0)
917 		request_resource(&ioport_resource, &lp0);
918 	if (mdesc->reserve_lp1)
919 		request_resource(&ioport_resource, &lp1);
920 	if (mdesc->reserve_lp2)
921 		request_resource(&ioport_resource, &lp2);
922 }
923 
924 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) || \
925     defined(CONFIG_EFI)
926 struct screen_info screen_info = {
927  .orig_video_lines	= 30,
928  .orig_video_cols	= 80,
929  .orig_video_mode	= 0,
930  .orig_video_ega_bx	= 0,
931  .orig_video_isVGA	= 1,
932  .orig_video_points	= 8
933 };
934 #endif
935 
936 static int __init customize_machine(void)
937 {
938 	/*
939 	 * customizes platform devices, or adds new ones
940 	 * On DT based machines, we fall back to populating the
941 	 * machine from the device tree, if no callback is provided,
942 	 * otherwise we would always need an init_machine callback.
943 	 */
944 	if (machine_desc->init_machine)
945 		machine_desc->init_machine();
946 
947 	return 0;
948 }
949 arch_initcall(customize_machine);
950 
951 static int __init init_machine_late(void)
952 {
953 	struct device_node *root;
954 	int ret;
955 
956 	if (machine_desc->init_late)
957 		machine_desc->init_late();
958 
959 	root = of_find_node_by_path("/");
960 	if (root) {
961 		ret = of_property_read_string(root, "serial-number",
962 					      &system_serial);
963 		if (ret)
964 			system_serial = NULL;
965 	}
966 
967 	if (!system_serial)
968 		system_serial = kasprintf(GFP_KERNEL, "%08x%08x",
969 					  system_serial_high,
970 					  system_serial_low);
971 
972 	return 0;
973 }
974 late_initcall(init_machine_late);
975 
976 #ifdef CONFIG_KEXEC
977 /*
978  * The crash region must be aligned to 128MB to avoid
979  * zImage relocating below the reserved region.
980  */
981 #define CRASH_ALIGN	(128 << 20)
982 
983 static inline unsigned long long get_total_mem(void)
984 {
985 	unsigned long total;
986 
987 	total = max_low_pfn - min_low_pfn;
988 	return total << PAGE_SHIFT;
989 }
990 
991 /**
992  * reserve_crashkernel() - reserves memory are for crash kernel
993  *
994  * This function reserves memory area given in "crashkernel=" kernel command
995  * line parameter. The memory reserved is used by a dump capture kernel when
996  * primary kernel is crashing.
997  */
998 static void __init reserve_crashkernel(void)
999 {
1000 	unsigned long long crash_size, crash_base;
1001 	unsigned long long total_mem;
1002 	int ret;
1003 
1004 	total_mem = get_total_mem();
1005 	ret = parse_crashkernel(boot_command_line, total_mem,
1006 				&crash_size, &crash_base);
1007 	if (ret)
1008 		return;
1009 
1010 	if (crash_base <= 0) {
1011 		unsigned long long crash_max = idmap_to_phys((u32)~0);
1012 		unsigned long long lowmem_max = __pa(high_memory - 1) + 1;
1013 		if (crash_max > lowmem_max)
1014 			crash_max = lowmem_max;
1015 		crash_base = memblock_find_in_range(CRASH_ALIGN, crash_max,
1016 						    crash_size, CRASH_ALIGN);
1017 		if (!crash_base) {
1018 			pr_err("crashkernel reservation failed - No suitable area found.\n");
1019 			return;
1020 		}
1021 	} else {
1022 		unsigned long long start;
1023 
1024 		start = memblock_find_in_range(crash_base,
1025 					       crash_base + crash_size,
1026 					       crash_size, SECTION_SIZE);
1027 		if (start != crash_base) {
1028 			pr_err("crashkernel reservation failed - memory is in use.\n");
1029 			return;
1030 		}
1031 	}
1032 
1033 	ret = memblock_reserve(crash_base, crash_size);
1034 	if (ret < 0) {
1035 		pr_warn("crashkernel reservation failed - memory is in use (0x%lx)\n",
1036 			(unsigned long)crash_base);
1037 		return;
1038 	}
1039 
1040 	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
1041 		(unsigned long)(crash_size >> 20),
1042 		(unsigned long)(crash_base >> 20),
1043 		(unsigned long)(total_mem >> 20));
1044 
1045 	/* The crashk resource must always be located in normal mem */
1046 	crashk_res.start = crash_base;
1047 	crashk_res.end = crash_base + crash_size - 1;
1048 	insert_resource(&iomem_resource, &crashk_res);
1049 
1050 	if (arm_has_idmap_alias()) {
1051 		/*
1052 		 * If we have a special RAM alias for use at boot, we
1053 		 * need to advertise to kexec tools where the alias is.
1054 		 */
1055 		static struct resource crashk_boot_res = {
1056 			.name = "Crash kernel (boot alias)",
1057 			.flags = IORESOURCE_BUSY | IORESOURCE_MEM,
1058 		};
1059 
1060 		crashk_boot_res.start = phys_to_idmap(crash_base);
1061 		crashk_boot_res.end = crashk_boot_res.start + crash_size - 1;
1062 		insert_resource(&iomem_resource, &crashk_boot_res);
1063 	}
1064 }
1065 #else
1066 static inline void reserve_crashkernel(void) {}
1067 #endif /* CONFIG_KEXEC */
1068 
1069 void __init hyp_mode_check(void)
1070 {
1071 #ifdef CONFIG_ARM_VIRT_EXT
1072 	sync_boot_mode();
1073 
1074 	if (is_hyp_mode_available()) {
1075 		pr_info("CPU: All CPU(s) started in HYP mode.\n");
1076 		pr_info("CPU: Virtualization extensions available.\n");
1077 	} else if (is_hyp_mode_mismatched()) {
1078 		pr_warn("CPU: WARNING: CPU(s) started in wrong/inconsistent modes (primary CPU mode 0x%x)\n",
1079 			__boot_cpu_mode & MODE_MASK);
1080 		pr_warn("CPU: This may indicate a broken bootloader or firmware.\n");
1081 	} else
1082 		pr_info("CPU: All CPU(s) started in SVC mode.\n");
1083 #endif
1084 }
1085 
1086 static void (*__arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
1087 
1088 static int arm_restart(struct notifier_block *nb, unsigned long action,
1089 		       void *data)
1090 {
1091 	__arm_pm_restart(action, data);
1092 	return NOTIFY_DONE;
1093 }
1094 
1095 static struct notifier_block arm_restart_nb = {
1096 	.notifier_call = arm_restart,
1097 	.priority = 128,
1098 };
1099 
1100 void __init setup_arch(char **cmdline_p)
1101 {
1102 	const struct machine_desc *mdesc = NULL;
1103 	void *atags_vaddr = NULL;
1104 
1105 	if (__atags_pointer)
1106 		atags_vaddr = FDT_VIRT_BASE(__atags_pointer);
1107 
1108 	setup_processor();
1109 	if (atags_vaddr) {
1110 		mdesc = setup_machine_fdt(atags_vaddr);
1111 		if (mdesc)
1112 			memblock_reserve(__atags_pointer,
1113 					 fdt_totalsize(atags_vaddr));
1114 	}
1115 	if (!mdesc)
1116 		mdesc = setup_machine_tags(atags_vaddr, __machine_arch_type);
1117 	if (!mdesc) {
1118 		early_print("\nError: invalid dtb and unrecognized/unsupported machine ID\n");
1119 		early_print("  r1=0x%08x, r2=0x%08x\n", __machine_arch_type,
1120 			    __atags_pointer);
1121 		if (__atags_pointer)
1122 			early_print("  r2[]=%*ph\n", 16, atags_vaddr);
1123 		dump_machine_table();
1124 	}
1125 
1126 	machine_desc = mdesc;
1127 	machine_name = mdesc->name;
1128 	dump_stack_set_arch_desc("%s", mdesc->name);
1129 
1130 	if (mdesc->reboot_mode != REBOOT_HARD)
1131 		reboot_mode = mdesc->reboot_mode;
1132 
1133 	setup_initial_init_mm(_text, _etext, _edata, _end);
1134 
1135 	/* populate cmd_line too for later use, preserving boot_command_line */
1136 	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
1137 	*cmdline_p = cmd_line;
1138 
1139 	early_fixmap_init();
1140 	early_ioremap_init();
1141 
1142 	parse_early_param();
1143 
1144 #ifdef CONFIG_MMU
1145 	early_mm_init(mdesc);
1146 #endif
1147 	setup_dma_zone(mdesc);
1148 	xen_early_init();
1149 	efi_init();
1150 	/*
1151 	 * Make sure the calculation for lowmem/highmem is set appropriately
1152 	 * before reserving/allocating any memory
1153 	 */
1154 	adjust_lowmem_bounds();
1155 	arm_memblock_init(mdesc);
1156 	/* Memory may have been removed so recalculate the bounds. */
1157 	adjust_lowmem_bounds();
1158 
1159 	early_ioremap_reset();
1160 
1161 	paging_init(mdesc);
1162 	kasan_init();
1163 	request_standard_resources(mdesc);
1164 
1165 	if (mdesc->restart) {
1166 		__arm_pm_restart = mdesc->restart;
1167 		register_restart_handler(&arm_restart_nb);
1168 	}
1169 
1170 	unflatten_device_tree();
1171 
1172 	arm_dt_init_cpu_maps();
1173 	psci_dt_init();
1174 #ifdef CONFIG_SMP
1175 	if (is_smp()) {
1176 		if (!mdesc->smp_init || !mdesc->smp_init()) {
1177 			if (psci_smp_available())
1178 				smp_set_ops(&psci_smp_ops);
1179 			else if (mdesc->smp)
1180 				smp_set_ops(mdesc->smp);
1181 		}
1182 		smp_init_cpus();
1183 		smp_build_mpidr_hash();
1184 	}
1185 #endif
1186 
1187 	if (!is_smp())
1188 		hyp_mode_check();
1189 
1190 	reserve_crashkernel();
1191 
1192 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
1193 	handle_arch_irq = mdesc->handle_irq;
1194 #endif
1195 
1196 #ifdef CONFIG_VT
1197 #if defined(CONFIG_VGA_CONSOLE)
1198 	conswitchp = &vga_con;
1199 #endif
1200 #endif
1201 
1202 	if (mdesc->init_early)
1203 		mdesc->init_early();
1204 }
1205 
1206 
1207 static int __init topology_init(void)
1208 {
1209 	int cpu;
1210 
1211 	for_each_possible_cpu(cpu) {
1212 		struct cpuinfo_arm *cpuinfo = &per_cpu(cpu_data, cpu);
1213 		cpuinfo->cpu.hotpluggable = platform_can_hotplug_cpu(cpu);
1214 		register_cpu(&cpuinfo->cpu, cpu);
1215 	}
1216 
1217 	return 0;
1218 }
1219 subsys_initcall(topology_init);
1220 
1221 #ifdef CONFIG_HAVE_PROC_CPU
1222 static int __init proc_cpu_init(void)
1223 {
1224 	struct proc_dir_entry *res;
1225 
1226 	res = proc_mkdir("cpu", NULL);
1227 	if (!res)
1228 		return -ENOMEM;
1229 	return 0;
1230 }
1231 fs_initcall(proc_cpu_init);
1232 #endif
1233 
1234 static const char *hwcap_str[] = {
1235 	"swp",
1236 	"half",
1237 	"thumb",
1238 	"26bit",
1239 	"fastmult",
1240 	"fpa",
1241 	"vfp",
1242 	"edsp",
1243 	"java",
1244 	"iwmmxt",
1245 	"crunch",
1246 	"thumbee",
1247 	"neon",
1248 	"vfpv3",
1249 	"vfpv3d16",
1250 	"tls",
1251 	"vfpv4",
1252 	"idiva",
1253 	"idivt",
1254 	"vfpd32",
1255 	"lpae",
1256 	"evtstrm",
1257 	NULL
1258 };
1259 
1260 static const char *hwcap2_str[] = {
1261 	"aes",
1262 	"pmull",
1263 	"sha1",
1264 	"sha2",
1265 	"crc32",
1266 	NULL
1267 };
1268 
1269 static int c_show(struct seq_file *m, void *v)
1270 {
1271 	int i, j;
1272 	u32 cpuid;
1273 
1274 	for_each_online_cpu(i) {
1275 		/*
1276 		 * glibc reads /proc/cpuinfo to determine the number of
1277 		 * online processors, looking for lines beginning with
1278 		 * "processor".  Give glibc what it expects.
1279 		 */
1280 		seq_printf(m, "processor\t: %d\n", i);
1281 		cpuid = is_smp() ? per_cpu(cpu_data, i).cpuid : read_cpuid_id();
1282 		seq_printf(m, "model name\t: %s rev %d (%s)\n",
1283 			   cpu_name, cpuid & 15, elf_platform);
1284 
1285 #if defined(CONFIG_SMP)
1286 		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
1287 			   per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ),
1288 			   (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100);
1289 #else
1290 		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
1291 			   loops_per_jiffy / (500000/HZ),
1292 			   (loops_per_jiffy / (5000/HZ)) % 100);
1293 #endif
1294 		/* dump out the processor features */
1295 		seq_puts(m, "Features\t: ");
1296 
1297 		for (j = 0; hwcap_str[j]; j++)
1298 			if (elf_hwcap & (1 << j))
1299 				seq_printf(m, "%s ", hwcap_str[j]);
1300 
1301 		for (j = 0; hwcap2_str[j]; j++)
1302 			if (elf_hwcap2 & (1 << j))
1303 				seq_printf(m, "%s ", hwcap2_str[j]);
1304 
1305 		seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24);
1306 		seq_printf(m, "CPU architecture: %s\n",
1307 			   proc_arch[cpu_architecture()]);
1308 
1309 		if ((cpuid & 0x0008f000) == 0x00000000) {
1310 			/* pre-ARM7 */
1311 			seq_printf(m, "CPU part\t: %07x\n", cpuid >> 4);
1312 		} else {
1313 			if ((cpuid & 0x0008f000) == 0x00007000) {
1314 				/* ARM7 */
1315 				seq_printf(m, "CPU variant\t: 0x%02x\n",
1316 					   (cpuid >> 16) & 127);
1317 			} else {
1318 				/* post-ARM7 */
1319 				seq_printf(m, "CPU variant\t: 0x%x\n",
1320 					   (cpuid >> 20) & 15);
1321 			}
1322 			seq_printf(m, "CPU part\t: 0x%03x\n",
1323 				   (cpuid >> 4) & 0xfff);
1324 		}
1325 		seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15);
1326 	}
1327 
1328 	seq_printf(m, "Hardware\t: %s\n", machine_name);
1329 	seq_printf(m, "Revision\t: %04x\n", system_rev);
1330 	seq_printf(m, "Serial\t\t: %s\n", system_serial);
1331 
1332 	return 0;
1333 }
1334 
1335 static void *c_start(struct seq_file *m, loff_t *pos)
1336 {
1337 	return *pos < 1 ? (void *)1 : NULL;
1338 }
1339 
1340 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
1341 {
1342 	++*pos;
1343 	return NULL;
1344 }
1345 
1346 static void c_stop(struct seq_file *m, void *v)
1347 {
1348 }
1349 
1350 const struct seq_operations cpuinfo_op = {
1351 	.start	= c_start,
1352 	.next	= c_next,
1353 	.stop	= c_stop,
1354 	.show	= c_show
1355 };
1356