xref: /linux/arch/arm/kernel/setup.c (revision 4f3c8320c78cdd11c8fdd23c33787407f719322e)
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	"r"
549 #else
550 #define PLC	"I"
551 #endif
552 
553 	/*
554 	 * setup stacks for re-entrant exception handlers
555 	 */
556 	__asm__ (
557 	"msr	cpsr_c, %1\n\t"
558 	"add	r14, %0, %2\n\t"
559 	"mov	sp, r14\n\t"
560 	"msr	cpsr_c, %3\n\t"
561 	"add	r14, %0, %4\n\t"
562 	"mov	sp, r14\n\t"
563 	"msr	cpsr_c, %5\n\t"
564 	"add	r14, %0, %6\n\t"
565 	"mov	sp, r14\n\t"
566 	"msr	cpsr_c, %7\n\t"
567 	"add	r14, %0, %8\n\t"
568 	"mov	sp, r14\n\t"
569 	"msr	cpsr_c, %9"
570 	    :
571 	    : "r" (stk),
572 	      PLC (PSR_F_BIT | PSR_I_BIT | IRQ_MODE),
573 	      "I" (offsetof(struct stack, irq[0])),
574 	      PLC (PSR_F_BIT | PSR_I_BIT | ABT_MODE),
575 	      "I" (offsetof(struct stack, abt[0])),
576 	      PLC (PSR_F_BIT | PSR_I_BIT | UND_MODE),
577 	      "I" (offsetof(struct stack, und[0])),
578 	      PLC (PSR_F_BIT | PSR_I_BIT | FIQ_MODE),
579 	      "I" (offsetof(struct stack, fiq[0])),
580 	      PLC (PSR_F_BIT | PSR_I_BIT | SVC_MODE)
581 	    : "r14");
582 #endif
583 }
584 
585 u32 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
586 
587 void __init smp_setup_processor_id(void)
588 {
589 	int i;
590 	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
591 	u32 cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
592 
593 	cpu_logical_map(0) = cpu;
594 	for (i = 1; i < nr_cpu_ids; ++i)
595 		cpu_logical_map(i) = i == cpu ? 0 : i;
596 
597 	/*
598 	 * clear __my_cpu_offset on boot CPU to avoid hang caused by
599 	 * using percpu variable early, for example, lockdep will
600 	 * access percpu variable inside lock_release
601 	 */
602 	set_my_cpu_offset(0);
603 
604 	pr_info("Booting Linux on physical CPU 0x%x\n", mpidr);
605 }
606 
607 struct mpidr_hash mpidr_hash;
608 #ifdef CONFIG_SMP
609 /**
610  * smp_build_mpidr_hash - Pre-compute shifts required at each affinity
611  *			  level in order to build a linear index from an
612  *			  MPIDR value. Resulting algorithm is a collision
613  *			  free hash carried out through shifting and ORing
614  */
615 static void __init smp_build_mpidr_hash(void)
616 {
617 	u32 i, affinity;
618 	u32 fs[3], bits[3], ls, mask = 0;
619 	/*
620 	 * Pre-scan the list of MPIDRS and filter out bits that do
621 	 * not contribute to affinity levels, ie they never toggle.
622 	 */
623 	for_each_possible_cpu(i)
624 		mask |= (cpu_logical_map(i) ^ cpu_logical_map(0));
625 	pr_debug("mask of set bits 0x%x\n", mask);
626 	/*
627 	 * Find and stash the last and first bit set at all affinity levels to
628 	 * check how many bits are required to represent them.
629 	 */
630 	for (i = 0; i < 3; i++) {
631 		affinity = MPIDR_AFFINITY_LEVEL(mask, i);
632 		/*
633 		 * Find the MSB bit and LSB bits position
634 		 * to determine how many bits are required
635 		 * to express the affinity level.
636 		 */
637 		ls = fls(affinity);
638 		fs[i] = affinity ? ffs(affinity) - 1 : 0;
639 		bits[i] = ls - fs[i];
640 	}
641 	/*
642 	 * An index can be created from the MPIDR by isolating the
643 	 * significant bits at each affinity level and by shifting
644 	 * them in order to compress the 24 bits values space to a
645 	 * compressed set of values. This is equivalent to hashing
646 	 * the MPIDR through shifting and ORing. It is a collision free
647 	 * hash though not minimal since some levels might contain a number
648 	 * of CPUs that is not an exact power of 2 and their bit
649 	 * representation might contain holes, eg MPIDR[7:0] = {0x2, 0x80}.
650 	 */
651 	mpidr_hash.shift_aff[0] = fs[0];
652 	mpidr_hash.shift_aff[1] = MPIDR_LEVEL_BITS + fs[1] - bits[0];
653 	mpidr_hash.shift_aff[2] = 2*MPIDR_LEVEL_BITS + fs[2] -
654 						(bits[1] + bits[0]);
655 	mpidr_hash.mask = mask;
656 	mpidr_hash.bits = bits[2] + bits[1] + bits[0];
657 	pr_debug("MPIDR hash: aff0[%u] aff1[%u] aff2[%u] mask[0x%x] bits[%u]\n",
658 				mpidr_hash.shift_aff[0],
659 				mpidr_hash.shift_aff[1],
660 				mpidr_hash.shift_aff[2],
661 				mpidr_hash.mask,
662 				mpidr_hash.bits);
663 	/*
664 	 * 4x is an arbitrary value used to warn on a hash table much bigger
665 	 * than expected on most systems.
666 	 */
667 	if (mpidr_hash_size() > 4 * num_possible_cpus())
668 		pr_warn("Large number of MPIDR hash buckets detected\n");
669 	sync_cache_w(&mpidr_hash);
670 }
671 #endif
672 
673 /*
674  * locate processor in the list of supported processor types.  The linker
675  * builds this table for us from the entries in arch/arm/mm/proc-*.S
676  */
677 struct proc_info_list *lookup_processor(u32 midr)
678 {
679 	struct proc_info_list *list = lookup_processor_type(midr);
680 
681 	if (!list) {
682 		pr_err("CPU%u: configuration botched (ID %08x), CPU halted\n",
683 		       smp_processor_id(), midr);
684 		while (1)
685 		/* can't use cpu_relax() here as it may require MMU setup */;
686 	}
687 
688 	return list;
689 }
690 
691 static void __init setup_processor(void)
692 {
693 	unsigned int midr = read_cpuid_id();
694 	struct proc_info_list *list = lookup_processor(midr);
695 
696 	cpu_name = list->cpu_name;
697 	__cpu_architecture = __get_cpu_architecture();
698 
699 	init_proc_vtable(list->proc);
700 #ifdef MULTI_TLB
701 	cpu_tlb = *list->tlb;
702 #endif
703 #ifdef MULTI_USER
704 	cpu_user = *list->user;
705 #endif
706 #ifdef MULTI_CACHE
707 	cpu_cache = *list->cache;
708 #endif
709 
710 	pr_info("CPU: %s [%08x] revision %d (ARMv%s), cr=%08lx\n",
711 		list->cpu_name, midr, midr & 15,
712 		proc_arch[cpu_architecture()], get_cr());
713 
714 	snprintf(init_utsname()->machine, __NEW_UTS_LEN + 1, "%s%c",
715 		 list->arch_name, ENDIANNESS);
716 	snprintf(elf_platform, ELF_PLATFORM_SIZE, "%s%c",
717 		 list->elf_name, ENDIANNESS);
718 	elf_hwcap = list->elf_hwcap;
719 
720 	cpuid_init_hwcaps();
721 	patch_aeabi_idiv();
722 
723 #ifndef CONFIG_ARM_THUMB
724 	elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT);
725 #endif
726 #ifdef CONFIG_MMU
727 	init_default_cache_policy(list->__cpu_mm_mmu_flags);
728 #endif
729 	erratum_a15_798181_init();
730 
731 	elf_hwcap_fixup();
732 
733 	cacheid_init();
734 	cpu_init();
735 }
736 
737 void __init dump_machine_table(void)
738 {
739 	const struct machine_desc *p;
740 
741 	early_print("Available machine support:\n\nID (hex)\tNAME\n");
742 	for_each_machine_desc(p)
743 		early_print("%08x\t%s\n", p->nr, p->name);
744 
745 	early_print("\nPlease check your kernel config and/or bootloader.\n");
746 
747 	while (true)
748 		/* can't use cpu_relax() here as it may require MMU setup */;
749 }
750 
751 int __init arm_add_memory(u64 start, u64 size)
752 {
753 	u64 aligned_start;
754 
755 	/*
756 	 * Ensure that start/size are aligned to a page boundary.
757 	 * Size is rounded down, start is rounded up.
758 	 */
759 	aligned_start = PAGE_ALIGN(start);
760 	if (aligned_start > start + size)
761 		size = 0;
762 	else
763 		size -= aligned_start - start;
764 
765 #ifndef CONFIG_PHYS_ADDR_T_64BIT
766 	if (aligned_start > ULONG_MAX) {
767 		pr_crit("Ignoring memory at 0x%08llx outside 32-bit physical address space\n",
768 			start);
769 		return -EINVAL;
770 	}
771 
772 	if (aligned_start + size > ULONG_MAX) {
773 		pr_crit("Truncating memory at 0x%08llx to fit in 32-bit physical address space\n",
774 			(long long)start);
775 		/*
776 		 * To ensure bank->start + bank->size is representable in
777 		 * 32 bits, we use ULONG_MAX as the upper limit rather than 4GB.
778 		 * This means we lose a page after masking.
779 		 */
780 		size = ULONG_MAX - aligned_start;
781 	}
782 #endif
783 
784 	if (aligned_start < PHYS_OFFSET) {
785 		if (aligned_start + size <= PHYS_OFFSET) {
786 			pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
787 				aligned_start, aligned_start + size);
788 			return -EINVAL;
789 		}
790 
791 		pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
792 			aligned_start, (u64)PHYS_OFFSET);
793 
794 		size -= PHYS_OFFSET - aligned_start;
795 		aligned_start = PHYS_OFFSET;
796 	}
797 
798 	start = aligned_start;
799 	size = size & ~(phys_addr_t)(PAGE_SIZE - 1);
800 
801 	/*
802 	 * Check whether this memory region has non-zero size or
803 	 * invalid node number.
804 	 */
805 	if (size == 0)
806 		return -EINVAL;
807 
808 	memblock_add(start, size);
809 	return 0;
810 }
811 
812 /*
813  * Pick out the memory size.  We look for mem=size@start,
814  * where start and size are "size[KkMm]"
815  */
816 
817 static int __init early_mem(char *p)
818 {
819 	static int usermem __initdata = 0;
820 	u64 size;
821 	u64 start;
822 	char *endp;
823 
824 	/*
825 	 * If the user specifies memory size, we
826 	 * blow away any automatically generated
827 	 * size.
828 	 */
829 	if (usermem == 0) {
830 		usermem = 1;
831 		memblock_remove(memblock_start_of_DRAM(),
832 			memblock_end_of_DRAM() - memblock_start_of_DRAM());
833 	}
834 
835 	start = PHYS_OFFSET;
836 	size  = memparse(p, &endp);
837 	if (*endp == '@')
838 		start = memparse(endp + 1, NULL);
839 
840 	arm_add_memory(start, size);
841 
842 	return 0;
843 }
844 early_param("mem", early_mem);
845 
846 static void __init request_standard_resources(const struct machine_desc *mdesc)
847 {
848 	phys_addr_t start, end, res_end;
849 	struct resource *res;
850 	u64 i;
851 
852 	kernel_code.start   = virt_to_phys(_text);
853 	kernel_code.end     = virt_to_phys(__init_begin - 1);
854 	kernel_data.start   = virt_to_phys(_sdata);
855 	kernel_data.end     = virt_to_phys(_end - 1);
856 
857 	for_each_mem_range(i, &start, &end) {
858 		unsigned long boot_alias_start;
859 
860 		/*
861 		 * In memblock, end points to the first byte after the
862 		 * range while in resourses, end points to the last byte in
863 		 * the range.
864 		 */
865 		res_end = end - 1;
866 
867 		/*
868 		 * Some systems have a special memory alias which is only
869 		 * used for booting.  We need to advertise this region to
870 		 * kexec-tools so they know where bootable RAM is located.
871 		 */
872 		boot_alias_start = phys_to_idmap(start);
873 		if (arm_has_idmap_alias() && boot_alias_start != IDMAP_INVALID_ADDR) {
874 			res = memblock_alloc(sizeof(*res), SMP_CACHE_BYTES);
875 			if (!res)
876 				panic("%s: Failed to allocate %zu bytes\n",
877 				      __func__, sizeof(*res));
878 			res->name = "System RAM (boot alias)";
879 			res->start = boot_alias_start;
880 			res->end = phys_to_idmap(res_end);
881 			res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
882 			request_resource(&iomem_resource, res);
883 		}
884 
885 		res = memblock_alloc(sizeof(*res), SMP_CACHE_BYTES);
886 		if (!res)
887 			panic("%s: Failed to allocate %zu bytes\n", __func__,
888 			      sizeof(*res));
889 		res->name  = "System RAM";
890 		res->start = start;
891 		res->end = res_end;
892 		res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
893 
894 		request_resource(&iomem_resource, res);
895 
896 		if (kernel_code.start >= res->start &&
897 		    kernel_code.end <= res->end)
898 			request_resource(res, &kernel_code);
899 		if (kernel_data.start >= res->start &&
900 		    kernel_data.end <= res->end)
901 			request_resource(res, &kernel_data);
902 	}
903 
904 	if (mdesc->video_start) {
905 		video_ram.start = mdesc->video_start;
906 		video_ram.end   = mdesc->video_end;
907 		request_resource(&iomem_resource, &video_ram);
908 	}
909 
910 	/*
911 	 * Some machines don't have the possibility of ever
912 	 * possessing lp0, lp1 or lp2
913 	 */
914 	if (mdesc->reserve_lp0)
915 		request_resource(&ioport_resource, &lp0);
916 	if (mdesc->reserve_lp1)
917 		request_resource(&ioport_resource, &lp1);
918 	if (mdesc->reserve_lp2)
919 		request_resource(&ioport_resource, &lp2);
920 }
921 
922 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) || \
923     defined(CONFIG_EFI)
924 struct screen_info screen_info = {
925  .orig_video_lines	= 30,
926  .orig_video_cols	= 80,
927  .orig_video_mode	= 0,
928  .orig_video_ega_bx	= 0,
929  .orig_video_isVGA	= 1,
930  .orig_video_points	= 8
931 };
932 #endif
933 
934 static int __init customize_machine(void)
935 {
936 	/*
937 	 * customizes platform devices, or adds new ones
938 	 * On DT based machines, we fall back to populating the
939 	 * machine from the device tree, if no callback is provided,
940 	 * otherwise we would always need an init_machine callback.
941 	 */
942 	if (machine_desc->init_machine)
943 		machine_desc->init_machine();
944 
945 	return 0;
946 }
947 arch_initcall(customize_machine);
948 
949 static int __init init_machine_late(void)
950 {
951 	struct device_node *root;
952 	int ret;
953 
954 	if (machine_desc->init_late)
955 		machine_desc->init_late();
956 
957 	root = of_find_node_by_path("/");
958 	if (root) {
959 		ret = of_property_read_string(root, "serial-number",
960 					      &system_serial);
961 		if (ret)
962 			system_serial = NULL;
963 	}
964 
965 	if (!system_serial)
966 		system_serial = kasprintf(GFP_KERNEL, "%08x%08x",
967 					  system_serial_high,
968 					  system_serial_low);
969 
970 	return 0;
971 }
972 late_initcall(init_machine_late);
973 
974 #ifdef CONFIG_KEXEC
975 /*
976  * The crash region must be aligned to 128MB to avoid
977  * zImage relocating below the reserved region.
978  */
979 #define CRASH_ALIGN	(128 << 20)
980 
981 static inline unsigned long long get_total_mem(void)
982 {
983 	unsigned long total;
984 
985 	total = max_low_pfn - min_low_pfn;
986 	return total << PAGE_SHIFT;
987 }
988 
989 /**
990  * reserve_crashkernel() - reserves memory are for crash kernel
991  *
992  * This function reserves memory area given in "crashkernel=" kernel command
993  * line parameter. The memory reserved is used by a dump capture kernel when
994  * primary kernel is crashing.
995  */
996 static void __init reserve_crashkernel(void)
997 {
998 	unsigned long long crash_size, crash_base;
999 	unsigned long long total_mem;
1000 	int ret;
1001 
1002 	total_mem = get_total_mem();
1003 	ret = parse_crashkernel(boot_command_line, total_mem,
1004 				&crash_size, &crash_base);
1005 	if (ret)
1006 		return;
1007 
1008 	if (crash_base <= 0) {
1009 		unsigned long long crash_max = idmap_to_phys((u32)~0);
1010 		unsigned long long lowmem_max = __pa(high_memory - 1) + 1;
1011 		if (crash_max > lowmem_max)
1012 			crash_max = lowmem_max;
1013 		crash_base = memblock_find_in_range(CRASH_ALIGN, crash_max,
1014 						    crash_size, CRASH_ALIGN);
1015 		if (!crash_base) {
1016 			pr_err("crashkernel reservation failed - No suitable area found.\n");
1017 			return;
1018 		}
1019 	} else {
1020 		unsigned long long start;
1021 
1022 		start = memblock_find_in_range(crash_base,
1023 					       crash_base + crash_size,
1024 					       crash_size, SECTION_SIZE);
1025 		if (start != crash_base) {
1026 			pr_err("crashkernel reservation failed - memory is in use.\n");
1027 			return;
1028 		}
1029 	}
1030 
1031 	ret = memblock_reserve(crash_base, crash_size);
1032 	if (ret < 0) {
1033 		pr_warn("crashkernel reservation failed - memory is in use (0x%lx)\n",
1034 			(unsigned long)crash_base);
1035 		return;
1036 	}
1037 
1038 	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
1039 		(unsigned long)(crash_size >> 20),
1040 		(unsigned long)(crash_base >> 20),
1041 		(unsigned long)(total_mem >> 20));
1042 
1043 	/* The crashk resource must always be located in normal mem */
1044 	crashk_res.start = crash_base;
1045 	crashk_res.end = crash_base + crash_size - 1;
1046 	insert_resource(&iomem_resource, &crashk_res);
1047 
1048 	if (arm_has_idmap_alias()) {
1049 		/*
1050 		 * If we have a special RAM alias for use at boot, we
1051 		 * need to advertise to kexec tools where the alias is.
1052 		 */
1053 		static struct resource crashk_boot_res = {
1054 			.name = "Crash kernel (boot alias)",
1055 			.flags = IORESOURCE_BUSY | IORESOURCE_MEM,
1056 		};
1057 
1058 		crashk_boot_res.start = phys_to_idmap(crash_base);
1059 		crashk_boot_res.end = crashk_boot_res.start + crash_size - 1;
1060 		insert_resource(&iomem_resource, &crashk_boot_res);
1061 	}
1062 }
1063 #else
1064 static inline void reserve_crashkernel(void) {}
1065 #endif /* CONFIG_KEXEC */
1066 
1067 void __init hyp_mode_check(void)
1068 {
1069 #ifdef CONFIG_ARM_VIRT_EXT
1070 	sync_boot_mode();
1071 
1072 	if (is_hyp_mode_available()) {
1073 		pr_info("CPU: All CPU(s) started in HYP mode.\n");
1074 		pr_info("CPU: Virtualization extensions available.\n");
1075 	} else if (is_hyp_mode_mismatched()) {
1076 		pr_warn("CPU: WARNING: CPU(s) started in wrong/inconsistent modes (primary CPU mode 0x%x)\n",
1077 			__boot_cpu_mode & MODE_MASK);
1078 		pr_warn("CPU: This may indicate a broken bootloader or firmware.\n");
1079 	} else
1080 		pr_info("CPU: All CPU(s) started in SVC mode.\n");
1081 #endif
1082 }
1083 
1084 void __init setup_arch(char **cmdline_p)
1085 {
1086 	const struct machine_desc *mdesc = NULL;
1087 	void *atags_vaddr = NULL;
1088 
1089 	if (__atags_pointer)
1090 		atags_vaddr = FDT_VIRT_BASE(__atags_pointer);
1091 
1092 	setup_processor();
1093 	if (atags_vaddr) {
1094 		mdesc = setup_machine_fdt(atags_vaddr);
1095 		if (mdesc)
1096 			memblock_reserve(__atags_pointer,
1097 					 fdt_totalsize(atags_vaddr));
1098 	}
1099 	if (!mdesc)
1100 		mdesc = setup_machine_tags(atags_vaddr, __machine_arch_type);
1101 	if (!mdesc) {
1102 		early_print("\nError: invalid dtb and unrecognized/unsupported machine ID\n");
1103 		early_print("  r1=0x%08x, r2=0x%08x\n", __machine_arch_type,
1104 			    __atags_pointer);
1105 		if (__atags_pointer)
1106 			early_print("  r2[]=%*ph\n", 16, atags_vaddr);
1107 		dump_machine_table();
1108 	}
1109 
1110 	machine_desc = mdesc;
1111 	machine_name = mdesc->name;
1112 	dump_stack_set_arch_desc("%s", mdesc->name);
1113 
1114 	if (mdesc->reboot_mode != REBOOT_HARD)
1115 		reboot_mode = mdesc->reboot_mode;
1116 
1117 	init_mm.start_code = (unsigned long) _text;
1118 	init_mm.end_code   = (unsigned long) _etext;
1119 	init_mm.end_data   = (unsigned long) _edata;
1120 	init_mm.brk	   = (unsigned long) _end;
1121 
1122 	/* populate cmd_line too for later use, preserving boot_command_line */
1123 	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
1124 	*cmdline_p = cmd_line;
1125 
1126 	early_fixmap_init();
1127 	early_ioremap_init();
1128 
1129 	parse_early_param();
1130 
1131 #ifdef CONFIG_MMU
1132 	early_mm_init(mdesc);
1133 #endif
1134 	setup_dma_zone(mdesc);
1135 	xen_early_init();
1136 	efi_init();
1137 	/*
1138 	 * Make sure the calculation for lowmem/highmem is set appropriately
1139 	 * before reserving/allocating any memory
1140 	 */
1141 	adjust_lowmem_bounds();
1142 	arm_memblock_init(mdesc);
1143 	/* Memory may have been removed so recalculate the bounds. */
1144 	adjust_lowmem_bounds();
1145 
1146 	early_ioremap_reset();
1147 
1148 	paging_init(mdesc);
1149 	kasan_init();
1150 	request_standard_resources(mdesc);
1151 
1152 	if (mdesc->restart)
1153 		arm_pm_restart = mdesc->restart;
1154 
1155 	unflatten_device_tree();
1156 
1157 	arm_dt_init_cpu_maps();
1158 	psci_dt_init();
1159 #ifdef CONFIG_SMP
1160 	if (is_smp()) {
1161 		if (!mdesc->smp_init || !mdesc->smp_init()) {
1162 			if (psci_smp_available())
1163 				smp_set_ops(&psci_smp_ops);
1164 			else if (mdesc->smp)
1165 				smp_set_ops(mdesc->smp);
1166 		}
1167 		smp_init_cpus();
1168 		smp_build_mpidr_hash();
1169 	}
1170 #endif
1171 
1172 	if (!is_smp())
1173 		hyp_mode_check();
1174 
1175 	reserve_crashkernel();
1176 
1177 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
1178 	handle_arch_irq = mdesc->handle_irq;
1179 #endif
1180 
1181 #ifdef CONFIG_VT
1182 #if defined(CONFIG_VGA_CONSOLE)
1183 	conswitchp = &vga_con;
1184 #endif
1185 #endif
1186 
1187 	if (mdesc->init_early)
1188 		mdesc->init_early();
1189 }
1190 
1191 
1192 static int __init topology_init(void)
1193 {
1194 	int cpu;
1195 
1196 	for_each_possible_cpu(cpu) {
1197 		struct cpuinfo_arm *cpuinfo = &per_cpu(cpu_data, cpu);
1198 		cpuinfo->cpu.hotpluggable = platform_can_hotplug_cpu(cpu);
1199 		register_cpu(&cpuinfo->cpu, cpu);
1200 	}
1201 
1202 	return 0;
1203 }
1204 subsys_initcall(topology_init);
1205 
1206 #ifdef CONFIG_HAVE_PROC_CPU
1207 static int __init proc_cpu_init(void)
1208 {
1209 	struct proc_dir_entry *res;
1210 
1211 	res = proc_mkdir("cpu", NULL);
1212 	if (!res)
1213 		return -ENOMEM;
1214 	return 0;
1215 }
1216 fs_initcall(proc_cpu_init);
1217 #endif
1218 
1219 static const char *hwcap_str[] = {
1220 	"swp",
1221 	"half",
1222 	"thumb",
1223 	"26bit",
1224 	"fastmult",
1225 	"fpa",
1226 	"vfp",
1227 	"edsp",
1228 	"java",
1229 	"iwmmxt",
1230 	"crunch",
1231 	"thumbee",
1232 	"neon",
1233 	"vfpv3",
1234 	"vfpv3d16",
1235 	"tls",
1236 	"vfpv4",
1237 	"idiva",
1238 	"idivt",
1239 	"vfpd32",
1240 	"lpae",
1241 	"evtstrm",
1242 	NULL
1243 };
1244 
1245 static const char *hwcap2_str[] = {
1246 	"aes",
1247 	"pmull",
1248 	"sha1",
1249 	"sha2",
1250 	"crc32",
1251 	NULL
1252 };
1253 
1254 static int c_show(struct seq_file *m, void *v)
1255 {
1256 	int i, j;
1257 	u32 cpuid;
1258 
1259 	for_each_online_cpu(i) {
1260 		/*
1261 		 * glibc reads /proc/cpuinfo to determine the number of
1262 		 * online processors, looking for lines beginning with
1263 		 * "processor".  Give glibc what it expects.
1264 		 */
1265 		seq_printf(m, "processor\t: %d\n", i);
1266 		cpuid = is_smp() ? per_cpu(cpu_data, i).cpuid : read_cpuid_id();
1267 		seq_printf(m, "model name\t: %s rev %d (%s)\n",
1268 			   cpu_name, cpuid & 15, elf_platform);
1269 
1270 #if defined(CONFIG_SMP)
1271 		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
1272 			   per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ),
1273 			   (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100);
1274 #else
1275 		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
1276 			   loops_per_jiffy / (500000/HZ),
1277 			   (loops_per_jiffy / (5000/HZ)) % 100);
1278 #endif
1279 		/* dump out the processor features */
1280 		seq_puts(m, "Features\t: ");
1281 
1282 		for (j = 0; hwcap_str[j]; j++)
1283 			if (elf_hwcap & (1 << j))
1284 				seq_printf(m, "%s ", hwcap_str[j]);
1285 
1286 		for (j = 0; hwcap2_str[j]; j++)
1287 			if (elf_hwcap2 & (1 << j))
1288 				seq_printf(m, "%s ", hwcap2_str[j]);
1289 
1290 		seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24);
1291 		seq_printf(m, "CPU architecture: %s\n",
1292 			   proc_arch[cpu_architecture()]);
1293 
1294 		if ((cpuid & 0x0008f000) == 0x00000000) {
1295 			/* pre-ARM7 */
1296 			seq_printf(m, "CPU part\t: %07x\n", cpuid >> 4);
1297 		} else {
1298 			if ((cpuid & 0x0008f000) == 0x00007000) {
1299 				/* ARM7 */
1300 				seq_printf(m, "CPU variant\t: 0x%02x\n",
1301 					   (cpuid >> 16) & 127);
1302 			} else {
1303 				/* post-ARM7 */
1304 				seq_printf(m, "CPU variant\t: 0x%x\n",
1305 					   (cpuid >> 20) & 15);
1306 			}
1307 			seq_printf(m, "CPU part\t: 0x%03x\n",
1308 				   (cpuid >> 4) & 0xfff);
1309 		}
1310 		seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15);
1311 	}
1312 
1313 	seq_printf(m, "Hardware\t: %s\n", machine_name);
1314 	seq_printf(m, "Revision\t: %04x\n", system_rev);
1315 	seq_printf(m, "Serial\t\t: %s\n", system_serial);
1316 
1317 	return 0;
1318 }
1319 
1320 static void *c_start(struct seq_file *m, loff_t *pos)
1321 {
1322 	return *pos < 1 ? (void *)1 : NULL;
1323 }
1324 
1325 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
1326 {
1327 	++*pos;
1328 	return NULL;
1329 }
1330 
1331 static void c_stop(struct seq_file *m, void *v)
1332 {
1333 }
1334 
1335 const struct seq_operations cpuinfo_op = {
1336 	.start	= c_start,
1337 	.next	= c_next,
1338 	.stop	= c_stop,
1339 	.show	= c_show
1340 };
1341