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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/sparc64/kernel/setup.c
4 *
5 * Copyright (C) 1995,1996 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7 */
8
9#include <linux/errno.h>
10#include <linux/sched.h>
11#include <linux/kernel.h>
12#include <linux/mm.h>
13#include <linux/stddef.h>
14#include <linux/unistd.h>
15#include <linux/ptrace.h>
16#include <asm/smp.h>
17#include <linux/user.h>
18#include <linux/delay.h>
19#include <linux/fs.h>
20#include <linux/seq_file.h>
21#include <linux/syscalls.h>
22#include <linux/kdev_t.h>
23#include <linux/major.h>
24#include <linux/string.h>
25#include <linux/init.h>
26#include <linux/inet.h>
27#include <linux/console.h>
28#include <linux/root_dev.h>
29#include <linux/interrupt.h>
30#include <linux/cpu.h>
31#include <linux/initrd.h>
32#include <linux/module.h>
33#include <linux/start_kernel.h>
34#include <linux/memblock.h>
35#include <uapi/linux/mount.h>
36
37#include <asm/io.h>
38#include <asm/processor.h>
39#include <asm/oplib.h>
40#include <asm/page.h>
41#include <asm/idprom.h>
42#include <asm/head.h>
43#include <asm/starfire.h>
44#include <asm/mmu_context.h>
45#include <asm/timer.h>
46#include <asm/sections.h>
47#include <asm/setup.h>
48#include <asm/mmu.h>
49#include <asm/ns87303.h>
50#include <asm/btext.h>
51#include <asm/elf.h>
52#include <asm/mdesc.h>
53#include <asm/cacheflush.h>
54#include <asm/dma.h>
55#include <asm/irq.h>
56
57#ifdef CONFIG_IP_PNP
58#include <net/ipconfig.h>
59#endif
60
61#include "entry.h"
62#include "kernel.h"
63
64/* Used to synchronize accesses to NatSemi SUPER I/O chip configure
65 * operations in asm/ns87303.h
66 */
67DEFINE_SPINLOCK(ns87303_lock);
68EXPORT_SYMBOL(ns87303_lock);
69
70static void
71prom_console_write(struct console *con, const char *s, unsigned int n)
72{
73 prom_write(s, n);
74}
75
76/* Exported for mm/init.c:paging_init. */
77unsigned long cmdline_memory_size = 0;
78
79static struct console prom_early_console = {
80 .name = "earlyprom",
81 .write = prom_console_write,
82 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
83 .index = -1,
84};
85
86/*
87 * Process kernel command line switches that are specific to the
88 * SPARC or that require special low-level processing.
89 */
90static void __init process_switch(char c)
91{
92 switch (c) {
93 case 'd':
94 case 's':
95 break;
96 case 'h':
97 prom_printf("boot_flags_init: Halt!\n");
98 prom_halt();
99 break;
100 case 'p':
101 prom_early_console.flags &= ~CON_BOOT;
102 break;
103 case 'P':
104 /* Force UltraSPARC-III P-Cache on. */
105 if (tlb_type != cheetah) {
106 printk("BOOT: Ignoring P-Cache force option.\n");
107 break;
108 }
109 cheetah_pcache_forced_on = 1;
110 add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
111 cheetah_enable_pcache();
112 break;
113
114 default:
115 printk("Unknown boot switch (-%c)\n", c);
116 break;
117 }
118}
119
120static void __init boot_flags_init(char *commands)
121{
122 while (*commands) {
123 /* Move to the start of the next "argument". */
124 while (*commands == ' ')
125 commands++;
126
127 /* Process any command switches, otherwise skip it. */
128 if (*commands == '\0')
129 break;
130 if (*commands == '-') {
131 commands++;
132 while (*commands && *commands != ' ')
133 process_switch(c: *commands++);
134 continue;
135 }
136 if (!strncmp(commands, "mem=", 4))
137 cmdline_memory_size = memparse(ptr: commands + 4, retptr: &commands);
138
139 while (*commands && *commands != ' ')
140 commands++;
141 }
142}
143
144extern unsigned short root_flags;
145extern unsigned short root_dev;
146extern unsigned short ram_flags;
147#define RAMDISK_IMAGE_START_MASK 0x07FF
148#define RAMDISK_PROMPT_FLAG 0x8000
149#define RAMDISK_LOAD_FLAG 0x4000
150
151extern int root_mountflags;
152
153char reboot_command[COMMAND_LINE_SIZE];
154
155static void __init per_cpu_patch(void)
156{
157 struct cpuid_patch_entry *p;
158 unsigned long ver;
159 int is_jbus;
160
161 if (tlb_type == spitfire && !this_is_starfire)
162 return;
163
164 is_jbus = 0;
165 if (tlb_type != hypervisor) {
166 __asm__ ("rdpr %%ver, %0" : "=r" (ver));
167 is_jbus = ((ver >> 32UL) == __JALAPENO_ID ||
168 (ver >> 32UL) == __SERRANO_ID);
169 }
170
171 p = &__cpuid_patch;
172 while (p < &__cpuid_patch_end) {
173 unsigned long addr = p->addr;
174 unsigned int *insns;
175
176 switch (tlb_type) {
177 case spitfire:
178 insns = &p->starfire[0];
179 break;
180 case cheetah:
181 case cheetah_plus:
182 if (is_jbus)
183 insns = &p->cheetah_jbus[0];
184 else
185 insns = &p->cheetah_safari[0];
186 break;
187 case hypervisor:
188 insns = &p->sun4v[0];
189 break;
190 default:
191 prom_printf("Unknown cpu type, halting.\n");
192 prom_halt();
193 }
194
195 *(unsigned int *) (addr + 0) = insns[0];
196 wmb();
197 __asm__ __volatile__("flush %0" : : "r" (addr + 0));
198
199 *(unsigned int *) (addr + 4) = insns[1];
200 wmb();
201 __asm__ __volatile__("flush %0" : : "r" (addr + 4));
202
203 *(unsigned int *) (addr + 8) = insns[2];
204 wmb();
205 __asm__ __volatile__("flush %0" : : "r" (addr + 8));
206
207 *(unsigned int *) (addr + 12) = insns[3];
208 wmb();
209 __asm__ __volatile__("flush %0" : : "r" (addr + 12));
210
211 p++;
212 }
213}
214
215void sun4v_patch_1insn_range(struct sun4v_1insn_patch_entry *start,
216 struct sun4v_1insn_patch_entry *end)
217{
218 while (start < end) {
219 unsigned long addr = start->addr;
220
221 *(unsigned int *) (addr + 0) = start->insn;
222 wmb();
223 __asm__ __volatile__("flush %0" : : "r" (addr + 0));
224
225 start++;
226 }
227}
228
229void sun4v_patch_2insn_range(struct sun4v_2insn_patch_entry *start,
230 struct sun4v_2insn_patch_entry *end)
231{
232 while (start < end) {
233 unsigned long addr = start->addr;
234
235 *(unsigned int *) (addr + 0) = start->insns[0];
236 wmb();
237 __asm__ __volatile__("flush %0" : : "r" (addr + 0));
238
239 *(unsigned int *) (addr + 4) = start->insns[1];
240 wmb();
241 __asm__ __volatile__("flush %0" : : "r" (addr + 4));
242
243 start++;
244 }
245}
246
247void sun_m7_patch_2insn_range(struct sun4v_2insn_patch_entry *start,
248 struct sun4v_2insn_patch_entry *end)
249{
250 while (start < end) {
251 unsigned long addr = start->addr;
252
253 *(unsigned int *) (addr + 0) = start->insns[0];
254 wmb();
255 __asm__ __volatile__("flush %0" : : "r" (addr + 0));
256
257 *(unsigned int *) (addr + 4) = start->insns[1];
258 wmb();
259 __asm__ __volatile__("flush %0" : : "r" (addr + 4));
260
261 start++;
262 }
263}
264
265static void __init sun4v_patch(void)
266{
267 extern void sun4v_hvapi_init(void);
268
269 if (tlb_type != hypervisor)
270 return;
271
272 sun4v_patch_1insn_range(&__sun4v_1insn_patch,
273 &__sun4v_1insn_patch_end);
274
275 sun4v_patch_2insn_range(&__sun4v_2insn_patch,
276 &__sun4v_2insn_patch_end);
277
278 switch (sun4v_chip_type) {
279 case SUN4V_CHIP_SPARC_M7:
280 case SUN4V_CHIP_SPARC_M8:
281 case SUN4V_CHIP_SPARC_SN:
282 sun4v_patch_1insn_range(&__sun_m7_1insn_patch,
283 &__sun_m7_1insn_patch_end);
284 sun_m7_patch_2insn_range(&__sun_m7_2insn_patch,
285 &__sun_m7_2insn_patch_end);
286 break;
287 default:
288 break;
289 }
290
291 if (sun4v_chip_type != SUN4V_CHIP_NIAGARA1) {
292 sun4v_patch_1insn_range(&__fast_win_ctrl_1insn_patch,
293 &__fast_win_ctrl_1insn_patch_end);
294 }
295
296 sun4v_hvapi_init();
297}
298
299static void __init popc_patch(void)
300{
301 struct popc_3insn_patch_entry *p3;
302 struct popc_6insn_patch_entry *p6;
303
304 p3 = &__popc_3insn_patch;
305 while (p3 < &__popc_3insn_patch_end) {
306 unsigned long i, addr = p3->addr;
307
308 for (i = 0; i < 3; i++) {
309 *(unsigned int *) (addr + (i * 4)) = p3->insns[i];
310 wmb();
311 __asm__ __volatile__("flush %0"
312 : : "r" (addr + (i * 4)));
313 }
314
315 p3++;
316 }
317
318 p6 = &__popc_6insn_patch;
319 while (p6 < &__popc_6insn_patch_end) {
320 unsigned long i, addr = p6->addr;
321
322 for (i = 0; i < 6; i++) {
323 *(unsigned int *) (addr + (i * 4)) = p6->insns[i];
324 wmb();
325 __asm__ __volatile__("flush %0"
326 : : "r" (addr + (i * 4)));
327 }
328
329 p6++;
330 }
331}
332
333static void __init pause_patch(void)
334{
335 struct pause_patch_entry *p;
336
337 p = &__pause_3insn_patch;
338 while (p < &__pause_3insn_patch_end) {
339 unsigned long i, addr = p->addr;
340
341 for (i = 0; i < 3; i++) {
342 *(unsigned int *) (addr + (i * 4)) = p->insns[i];
343 wmb();
344 __asm__ __volatile__("flush %0"
345 : : "r" (addr + (i * 4)));
346 }
347
348 p++;
349 }
350}
351
352void __init start_early_boot(void)
353{
354 int cpu;
355
356 check_if_starfire();
357 per_cpu_patch();
358 sun4v_patch();
359 smp_init_cpu_poke();
360
361 cpu = hard_smp_processor_id();
362 if (cpu >= NR_CPUS) {
363 prom_printf("Serious problem, boot cpu id (%d) >= NR_CPUS (%d)\n",
364 cpu, NR_CPUS);
365 prom_halt();
366 }
367 current_thread_info()->cpu = cpu;
368
369 time_init_early();
370 prom_init_report();
371 start_kernel();
372}
373
374/* On Ultra, we support all of the v8 capabilities. */
375unsigned long sparc64_elf_hwcap = (HWCAP_SPARC_FLUSH | HWCAP_SPARC_STBAR |
376 HWCAP_SPARC_SWAP | HWCAP_SPARC_MULDIV |
377 HWCAP_SPARC_V9);
378EXPORT_SYMBOL(sparc64_elf_hwcap);
379
380static const char *hwcaps[] = {
381 "flush", "stbar", "swap", "muldiv", "v9",
382 "ultra3", "blkinit", "n2",
383
384 /* These strings are as they appear in the machine description
385 * 'hwcap-list' property for cpu nodes.
386 */
387 "mul32", "div32", "fsmuld", "v8plus", "popc", "vis", "vis2",
388 "ASIBlkInit", "fmaf", "vis3", "hpc", "random", "trans", "fjfmau",
389 "ima", "cspare", "pause", "cbcond", NULL /*reserved for crypto */,
390 "adp",
391};
392
393static const char *crypto_hwcaps[] = {
394 "aes", "des", "kasumi", "camellia", "md5", "sha1", "sha256",
395 "sha512", "mpmul", "montmul", "montsqr", "crc32c",
396};
397
398void cpucap_info(struct seq_file *m)
399{
400 unsigned long caps = sparc64_elf_hwcap;
401 int i, printed = 0;
402
403 seq_puts(m, s: "cpucaps\t\t: ");
404 for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
405 unsigned long bit = 1UL << i;
406 if (hwcaps[i] && (caps & bit)) {
407 seq_printf(m, fmt: "%s%s",
408 printed ? "," : "", hwcaps[i]);
409 printed++;
410 }
411 }
412 if (caps & HWCAP_SPARC_CRYPTO) {
413 unsigned long cfr;
414
415 __asm__ __volatile__("rd %%asr26, %0" : "=r" (cfr));
416 for (i = 0; i < ARRAY_SIZE(crypto_hwcaps); i++) {
417 unsigned long bit = 1UL << i;
418 if (cfr & bit) {
419 seq_printf(m, fmt: "%s%s",
420 printed ? "," : "", crypto_hwcaps[i]);
421 printed++;
422 }
423 }
424 }
425 seq_putc(m, c: '\n');
426}
427
428static void __init report_one_hwcap(int *printed, const char *name)
429{
430 if ((*printed) == 0)
431 printk(KERN_INFO "CPU CAPS: [");
432 printk(KERN_CONT "%s%s",
433 (*printed) ? "," : "", name);
434 if (++(*printed) == 8) {
435 printk(KERN_CONT "]\n");
436 *printed = 0;
437 }
438}
439
440static void __init report_crypto_hwcaps(int *printed)
441{
442 unsigned long cfr;
443 int i;
444
445 __asm__ __volatile__("rd %%asr26, %0" : "=r" (cfr));
446
447 for (i = 0; i < ARRAY_SIZE(crypto_hwcaps); i++) {
448 unsigned long bit = 1UL << i;
449 if (cfr & bit)
450 report_one_hwcap(printed, name: crypto_hwcaps[i]);
451 }
452}
453
454static void __init report_hwcaps(unsigned long caps)
455{
456 int i, printed = 0;
457
458 for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
459 unsigned long bit = 1UL << i;
460 if (hwcaps[i] && (caps & bit))
461 report_one_hwcap(printed: &printed, name: hwcaps[i]);
462 }
463 if (caps & HWCAP_SPARC_CRYPTO)
464 report_crypto_hwcaps(printed: &printed);
465 if (printed != 0)
466 printk(KERN_CONT "]\n");
467}
468
469static unsigned long __init mdesc_cpu_hwcap_list(void)
470{
471 struct mdesc_handle *hp;
472 unsigned long caps = 0;
473 const char *prop;
474 int len;
475 u64 pn;
476
477 hp = mdesc_grab();
478 if (!hp)
479 return 0;
480
481 pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "cpu");
482 if (pn == MDESC_NODE_NULL)
483 goto out;
484
485 prop = mdesc_get_property(hp, pn, "hwcap-list", &len);
486 if (!prop)
487 goto out;
488
489 while (len) {
490 int i, plen;
491
492 for (i = 0; i < ARRAY_SIZE(hwcaps); i++) {
493 unsigned long bit = 1UL << i;
494
495 if (hwcaps[i] && !strcmp(prop, hwcaps[i])) {
496 caps |= bit;
497 break;
498 }
499 }
500 for (i = 0; i < ARRAY_SIZE(crypto_hwcaps); i++) {
501 if (!strcmp(prop, crypto_hwcaps[i]))
502 caps |= HWCAP_SPARC_CRYPTO;
503 }
504
505 plen = strlen(prop) + 1;
506 prop += plen;
507 len -= plen;
508 }
509
510out:
511 mdesc_release(hp);
512 return caps;
513}
514
515/* This yields a mask that user programs can use to figure out what
516 * instruction set this cpu supports.
517 */
518static void __init init_sparc64_elf_hwcap(void)
519{
520 unsigned long cap = sparc64_elf_hwcap;
521 unsigned long mdesc_caps;
522
523 if (tlb_type == cheetah || tlb_type == cheetah_plus)
524 cap |= HWCAP_SPARC_ULTRA3;
525 else if (tlb_type == hypervisor) {
526 if (sun4v_chip_type == SUN4V_CHIP_NIAGARA1 ||
527 sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
528 sun4v_chip_type == SUN4V_CHIP_NIAGARA3 ||
529 sun4v_chip_type == SUN4V_CHIP_NIAGARA4 ||
530 sun4v_chip_type == SUN4V_CHIP_NIAGARA5 ||
531 sun4v_chip_type == SUN4V_CHIP_SPARC_M6 ||
532 sun4v_chip_type == SUN4V_CHIP_SPARC_M7 ||
533 sun4v_chip_type == SUN4V_CHIP_SPARC_M8 ||
534 sun4v_chip_type == SUN4V_CHIP_SPARC_SN ||
535 sun4v_chip_type == SUN4V_CHIP_SPARC64X)
536 cap |= HWCAP_SPARC_BLKINIT;
537 if (sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
538 sun4v_chip_type == SUN4V_CHIP_NIAGARA3 ||
539 sun4v_chip_type == SUN4V_CHIP_NIAGARA4 ||
540 sun4v_chip_type == SUN4V_CHIP_NIAGARA5 ||
541 sun4v_chip_type == SUN4V_CHIP_SPARC_M6 ||
542 sun4v_chip_type == SUN4V_CHIP_SPARC_M7 ||
543 sun4v_chip_type == SUN4V_CHIP_SPARC_M8 ||
544 sun4v_chip_type == SUN4V_CHIP_SPARC_SN ||
545 sun4v_chip_type == SUN4V_CHIP_SPARC64X)
546 cap |= HWCAP_SPARC_N2;
547 }
548
549 cap |= (AV_SPARC_MUL32 | AV_SPARC_DIV32 | AV_SPARC_V8PLUS);
550
551 mdesc_caps = mdesc_cpu_hwcap_list();
552 if (!mdesc_caps) {
553 if (tlb_type == spitfire)
554 cap |= AV_SPARC_VIS;
555 if (tlb_type == cheetah || tlb_type == cheetah_plus)
556 cap |= AV_SPARC_VIS | AV_SPARC_VIS2;
557 if (tlb_type == cheetah_plus) {
558 unsigned long impl, ver;
559
560 __asm__ __volatile__("rdpr %%ver, %0" : "=r" (ver));
561 impl = ((ver >> 32) & 0xffff);
562 if (impl == PANTHER_IMPL)
563 cap |= AV_SPARC_POPC;
564 }
565 if (tlb_type == hypervisor) {
566 if (sun4v_chip_type == SUN4V_CHIP_NIAGARA1)
567 cap |= AV_SPARC_ASI_BLK_INIT;
568 if (sun4v_chip_type == SUN4V_CHIP_NIAGARA2 ||
569 sun4v_chip_type == SUN4V_CHIP_NIAGARA3 ||
570 sun4v_chip_type == SUN4V_CHIP_NIAGARA4 ||
571 sun4v_chip_type == SUN4V_CHIP_NIAGARA5 ||
572 sun4v_chip_type == SUN4V_CHIP_SPARC_M6 ||
573 sun4v_chip_type == SUN4V_CHIP_SPARC_M7 ||
574 sun4v_chip_type == SUN4V_CHIP_SPARC_M8 ||
575 sun4v_chip_type == SUN4V_CHIP_SPARC_SN ||
576 sun4v_chip_type == SUN4V_CHIP_SPARC64X)
577 cap |= (AV_SPARC_VIS | AV_SPARC_VIS2 |
578 AV_SPARC_ASI_BLK_INIT |
579 AV_SPARC_POPC);
580 if (sun4v_chip_type == SUN4V_CHIP_NIAGARA3 ||
581 sun4v_chip_type == SUN4V_CHIP_NIAGARA4 ||
582 sun4v_chip_type == SUN4V_CHIP_NIAGARA5 ||
583 sun4v_chip_type == SUN4V_CHIP_SPARC_M6 ||
584 sun4v_chip_type == SUN4V_CHIP_SPARC_M7 ||
585 sun4v_chip_type == SUN4V_CHIP_SPARC_M8 ||
586 sun4v_chip_type == SUN4V_CHIP_SPARC_SN ||
587 sun4v_chip_type == SUN4V_CHIP_SPARC64X)
588 cap |= (AV_SPARC_VIS3 | AV_SPARC_HPC |
589 AV_SPARC_FMAF);
590 }
591 }
592 sparc64_elf_hwcap = cap | mdesc_caps;
593
594 report_hwcaps(caps: sparc64_elf_hwcap);
595
596 if (sparc64_elf_hwcap & AV_SPARC_POPC)
597 popc_patch();
598 if (sparc64_elf_hwcap & AV_SPARC_PAUSE)
599 pause_patch();
600}
601
602static void __init alloc_irqstack_bootmem(void)
603{
604 unsigned int i, node;
605
606 for_each_possible_cpu(i) {
607 node = cpu_to_node(cpu: i);
608
609 softirq_stack[i] = memblock_alloc_node(THREAD_SIZE,
610 THREAD_SIZE, node);
611 if (!softirq_stack[i])
612 panic(fmt: "%s: Failed to allocate %lu bytes align=%lx nid=%d\n",
613 __func__, THREAD_SIZE, THREAD_SIZE, node);
614 hardirq_stack[i] = memblock_alloc_node(THREAD_SIZE,
615 THREAD_SIZE, node);
616 if (!hardirq_stack[i])
617 panic(fmt: "%s: Failed to allocate %lu bytes align=%lx nid=%d\n",
618 __func__, THREAD_SIZE, THREAD_SIZE, node);
619 }
620}
621
622void __init setup_arch(char **cmdline_p)
623{
624 /* Initialize PROM console and command line. */
625 *cmdline_p = prom_getbootargs();
626 strscpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
627 parse_early_param();
628
629 boot_flags_init(commands: *cmdline_p);
630#ifdef CONFIG_EARLYFB
631 if (btext_find_display())
632#endif
633 register_console(&prom_early_console);
634
635 if (tlb_type == hypervisor)
636 pr_info("ARCH: SUN4V\n");
637 else
638 pr_info("ARCH: SUN4U\n");
639
640 idprom_init();
641
642 if (!root_flags)
643 root_mountflags &= ~MS_RDONLY;
644 ROOT_DEV = old_decode_dev(val: root_dev);
645#ifdef CONFIG_BLK_DEV_RAM
646 rd_image_start = ram_flags & RAMDISK_IMAGE_START_MASK;
647#endif
648
649#ifdef CONFIG_IP_PNP
650 if (!ic_set_manually) {
651 phandle chosen = prom_finddevice("/chosen");
652 u32 cl, sv, gw;
653
654 cl = prom_getintdefault (chosen, "client-ip", 0);
655 sv = prom_getintdefault (chosen, "server-ip", 0);
656 gw = prom_getintdefault (chosen, "gateway-ip", 0);
657 if (cl && sv) {
658 ic_myaddr = cl;
659 ic_servaddr = sv;
660 if (gw)
661 ic_gateway = gw;
662#if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_RARP)
663 ic_proto_enabled = 0;
664#endif
665 }
666 }
667#endif
668
669 /* Get boot processor trap_block[] setup. */
670 init_cur_cpu_trap(current_thread_info());
671
672 paging_init();
673 init_sparc64_elf_hwcap();
674 /*
675 * Once the OF device tree and MDESC have been setup and nr_cpus has
676 * been parsed, we know the list of possible cpus. Therefore we can
677 * allocate the IRQ stacks.
678 */
679 alloc_irqstack_bootmem();
680}
681
682extern int stop_a_enabled;
683
684void sun_do_break(void)
685{
686 if (!stop_a_enabled)
687 return;
688
689 prom_printf("\n");
690 flush_user_windows();
691
692 prom_cmdline();
693}
694EXPORT_SYMBOL(sun_do_break);
695
696int stop_a_enabled = 1;
697EXPORT_SYMBOL(stop_a_enabled);
698

source code of linux/arch/sparc/kernel/setup_64.c