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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * PARISC Architecture-dependent parts of process handling
4 * based on the work for i386
5 *
6 * Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
7 * Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
8 * Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
9 * Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
10 * Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
11 * Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
12 * Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
13 * Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
14 * Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
15 * Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
16 * Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
17 * Copyright (C) 2001-2014 Helge Deller <[email protected]>
18 * Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
19 */
20#include <linux/elf.h>
21#include <linux/errno.h>
22#include <linux/kernel.h>
23#include <linux/mm.h>
24#include <linux/fs.h>
25#include <linux/cpu.h>
26#include <linux/module.h>
27#include <linux/personality.h>
28#include <linux/ptrace.h>
29#include <linux/reboot.h>
30#include <linux/sched.h>
31#include <linux/sched/debug.h>
32#include <linux/sched/task.h>
33#include <linux/sched/task_stack.h>
34#include <linux/slab.h>
35#include <linux/stddef.h>
36#include <linux/unistd.h>
37#include <linux/kallsyms.h>
38#include <linux/uaccess.h>
39#include <linux/rcupdate.h>
40#include <linux/random.h>
41#include <linux/nmi.h>
42#include <linux/sched/hotplug.h>
43
44#include <asm/io.h>
45#include <asm/asm-offsets.h>
46#include <asm/assembly.h>
47#include <asm/pdc.h>
48#include <asm/pdc_chassis.h>
49#include <asm/unwind.h>
50#include <asm/sections.h>
51#include <asm/cacheflush.h>
52
53#define COMMAND_GLOBAL F_EXTEND(0xfffe0030)
54#define CMD_RESET 5 /* reset any module */
55
56/*
57** The Wright Brothers and Gecko systems have a H/W problem
58** (Lasi...'nuf said) may cause a broadcast reset to lockup
59** the system. An HVERSION dependent PDC call was developed
60** to perform a "safe", platform specific broadcast reset instead
61** of kludging up all the code.
62**
63** Older machines which do not implement PDC_BROADCAST_RESET will
64** return (with an error) and the regular broadcast reset can be
65** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
66** the PDC call will not return (the system will be reset).
67*/
68void machine_restart(char *cmd)
69{
70#ifdef FASTBOOT_SELFTEST_SUPPORT
71 /*
72 ** If user has modified the Firmware Selftest Bitmap,
73 ** run the tests specified in the bitmap after the
74 ** system is rebooted w/PDC_DO_RESET.
75 **
76 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
77 **
78 ** Using "directed resets" at each processor with the MEM_TOC
79 ** vector cleared will also avoid running destructive
80 ** memory self tests. (Not implemented yet)
81 */
82 if (ftc_bitmap) {
83 pdc_do_firm_test_reset(ftc_bitmap);
84 }
85#endif
86 /* set up a new led state on systems shipped with a LED State panel */
87 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
88
89 /* prevent interrupts during reboot */
90 set_eiem(0);
91
92 /* "Normal" system reset */
93 pdc_do_reset();
94
95 /* Nope...box should reset with just CMD_RESET now */
96 gsc_writel(CMD_RESET, COMMAND_GLOBAL);
97
98 /* Wait for RESET to lay us to rest. */
99 while (1) ;
100
101}
102
103/*
104 * This routine is called from sys_reboot to actually turn off the
105 * machine
106 */
107void machine_power_off(void)
108{
109 /* Put the soft power button back under hardware control.
110 * If the user had already pressed the power button, the
111 * following call will immediately power off. */
112 pdc_soft_power_button(0);
113
114 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
115
116 /* ipmi_poweroff may have been installed. */
117 do_kernel_power_off();
118
119 /* It seems we have no way to power the system off via
120 * software. The user has to press the button himself. */
121
122 printk("Power off or press RETURN to reboot.\n");
123
124 /* prevent soft lockup/stalled CPU messages for endless loop. */
125 rcu_sysrq_start();
126 lockup_detector_soft_poweroff();
127 while (1) {
128 /* reboot if user presses RETURN key */
129 if (pdc_iodc_getc() == 13) {
130 printk("Rebooting...\n");
131 machine_restart(NULL);
132 }
133 }
134}
135
136void (*pm_power_off)(void);
137EXPORT_SYMBOL(pm_power_off);
138
139void machine_halt(void)
140{
141 machine_power_off();
142}
143
144void flush_thread(void)
145{
146 /* Only needs to handle fpu stuff or perf monitors.
147 ** REVISIT: several arches implement a "lazy fpu state".
148 */
149}
150
151/*
152 * Idle thread support
153 *
154 * Detect when running on QEMU with SeaBIOS PDC Firmware and let
155 * QEMU idle the host too.
156 */
157
158int running_on_qemu __ro_after_init;
159EXPORT_SYMBOL(running_on_qemu);
160
161/*
162 * Called from the idle thread for the CPU which has been shutdown.
163 */
164void __noreturn arch_cpu_idle_dead(void)
165{
166#ifdef CONFIG_HOTPLUG_CPU
167 idle_task_exit();
168
169 local_irq_disable();
170
171 /* Tell the core that this CPU is now safe to dispose of. */
172 cpuhp_ap_report_dead();
173
174 /* Ensure that the cache lines are written out. */
175 flush_cache_all_local();
176 flush_tlb_all_local(NULL);
177
178 /* Let PDC firmware put CPU into firmware idle loop. */
179 __pdc_cpu_rendezvous();
180
181 pr_warn("PDC does not provide rendezvous function.\n");
182#endif
183 while (1);
184}
185
186void __cpuidle arch_cpu_idle(void)
187{
188 /* nop on real hardware, qemu will idle sleep. */
189 asm volatile("or %%r10,%%r10,%%r10\n":::);
190}
191
192static int __init parisc_idle_init(void)
193{
194 if (!running_on_qemu)
195 cpu_idle_poll_ctrl(1);
196
197 return 0;
198}
199arch_initcall(parisc_idle_init);
200
201/*
202 * Copy architecture-specific thread state
203 */
204int
205copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
206{
207 u64 clone_flags = args->flags;
208 unsigned long usp = args->stack;
209 unsigned long tls = args->tls;
210 struct pt_regs *cregs = &(p->thread.regs);
211 void *stack = task_stack_page(p);
212
213 /* We have to use void * instead of a function pointer, because
214 * function pointers aren't a pointer to the function on 64-bit.
215 * Make them const so the compiler knows they live in .text */
216 extern void * const ret_from_kernel_thread;
217 extern void * const child_return;
218
219 if (unlikely(args->fn)) {
220 /* kernel thread */
221 memset(cregs, 0, sizeof(struct pt_regs));
222 if (args->idle) /* idle thread */
223 return 0;
224 /* Must exit via ret_from_kernel_thread in order
225 * to call schedule_tail()
226 */
227 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN;
228 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
229 /*
230 * Copy function and argument to be called from
231 * ret_from_kernel_thread.
232 */
233#ifdef CONFIG_64BIT
234 cregs->gr[27] = ((unsigned long *)args->fn)[3];
235 cregs->gr[26] = ((unsigned long *)args->fn)[2];
236#else
237 cregs->gr[26] = (unsigned long) args->fn;
238#endif
239 cregs->gr[25] = (unsigned long) args->fn_arg;
240 } else {
241 /* user thread */
242 /* usp must be word aligned. This also prevents users from
243 * passing in the value 1 (which is the signal for a special
244 * return for a kernel thread) */
245 if (usp) {
246 usp = ALIGN(usp, 4);
247 if (likely(usp))
248 cregs->gr[30] = usp;
249 }
250 cregs->ksp = (unsigned long) stack + FRAME_SIZE;
251 cregs->kpc = (unsigned long) &child_return;
252
253 /* Setup thread TLS area */
254 if (clone_flags & CLONE_SETTLS)
255 cregs->cr27 = tls;
256 }
257
258 return 0;
259}
260
261unsigned long
262__get_wchan(struct task_struct *p)
263{
264 struct unwind_frame_info info;
265 unsigned long ip;
266 int count = 0;
267
268 /*
269 * These bracket the sleeping functions..
270 */
271
272 unwind_frame_init_from_blocked_task(&info, p);
273 do {
274 if (unwind_once(&info) < 0)
275 return 0;
276 if (task_is_running(p))
277 return 0;
278 ip = info.ip;
279 if (!in_sched_functions(ip))
280 return ip;
281 } while (count++ < MAX_UNWIND_ENTRIES);
282 return 0;
283}