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 <deller@gmx.de>
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 */
68 void 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 /* "Normal" system reset */
90 pdc_do_reset();
91
92 /* Nope...box should reset with just CMD_RESET now */
93 gsc_writel(CMD_RESET, COMMAND_GLOBAL);
94
95 /* Wait for RESET to lay us to rest. */
96 while (1) ;
97
98 }
99
100 /*
101 * This routine is called from sys_reboot to actually turn off the
102 * machine
103 */
104 void machine_power_off(void)
105 {
106 /* Put the soft power button back under hardware control.
107 * If the user had already pressed the power button, the
108 * following call will immediately power off. */
109 pdc_soft_power_button(0);
110
111 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
112
113 /* ipmi_poweroff may have been installed. */
114 do_kernel_power_off();
115
116 /* It seems we have no way to power the system off via
117 * software. The user has to press the button himself. */
118
119 printk("Power off or press RETURN to reboot.\n");
120
121 /* prevent soft lockup/stalled CPU messages for endless loop. */
122 rcu_sysrq_start();
123 lockup_detector_soft_poweroff();
124 while (1) {
125 /* reboot if user presses RETURN key */
126 if (pdc_iodc_getc() == 13) {
127 printk("Rebooting...\n");
128 machine_restart(NULL);
129 }
130 }
131 }
132
133 void (*pm_power_off)(void);
134 EXPORT_SYMBOL(pm_power_off);
135
136 void machine_halt(void)
137 {
138 machine_power_off();
139 }
140
141 void flush_thread(void)
142 {
143 /* Only needs to handle fpu stuff or perf monitors.
144 ** REVISIT: several arches implement a "lazy fpu state".
145 */
146 }
147
148 /*
149 * Idle thread support
150 *
151 * Detect when running on QEMU with SeaBIOS PDC Firmware and let
152 * QEMU idle the host too.
153 */
154
155 int running_on_qemu __ro_after_init;
156 EXPORT_SYMBOL(running_on_qemu);
157
158 /*
159 * Called from the idle thread for the CPU which has been shutdown.
160 */
161 void __noreturn arch_cpu_idle_dead(void)
162 {
163 #ifdef CONFIG_HOTPLUG_CPU
164 idle_task_exit();
165
166 local_irq_disable();
167
168 /* Tell the core that this CPU is now safe to dispose of. */
169 cpuhp_ap_report_dead();
170
171 /* Ensure that the cache lines are written out. */
172 flush_cache_all_local();
173 flush_tlb_all_local(NULL);
174
175 /* Let PDC firmware put CPU into firmware idle loop. */
176 __pdc_cpu_rendezvous();
177
178 pr_warn("PDC does not provide rendezvous function.\n");
179 #endif
180 while (1);
181 }
182
183 void __cpuidle arch_cpu_idle(void)
184 {
185 /* nop on real hardware, qemu will idle sleep. */
186 asm volatile("or %%r10,%%r10,%%r10\n":::);
187 }
188
189 static int __init parisc_idle_init(void)
190 {
191 if (!running_on_qemu)
192 cpu_idle_poll_ctrl(1);
193
194 return 0;
195 }
196 arch_initcall(parisc_idle_init);
197
198 /*
199 * Copy architecture-specific thread state
200 */
201 int
202 copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
203 {
204 unsigned long clone_flags = args->flags;
205 unsigned long usp = args->stack;
206 unsigned long tls = args->tls;
207 struct pt_regs *cregs = &(p->thread.regs);
208 void *stack = task_stack_page(p);
209
210 /* We have to use void * instead of a function pointer, because
211 * function pointers aren't a pointer to the function on 64-bit.
212 * Make them const so the compiler knows they live in .text */
213 extern void * const ret_from_kernel_thread;
214 extern void * const child_return;
215
216 if (unlikely(args->fn)) {
217 /* kernel thread */
218 memset(cregs, 0, sizeof(struct pt_regs));
219 if (args->idle) /* idle thread */
220 return 0;
221 /* Must exit via ret_from_kernel_thread in order
222 * to call schedule_tail()
223 */
224 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN;
225 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
226 /*
227 * Copy function and argument to be called from
228 * ret_from_kernel_thread.
229 */
230 #ifdef CONFIG_64BIT
231 cregs->gr[27] = ((unsigned long *)args->fn)[3];
232 cregs->gr[26] = ((unsigned long *)args->fn)[2];
233 #else
234 cregs->gr[26] = (unsigned long) args->fn;
235 #endif
236 cregs->gr[25] = (unsigned long) args->fn_arg;
237 } else {
238 /* user thread */
239 /* usp must be word aligned. This also prevents users from
240 * passing in the value 1 (which is the signal for a special
241 * return for a kernel thread) */
242 if (usp) {
243 usp = ALIGN(usp, 4);
244 if (likely(usp))
245 cregs->gr[30] = usp;
246 }
247 cregs->ksp = (unsigned long) stack + FRAME_SIZE;
248 cregs->kpc = (unsigned long) &child_return;
249
250 /* Setup thread TLS area */
251 if (clone_flags & CLONE_SETTLS)
252 cregs->cr27 = tls;
253 }
254
255 return 0;
256 }
257
258 unsigned long
259 __get_wchan(struct task_struct *p)
260 {
261 struct unwind_frame_info info;
262 unsigned long ip;
263 int count = 0;
264
265 /*
266 * These bracket the sleeping functions..
267 */
268
269 unwind_frame_init_from_blocked_task(&info, p);
270 do {
271 if (unwind_once(&info) < 0)
272 return 0;
273 if (task_is_running(p))
274 return 0;
275 ip = info.ip;
276 if (!in_sched_functions(ip))
277 return ip;
278 } while (count++ < MAX_UNWIND_ENTRIES);
279 return 0;
280 }
281
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