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 */
machine_restart(char * cmd)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 void (*chassis_power_off)(void);
101
102 /*
103 * This routine is called from sys_reboot to actually turn off the
104 * machine
105 */
machine_power_off(void)106 void machine_power_off(void)
107 {
108 /* If there is a registered power off handler, call it. */
109 if (chassis_power_off)
110 chassis_power_off();
111
112 /* Put the soft power button back under hardware control.
113 * If the user had already pressed the power button, the
114 * following call will immediately power off. */
115 pdc_soft_power_button(0);
116
117 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
118
119 /* ipmi_poweroff may have been installed. */
120 do_kernel_power_off();
121
122 /* It seems we have no way to power the system off via
123 * software. The user has to press the button himself. */
124
125 printk(KERN_EMERG "System shut down completed.\n"
126 "Please power this system off now.");
127
128 /* prevent soft lockup/stalled CPU messages for endless loop. */
129 rcu_sysrq_start();
130 lockup_detector_soft_poweroff();
131 for (;;);
132 }
133
134 void (*pm_power_off)(void);
135 EXPORT_SYMBOL(pm_power_off);
136
machine_halt(void)137 void machine_halt(void)
138 {
139 machine_power_off();
140 }
141
flush_thread(void)142 void flush_thread(void)
143 {
144 /* Only needs to handle fpu stuff or perf monitors.
145 ** REVISIT: several arches implement a "lazy fpu state".
146 */
147 }
148
149 /*
150 * Idle thread support
151 *
152 * Detect when running on QEMU with SeaBIOS PDC Firmware and let
153 * QEMU idle the host too.
154 */
155
156 int running_on_qemu __ro_after_init;
157 EXPORT_SYMBOL(running_on_qemu);
158
159 /*
160 * Called from the idle thread for the CPU which has been shutdown.
161 */
arch_cpu_idle_dead(void)162 void arch_cpu_idle_dead(void)
163 {
164 #ifdef CONFIG_HOTPLUG_CPU
165 idle_task_exit();
166
167 local_irq_disable();
168
169 /* Tell __cpu_die() that this CPU is now safe to dispose of. */
170 (void)cpu_report_death();
171
172 /* Ensure that the cache lines are written out. */
173 flush_cache_all_local();
174 flush_tlb_all_local(NULL);
175
176 /* Let PDC firmware put CPU into firmware idle loop. */
177 __pdc_cpu_rendezvous();
178
179 pr_warn("PDC does not provide rendezvous function.\n");
180 #endif
181 while (1);
182 }
183
arch_cpu_idle(void)184 void __cpuidle arch_cpu_idle(void)
185 {
186 /* nop on real hardware, qemu will idle sleep. */
187 asm volatile("or %%r10,%%r10,%%r10\n":::);
188 }
189
parisc_idle_init(void)190 static int __init parisc_idle_init(void)
191 {
192 if (!running_on_qemu)
193 cpu_idle_poll_ctrl(1);
194
195 return 0;
196 }
197 arch_initcall(parisc_idle_init);
198
199 /*
200 * Copy architecture-specific thread state
201 */
202 int
copy_thread(struct task_struct * p,const struct kernel_clone_args * args)203 copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
204 {
205 unsigned long clone_flags = args->flags;
206 unsigned long usp = args->stack;
207 unsigned long tls = args->tls;
208 struct pt_regs *cregs = &(p->thread.regs);
209 void *stack = task_stack_page(p);
210
211 /* We have to use void * instead of a function pointer, because
212 * function pointers aren't a pointer to the function on 64-bit.
213 * Make them const so the compiler knows they live in .text */
214 extern void * const ret_from_kernel_thread;
215 extern void * const child_return;
216
217 if (unlikely(args->fn)) {
218 /* kernel thread */
219 memset(cregs, 0, sizeof(struct pt_regs));
220 if (args->idle) /* idle thread */
221 return 0;
222 /* Must exit via ret_from_kernel_thread in order
223 * to call schedule_tail()
224 */
225 cregs->ksp = (unsigned long) stack + FRAME_SIZE + PT_SZ_ALGN;
226 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
227 /*
228 * Copy function and argument to be called from
229 * ret_from_kernel_thread.
230 */
231 #ifdef CONFIG_64BIT
232 cregs->gr[27] = ((unsigned long *)args->fn)[3];
233 cregs->gr[26] = ((unsigned long *)args->fn)[2];
234 #else
235 cregs->gr[26] = (unsigned long) args->fn;
236 #endif
237 cregs->gr[25] = (unsigned long) args->fn_arg;
238 } else {
239 /* user thread */
240 /* usp must be word aligned. This also prevents users from
241 * passing in the value 1 (which is the signal for a special
242 * return for a kernel thread) */
243 if (usp) {
244 usp = ALIGN(usp, 4);
245 if (likely(usp))
246 cregs->gr[30] = usp;
247 }
248 cregs->ksp = (unsigned long) stack + FRAME_SIZE;
249 cregs->kpc = (unsigned long) &child_return;
250
251 /* Setup thread TLS area */
252 if (clone_flags & CLONE_SETTLS)
253 cregs->cr27 = tls;
254 }
255
256 return 0;
257 }
258
259 unsigned long
__get_wchan(struct task_struct * p)260 __get_wchan(struct task_struct *p)
261 {
262 struct unwind_frame_info info;
263 unsigned long ip;
264 int count = 0;
265
266 /*
267 * These bracket the sleeping functions..
268 */
269
270 unwind_frame_init_from_blocked_task(&info, p);
271 do {
272 if (unwind_once(&info) < 0)
273 return 0;
274 if (task_is_running(p))
275 return 0;
276 ip = info.ip;
277 if (!in_sched_functions(ip))
278 return ip;
279 } while (count++ < MAX_UNWIND_ENTRIES);
280 return 0;
281 }
282
brk_rnd(void)283 static inline unsigned long brk_rnd(void)
284 {
285 return (get_random_u32() & BRK_RND_MASK) << PAGE_SHIFT;
286 }
287
arch_randomize_brk(struct mm_struct * mm)288 unsigned long arch_randomize_brk(struct mm_struct *mm)
289 {
290 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
291
292 if (ret < mm->brk)
293 return mm->brk;
294 return ret;
295 }
296