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
21 #include <stdarg.h>
22
23 #include <linux/elf.h>
24 #include <linux/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/mm.h>
27 #include <linux/fs.h>
28 #include <linux/cpu.h>
29 #include <linux/module.h>
30 #include <linux/personality.h>
31 #include <linux/ptrace.h>
32 #include <linux/sched.h>
33 #include <linux/sched/debug.h>
34 #include <linux/sched/task.h>
35 #include <linux/sched/task_stack.h>
36 #include <linux/slab.h>
37 #include <linux/stddef.h>
38 #include <linux/unistd.h>
39 #include <linux/kallsyms.h>
40 #include <linux/uaccess.h>
41 #include <linux/rcupdate.h>
42 #include <linux/random.h>
43 #include <linux/nmi.h>
44
45 #include <asm/io.h>
46 #include <asm/asm-offsets.h>
47 #include <asm/assembly.h>
48 #include <asm/pdc.h>
49 #include <asm/pdc_chassis.h>
50 #include <asm/pgalloc.h>
51 #include <asm/unwind.h>
52 #include <asm/sections.h>
53
54 #define COMMAND_GLOBAL F_EXTEND(0xfffe0030)
55 #define CMD_RESET 5 /* reset any module */
56
57 /*
58 ** The Wright Brothers and Gecko systems have a H/W problem
59 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
60 ** the system. An HVERSION dependent PDC call was developed
61 ** to perform a "safe", platform specific broadcast reset instead
62 ** of kludging up all the code.
63 **
64 ** Older machines which do not implement PDC_BROADCAST_RESET will
65 ** return (with an error) and the regular broadcast reset can be
66 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
67 ** the PDC call will not return (the system will be reset).
68 */
machine_restart(char * cmd)69 void machine_restart(char *cmd)
70 {
71 #ifdef FASTBOOT_SELFTEST_SUPPORT
72 /*
73 ** If user has modified the Firmware Selftest Bitmap,
74 ** run the tests specified in the bitmap after the
75 ** system is rebooted w/PDC_DO_RESET.
76 **
77 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
78 **
79 ** Using "directed resets" at each processor with the MEM_TOC
80 ** vector cleared will also avoid running destructive
81 ** memory self tests. (Not implemented yet)
82 */
83 if (ftc_bitmap) {
84 pdc_do_firm_test_reset(ftc_bitmap);
85 }
86 #endif
87 /* set up a new led state on systems shipped with a LED State panel */
88 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
89
90 /* "Normal" system reset */
91 pdc_do_reset();
92
93 /* Nope...box should reset with just CMD_RESET now */
94 gsc_writel(CMD_RESET, COMMAND_GLOBAL);
95
96 /* Wait for RESET to lay us to rest. */
97 while (1) ;
98
99 }
100
101 void (*chassis_power_off)(void);
102
103 /*
104 * This routine is called from sys_reboot to actually turn off the
105 * machine
106 */
machine_power_off(void)107 void machine_power_off(void)
108 {
109 /* If there is a registered power off handler, call it. */
110 if (chassis_power_off)
111 chassis_power_off();
112
113 /* Put the soft power button back under hardware control.
114 * If the user had already pressed the power button, the
115 * following call will immediately power off. */
116 pdc_soft_power_button(0);
117
118 pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
119
120 /* ipmi_poweroff may have been installed. */
121 if (pm_power_off)
122 pm_power_off();
123
124 /* It seems we have no way to power the system off via
125 * software. The user has to press the button himself. */
126
127 printk("Power off or press RETURN to reboot.\n");
128
129 /* prevent soft lockup/stalled CPU messages for endless loop. */
130 rcu_sysrq_start();
131 lockup_detector_soft_poweroff();
132 while (1) {
133 /* reboot if user presses RETURN key */
134 if (pdc_iodc_getc() == 13) {
135 printk("Rebooting...\n");
136 machine_restart(NULL);
137 }
138 }
139 }
140
141 void (*pm_power_off)(void);
142 EXPORT_SYMBOL(pm_power_off);
143
machine_halt(void)144 void machine_halt(void)
145 {
146 machine_power_off();
147 }
148
flush_thread(void)149 void flush_thread(void)
150 {
151 /* Only needs to handle fpu stuff or perf monitors.
152 ** REVISIT: several arches implement a "lazy fpu state".
153 */
154 }
155
release_thread(struct task_struct * dead_task)156 void release_thread(struct task_struct *dead_task)
157 {
158 }
159
160 /*
161 * Fill in the FPU structure for a core dump.
162 */
163
dump_fpu(struct pt_regs * regs,elf_fpregset_t * r)164 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
165 {
166 if (regs == NULL)
167 return 0;
168
169 memcpy(r, regs->fr, sizeof *r);
170 return 1;
171 }
172
dump_task_fpu(struct task_struct * tsk,elf_fpregset_t * r)173 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
174 {
175 memcpy(r, tsk->thread.regs.fr, sizeof(*r));
176 return 1;
177 }
178
179 /*
180 * Idle thread support
181 *
182 * Detect when running on QEMU with SeaBIOS PDC Firmware and let
183 * QEMU idle the host too.
184 */
185
186 int running_on_qemu __ro_after_init;
187 EXPORT_SYMBOL(running_on_qemu);
188
arch_cpu_idle_dead(void)189 void __cpuidle arch_cpu_idle_dead(void)
190 {
191 /* nop on real hardware, qemu will offline CPU. */
192 asm volatile("or %%r31,%%r31,%%r31\n":::);
193 }
194
arch_cpu_idle(void)195 void __cpuidle arch_cpu_idle(void)
196 {
197 local_irq_enable();
198
199 /* nop on real hardware, qemu will idle sleep. */
200 asm volatile("or %%r10,%%r10,%%r10\n":::);
201 }
202
parisc_idle_init(void)203 static int __init parisc_idle_init(void)
204 {
205 if (!running_on_qemu)
206 cpu_idle_poll_ctrl(1);
207
208 return 0;
209 }
210 arch_initcall(parisc_idle_init);
211
212 /*
213 * Copy architecture-specific thread state
214 */
215 int
copy_thread_tls(unsigned long clone_flags,unsigned long usp,unsigned long kthread_arg,struct task_struct * p,unsigned long tls)216 copy_thread_tls(unsigned long clone_flags, unsigned long usp,
217 unsigned long kthread_arg, struct task_struct *p, unsigned long tls)
218 {
219 struct pt_regs *cregs = &(p->thread.regs);
220 void *stack = task_stack_page(p);
221
222 /* We have to use void * instead of a function pointer, because
223 * function pointers aren't a pointer to the function on 64-bit.
224 * Make them const so the compiler knows they live in .text */
225 extern void * const ret_from_kernel_thread;
226 extern void * const child_return;
227
228 if (unlikely(p->flags & PF_KTHREAD)) {
229 /* kernel thread */
230 memset(cregs, 0, sizeof(struct pt_regs));
231 if (!usp) /* idle thread */
232 return 0;
233 /* Must exit via ret_from_kernel_thread in order
234 * to call schedule_tail()
235 */
236 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
237 cregs->kpc = (unsigned long) &ret_from_kernel_thread;
238 /*
239 * Copy function and argument to be called from
240 * ret_from_kernel_thread.
241 */
242 #ifdef CONFIG_64BIT
243 cregs->gr[27] = ((unsigned long *)usp)[3];
244 cregs->gr[26] = ((unsigned long *)usp)[2];
245 #else
246 cregs->gr[26] = usp;
247 #endif
248 cregs->gr[25] = kthread_arg;
249 } else {
250 /* user thread */
251 /* usp must be word aligned. This also prevents users from
252 * passing in the value 1 (which is the signal for a special
253 * return for a kernel thread) */
254 if (usp) {
255 usp = ALIGN(usp, 4);
256 if (likely(usp))
257 cregs->gr[30] = usp;
258 }
259 cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
260 cregs->kpc = (unsigned long) &child_return;
261
262 /* Setup thread TLS area */
263 if (clone_flags & CLONE_SETTLS)
264 cregs->cr27 = tls;
265 }
266
267 return 0;
268 }
269
270 unsigned long
get_wchan(struct task_struct * p)271 get_wchan(struct task_struct *p)
272 {
273 struct unwind_frame_info info;
274 unsigned long ip;
275 int count = 0;
276
277 if (!p || p == current || p->state == TASK_RUNNING)
278 return 0;
279
280 /*
281 * These bracket the sleeping functions..
282 */
283
284 unwind_frame_init_from_blocked_task(&info, p);
285 do {
286 if (unwind_once(&info) < 0)
287 return 0;
288 ip = info.ip;
289 if (!in_sched_functions(ip))
290 return ip;
291 } while (count++ < MAX_UNWIND_ENTRIES);
292 return 0;
293 }
294
295 #ifdef CONFIG_64BIT
dereference_function_descriptor(void * ptr)296 void *dereference_function_descriptor(void *ptr)
297 {
298 Elf64_Fdesc *desc = ptr;
299 void *p;
300
301 if (!probe_kernel_address(&desc->addr, p))
302 ptr = p;
303 return ptr;
304 }
305
dereference_kernel_function_descriptor(void * ptr)306 void *dereference_kernel_function_descriptor(void *ptr)
307 {
308 if (ptr < (void *)__start_opd ||
309 ptr >= (void *)__end_opd)
310 return ptr;
311
312 return dereference_function_descriptor(ptr);
313 }
314 #endif
315
brk_rnd(void)316 static inline unsigned long brk_rnd(void)
317 {
318 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
319 }
320
arch_randomize_brk(struct mm_struct * mm)321 unsigned long arch_randomize_brk(struct mm_struct *mm)
322 {
323 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
324
325 if (ret < mm->brk)
326 return mm->brk;
327 return ret;
328 }
329