xref: /openbmc/linux/arch/parisc/kernel/process.c (revision b732539e)
1 /*
2  *    PARISC Architecture-dependent parts of process handling
3  *    based on the work for i386
4  *
5  *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
6  *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
7  *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
8  *    Copyright (C) 2000 David Huggins-Daines <dhd with pobox.org>
9  *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
10  *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
11  *    Copyright (C) 2000 David Kennedy <dkennedy with linuxcare.com>
12  *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
13  *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
14  *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
15  *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
16  *    Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
17  *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
18  *
19  *
20  *    This program is free software; you can redistribute it and/or modify
21  *    it under the terms of the GNU General Public License as published by
22  *    the Free Software Foundation; either version 2 of the License, or
23  *    (at your option) any later version.
24  *
25  *    This program is distributed in the hope that it will be useful,
26  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
27  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
28  *    GNU General Public License for more details.
29  *
30  *    You should have received a copy of the GNU General Public License
31  *    along with this program; if not, write to the Free Software
32  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
33  */
34 
35 #include <stdarg.h>
36 
37 #include <linux/elf.h>
38 #include <linux/errno.h>
39 #include <linux/kernel.h>
40 #include <linux/mm.h>
41 #include <linux/fs.h>
42 #include <linux/cpu.h>
43 #include <linux/module.h>
44 #include <linux/personality.h>
45 #include <linux/ptrace.h>
46 #include <linux/sched.h>
47 #include <linux/sched/debug.h>
48 #include <linux/sched/task.h>
49 #include <linux/sched/task_stack.h>
50 #include <linux/slab.h>
51 #include <linux/stddef.h>
52 #include <linux/unistd.h>
53 #include <linux/kallsyms.h>
54 #include <linux/uaccess.h>
55 #include <linux/rcupdate.h>
56 #include <linux/random.h>
57 #include <linux/nmi.h>
58 
59 #include <asm/io.h>
60 #include <asm/asm-offsets.h>
61 #include <asm/assembly.h>
62 #include <asm/pdc.h>
63 #include <asm/pdc_chassis.h>
64 #include <asm/pgalloc.h>
65 #include <asm/unwind.h>
66 #include <asm/sections.h>
67 
68 #define COMMAND_GLOBAL  F_EXTEND(0xfffe0030)
69 #define CMD_RESET       5       /* reset any module */
70 
71 /*
72 ** The Wright Brothers and Gecko systems have a H/W problem
73 ** (Lasi...'nuf said) may cause a broadcast reset to lockup
74 ** the system. An HVERSION dependent PDC call was developed
75 ** to perform a "safe", platform specific broadcast reset instead
76 ** of kludging up all the code.
77 **
78 ** Older machines which do not implement PDC_BROADCAST_RESET will
79 ** return (with an error) and the regular broadcast reset can be
80 ** issued. Obviously, if the PDC does implement PDC_BROADCAST_RESET
81 ** the PDC call will not return (the system will be reset).
82 */
83 void machine_restart(char *cmd)
84 {
85 #ifdef FASTBOOT_SELFTEST_SUPPORT
86 	/*
87 	 ** If user has modified the Firmware Selftest Bitmap,
88 	 ** run the tests specified in the bitmap after the
89 	 ** system is rebooted w/PDC_DO_RESET.
90 	 **
91 	 ** ftc_bitmap = 0x1AUL "Skip destructive memory tests"
92 	 **
93 	 ** Using "directed resets" at each processor with the MEM_TOC
94 	 ** vector cleared will also avoid running destructive
95 	 ** memory self tests. (Not implemented yet)
96 	 */
97 	if (ftc_bitmap) {
98 		pdc_do_firm_test_reset(ftc_bitmap);
99 	}
100 #endif
101 	/* set up a new led state on systems shipped with a LED State panel */
102 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
103 
104 	/* "Normal" system reset */
105 	pdc_do_reset();
106 
107 	/* Nope...box should reset with just CMD_RESET now */
108 	gsc_writel(CMD_RESET, COMMAND_GLOBAL);
109 
110 	/* Wait for RESET to lay us to rest. */
111 	while (1) ;
112 
113 }
114 
115 void (*chassis_power_off)(void);
116 
117 /*
118  * This routine is called from sys_reboot to actually turn off the
119  * machine
120  */
121 void machine_power_off(void)
122 {
123 	/* If there is a registered power off handler, call it. */
124 	if (chassis_power_off)
125 		chassis_power_off();
126 
127 	/* Put the soft power button back under hardware control.
128 	 * If the user had already pressed the power button, the
129 	 * following call will immediately power off. */
130 	pdc_soft_power_button(0);
131 
132 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
133 
134 	/* ipmi_poweroff may have been installed. */
135 	if (pm_power_off)
136 		pm_power_off();
137 
138 	/* It seems we have no way to power the system off via
139 	 * software. The user has to press the button himself. */
140 
141 	printk(KERN_EMERG "System shut down completed.\n"
142 	       "Please power this system off now.");
143 
144 	/* prevent soft lockup/stalled CPU messages for endless loop. */
145 	rcu_sysrq_start();
146 	lockup_detector_soft_poweroff();
147 	for (;;);
148 }
149 
150 void (*pm_power_off)(void);
151 EXPORT_SYMBOL(pm_power_off);
152 
153 void machine_halt(void)
154 {
155 	machine_power_off();
156 }
157 
158 void flush_thread(void)
159 {
160 	/* Only needs to handle fpu stuff or perf monitors.
161 	** REVISIT: several arches implement a "lazy fpu state".
162 	*/
163 }
164 
165 void release_thread(struct task_struct *dead_task)
166 {
167 }
168 
169 /*
170  * Fill in the FPU structure for a core dump.
171  */
172 
173 int dump_fpu (struct pt_regs * regs, elf_fpregset_t *r)
174 {
175 	if (regs == NULL)
176 		return 0;
177 
178 	memcpy(r, regs->fr, sizeof *r);
179 	return 1;
180 }
181 
182 int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r)
183 {
184 	memcpy(r, tsk->thread.regs.fr, sizeof(*r));
185 	return 1;
186 }
187 
188 /*
189  * Idle thread support
190  *
191  * Detect when running on QEMU with SeaBIOS PDC Firmware and let
192  * QEMU idle the host too.
193  */
194 
195 int running_on_qemu __read_mostly;
196 
197 void __cpuidle arch_cpu_idle_dead(void)
198 {
199 	/* nop on real hardware, qemu will offline CPU. */
200 	asm volatile("or %%r31,%%r31,%%r31\n":::);
201 }
202 
203 void __cpuidle arch_cpu_idle(void)
204 {
205 	local_irq_enable();
206 
207 	/* nop on real hardware, qemu will idle sleep. */
208 	asm volatile("or %%r10,%%r10,%%r10\n":::);
209 }
210 
211 static int __init parisc_idle_init(void)
212 {
213 	const char *marker;
214 
215 	/* check QEMU/SeaBIOS marker in PAGE0 */
216 	marker = (char *) &PAGE0->pad0;
217 	running_on_qemu = (memcmp(marker, "SeaBIOS", 8) == 0);
218 
219 	if (!running_on_qemu)
220 		cpu_idle_poll_ctrl(1);
221 
222 	return 0;
223 }
224 arch_initcall(parisc_idle_init);
225 
226 /*
227  * Copy architecture-specific thread state
228  */
229 int
230 copy_thread(unsigned long clone_flags, unsigned long usp,
231 	    unsigned long kthread_arg, struct task_struct *p)
232 {
233 	struct pt_regs *cregs = &(p->thread.regs);
234 	void *stack = task_stack_page(p);
235 
236 	/* We have to use void * instead of a function pointer, because
237 	 * function pointers aren't a pointer to the function on 64-bit.
238 	 * Make them const so the compiler knows they live in .text */
239 	extern void * const ret_from_kernel_thread;
240 	extern void * const child_return;
241 
242 	if (unlikely(p->flags & PF_KTHREAD)) {
243 		/* kernel thread */
244 		memset(cregs, 0, sizeof(struct pt_regs));
245 		if (!usp) /* idle thread */
246 			return 0;
247 		/* Must exit via ret_from_kernel_thread in order
248 		 * to call schedule_tail()
249 		 */
250 		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
251 		cregs->kpc = (unsigned long) &ret_from_kernel_thread;
252 		/*
253 		 * Copy function and argument to be called from
254 		 * ret_from_kernel_thread.
255 		 */
256 #ifdef CONFIG_64BIT
257 		cregs->gr[27] = ((unsigned long *)usp)[3];
258 		cregs->gr[26] = ((unsigned long *)usp)[2];
259 #else
260 		cregs->gr[26] = usp;
261 #endif
262 		cregs->gr[25] = kthread_arg;
263 	} else {
264 		/* user thread */
265 		/* usp must be word aligned.  This also prevents users from
266 		 * passing in the value 1 (which is the signal for a special
267 		 * return for a kernel thread) */
268 		if (usp) {
269 			usp = ALIGN(usp, 4);
270 			if (likely(usp))
271 				cregs->gr[30] = usp;
272 		}
273 		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
274 		cregs->kpc = (unsigned long) &child_return;
275 
276 		/* Setup thread TLS area from the 4th parameter in clone */
277 		if (clone_flags & CLONE_SETTLS)
278 			cregs->cr27 = cregs->gr[23];
279 	}
280 
281 	return 0;
282 }
283 
284 unsigned long
285 get_wchan(struct task_struct *p)
286 {
287 	struct unwind_frame_info info;
288 	unsigned long ip;
289 	int count = 0;
290 
291 	if (!p || p == current || p->state == TASK_RUNNING)
292 		return 0;
293 
294 	/*
295 	 * These bracket the sleeping functions..
296 	 */
297 
298 	unwind_frame_init_from_blocked_task(&info, p);
299 	do {
300 		if (unwind_once(&info) < 0)
301 			return 0;
302 		ip = info.ip;
303 		if (!in_sched_functions(ip))
304 			return ip;
305 	} while (count++ < 16);
306 	return 0;
307 }
308 
309 #ifdef CONFIG_64BIT
310 void *dereference_function_descriptor(void *ptr)
311 {
312 	Elf64_Fdesc *desc = ptr;
313 	void *p;
314 
315 	if (!probe_kernel_address(&desc->addr, p))
316 		ptr = p;
317 	return ptr;
318 }
319 
320 void *dereference_kernel_function_descriptor(void *ptr)
321 {
322 	if (ptr < (void *)__start_opd ||
323 			ptr >= (void *)__end_opd)
324 		return ptr;
325 
326 	return dereference_function_descriptor(ptr);
327 }
328 #endif
329 
330 static inline unsigned long brk_rnd(void)
331 {
332 	return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
333 }
334 
335 unsigned long arch_randomize_brk(struct mm_struct *mm)
336 {
337 	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
338 
339 	if (ret < mm->brk)
340 		return mm->brk;
341 	return ret;
342 }
343