1/* process.c: FRV specific parts of process handling
2 *
3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from arch/m68k/kernel/process.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/module.h>
14#include <linux/errno.h>
15#include <linux/sched.h>
16#include <linux/kernel.h>
17#include <linux/mm.h>
18#include <linux/smp.h>
19#include <linux/stddef.h>
20#include <linux/unistd.h>
21#include <linux/ptrace.h>
22#include <linux/slab.h>
23#include <linux/user.h>
24#include <linux/elf.h>
25#include <linux/reboot.h>
26#include <linux/interrupt.h>
27#include <linux/pagemap.h>
28#include <linux/rcupdate.h>
29
30#include <asm/asm-offsets.h>
31#include <asm/uaccess.h>
32#include <asm/setup.h>
33#include <asm/pgtable.h>
34#include <asm/tlb.h>
35#include <asm/gdb-stub.h>
36#include <asm/mb-regs.h>
37
38#include "local.h"
39
40asmlinkage void ret_from_fork(void);
41asmlinkage void ret_from_kernel_thread(void);
42
43#include <asm/pgalloc.h>
44
45void (*pm_power_off)(void);
46EXPORT_SYMBOL(pm_power_off);
47
48static void core_sleep_idle(void)
49{
50#ifdef LED_DEBUG_SLEEP
51	/* Show that we're sleeping... */
52	__set_LEDS(0x55aa);
53#endif
54	frv_cpu_core_sleep();
55#ifdef LED_DEBUG_SLEEP
56	/* ... and that we woke up */
57	__set_LEDS(0);
58#endif
59	mb();
60}
61
62void arch_cpu_idle(void)
63{
64	if (!frv_dma_inprogress)
65		core_sleep_idle();
66	else
67		local_irq_enable();
68}
69
70void machine_restart(char * __unused)
71{
72	unsigned long reset_addr;
73#ifdef CONFIG_GDBSTUB
74	gdbstub_exit(0);
75#endif
76
77	if (PSR_IMPLE(__get_PSR()) == PSR_IMPLE_FR551)
78		reset_addr = 0xfefff500;
79	else
80		reset_addr = 0xfeff0500;
81
82	/* Software reset. */
83	asm volatile("      dcef @(gr0,gr0),1 ! membar !"
84		     "      sti     %1,@(%0,0) !"
85		     "      nop ! nop ! nop ! nop ! nop ! "
86		     "      nop ! nop ! nop ! nop ! nop ! "
87		     "      nop ! nop ! nop ! nop ! nop ! "
88		     "      nop ! nop ! nop ! nop ! nop ! "
89		     : : "r" (reset_addr), "r" (1) );
90
91	for (;;)
92		;
93}
94
95void machine_halt(void)
96{
97#ifdef CONFIG_GDBSTUB
98	gdbstub_exit(0);
99#endif
100
101	for (;;);
102}
103
104void machine_power_off(void)
105{
106#ifdef CONFIG_GDBSTUB
107	gdbstub_exit(0);
108#endif
109
110	for (;;);
111}
112
113void flush_thread(void)
114{
115	/* nothing */
116}
117
118inline unsigned long user_stack(const struct pt_regs *regs)
119{
120	while (regs->next_frame)
121		regs = regs->next_frame;
122	return user_mode(regs) ? regs->sp : 0;
123}
124
125/*
126 * set up the kernel stack and exception frames for a new process
127 */
128int copy_thread(unsigned long clone_flags,
129		unsigned long usp, unsigned long arg,
130		struct task_struct *p)
131{
132	struct pt_regs *childregs;
133
134	childregs = (struct pt_regs *)
135		(task_stack_page(p) + THREAD_SIZE - FRV_FRAME0_SIZE);
136
137	/* set up the userspace frame (the only place that the USP is stored) */
138	*childregs = *current_pt_regs();
139
140	p->thread.frame	 = childregs;
141	p->thread.curr	 = p;
142	p->thread.sp	 = (unsigned long) childregs;
143	p->thread.fp	 = 0;
144	p->thread.lr	 = 0;
145	p->thread.frame0 = childregs;
146
147	if (unlikely(p->flags & PF_KTHREAD)) {
148		childregs->gr9 = usp; /* function */
149		childregs->gr8 = arg;
150		p->thread.pc = (unsigned long) ret_from_kernel_thread;
151		save_user_regs(p->thread.user);
152		return 0;
153	}
154	if (usp)
155		childregs->sp = usp;
156	childregs->next_frame	= NULL;
157
158	p->thread.pc = (unsigned long) ret_from_fork;
159
160	/* the new TLS pointer is passed in as arg #5 to sys_clone() */
161	if (clone_flags & CLONE_SETTLS)
162		childregs->gr29 = childregs->gr12;
163
164	save_user_regs(p->thread.user);
165
166	return 0;
167} /* end copy_thread() */
168
169unsigned long get_wchan(struct task_struct *p)
170{
171	struct pt_regs *regs0;
172	unsigned long fp, pc;
173	unsigned long stack_limit;
174	int count = 0;
175	if (!p || p == current || p->state == TASK_RUNNING)
176		return 0;
177
178	stack_limit = (unsigned long) (p + 1);
179	fp = p->thread.fp;
180	regs0 = p->thread.frame0;
181
182	do {
183		if (fp < stack_limit || fp >= (unsigned long) regs0 || fp & 3)
184			return 0;
185
186		pc = ((unsigned long *) fp)[2];
187
188		/* FIXME: This depends on the order of these functions. */
189		if (!in_sched_functions(pc))
190			return pc;
191
192		fp = *(unsigned long *) fp;
193	} while (count++ < 16);
194
195	return 0;
196}
197
198unsigned long thread_saved_pc(struct task_struct *tsk)
199{
200	/* Check whether the thread is blocked in resume() */
201	if (in_sched_functions(tsk->thread.pc))
202		return ((unsigned long *)tsk->thread.fp)[2];
203	else
204		return tsk->thread.pc;
205}
206
207int elf_check_arch(const struct elf32_hdr *hdr)
208{
209	unsigned long hsr0 = __get_HSR(0);
210	unsigned long psr = __get_PSR();
211
212	if (hdr->e_machine != EM_FRV)
213		return 0;
214
215	switch (hdr->e_flags & EF_FRV_GPR_MASK) {
216	case EF_FRV_GPR64:
217		if ((hsr0 & HSR0_GRN) == HSR0_GRN_32)
218			return 0;
219	case EF_FRV_GPR32:
220	case 0:
221		break;
222	default:
223		return 0;
224	}
225
226	switch (hdr->e_flags & EF_FRV_FPR_MASK) {
227	case EF_FRV_FPR64:
228		if ((hsr0 & HSR0_FRN) == HSR0_FRN_32)
229			return 0;
230	case EF_FRV_FPR32:
231	case EF_FRV_FPR_NONE:
232	case 0:
233		break;
234	default:
235		return 0;
236	}
237
238	if ((hdr->e_flags & EF_FRV_MULADD) == EF_FRV_MULADD)
239		if (PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
240		    PSR_IMPLE(psr) != PSR_IMPLE_FR451)
241			return 0;
242
243	switch (hdr->e_flags & EF_FRV_CPU_MASK) {
244	case EF_FRV_CPU_GENERIC:
245		break;
246	case EF_FRV_CPU_FR300:
247	case EF_FRV_CPU_SIMPLE:
248	case EF_FRV_CPU_TOMCAT:
249	default:
250		return 0;
251	case EF_FRV_CPU_FR400:
252		if (PSR_IMPLE(psr) != PSR_IMPLE_FR401 &&
253		    PSR_IMPLE(psr) != PSR_IMPLE_FR405 &&
254		    PSR_IMPLE(psr) != PSR_IMPLE_FR451 &&
255		    PSR_IMPLE(psr) != PSR_IMPLE_FR551)
256			return 0;
257		break;
258	case EF_FRV_CPU_FR450:
259		if (PSR_IMPLE(psr) != PSR_IMPLE_FR451)
260			return 0;
261		break;
262	case EF_FRV_CPU_FR500:
263		if (PSR_IMPLE(psr) != PSR_IMPLE_FR501)
264			return 0;
265		break;
266	case EF_FRV_CPU_FR550:
267		if (PSR_IMPLE(psr) != PSR_IMPLE_FR551)
268			return 0;
269		break;
270	}
271
272	return 1;
273}
274
275int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
276{
277	memcpy(fpregs,
278	       &current->thread.user->f,
279	       sizeof(current->thread.user->f));
280	return 1;
281}
282