1 /*
2 * This file handles the architecture dependent parts of process handling.
3 *
4 * Copyright IBM Corp. 1999, 2009
5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
6 * Hartmut Penner <hp@de.ibm.com>,
7 * Denis Joseph Barrow,
8 */
9
10 #include <linux/compiler.h>
11 #include <linux/cpu.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/elfcore.h>
16 #include <linux/smp.h>
17 #include <linux/slab.h>
18 #include <linux/interrupt.h>
19 #include <linux/tick.h>
20 #include <linux/personality.h>
21 #include <linux/syscalls.h>
22 #include <linux/compat.h>
23 #include <linux/kprobes.h>
24 #include <linux/random.h>
25 #include <linux/module.h>
26 #include <asm/io.h>
27 #include <asm/processor.h>
28 #include <asm/vtimer.h>
29 #include <asm/exec.h>
30 #include <asm/irq.h>
31 #include <asm/nmi.h>
32 #include <asm/smp.h>
33 #include <asm/switch_to.h>
34 #include <asm/runtime_instr.h>
35 #include "entry.h"
36
37 asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
38
39 /*
40 * Return saved PC of a blocked thread. used in kernel/sched.
41 * resume in entry.S does not create a new stack frame, it
42 * just stores the registers %r6-%r15 to the frame given by
43 * schedule. We want to return the address of the caller of
44 * schedule, so we have to walk the backchain one time to
45 * find the frame schedule() store its return address.
46 */
thread_saved_pc(struct task_struct * tsk)47 unsigned long thread_saved_pc(struct task_struct *tsk)
48 {
49 struct stack_frame *sf, *low, *high;
50
51 if (!tsk || !task_stack_page(tsk))
52 return 0;
53 low = task_stack_page(tsk);
54 high = (struct stack_frame *) task_pt_regs(tsk);
55 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
56 if (sf <= low || sf > high)
57 return 0;
58 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
59 if (sf <= low || sf > high)
60 return 0;
61 return sf->gprs[8];
62 }
63
arch_cpu_idle(void)64 void arch_cpu_idle(void)
65 {
66 local_mcck_disable();
67 if (test_thread_flag(TIF_MCCK_PENDING)) {
68 local_mcck_enable();
69 local_irq_enable();
70 return;
71 }
72 /* Halt the cpu and keep track of cpu time accounting. */
73 vtime_stop_cpu();
74 }
75
arch_cpu_idle_exit(void)76 void arch_cpu_idle_exit(void)
77 {
78 if (test_thread_flag(TIF_MCCK_PENDING))
79 s390_handle_mcck();
80 }
81
arch_cpu_idle_dead(void)82 void arch_cpu_idle_dead(void)
83 {
84 cpu_die();
85 }
86
87 extern void __kprobes kernel_thread_starter(void);
88
89 /*
90 * Free current thread data structures etc..
91 */
exit_thread(void)92 void exit_thread(void)
93 {
94 exit_thread_runtime_instr();
95 }
96
flush_thread(void)97 void flush_thread(void)
98 {
99 }
100
release_thread(struct task_struct * dead_task)101 void release_thread(struct task_struct *dead_task)
102 {
103 }
104
copy_thread(unsigned long clone_flags,unsigned long new_stackp,unsigned long arg,struct task_struct * p)105 int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
106 unsigned long arg, struct task_struct *p)
107 {
108 struct thread_info *ti;
109 struct fake_frame
110 {
111 struct stack_frame sf;
112 struct pt_regs childregs;
113 } *frame;
114
115 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
116 p->thread.ksp = (unsigned long) frame;
117 /* Save access registers to new thread structure. */
118 save_access_regs(&p->thread.acrs[0]);
119 /* start new process with ar4 pointing to the correct address space */
120 p->thread.mm_segment = get_fs();
121 /* Don't copy debug registers */
122 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
123 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
124 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
125 clear_tsk_thread_flag(p, TIF_PER_TRAP);
126 /* Initialize per thread user and system timer values */
127 ti = task_thread_info(p);
128 ti->user_timer = 0;
129 ti->system_timer = 0;
130
131 frame->sf.back_chain = 0;
132 /* new return point is ret_from_fork */
133 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
134 /* fake return stack for resume(), don't go back to schedule */
135 frame->sf.gprs[9] = (unsigned long) frame;
136
137 /* Store access registers to kernel stack of new process. */
138 if (unlikely(p->flags & PF_KTHREAD)) {
139 /* kernel thread */
140 memset(&frame->childregs, 0, sizeof(struct pt_regs));
141 frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT |
142 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
143 frame->childregs.psw.addr = PSW_ADDR_AMODE |
144 (unsigned long) kernel_thread_starter;
145 frame->childregs.gprs[9] = new_stackp; /* function */
146 frame->childregs.gprs[10] = arg;
147 frame->childregs.gprs[11] = (unsigned long) do_exit;
148 frame->childregs.orig_gpr2 = -1;
149
150 return 0;
151 }
152 frame->childregs = *current_pt_regs();
153 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
154 if (new_stackp)
155 frame->childregs.gprs[15] = new_stackp;
156
157 /* Don't copy runtime instrumentation info */
158 p->thread.ri_cb = NULL;
159 p->thread.ri_signum = 0;
160 frame->childregs.psw.mask &= ~PSW_MASK_RI;
161
162 #ifndef CONFIG_64BIT
163 /*
164 * save fprs to current->thread.fp_regs to merge them with
165 * the emulated registers and then copy the result to the child.
166 */
167 save_fp_regs(¤t->thread.fp_regs);
168 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
169 sizeof(s390_fp_regs));
170 /* Set a new TLS ? */
171 if (clone_flags & CLONE_SETTLS)
172 p->thread.acrs[0] = frame->childregs.gprs[6];
173 #else /* CONFIG_64BIT */
174 /* Save the fpu registers to new thread structure. */
175 save_fp_regs(&p->thread.fp_regs);
176 /* Set a new TLS ? */
177 if (clone_flags & CLONE_SETTLS) {
178 unsigned long tls = frame->childregs.gprs[6];
179 if (is_compat_task()) {
180 p->thread.acrs[0] = (unsigned int)tls;
181 } else {
182 p->thread.acrs[0] = (unsigned int)(tls >> 32);
183 p->thread.acrs[1] = (unsigned int)tls;
184 }
185 }
186 #endif /* CONFIG_64BIT */
187 return 0;
188 }
189
execve_tail(void)190 asmlinkage void execve_tail(void)
191 {
192 current->thread.fp_regs.fpc = 0;
193 if (MACHINE_HAS_IEEE)
194 asm volatile("sfpc %0,%0" : : "d" (0));
195 }
196
197 /*
198 * fill in the FPU structure for a core dump.
199 */
dump_fpu(struct pt_regs * regs,s390_fp_regs * fpregs)200 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
201 {
202 #ifndef CONFIG_64BIT
203 /*
204 * save fprs to current->thread.fp_regs to merge them with
205 * the emulated registers and then copy the result to the dump.
206 */
207 save_fp_regs(¤t->thread.fp_regs);
208 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
209 #else /* CONFIG_64BIT */
210 save_fp_regs(fpregs);
211 #endif /* CONFIG_64BIT */
212 return 1;
213 }
214 EXPORT_SYMBOL(dump_fpu);
215
get_wchan(struct task_struct * p)216 unsigned long get_wchan(struct task_struct *p)
217 {
218 struct stack_frame *sf, *low, *high;
219 unsigned long return_address;
220 int count;
221
222 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
223 return 0;
224 low = task_stack_page(p);
225 high = (struct stack_frame *) task_pt_regs(p);
226 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
227 if (sf <= low || sf > high)
228 return 0;
229 for (count = 0; count < 16; count++) {
230 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
231 if (sf <= low || sf > high)
232 return 0;
233 return_address = sf->gprs[8] & PSW_ADDR_INSN;
234 if (!in_sched_functions(return_address))
235 return return_address;
236 }
237 return 0;
238 }
239
arch_align_stack(unsigned long sp)240 unsigned long arch_align_stack(unsigned long sp)
241 {
242 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
243 sp -= get_random_int() & ~PAGE_MASK;
244 return sp & ~0xf;
245 }
246
brk_rnd(void)247 static inline unsigned long brk_rnd(void)
248 {
249 /* 8MB for 32bit, 1GB for 64bit */
250 if (is_32bit_task())
251 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
252 else
253 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
254 }
255
arch_randomize_brk(struct mm_struct * mm)256 unsigned long arch_randomize_brk(struct mm_struct *mm)
257 {
258 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
259
260 if (ret < mm->brk)
261 return mm->brk;
262 return ret;
263 }
264
randomize_et_dyn(unsigned long base)265 unsigned long randomize_et_dyn(unsigned long base)
266 {
267 unsigned long ret = PAGE_ALIGN(base + brk_rnd());
268
269 if (!(current->flags & PF_RANDOMIZE))
270 return base;
271 if (ret < base)
272 return base;
273 return ret;
274 }
275