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
64 extern void __kprobes kernel_thread_starter(void);
65
66 /*
67 * Free current thread data structures etc..
68 */
exit_thread(struct task_struct * tsk)69 void exit_thread(struct task_struct *tsk)
70 {
71 if (tsk == current)
72 exit_thread_runtime_instr();
73 }
74
flush_thread(void)75 void flush_thread(void)
76 {
77 }
78
release_thread(struct task_struct * dead_task)79 void release_thread(struct task_struct *dead_task)
80 {
81 }
82
copy_thread(unsigned long clone_flags,unsigned long new_stackp,unsigned long arg,struct task_struct * p)83 int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
84 unsigned long arg, struct task_struct *p)
85 {
86 struct thread_info *ti;
87 struct fake_frame
88 {
89 struct stack_frame sf;
90 struct pt_regs childregs;
91 } *frame;
92
93 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
94 p->thread.ksp = (unsigned long) frame;
95 /* Save access registers to new thread structure. */
96 save_access_regs(&p->thread.acrs[0]);
97 /* start new process with ar4 pointing to the correct address space */
98 p->thread.mm_segment = get_fs();
99 /* Don't copy debug registers */
100 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
101 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
102 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
103 /* Initialize per thread user and system timer values */
104 ti = task_thread_info(p);
105 ti->user_timer = 0;
106 ti->system_timer = 0;
107
108 frame->sf.back_chain = 0;
109 /* new return point is ret_from_fork */
110 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
111 /* fake return stack for resume(), don't go back to schedule */
112 frame->sf.gprs[9] = (unsigned long) frame;
113
114 /* Store access registers to kernel stack of new process. */
115 if (unlikely(p->flags & PF_KTHREAD)) {
116 /* kernel thread */
117 memset(&frame->childregs, 0, sizeof(struct pt_regs));
118 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
119 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
120 frame->childregs.psw.addr = PSW_ADDR_AMODE |
121 (unsigned long) kernel_thread_starter;
122 frame->childregs.gprs[9] = new_stackp; /* function */
123 frame->childregs.gprs[10] = arg;
124 frame->childregs.gprs[11] = (unsigned long) do_exit;
125 frame->childregs.orig_gpr2 = -1;
126
127 return 0;
128 }
129 frame->childregs = *current_pt_regs();
130 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
131 frame->childregs.flags = 0;
132 if (new_stackp)
133 frame->childregs.gprs[15] = new_stackp;
134
135 /* Don't copy runtime instrumentation info */
136 p->thread.ri_cb = NULL;
137 p->thread.ri_signum = 0;
138 frame->childregs.psw.mask &= ~PSW_MASK_RI;
139
140 #ifndef CONFIG_64BIT
141 /*
142 * save fprs to current->thread.fp_regs to merge them with
143 * the emulated registers and then copy the result to the child.
144 */
145 save_fp_ctl(¤t->thread.fp_regs.fpc);
146 save_fp_regs(current->thread.fp_regs.fprs);
147 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
148 sizeof(s390_fp_regs));
149 /* Set a new TLS ? */
150 if (clone_flags & CLONE_SETTLS)
151 p->thread.acrs[0] = frame->childregs.gprs[6];
152 #else /* CONFIG_64BIT */
153 /* Save the fpu registers to new thread structure. */
154 save_fp_ctl(&p->thread.fp_regs.fpc);
155 save_fp_regs(p->thread.fp_regs.fprs);
156 p->thread.fp_regs.pad = 0;
157 /* Set a new TLS ? */
158 if (clone_flags & CLONE_SETTLS) {
159 unsigned long tls = frame->childregs.gprs[6];
160 if (is_compat_task()) {
161 p->thread.acrs[0] = (unsigned int)tls;
162 } else {
163 p->thread.acrs[0] = (unsigned int)(tls >> 32);
164 p->thread.acrs[1] = (unsigned int)tls;
165 }
166 }
167 #endif /* CONFIG_64BIT */
168 return 0;
169 }
170
execve_tail(void)171 asmlinkage void execve_tail(void)
172 {
173 current->thread.fp_regs.fpc = 0;
174 if (MACHINE_HAS_IEEE)
175 asm volatile("sfpc %0,%0" : : "d" (0));
176 }
177
178 /*
179 * fill in the FPU structure for a core dump.
180 */
dump_fpu(struct pt_regs * regs,s390_fp_regs * fpregs)181 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
182 {
183 #ifndef CONFIG_64BIT
184 /*
185 * save fprs to current->thread.fp_regs to merge them with
186 * the emulated registers and then copy the result to the dump.
187 */
188 save_fp_ctl(¤t->thread.fp_regs.fpc);
189 save_fp_regs(current->thread.fp_regs.fprs);
190 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
191 #else /* CONFIG_64BIT */
192 save_fp_ctl(&fpregs->fpc);
193 save_fp_regs(fpregs->fprs);
194 #endif /* CONFIG_64BIT */
195 return 1;
196 }
197 EXPORT_SYMBOL(dump_fpu);
198
get_wchan(struct task_struct * p)199 unsigned long get_wchan(struct task_struct *p)
200 {
201 struct stack_frame *sf, *low, *high;
202 unsigned long return_address;
203 int count;
204
205 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
206 return 0;
207 low = task_stack_page(p);
208 high = (struct stack_frame *) task_pt_regs(p);
209 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
210 if (sf <= low || sf > high)
211 return 0;
212 for (count = 0; count < 16; count++) {
213 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
214 if (sf <= low || sf > high)
215 return 0;
216 return_address = sf->gprs[8] & PSW_ADDR_INSN;
217 if (!in_sched_functions(return_address))
218 return return_address;
219 }
220 return 0;
221 }
222
arch_align_stack(unsigned long sp)223 unsigned long arch_align_stack(unsigned long sp)
224 {
225 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
226 sp -= get_random_int() & ~PAGE_MASK;
227 return sp & ~0xf;
228 }
229
brk_rnd(void)230 static inline unsigned long brk_rnd(void)
231 {
232 /* 8MB for 32bit, 1GB for 64bit */
233 if (is_32bit_task())
234 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
235 else
236 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
237 }
238
arch_randomize_brk(struct mm_struct * mm)239 unsigned long arch_randomize_brk(struct mm_struct *mm)
240 {
241 unsigned long ret;
242
243 ret = PAGE_ALIGN(mm->brk + brk_rnd());
244 return (ret > mm->brk) ? ret : mm->brk;
245 }
246
randomize_et_dyn(unsigned long base)247 unsigned long randomize_et_dyn(unsigned long base)
248 {
249 unsigned long ret;
250
251 if (!(current->flags & PF_RANDOMIZE))
252 return base;
253 ret = PAGE_ALIGN(base + brk_rnd());
254 return (ret > base) ? ret : base;
255 }
256