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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/elf-randomize.h>
11#include <linux/compiler.h>
12#include <linux/cpu.h>
13#include <linux/sched.h>
14#include <linux/kernel.h>
15#include <linux/mm.h>
16#include <linux/elfcore.h>
17#include <linux/smp.h>
18#include <linux/slab.h>
19#include <linux/interrupt.h>
20#include <linux/tick.h>
21#include <linux/personality.h>
22#include <linux/syscalls.h>
23#include <linux/compat.h>
24#include <linux/kprobes.h>
25#include <linux/random.h>
26#include <linux/module.h>
27#include <linux/init_task.h>
28#include <asm/io.h>
29#include <asm/processor.h>
30#include <asm/vtimer.h>
31#include <asm/exec.h>
32#include <asm/irq.h>
33#include <asm/nmi.h>
34#include <asm/smp.h>
35#include <asm/switch_to.h>
36#include <asm/runtime_instr.h>
37#include "entry.h"
38
39asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
40
41/*
42 * Return saved PC of a blocked thread. used in kernel/sched.
43 * resume in entry.S does not create a new stack frame, it
44 * just stores the registers %r6-%r15 to the frame given by
45 * schedule. We want to return the address of the caller of
46 * schedule, so we have to walk the backchain one time to
47 * find the frame schedule() store its return address.
48 */
49unsigned long thread_saved_pc(struct task_struct *tsk)
50{
51 struct stack_frame *sf, *low, *high;
52
53 if (!tsk || !task_stack_page(tsk))
54 return 0;
55 low = task_stack_page(tsk);
56 high = (struct stack_frame *) task_pt_regs(tsk);
57 sf = (struct stack_frame *) tsk->thread.ksp;
58 if (sf <= low || sf > high)
59 return 0;
60 sf = (struct stack_frame *) sf->back_chain;
61 if (sf <= low || sf > high)
62 return 0;
63 return sf->gprs[8];
64}
65
66extern void kernel_thread_starter(void);
67
68/*
69 * Free current thread data structures etc..
70 */
71void exit_thread(struct task_struct *tsk)
72{
73 if (tsk == current)
74 exit_thread_runtime_instr();
75}
76
77void flush_thread(void)
78{
79}
80
81void release_thread(struct task_struct *dead_task)
82{
83}
84
85void arch_release_task_struct(struct task_struct *tsk)
86{
87}
88
89int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
90{
91 /*
92 * Save the floating-point or vector register state of the current
93 * task and set the CIF_FPU flag to lazy restore the FPU register
94 * state when returning to user space.
95 */
96 save_fpu_regs();
97
98 memcpy(dst, src, arch_task_struct_size);
99 dst->thread.fpu.regs = dst->thread.fpu.fprs;
100 return 0;
101}
102
103int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
104 unsigned long arg, struct task_struct *p)
105{
106 struct fake_frame
107 {
108 struct stack_frame sf;
109 struct pt_regs childregs;
110 } *frame;
111
112 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
113 p->thread.ksp = (unsigned long) frame;
114 /* Save access registers to new thread structure. */
115 save_access_regs(&p->thread.acrs[0]);
116 /* start new process with ar4 pointing to the correct address space */
117 p->thread.mm_segment = get_fs();
118 /* Don't copy debug registers */
119 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
120 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
121 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
122 /* Initialize per thread user and system timer values */
123 p->thread.user_timer = 0;
124 p->thread.system_timer = 0;
125
126 frame->sf.back_chain = 0;
127 /* new return point is ret_from_fork */
128 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
129 /* fake return stack for resume(), don't go back to schedule */
130 frame->sf.gprs[9] = (unsigned long) frame;
131
132 /* Store access registers to kernel stack of new process. */
133 if (unlikely(p->flags & PF_KTHREAD)) {
134 /* kernel thread */
135 memset(&frame->childregs, 0, sizeof(struct pt_regs));
136 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
137 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
138 frame->childregs.psw.addr =
139 (unsigned long) kernel_thread_starter;
140 frame->childregs.gprs[9] = new_stackp; /* function */
141 frame->childregs.gprs[10] = arg;
142 frame->childregs.gprs[11] = (unsigned long) do_exit;
143 frame->childregs.orig_gpr2 = -1;
144
145 return 0;
146 }
147 frame->childregs = *current_pt_regs();
148 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
149 frame->childregs.flags = 0;
150 if (new_stackp)
151 frame->childregs.gprs[15] = new_stackp;
152
153 /* Don't copy runtime instrumentation info */
154 p->thread.ri_cb = NULL;
155 frame->childregs.psw.mask &= ~PSW_MASK_RI;
156
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 return 0;
168}
169
170asmlinkage void execve_tail(void)
171{
172 current->thread.fpu.fpc = 0;
173 asm volatile("sfpc %0" : : "d" (0));
174}
175
176/*
177 * fill in the FPU structure for a core dump.
178 */
179int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
180{
181 save_fpu_regs();
182 fpregs->fpc = current->thread.fpu.fpc;
183 fpregs->pad = 0;
184 if (MACHINE_HAS_VX)
185 convert_vx_to_fp((freg_t *)&fpregs->fprs,
186 current->thread.fpu.vxrs);
187 else
188 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
189 sizeof(fpregs->fprs));
190 return 1;
191}
192EXPORT_SYMBOL(dump_fpu);
193
194unsigned long get_wchan(struct task_struct *p)
195{
196 struct stack_frame *sf, *low, *high;
197 unsigned long return_address;
198 int count;
199
200 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
201 return 0;
202 low = task_stack_page(p);
203 high = (struct stack_frame *) task_pt_regs(p);
204 sf = (struct stack_frame *) p->thread.ksp;
205 if (sf <= low || sf > high)
206 return 0;
207 for (count = 0; count < 16; count++) {
208 sf = (struct stack_frame *) sf->back_chain;
209 if (sf <= low || sf > high)
210 return 0;
211 return_address = sf->gprs[8];
212 if (!in_sched_functions(return_address))
213 return return_address;
214 }
215 return 0;
216}
217
218unsigned long arch_align_stack(unsigned long sp)
219{
220 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
221 sp -= get_random_int() & ~PAGE_MASK;
222 return sp & ~0xf;
223}
224
225static inline unsigned long brk_rnd(void)
226{
227 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
228}
229
230unsigned long arch_randomize_brk(struct mm_struct *mm)
231{
232 unsigned long ret;
233
234 ret = PAGE_ALIGN(mm->brk + brk_rnd());
235 return (ret > mm->brk) ? ret : mm->brk;
236}
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/smp.h>
16#include <linux/slab.h>
17#include <linux/interrupt.h>
18#include <linux/tick.h>
19#include <linux/personality.h>
20#include <linux/syscalls.h>
21#include <linux/compat.h>
22#include <linux/kprobes.h>
23#include <linux/random.h>
24#include <linux/module.h>
25#include <asm/system.h>
26#include <asm/io.h>
27#include <asm/processor.h>
28#include <asm/irq.h>
29#include <asm/timer.h>
30#include <asm/nmi.h>
31#include <asm/compat.h>
32#include <asm/smp.h>
33#include "entry.h"
34
35asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
36
37/*
38 * Return saved PC of a blocked thread. used in kernel/sched.
39 * resume in entry.S does not create a new stack frame, it
40 * just stores the registers %r6-%r15 to the frame given by
41 * schedule. We want to return the address of the caller of
42 * schedule, so we have to walk the backchain one time to
43 * find the frame schedule() store its return address.
44 */
45unsigned long thread_saved_pc(struct task_struct *tsk)
46{
47 struct stack_frame *sf, *low, *high;
48
49 if (!tsk || !task_stack_page(tsk))
50 return 0;
51 low = task_stack_page(tsk);
52 high = (struct stack_frame *) task_pt_regs(tsk);
53 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
54 if (sf <= low || sf > high)
55 return 0;
56 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
57 if (sf <= low || sf > high)
58 return 0;
59 return sf->gprs[8];
60}
61
62/*
63 * The idle loop on a S390...
64 */
65static void default_idle(void)
66{
67 if (cpu_is_offline(smp_processor_id()))
68 cpu_die();
69 local_irq_disable();
70 if (need_resched()) {
71 local_irq_enable();
72 return;
73 }
74 local_mcck_disable();
75 if (test_thread_flag(TIF_MCCK_PENDING)) {
76 local_mcck_enable();
77 local_irq_enable();
78 s390_handle_mcck();
79 return;
80 }
81 trace_hardirqs_on();
82 /* Don't trace preempt off for idle. */
83 stop_critical_timings();
84 /* Stop virtual timer and halt the cpu. */
85 vtime_stop_cpu();
86 /* Reenable preemption tracer. */
87 start_critical_timings();
88}
89
90void cpu_idle(void)
91{
92 for (;;) {
93 tick_nohz_stop_sched_tick(1);
94 while (!need_resched())
95 default_idle();
96 tick_nohz_restart_sched_tick();
97 preempt_enable_no_resched();
98 schedule();
99 preempt_disable();
100 }
101}
102
103extern void __kprobes kernel_thread_starter(void);
104
105asm(
106 ".section .kprobes.text, \"ax\"\n"
107 ".global kernel_thread_starter\n"
108 "kernel_thread_starter:\n"
109 " la 2,0(10)\n"
110 " basr 14,9\n"
111 " la 2,0\n"
112 " br 11\n"
113 ".previous\n");
114
115int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
116{
117 struct pt_regs regs;
118
119 memset(®s, 0, sizeof(regs));
120 regs.psw.mask = psw_kernel_bits | PSW_MASK_IO | PSW_MASK_EXT;
121 regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
122 regs.gprs[9] = (unsigned long) fn;
123 regs.gprs[10] = (unsigned long) arg;
124 regs.gprs[11] = (unsigned long) do_exit;
125 regs.orig_gpr2 = -1;
126
127 /* Ok, create the new process.. */
128 return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
129 0, ®s, 0, NULL, NULL);
130}
131EXPORT_SYMBOL(kernel_thread);
132
133/*
134 * Free current thread data structures etc..
135 */
136void exit_thread(void)
137{
138}
139
140void flush_thread(void)
141{
142}
143
144void release_thread(struct task_struct *dead_task)
145{
146}
147
148int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
149 unsigned long unused,
150 struct task_struct *p, struct pt_regs *regs)
151{
152 struct thread_info *ti;
153 struct fake_frame
154 {
155 struct stack_frame sf;
156 struct pt_regs childregs;
157 } *frame;
158
159 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
160 p->thread.ksp = (unsigned long) frame;
161 /* Store access registers to kernel stack of new process. */
162 frame->childregs = *regs;
163 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
164 frame->childregs.gprs[15] = new_stackp;
165 frame->sf.back_chain = 0;
166
167 /* new return point is ret_from_fork */
168 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
169
170 /* fake return stack for resume(), don't go back to schedule */
171 frame->sf.gprs[9] = (unsigned long) frame;
172
173 /* Save access registers to new thread structure. */
174 save_access_regs(&p->thread.acrs[0]);
175
176#ifndef CONFIG_64BIT
177 /*
178 * save fprs to current->thread.fp_regs to merge them with
179 * the emulated registers and then copy the result to the child.
180 */
181 save_fp_regs(¤t->thread.fp_regs);
182 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
183 sizeof(s390_fp_regs));
184 /* Set a new TLS ? */
185 if (clone_flags & CLONE_SETTLS)
186 p->thread.acrs[0] = regs->gprs[6];
187#else /* CONFIG_64BIT */
188 /* Save the fpu registers to new thread structure. */
189 save_fp_regs(&p->thread.fp_regs);
190 /* Set a new TLS ? */
191 if (clone_flags & CLONE_SETTLS) {
192 if (is_compat_task()) {
193 p->thread.acrs[0] = (unsigned int) regs->gprs[6];
194 } else {
195 p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32);
196 p->thread.acrs[1] = (unsigned int) regs->gprs[6];
197 }
198 }
199#endif /* CONFIG_64BIT */
200 /* start new process with ar4 pointing to the correct address space */
201 p->thread.mm_segment = get_fs();
202 /* Don't copy debug registers */
203 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
204 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
205 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
206 clear_tsk_thread_flag(p, TIF_PER_TRAP);
207 /* Initialize per thread user and system timer values */
208 ti = task_thread_info(p);
209 ti->user_timer = 0;
210 ti->system_timer = 0;
211 return 0;
212}
213
214SYSCALL_DEFINE0(fork)
215{
216 struct pt_regs *regs = task_pt_regs(current);
217 return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL);
218}
219
220SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,
221 int __user *, parent_tidptr, int __user *, child_tidptr)
222{
223 struct pt_regs *regs = task_pt_regs(current);
224
225 if (!newsp)
226 newsp = regs->gprs[15];
227 return do_fork(clone_flags, newsp, regs, 0,
228 parent_tidptr, child_tidptr);
229}
230
231/*
232 * This is trivial, and on the face of it looks like it
233 * could equally well be done in user mode.
234 *
235 * Not so, for quite unobvious reasons - register pressure.
236 * In user mode vfork() cannot have a stack frame, and if
237 * done by calling the "clone()" system call directly, you
238 * do not have enough call-clobbered registers to hold all
239 * the information you need.
240 */
241SYSCALL_DEFINE0(vfork)
242{
243 struct pt_regs *regs = task_pt_regs(current);
244 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
245 regs->gprs[15], regs, 0, NULL, NULL);
246}
247
248asmlinkage void execve_tail(void)
249{
250 current->thread.fp_regs.fpc = 0;
251 if (MACHINE_HAS_IEEE)
252 asm volatile("sfpc %0,%0" : : "d" (0));
253}
254
255/*
256 * sys_execve() executes a new program.
257 */
258SYSCALL_DEFINE3(execve, const char __user *, name,
259 const char __user *const __user *, argv,
260 const char __user *const __user *, envp)
261{
262 struct pt_regs *regs = task_pt_regs(current);
263 char *filename;
264 long rc;
265
266 filename = getname(name);
267 rc = PTR_ERR(filename);
268 if (IS_ERR(filename))
269 return rc;
270 rc = do_execve(filename, argv, envp, regs);
271 if (rc)
272 goto out;
273 execve_tail();
274 rc = regs->gprs[2];
275out:
276 putname(filename);
277 return rc;
278}
279
280/*
281 * fill in the FPU structure for a core dump.
282 */
283int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
284{
285#ifndef CONFIG_64BIT
286 /*
287 * save fprs to current->thread.fp_regs to merge them with
288 * the emulated registers and then copy the result to the dump.
289 */
290 save_fp_regs(¤t->thread.fp_regs);
291 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
292#else /* CONFIG_64BIT */
293 save_fp_regs(fpregs);
294#endif /* CONFIG_64BIT */
295 return 1;
296}
297EXPORT_SYMBOL(dump_fpu);
298
299unsigned long get_wchan(struct task_struct *p)
300{
301 struct stack_frame *sf, *low, *high;
302 unsigned long return_address;
303 int count;
304
305 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
306 return 0;
307 low = task_stack_page(p);
308 high = (struct stack_frame *) task_pt_regs(p);
309 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
310 if (sf <= low || sf > high)
311 return 0;
312 for (count = 0; count < 16; count++) {
313 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
314 if (sf <= low || sf > high)
315 return 0;
316 return_address = sf->gprs[8] & PSW_ADDR_INSN;
317 if (!in_sched_functions(return_address))
318 return return_address;
319 }
320 return 0;
321}
322
323unsigned long arch_align_stack(unsigned long sp)
324{
325 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
326 sp -= get_random_int() & ~PAGE_MASK;
327 return sp & ~0xf;
328}
329
330static inline unsigned long brk_rnd(void)
331{
332 /* 8MB for 32bit, 1GB for 64bit */
333 if (is_32bit_task())
334 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
335 else
336 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
337}
338
339unsigned long arch_randomize_brk(struct mm_struct *mm)
340{
341 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
342
343 if (ret < mm->brk)
344 return mm->brk;
345 return ret;
346}
347
348unsigned long randomize_et_dyn(unsigned long base)
349{
350 unsigned long ret = PAGE_ALIGN(base + brk_rnd());
351
352 if (!(current->flags & PF_RANDOMIZE))
353 return base;
354 if (ret < base)
355 return base;
356 return ret;
357}