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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/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}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This file handles the architecture dependent parts of process handling.
4 *
5 * Copyright IBM Corp. 1999, 2009
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
7 * Hartmut Penner <hp@de.ibm.com>,
8 * Denis Joseph Barrow,
9 */
10
11#include <linux/elf-randomize.h>
12#include <linux/compiler.h>
13#include <linux/cpu.h>
14#include <linux/sched.h>
15#include <linux/sched/debug.h>
16#include <linux/sched/task.h>
17#include <linux/sched/task_stack.h>
18#include <linux/kernel.h>
19#include <linux/mm.h>
20#include <linux/elfcore.h>
21#include <linux/smp.h>
22#include <linux/slab.h>
23#include <linux/interrupt.h>
24#include <linux/tick.h>
25#include <linux/personality.h>
26#include <linux/syscalls.h>
27#include <linux/compat.h>
28#include <linux/kprobes.h>
29#include <linux/random.h>
30#include <linux/export.h>
31#include <linux/init_task.h>
32#include <asm/cpu_mf.h>
33#include <asm/io.h>
34#include <asm/processor.h>
35#include <asm/vtimer.h>
36#include <asm/exec.h>
37#include <asm/irq.h>
38#include <asm/nmi.h>
39#include <asm/smp.h>
40#include <asm/switch_to.h>
41#include <asm/runtime_instr.h>
42#include "entry.h"
43
44asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
45
46extern void kernel_thread_starter(void);
47
48void flush_thread(void)
49{
50}
51
52void arch_setup_new_exec(void)
53{
54 if (S390_lowcore.current_pid != current->pid) {
55 S390_lowcore.current_pid = current->pid;
56 if (test_facility(40))
57 lpp(&S390_lowcore.lpp);
58 }
59}
60
61void arch_release_task_struct(struct task_struct *tsk)
62{
63 runtime_instr_release(tsk);
64 guarded_storage_release(tsk);
65}
66
67int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
68{
69 /*
70 * Save the floating-point or vector register state of the current
71 * task and set the CIF_FPU flag to lazy restore the FPU register
72 * state when returning to user space.
73 */
74 save_fpu_regs();
75
76 memcpy(dst, src, arch_task_struct_size);
77 dst->thread.fpu.regs = dst->thread.fpu.fprs;
78 return 0;
79}
80
81int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
82 unsigned long arg, struct task_struct *p, unsigned long tls)
83{
84 struct fake_frame
85 {
86 struct stack_frame sf;
87 struct pt_regs childregs;
88 } *frame;
89
90 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
91 p->thread.ksp = (unsigned long) frame;
92 /* Save access registers to new thread structure. */
93 save_access_regs(&p->thread.acrs[0]);
94 /* start new process with ar4 pointing to the correct address space */
95 p->thread.mm_segment = get_fs();
96 /* Don't copy debug registers */
97 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
98 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
99 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
100 p->thread.per_flags = 0;
101 /* Initialize per thread user and system timer values */
102 p->thread.user_timer = 0;
103 p->thread.guest_timer = 0;
104 p->thread.system_timer = 0;
105 p->thread.hardirq_timer = 0;
106 p->thread.softirq_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 =
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 frame->childregs.psw.mask &= ~PSW_MASK_RI;
138 /* Don't copy guarded storage control block */
139 p->thread.gs_cb = NULL;
140 p->thread.gs_bc_cb = NULL;
141
142 /* Set a new TLS ? */
143 if (clone_flags & CLONE_SETTLS) {
144 if (is_compat_task()) {
145 p->thread.acrs[0] = (unsigned int)tls;
146 } else {
147 p->thread.acrs[0] = (unsigned int)(tls >> 32);
148 p->thread.acrs[1] = (unsigned int)tls;
149 }
150 }
151 return 0;
152}
153
154asmlinkage void execve_tail(void)
155{
156 current->thread.fpu.fpc = 0;
157 asm volatile("sfpc %0" : : "d" (0));
158}
159
160/*
161 * fill in the FPU structure for a core dump.
162 */
163int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
164{
165 save_fpu_regs();
166 fpregs->fpc = current->thread.fpu.fpc;
167 fpregs->pad = 0;
168 if (MACHINE_HAS_VX)
169 convert_vx_to_fp((freg_t *)&fpregs->fprs,
170 current->thread.fpu.vxrs);
171 else
172 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
173 sizeof(fpregs->fprs));
174 return 1;
175}
176EXPORT_SYMBOL(dump_fpu);
177
178unsigned long get_wchan(struct task_struct *p)
179{
180 struct stack_frame *sf, *low, *high;
181 unsigned long return_address;
182 int count;
183
184 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
185 return 0;
186 low = task_stack_page(p);
187 high = (struct stack_frame *) task_pt_regs(p);
188 sf = (struct stack_frame *) p->thread.ksp;
189 if (sf <= low || sf > high)
190 return 0;
191 for (count = 0; count < 16; count++) {
192 sf = (struct stack_frame *) sf->back_chain;
193 if (sf <= low || sf > high)
194 return 0;
195 return_address = sf->gprs[8];
196 if (!in_sched_functions(return_address))
197 return return_address;
198 }
199 return 0;
200}
201
202unsigned long arch_align_stack(unsigned long sp)
203{
204 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
205 sp -= get_random_int() & ~PAGE_MASK;
206 return sp & ~0xf;
207}
208
209static inline unsigned long brk_rnd(void)
210{
211 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
212}
213
214unsigned long arch_randomize_brk(struct mm_struct *mm)
215{
216 unsigned long ret;
217
218 ret = PAGE_ALIGN(mm->brk + brk_rnd());
219 return (ret > mm->brk) ? ret : mm->brk;
220}
221
222void set_fs_fixup(void)
223{
224 struct pt_regs *regs = current_pt_regs();
225 static bool warned;
226
227 set_fs(USER_DS);
228 if (warned)
229 return;
230 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
231 show_registers(regs);
232 warned = true;
233}