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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 <linux/entry-common.h>
33#include <linux/io.h>
34#include <asm/cpu_mf.h>
35#include <asm/processor.h>
36#include <asm/vtimer.h>
37#include <asm/exec.h>
38#include <asm/irq.h>
39#include <asm/nmi.h>
40#include <asm/smp.h>
41#include <asm/stacktrace.h>
42#include <asm/switch_to.h>
43#include <asm/runtime_instr.h>
44#include <asm/unwind.h>
45#include "entry.h"
46
47void ret_from_fork(void) asm("ret_from_fork");
48
49void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
50{
51 void (*func)(void *arg);
52
53 schedule_tail(prev);
54
55 if (!user_mode(regs)) {
56 /* Kernel thread */
57 func = (void *)regs->gprs[9];
58 func((void *)regs->gprs[10]);
59 }
60 clear_pt_regs_flag(regs, PIF_SYSCALL);
61 syscall_exit_to_user_mode(regs);
62}
63
64void flush_thread(void)
65{
66}
67
68void arch_setup_new_exec(void)
69{
70 if (S390_lowcore.current_pid != current->pid) {
71 S390_lowcore.current_pid = current->pid;
72 if (test_facility(40))
73 lpp(&S390_lowcore.lpp);
74 }
75}
76
77void arch_release_task_struct(struct task_struct *tsk)
78{
79 runtime_instr_release(tsk);
80 guarded_storage_release(tsk);
81}
82
83int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
84{
85 /*
86 * Save the floating-point or vector register state of the current
87 * task and set the CIF_FPU flag to lazy restore the FPU register
88 * state when returning to user space.
89 */
90 save_fpu_regs();
91
92 *dst = *src;
93 dst->thread.fpu.regs = dst->thread.fpu.fprs;
94
95 /*
96 * Don't transfer over the runtime instrumentation or the guarded
97 * storage control block pointers. These fields are cleared here instead
98 * of in copy_thread() to avoid premature freeing of associated memory
99 * on fork() failure. Wait to clear the RI flag because ->stack still
100 * refers to the source thread.
101 */
102 dst->thread.ri_cb = NULL;
103 dst->thread.gs_cb = NULL;
104 dst->thread.gs_bc_cb = NULL;
105
106 return 0;
107}
108
109int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
110{
111 unsigned long clone_flags = args->flags;
112 unsigned long new_stackp = args->stack;
113 unsigned long tls = args->tls;
114 struct fake_frame
115 {
116 struct stack_frame sf;
117 struct pt_regs childregs;
118 } *frame;
119
120 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
121 p->thread.ksp = (unsigned long) frame;
122 /* Save access registers to new thread structure. */
123 save_access_regs(&p->thread.acrs[0]);
124 /* start new process with ar4 pointing to the correct address space */
125 /* Don't copy debug registers */
126 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
127 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
128 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
129 p->thread.per_flags = 0;
130 /* Initialize per thread user and system timer values */
131 p->thread.user_timer = 0;
132 p->thread.guest_timer = 0;
133 p->thread.system_timer = 0;
134 p->thread.hardirq_timer = 0;
135 p->thread.softirq_timer = 0;
136 p->thread.last_break = 1;
137
138 frame->sf.back_chain = 0;
139 frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
140 frame->sf.gprs[12 - 6] = (unsigned long)p;
141 /* new return point is ret_from_fork */
142 frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
143 /* fake return stack for resume(), don't go back to schedule */
144 frame->sf.gprs[15 - 6] = (unsigned long)frame;
145
146 /* Store access registers to kernel stack of new process. */
147 if (unlikely(args->fn)) {
148 /* kernel thread */
149 memset(&frame->childregs, 0, sizeof(struct pt_regs));
150 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
151 PSW_MASK_EXT | PSW_MASK_MCHECK;
152 frame->childregs.gprs[9] = (unsigned long)args->fn;
153 frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
154 frame->childregs.orig_gpr2 = -1;
155 frame->childregs.last_break = 1;
156 return 0;
157 }
158 frame->childregs = *current_pt_regs();
159 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
160 frame->childregs.flags = 0;
161 if (new_stackp)
162 frame->childregs.gprs[15] = new_stackp;
163 /*
164 * Clear the runtime instrumentation flag after the above childregs
165 * copy. The CB pointer was already cleared in arch_dup_task_struct().
166 */
167 frame->childregs.psw.mask &= ~PSW_MASK_RI;
168
169 /* Set a new TLS ? */
170 if (clone_flags & CLONE_SETTLS) {
171 if (is_compat_task()) {
172 p->thread.acrs[0] = (unsigned int)tls;
173 } else {
174 p->thread.acrs[0] = (unsigned int)(tls >> 32);
175 p->thread.acrs[1] = (unsigned int)tls;
176 }
177 }
178 /*
179 * s390 stores the svc return address in arch_data when calling
180 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
181 * stored.
182 */
183 p->restart_block.arch_data = 1;
184 return 0;
185}
186
187void execve_tail(void)
188{
189 current->thread.fpu.fpc = 0;
190 asm volatile("sfpc %0" : : "d" (0));
191}
192
193unsigned long __get_wchan(struct task_struct *p)
194{
195 struct unwind_state state;
196 unsigned long ip = 0;
197
198 if (!task_stack_page(p))
199 return 0;
200
201 if (!try_get_task_stack(p))
202 return 0;
203
204 unwind_for_each_frame(&state, p, NULL, 0) {
205 if (state.stack_info.type != STACK_TYPE_TASK) {
206 ip = 0;
207 break;
208 }
209
210 ip = unwind_get_return_address(&state);
211 if (!ip)
212 break;
213
214 if (!in_sched_functions(ip))
215 break;
216 }
217
218 put_task_stack(p);
219 return ip;
220}
221
222unsigned long arch_align_stack(unsigned long sp)
223{
224 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
225 sp -= get_random_u32_below(PAGE_SIZE);
226 return sp & ~0xf;
227}
228
229static inline unsigned long brk_rnd(void)
230{
231 return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT;
232}
233
234unsigned long arch_randomize_brk(struct mm_struct *mm)
235{
236 unsigned long ret;
237
238 ret = PAGE_ALIGN(mm->brk + brk_rnd());
239 return (ret > mm->brk) ? ret : mm->brk;
240}
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
37asmlinkage 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 */
47unsigned 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
64void 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 local_irq_enable();
75}
76
77void arch_cpu_idle_exit(void)
78{
79 if (test_thread_flag(TIF_MCCK_PENDING))
80 s390_handle_mcck();
81}
82
83void arch_cpu_idle_dead(void)
84{
85 cpu_die();
86}
87
88extern void __kprobes kernel_thread_starter(void);
89
90/*
91 * Free current thread data structures etc..
92 */
93void exit_thread(void)
94{
95 exit_thread_runtime_instr();
96}
97
98void flush_thread(void)
99{
100}
101
102void release_thread(struct task_struct *dead_task)
103{
104}
105
106int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
107 unsigned long arg, struct task_struct *p)
108{
109 struct thread_info *ti;
110 struct fake_frame
111 {
112 struct stack_frame sf;
113 struct pt_regs childregs;
114 } *frame;
115
116 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
117 p->thread.ksp = (unsigned long) frame;
118 /* Save access registers to new thread structure. */
119 save_access_regs(&p->thread.acrs[0]);
120 /* start new process with ar4 pointing to the correct address space */
121 p->thread.mm_segment = get_fs();
122 /* Don't copy debug registers */
123 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
124 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
125 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
126 clear_tsk_thread_flag(p, TIF_PER_TRAP);
127 /* Initialize per thread user and system timer values */
128 ti = task_thread_info(p);
129 ti->user_timer = 0;
130 ti->system_timer = 0;
131
132 frame->sf.back_chain = 0;
133 /* new return point is ret_from_fork */
134 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
135 /* fake return stack for resume(), don't go back to schedule */
136 frame->sf.gprs[9] = (unsigned long) frame;
137
138 /* Store access registers to kernel stack of new process. */
139 if (unlikely(p->flags & PF_KTHREAD)) {
140 /* kernel thread */
141 memset(&frame->childregs, 0, sizeof(struct pt_regs));
142 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
143 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
144 frame->childregs.psw.addr = PSW_ADDR_AMODE |
145 (unsigned long) kernel_thread_starter;
146 frame->childregs.gprs[9] = new_stackp; /* function */
147 frame->childregs.gprs[10] = arg;
148 frame->childregs.gprs[11] = (unsigned long) do_exit;
149 frame->childregs.orig_gpr2 = -1;
150
151 return 0;
152 }
153 frame->childregs = *current_pt_regs();
154 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
155 if (new_stackp)
156 frame->childregs.gprs[15] = new_stackp;
157
158 /* Don't copy runtime instrumentation info */
159 p->thread.ri_cb = NULL;
160 p->thread.ri_signum = 0;
161 frame->childregs.psw.mask &= ~PSW_MASK_RI;
162
163#ifndef CONFIG_64BIT
164 /*
165 * save fprs to current->thread.fp_regs to merge them with
166 * the emulated registers and then copy the result to the child.
167 */
168 save_fp_ctl(¤t->thread.fp_regs.fpc);
169 save_fp_regs(current->thread.fp_regs.fprs);
170 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
171 sizeof(s390_fp_regs));
172 /* Set a new TLS ? */
173 if (clone_flags & CLONE_SETTLS)
174 p->thread.acrs[0] = frame->childregs.gprs[6];
175#else /* CONFIG_64BIT */
176 /* Save the fpu registers to new thread structure. */
177 save_fp_ctl(&p->thread.fp_regs.fpc);
178 save_fp_regs(p->thread.fp_regs.fprs);
179 p->thread.fp_regs.pad = 0;
180 /* Set a new TLS ? */
181 if (clone_flags & CLONE_SETTLS) {
182 unsigned long tls = frame->childregs.gprs[6];
183 if (is_compat_task()) {
184 p->thread.acrs[0] = (unsigned int)tls;
185 } else {
186 p->thread.acrs[0] = (unsigned int)(tls >> 32);
187 p->thread.acrs[1] = (unsigned int)tls;
188 }
189 }
190#endif /* CONFIG_64BIT */
191 return 0;
192}
193
194asmlinkage void execve_tail(void)
195{
196 current->thread.fp_regs.fpc = 0;
197 if (MACHINE_HAS_IEEE)
198 asm volatile("sfpc %0,%0" : : "d" (0));
199}
200
201/*
202 * fill in the FPU structure for a core dump.
203 */
204int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
205{
206#ifndef CONFIG_64BIT
207 /*
208 * save fprs to current->thread.fp_regs to merge them with
209 * the emulated registers and then copy the result to the dump.
210 */
211 save_fp_ctl(¤t->thread.fp_regs.fpc);
212 save_fp_regs(current->thread.fp_regs.fprs);
213 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
214#else /* CONFIG_64BIT */
215 save_fp_ctl(&fpregs->fpc);
216 save_fp_regs(fpregs->fprs);
217#endif /* CONFIG_64BIT */
218 return 1;
219}
220EXPORT_SYMBOL(dump_fpu);
221
222unsigned long get_wchan(struct task_struct *p)
223{
224 struct stack_frame *sf, *low, *high;
225 unsigned long return_address;
226 int count;
227
228 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
229 return 0;
230 low = task_stack_page(p);
231 high = (struct stack_frame *) task_pt_regs(p);
232 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
233 if (sf <= low || sf > high)
234 return 0;
235 for (count = 0; count < 16; count++) {
236 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
237 if (sf <= low || sf > high)
238 return 0;
239 return_address = sf->gprs[8] & PSW_ADDR_INSN;
240 if (!in_sched_functions(return_address))
241 return return_address;
242 }
243 return 0;
244}
245
246unsigned long arch_align_stack(unsigned long sp)
247{
248 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
249 sp -= get_random_int() & ~PAGE_MASK;
250 return sp & ~0xf;
251}
252
253static inline unsigned long brk_rnd(void)
254{
255 /* 8MB for 32bit, 1GB for 64bit */
256 if (is_32bit_task())
257 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
258 else
259 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
260}
261
262unsigned long arch_randomize_brk(struct mm_struct *mm)
263{
264 unsigned long ret;
265
266 ret = PAGE_ALIGN(mm->brk + brk_rnd());
267 return (ret > mm->brk) ? ret : mm->brk;
268}
269
270unsigned long randomize_et_dyn(unsigned long base)
271{
272 unsigned long ret;
273
274 if (!(current->flags & PF_RANDOMIZE))
275 return base;
276 ret = PAGE_ALIGN(base + brk_rnd());
277 return (ret > base) ? ret : base;
278}