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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/guarded_storage.h>
35#include <asm/access-regs.h>
36#include <asm/switch_to.h>
37#include <asm/cpu_mf.h>
38#include <asm/processor.h>
39#include <asm/ptrace.h>
40#include <asm/vtimer.h>
41#include <asm/exec.h>
42#include <asm/fpu.h>
43#include <asm/irq.h>
44#include <asm/nmi.h>
45#include <asm/smp.h>
46#include <asm/stacktrace.h>
47#include <asm/runtime_instr.h>
48#include <asm/unwind.h>
49#include "entry.h"
50
51void ret_from_fork(void) asm("ret_from_fork");
52
53void __ret_from_fork(struct task_struct *prev, struct pt_regs *regs)
54{
55 void (*func)(void *arg);
56
57 schedule_tail(prev);
58
59 if (!user_mode(regs)) {
60 /* Kernel thread */
61 func = (void *)regs->gprs[9];
62 func((void *)regs->gprs[10]);
63 }
64 clear_pt_regs_flag(regs, PIF_SYSCALL);
65 syscall_exit_to_user_mode(regs);
66}
67
68void flush_thread(void)
69{
70}
71
72void arch_setup_new_exec(void)
73{
74 if (get_lowcore()->current_pid != current->pid) {
75 get_lowcore()->current_pid = current->pid;
76 if (test_facility(40))
77 lpp(&get_lowcore()->lpp);
78 }
79}
80
81void arch_release_task_struct(struct task_struct *tsk)
82{
83 runtime_instr_release(tsk);
84 guarded_storage_release(tsk);
85}
86
87int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
88{
89 save_user_fpu_regs();
90
91 *dst = *src;
92 dst->thread.kfpu_flags = 0;
93
94 /*
95 * Don't transfer over the runtime instrumentation or the guarded
96 * storage control block pointers. These fields are cleared here instead
97 * of in copy_thread() to avoid premature freeing of associated memory
98 * on fork() failure. Wait to clear the RI flag because ->stack still
99 * refers to the source thread.
100 */
101 dst->thread.ri_cb = NULL;
102 dst->thread.gs_cb = NULL;
103 dst->thread.gs_bc_cb = NULL;
104
105 return 0;
106}
107
108int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
109{
110 unsigned long clone_flags = args->flags;
111 unsigned long new_stackp = args->stack;
112 unsigned long tls = args->tls;
113 struct fake_frame
114 {
115 struct stack_frame sf;
116 struct pt_regs childregs;
117 } *frame;
118
119 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
120 p->thread.ksp = (unsigned long) frame;
121 /* Save access registers to new thread structure. */
122 save_access_regs(&p->thread.acrs[0]);
123 /* start new process with ar4 pointing to the correct address space */
124 /* Don't copy debug registers */
125 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
126 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
127 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
128 p->thread.per_flags = 0;
129 /* Initialize per thread user and system timer values */
130 p->thread.user_timer = 0;
131 p->thread.guest_timer = 0;
132 p->thread.system_timer = 0;
133 p->thread.hardirq_timer = 0;
134 p->thread.softirq_timer = 0;
135 p->thread.last_break = 1;
136
137 frame->sf.back_chain = 0;
138 frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
139 frame->sf.gprs[12 - 6] = (unsigned long)p;
140 /* new return point is ret_from_fork */
141 frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
142 /* fake return stack for resume(), don't go back to schedule */
143 frame->sf.gprs[15 - 6] = (unsigned long)frame;
144
145 /* Store access registers to kernel stack of new process. */
146 if (unlikely(args->fn)) {
147 /* kernel thread */
148 memset(&frame->childregs, 0, sizeof(struct pt_regs));
149 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
150 PSW_MASK_EXT | PSW_MASK_MCHECK;
151 frame->childregs.gprs[9] = (unsigned long)args->fn;
152 frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
153 frame->childregs.orig_gpr2 = -1;
154 frame->childregs.last_break = 1;
155 return 0;
156 }
157 frame->childregs = *current_pt_regs();
158 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
159 frame->childregs.flags = 0;
160 if (new_stackp)
161 frame->childregs.gprs[15] = new_stackp;
162 /*
163 * Clear the runtime instrumentation flag after the above childregs
164 * copy. The CB pointer was already cleared in arch_dup_task_struct().
165 */
166 frame->childregs.psw.mask &= ~PSW_MASK_RI;
167
168 /* Set a new TLS ? */
169 if (clone_flags & CLONE_SETTLS) {
170 if (is_compat_task()) {
171 p->thread.acrs[0] = (unsigned int)tls;
172 } else {
173 p->thread.acrs[0] = (unsigned int)(tls >> 32);
174 p->thread.acrs[1] = (unsigned int)tls;
175 }
176 }
177 /*
178 * s390 stores the svc return address in arch_data when calling
179 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
180 * stored.
181 */
182 p->restart_block.arch_data = 1;
183 return 0;
184}
185
186void execve_tail(void)
187{
188 current->thread.ufpu.fpc = 0;
189 fpu_sfpc(0);
190}
191
192struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
193{
194 save_user_fpu_regs();
195 save_kernel_fpu_regs(&prev->thread);
196 save_access_regs(&prev->thread.acrs[0]);
197 save_ri_cb(prev->thread.ri_cb);
198 save_gs_cb(prev->thread.gs_cb);
199 update_cr_regs(next);
200 restore_kernel_fpu_regs(&next->thread);
201 restore_access_regs(&next->thread.acrs[0]);
202 restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);
203 restore_gs_cb(next->thread.gs_cb);
204 return __switch_to_asm(prev, next);
205}
206
207unsigned long __get_wchan(struct task_struct *p)
208{
209 struct unwind_state state;
210 unsigned long ip = 0;
211
212 if (!task_stack_page(p))
213 return 0;
214
215 if (!try_get_task_stack(p))
216 return 0;
217
218 unwind_for_each_frame(&state, p, NULL, 0) {
219 if (state.stack_info.type != STACK_TYPE_TASK) {
220 ip = 0;
221 break;
222 }
223
224 ip = unwind_get_return_address(&state);
225 if (!ip)
226 break;
227
228 if (!in_sched_functions(ip))
229 break;
230 }
231
232 put_task_stack(p);
233 return ip;
234}
235
236unsigned long arch_align_stack(unsigned long sp)
237{
238 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
239 sp -= get_random_u32_below(PAGE_SIZE);
240 return sp & ~0xf;
241}
242
243static inline unsigned long brk_rnd(void)
244{
245 return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT;
246}
247
248unsigned long arch_randomize_brk(struct mm_struct *mm)
249{
250 unsigned long ret;
251
252 ret = PAGE_ALIGN(mm->brk + brk_rnd());
253 return (ret > mm->brk) ? ret : mm->brk;
254}
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}