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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 <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/stacktrace.h>
41#include <asm/switch_to.h>
42#include <asm/runtime_instr.h>
43#include "entry.h"
44
45asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
46
47extern void kernel_thread_starter(void);
48
49void flush_thread(void)
50{
51}
52
53void arch_setup_new_exec(void)
54{
55 if (S390_lowcore.current_pid != current->pid) {
56 S390_lowcore.current_pid = current->pid;
57 if (test_facility(40))
58 lpp(&S390_lowcore.lpp);
59 }
60}
61
62void arch_release_task_struct(struct task_struct *tsk)
63{
64 runtime_instr_release(tsk);
65 guarded_storage_release(tsk);
66}
67
68int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
69{
70 /*
71 * Save the floating-point or vector register state of the current
72 * task and set the CIF_FPU flag to lazy restore the FPU register
73 * state when returning to user space.
74 */
75 save_fpu_regs();
76
77 memcpy(dst, src, arch_task_struct_size);
78 dst->thread.fpu.regs = dst->thread.fpu.fprs;
79 return 0;
80}
81
82int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp,
83 unsigned long arg, struct task_struct *p, unsigned long tls)
84{
85 struct fake_frame
86 {
87 struct stack_frame sf;
88 struct pt_regs childregs;
89 } *frame;
90
91 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
92 p->thread.ksp = (unsigned long) frame;
93 /* Save access registers to new thread structure. */
94 save_access_regs(&p->thread.acrs[0]);
95 /* start new process with ar4 pointing to the correct address space */
96 p->thread.mm_segment = get_fs();
97 /* Don't copy debug registers */
98 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
99 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
100 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
101 p->thread.per_flags = 0;
102 /* Initialize per thread user and system timer values */
103 p->thread.user_timer = 0;
104 p->thread.guest_timer = 0;
105 p->thread.system_timer = 0;
106 p->thread.hardirq_timer = 0;
107 p->thread.softirq_timer = 0;
108
109 frame->sf.back_chain = 0;
110 /* new return point is ret_from_fork */
111 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
112 /* fake return stack for resume(), don't go back to schedule */
113 frame->sf.gprs[9] = (unsigned long) frame;
114
115 /* Store access registers to kernel stack of new process. */
116 if (unlikely(p->flags & PF_KTHREAD)) {
117 /* kernel thread */
118 memset(&frame->childregs, 0, sizeof(struct pt_regs));
119 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
120 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
121 frame->childregs.psw.addr =
122 (unsigned long) kernel_thread_starter;
123 frame->childregs.gprs[9] = new_stackp; /* function */
124 frame->childregs.gprs[10] = arg;
125 frame->childregs.gprs[11] = (unsigned long) do_exit;
126 frame->childregs.orig_gpr2 = -1;
127
128 return 0;
129 }
130 frame->childregs = *current_pt_regs();
131 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
132 frame->childregs.flags = 0;
133 if (new_stackp)
134 frame->childregs.gprs[15] = new_stackp;
135
136 /* Don't copy runtime instrumentation info */
137 p->thread.ri_cb = NULL;
138 frame->childregs.psw.mask &= ~PSW_MASK_RI;
139 /* Don't copy guarded storage control block */
140 p->thread.gs_cb = NULL;
141 p->thread.gs_bc_cb = NULL;
142
143 /* Set a new TLS ? */
144 if (clone_flags & CLONE_SETTLS) {
145 if (is_compat_task()) {
146 p->thread.acrs[0] = (unsigned int)tls;
147 } else {
148 p->thread.acrs[0] = (unsigned int)(tls >> 32);
149 p->thread.acrs[1] = (unsigned int)tls;
150 }
151 }
152 return 0;
153}
154
155asmlinkage void execve_tail(void)
156{
157 current->thread.fpu.fpc = 0;
158 asm volatile("sfpc %0" : : "d" (0));
159}
160
161/*
162 * fill in the FPU structure for a core dump.
163 */
164int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
165{
166 save_fpu_regs();
167 fpregs->fpc = current->thread.fpu.fpc;
168 fpregs->pad = 0;
169 if (MACHINE_HAS_VX)
170 convert_vx_to_fp((freg_t *)&fpregs->fprs,
171 current->thread.fpu.vxrs);
172 else
173 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
174 sizeof(fpregs->fprs));
175 return 1;
176}
177EXPORT_SYMBOL(dump_fpu);
178
179unsigned long get_wchan(struct task_struct *p)
180{
181 struct stack_frame *sf, *low, *high;
182 unsigned long return_address;
183 int count;
184
185 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
186 return 0;
187
188 if (!try_get_task_stack(p))
189 return 0;
190
191 low = task_stack_page(p);
192 high = (struct stack_frame *) task_pt_regs(p);
193 sf = (struct stack_frame *) p->thread.ksp;
194 if (sf <= low || sf > high) {
195 return_address = 0;
196 goto out;
197 }
198 for (count = 0; count < 16; count++) {
199 sf = (struct stack_frame *)READ_ONCE_NOCHECK(sf->back_chain);
200 if (sf <= low || sf > high) {
201 return_address = 0;
202 goto out;
203 }
204 return_address = READ_ONCE_NOCHECK(sf->gprs[8]);
205 if (!in_sched_functions(return_address))
206 goto out;
207 }
208out:
209 put_task_stack(p);
210 return return_address;
211}
212
213unsigned long arch_align_stack(unsigned long sp)
214{
215 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
216 sp -= get_random_int() & ~PAGE_MASK;
217 return sp & ~0xf;
218}
219
220static inline unsigned long brk_rnd(void)
221{
222 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
223}
224
225unsigned long arch_randomize_brk(struct mm_struct *mm)
226{
227 unsigned long ret;
228
229 ret = PAGE_ALIGN(mm->brk + brk_rnd());
230 return (ret > mm->brk) ? ret : mm->brk;
231}
232
233void set_fs_fixup(void)
234{
235 struct pt_regs *regs = current_pt_regs();
236 static bool warned;
237
238 set_fs(USER_DS);
239 if (warned)
240 return;
241 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code);
242 show_registers(regs);
243 warned = true;
244}
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 <linux/init_task.h>
27#include <asm/io.h>
28#include <asm/processor.h>
29#include <asm/vtimer.h>
30#include <asm/exec.h>
31#include <asm/irq.h>
32#include <asm/nmi.h>
33#include <asm/smp.h>
34#include <asm/switch_to.h>
35#include <asm/runtime_instr.h>
36#include "entry.h"
37
38asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
39
40/* FPU save area for the init task */
41__vector128 init_task_fpu_regs[__NUM_VXRS] __init_task_data;
42
43/*
44 * Return saved PC of a blocked thread. used in kernel/sched.
45 * resume in entry.S does not create a new stack frame, it
46 * just stores the registers %r6-%r15 to the frame given by
47 * schedule. We want to return the address of the caller of
48 * schedule, so we have to walk the backchain one time to
49 * find the frame schedule() store its return address.
50 */
51unsigned long thread_saved_pc(struct task_struct *tsk)
52{
53 struct stack_frame *sf, *low, *high;
54
55 if (!tsk || !task_stack_page(tsk))
56 return 0;
57 low = task_stack_page(tsk);
58 high = (struct stack_frame *) task_pt_regs(tsk);
59 sf = (struct stack_frame *) tsk->thread.ksp;
60 if (sf <= low || sf > high)
61 return 0;
62 sf = (struct stack_frame *) sf->back_chain;
63 if (sf <= low || sf > high)
64 return 0;
65 return sf->gprs[8];
66}
67
68extern void kernel_thread_starter(void);
69
70/*
71 * Free current thread data structures etc..
72 */
73void exit_thread(void)
74{
75 exit_thread_runtime_instr();
76}
77
78void flush_thread(void)
79{
80}
81
82void release_thread(struct task_struct *dead_task)
83{
84}
85
86void arch_release_task_struct(struct task_struct *tsk)
87{
88 /* Free either the floating-point or the vector register save area */
89 kfree(tsk->thread.fpu.regs);
90}
91
92int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
93{
94 size_t fpu_regs_size;
95
96 *dst = *src;
97
98 /*
99 * If the vector extension is available, it is enabled for all tasks,
100 * and, thus, the FPU register save area must be allocated accordingly.
101 */
102 fpu_regs_size = MACHINE_HAS_VX ? sizeof(__vector128) * __NUM_VXRS
103 : sizeof(freg_t) * __NUM_FPRS;
104 dst->thread.fpu.regs = kzalloc(fpu_regs_size, GFP_KERNEL|__GFP_REPEAT);
105 if (!dst->thread.fpu.regs)
106 return -ENOMEM;
107
108 /*
109 * Save the floating-point or vector register state of the current
110 * task and set the CIF_FPU flag to lazy restore the FPU register
111 * state when returning to user space.
112 */
113 save_fpu_regs();
114 dst->thread.fpu.fpc = current->thread.fpu.fpc;
115 memcpy(dst->thread.fpu.regs, current->thread.fpu.regs, fpu_regs_size);
116
117 return 0;
118}
119
120int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
121 unsigned long arg, struct task_struct *p)
122{
123 struct thread_info *ti;
124 struct fake_frame
125 {
126 struct stack_frame sf;
127 struct pt_regs childregs;
128 } *frame;
129
130 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
131 p->thread.ksp = (unsigned long) frame;
132 /* Save access registers to new thread structure. */
133 save_access_regs(&p->thread.acrs[0]);
134 /* start new process with ar4 pointing to the correct address space */
135 p->thread.mm_segment = get_fs();
136 /* Don't copy debug registers */
137 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
138 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
139 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
140 /* Initialize per thread user and system timer values */
141 ti = task_thread_info(p);
142 ti->user_timer = 0;
143 ti->system_timer = 0;
144
145 frame->sf.back_chain = 0;
146 /* new return point is ret_from_fork */
147 frame->sf.gprs[8] = (unsigned long) ret_from_fork;
148 /* fake return stack for resume(), don't go back to schedule */
149 frame->sf.gprs[9] = (unsigned long) frame;
150
151 /* Store access registers to kernel stack of new process. */
152 if (unlikely(p->flags & PF_KTHREAD)) {
153 /* kernel thread */
154 memset(&frame->childregs, 0, sizeof(struct pt_regs));
155 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
156 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
157 frame->childregs.psw.addr =
158 (unsigned long) kernel_thread_starter;
159 frame->childregs.gprs[9] = new_stackp; /* function */
160 frame->childregs.gprs[10] = arg;
161 frame->childregs.gprs[11] = (unsigned long) do_exit;
162 frame->childregs.orig_gpr2 = -1;
163
164 return 0;
165 }
166 frame->childregs = *current_pt_regs();
167 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
168 frame->childregs.flags = 0;
169 if (new_stackp)
170 frame->childregs.gprs[15] = new_stackp;
171
172 /* Don't copy runtime instrumentation info */
173 p->thread.ri_cb = NULL;
174 frame->childregs.psw.mask &= ~PSW_MASK_RI;
175
176 /* Set a new TLS ? */
177 if (clone_flags & CLONE_SETTLS) {
178 unsigned long tls = frame->childregs.gprs[6];
179 if (is_compat_task()) {
180 p->thread.acrs[0] = (unsigned int)tls;
181 } else {
182 p->thread.acrs[0] = (unsigned int)(tls >> 32);
183 p->thread.acrs[1] = (unsigned int)tls;
184 }
185 }
186 return 0;
187}
188
189asmlinkage void execve_tail(void)
190{
191 current->thread.fpu.fpc = 0;
192 asm volatile("sfpc %0" : : "d" (0));
193}
194
195/*
196 * fill in the FPU structure for a core dump.
197 */
198int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
199{
200 save_fpu_regs();
201 fpregs->fpc = current->thread.fpu.fpc;
202 fpregs->pad = 0;
203 if (MACHINE_HAS_VX)
204 convert_vx_to_fp((freg_t *)&fpregs->fprs,
205 current->thread.fpu.vxrs);
206 else
207 memcpy(&fpregs->fprs, current->thread.fpu.fprs,
208 sizeof(fpregs->fprs));
209 return 1;
210}
211EXPORT_SYMBOL(dump_fpu);
212
213unsigned long get_wchan(struct task_struct *p)
214{
215 struct stack_frame *sf, *low, *high;
216 unsigned long return_address;
217 int count;
218
219 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
220 return 0;
221 low = task_stack_page(p);
222 high = (struct stack_frame *) task_pt_regs(p);
223 sf = (struct stack_frame *) p->thread.ksp;
224 if (sf <= low || sf > high)
225 return 0;
226 for (count = 0; count < 16; count++) {
227 sf = (struct stack_frame *) sf->back_chain;
228 if (sf <= low || sf > high)
229 return 0;
230 return_address = sf->gprs[8];
231 if (!in_sched_functions(return_address))
232 return return_address;
233 }
234 return 0;
235}
236
237unsigned long arch_align_stack(unsigned long sp)
238{
239 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
240 sp -= get_random_int() & ~PAGE_MASK;
241 return sp & ~0xf;
242}
243
244static inline unsigned long brk_rnd(void)
245{
246 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
247}
248
249unsigned long arch_randomize_brk(struct mm_struct *mm)
250{
251 unsigned long ret;
252
253 ret = PAGE_ALIGN(mm->brk + brk_rnd());
254 return (ret > mm->brk) ? ret : mm->brk;
255}