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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// 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 (S390_lowcore.current_pid != current->pid) {
75 S390_lowcore.current_pid = current->pid;
76 if (test_facility(40))
77 lpp(&S390_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 /*
90 * Save the floating-point or vector register state of the current
91 * task and set the TIF_FPU flag to lazy restore the FPU register
92 * state when returning to user space.
93 */
94 save_user_fpu_regs();
95
96 *dst = *src;
97 dst->thread.kfpu_flags = 0;
98
99 /*
100 * Don't transfer over the runtime instrumentation or the guarded
101 * storage control block pointers. These fields are cleared here instead
102 * of in copy_thread() to avoid premature freeing of associated memory
103 * on fork() failure. Wait to clear the RI flag because ->stack still
104 * refers to the source thread.
105 */
106 dst->thread.ri_cb = NULL;
107 dst->thread.gs_cb = NULL;
108 dst->thread.gs_bc_cb = NULL;
109
110 return 0;
111}
112
113int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
114{
115 unsigned long clone_flags = args->flags;
116 unsigned long new_stackp = args->stack;
117 unsigned long tls = args->tls;
118 struct fake_frame
119 {
120 struct stack_frame sf;
121 struct pt_regs childregs;
122 } *frame;
123
124 frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
125 p->thread.ksp = (unsigned long) frame;
126 /* Save access registers to new thread structure. */
127 save_access_regs(&p->thread.acrs[0]);
128 /* start new process with ar4 pointing to the correct address space */
129 /* Don't copy debug registers */
130 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
131 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
132 clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
133 p->thread.per_flags = 0;
134 /* Initialize per thread user and system timer values */
135 p->thread.user_timer = 0;
136 p->thread.guest_timer = 0;
137 p->thread.system_timer = 0;
138 p->thread.hardirq_timer = 0;
139 p->thread.softirq_timer = 0;
140 p->thread.last_break = 1;
141
142 frame->sf.back_chain = 0;
143 frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
144 frame->sf.gprs[12 - 6] = (unsigned long)p;
145 /* new return point is ret_from_fork */
146 frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
147 /* fake return stack for resume(), don't go back to schedule */
148 frame->sf.gprs[15 - 6] = (unsigned long)frame;
149
150 /* Store access registers to kernel stack of new process. */
151 if (unlikely(args->fn)) {
152 /* kernel thread */
153 memset(&frame->childregs, 0, sizeof(struct pt_regs));
154 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
155 PSW_MASK_EXT | PSW_MASK_MCHECK;
156 frame->childregs.gprs[9] = (unsigned long)args->fn;
157 frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
158 frame->childregs.orig_gpr2 = -1;
159 frame->childregs.last_break = 1;
160 return 0;
161 }
162 frame->childregs = *current_pt_regs();
163 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
164 frame->childregs.flags = 0;
165 if (new_stackp)
166 frame->childregs.gprs[15] = new_stackp;
167 /*
168 * Clear the runtime instrumentation flag after the above childregs
169 * copy. The CB pointer was already cleared in arch_dup_task_struct().
170 */
171 frame->childregs.psw.mask &= ~PSW_MASK_RI;
172
173 /* Set a new TLS ? */
174 if (clone_flags & CLONE_SETTLS) {
175 if (is_compat_task()) {
176 p->thread.acrs[0] = (unsigned int)tls;
177 } else {
178 p->thread.acrs[0] = (unsigned int)(tls >> 32);
179 p->thread.acrs[1] = (unsigned int)tls;
180 }
181 }
182 /*
183 * s390 stores the svc return address in arch_data when calling
184 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
185 * stored.
186 */
187 p->restart_block.arch_data = 1;
188 return 0;
189}
190
191void execve_tail(void)
192{
193 current->thread.ufpu.fpc = 0;
194 fpu_sfpc(0);
195}
196
197struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
198{
199 save_user_fpu_regs();
200 save_kernel_fpu_regs(&prev->thread);
201 save_access_regs(&prev->thread.acrs[0]);
202 save_ri_cb(prev->thread.ri_cb);
203 save_gs_cb(prev->thread.gs_cb);
204 update_cr_regs(next);
205 restore_kernel_fpu_regs(&next->thread);
206 restore_access_regs(&next->thread.acrs[0]);
207 restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);
208 restore_gs_cb(next->thread.gs_cb);
209 return __switch_to_asm(prev, next);
210}
211
212unsigned long __get_wchan(struct task_struct *p)
213{
214 struct unwind_state state;
215 unsigned long ip = 0;
216
217 if (!task_stack_page(p))
218 return 0;
219
220 if (!try_get_task_stack(p))
221 return 0;
222
223 unwind_for_each_frame(&state, p, NULL, 0) {
224 if (state.stack_info.type != STACK_TYPE_TASK) {
225 ip = 0;
226 break;
227 }
228
229 ip = unwind_get_return_address(&state);
230 if (!ip)
231 break;
232
233 if (!in_sched_functions(ip))
234 break;
235 }
236
237 put_task_stack(p);
238 return ip;
239}
240
241unsigned long arch_align_stack(unsigned long sp)
242{
243 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
244 sp -= get_random_u32_below(PAGE_SIZE);
245 return sp & ~0xf;
246}
247
248static inline unsigned long brk_rnd(void)
249{
250 return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT;
251}
252
253unsigned long arch_randomize_brk(struct mm_struct *mm)
254{
255 unsigned long ret;
256
257 ret = PAGE_ALIGN(mm->brk + brk_rnd());
258 return (ret > mm->brk) ? ret : mm->brk;
259}