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