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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 <asm/cpu_mf.h>
34#include <asm/io.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 memcpy(dst, src, arch_task_struct_size);
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[5] = (unsigned long)frame + sizeof(struct stack_frame);
140 frame->sf.gprs[6] = (unsigned long)p;
141 /* new return point is ret_from_fork */
142 frame->sf.gprs[8] = (unsigned long)ret_from_fork;
143 /* fake return stack for resume(), don't go back to schedule */
144 frame->sf.gprs[9] = (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_DAT |
151 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
152 frame->childregs.psw.addr =
153 (unsigned long)__ret_from_fork;
154 frame->childregs.gprs[9] = (unsigned long)args->fn;
155 frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
156 frame->childregs.orig_gpr2 = -1;
157 frame->childregs.last_break = 1;
158 return 0;
159 }
160 frame->childregs = *current_pt_regs();
161 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
162 frame->childregs.flags = 0;
163 if (new_stackp)
164 frame->childregs.gprs[15] = new_stackp;
165 /*
166 * Clear the runtime instrumentation flag after the above childregs
167 * copy. The CB pointer was already cleared in arch_dup_task_struct().
168 */
169 frame->childregs.psw.mask &= ~PSW_MASK_RI;
170
171 /* Set a new TLS ? */
172 if (clone_flags & CLONE_SETTLS) {
173 if (is_compat_task()) {
174 p->thread.acrs[0] = (unsigned int)tls;
175 } else {
176 p->thread.acrs[0] = (unsigned int)(tls >> 32);
177 p->thread.acrs[1] = (unsigned int)tls;
178 }
179 }
180 /*
181 * s390 stores the svc return address in arch_data when calling
182 * sigreturn()/restart_syscall() via vdso. 1 means no valid address
183 * stored.
184 */
185 p->restart_block.arch_data = 1;
186 return 0;
187}
188
189void execve_tail(void)
190{
191 current->thread.fpu.fpc = 0;
192 asm volatile("sfpc %0" : : "d" (0));
193}
194
195unsigned long __get_wchan(struct task_struct *p)
196{
197 struct unwind_state state;
198 unsigned long ip = 0;
199
200 if (!task_stack_page(p))
201 return 0;
202
203 if (!try_get_task_stack(p))
204 return 0;
205
206 unwind_for_each_frame(&state, p, NULL, 0) {
207 if (state.stack_info.type != STACK_TYPE_TASK) {
208 ip = 0;
209 break;
210 }
211
212 ip = unwind_get_return_address(&state);
213 if (!ip)
214 break;
215
216 if (!in_sched_functions(ip))
217 break;
218 }
219
220 put_task_stack(p);
221 return ip;
222}
223
224unsigned long arch_align_stack(unsigned long sp)
225{
226 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
227 sp -= get_random_u32_below(PAGE_SIZE);
228 return sp & ~0xf;
229}
230
231static inline unsigned long brk_rnd(void)
232{
233 return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT;
234}
235
236unsigned long arch_randomize_brk(struct mm_struct *mm)
237{
238 unsigned long ret;
239
240 ret = PAGE_ALIGN(mm->brk + brk_rnd());
241 return (ret > mm->brk) ? ret : mm->brk;
242}
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}