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 <asm/unwind.h> 44 #include "entry.h" 45 46 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 47 48 extern void kernel_thread_starter(void); 49 50 void flush_thread(void) 51 { 52 } 53 54 void arch_setup_new_exec(void) 55 { 56 if (S390_lowcore.current_pid != current->pid) { 57 S390_lowcore.current_pid = current->pid; 58 if (test_facility(40)) 59 lpp(&S390_lowcore.lpp); 60 } 61 } 62 63 void arch_release_task_struct(struct task_struct *tsk) 64 { 65 runtime_instr_release(tsk); 66 guarded_storage_release(tsk); 67 } 68 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 83 int copy_thread(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 /* 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 p->thread.last_break = 1; 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 } 155 156 asmlinkage void execve_tail(void) 157 { 158 current->thread.fpu.fpc = 0; 159 asm volatile("sfpc %0" : : "d" (0)); 160 } 161 162 unsigned long get_wchan(struct task_struct *p) 163 { 164 struct unwind_state state; 165 unsigned long ip = 0; 166 167 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 168 return 0; 169 170 if (!try_get_task_stack(p)) 171 return 0; 172 173 unwind_for_each_frame(&state, p, NULL, 0) { 174 if (state.stack_info.type != STACK_TYPE_TASK) { 175 ip = 0; 176 break; 177 } 178 179 ip = unwind_get_return_address(&state); 180 if (!ip) 181 break; 182 183 if (!in_sched_functions(ip)) 184 break; 185 } 186 187 put_task_stack(p); 188 return ip; 189 } 190 191 unsigned long arch_align_stack(unsigned long sp) 192 { 193 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 194 sp -= get_random_int() & ~PAGE_MASK; 195 return sp & ~0xf; 196 } 197 198 static inline unsigned long brk_rnd(void) 199 { 200 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 201 } 202 203 unsigned long arch_randomize_brk(struct mm_struct *mm) 204 { 205 unsigned long ret; 206 207 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 208 return (ret > mm->brk) ? ret : mm->brk; 209 } 210