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