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/switch_to.h> 41 #include <asm/runtime_instr.h> 42 #include "entry.h" 43 44 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 45 46 extern void kernel_thread_starter(void); 47 48 void flush_thread(void) 49 { 50 } 51 52 void arch_setup_new_exec(void) 53 { 54 if (S390_lowcore.current_pid != current->pid) { 55 S390_lowcore.current_pid = current->pid; 56 if (test_facility(40)) 57 lpp(&S390_lowcore.lpp); 58 } 59 } 60 61 void arch_release_task_struct(struct task_struct *tsk) 62 { 63 runtime_instr_release(tsk); 64 guarded_storage_release(tsk); 65 } 66 67 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 68 { 69 /* 70 * Save the floating-point or vector register state of the current 71 * task and set the CIF_FPU flag to lazy restore the FPU register 72 * state when returning to user space. 73 */ 74 save_fpu_regs(); 75 76 memcpy(dst, src, arch_task_struct_size); 77 dst->thread.fpu.regs = dst->thread.fpu.fprs; 78 return 0; 79 } 80 81 int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp, 82 unsigned long arg, struct task_struct *p, unsigned long tls) 83 { 84 struct fake_frame 85 { 86 struct stack_frame sf; 87 struct pt_regs childregs; 88 } *frame; 89 90 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 91 p->thread.ksp = (unsigned long) frame; 92 /* Save access registers to new thread structure. */ 93 save_access_regs(&p->thread.acrs[0]); 94 /* start new process with ar4 pointing to the correct address space */ 95 p->thread.mm_segment = get_fs(); 96 /* Don't copy debug registers */ 97 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 98 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 99 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 100 p->thread.per_flags = 0; 101 /* Initialize per thread user and system timer values */ 102 p->thread.user_timer = 0; 103 p->thread.guest_timer = 0; 104 p->thread.system_timer = 0; 105 p->thread.hardirq_timer = 0; 106 p->thread.softirq_timer = 0; 107 108 frame->sf.back_chain = 0; 109 /* new return point is ret_from_fork */ 110 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 111 /* fake return stack for resume(), don't go back to schedule */ 112 frame->sf.gprs[9] = (unsigned long) frame; 113 114 /* Store access registers to kernel stack of new process. */ 115 if (unlikely(p->flags & PF_KTHREAD)) { 116 /* kernel thread */ 117 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 118 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 119 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 120 frame->childregs.psw.addr = 121 (unsigned long) kernel_thread_starter; 122 frame->childregs.gprs[9] = new_stackp; /* function */ 123 frame->childregs.gprs[10] = arg; 124 frame->childregs.gprs[11] = (unsigned long) do_exit; 125 frame->childregs.orig_gpr2 = -1; 126 127 return 0; 128 } 129 frame->childregs = *current_pt_regs(); 130 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 131 frame->childregs.flags = 0; 132 if (new_stackp) 133 frame->childregs.gprs[15] = new_stackp; 134 135 /* Don't copy runtime instrumentation info */ 136 p->thread.ri_cb = NULL; 137 frame->childregs.psw.mask &= ~PSW_MASK_RI; 138 /* Don't copy guarded storage control block */ 139 p->thread.gs_cb = NULL; 140 p->thread.gs_bc_cb = NULL; 141 142 /* Set a new TLS ? */ 143 if (clone_flags & CLONE_SETTLS) { 144 if (is_compat_task()) { 145 p->thread.acrs[0] = (unsigned int)tls; 146 } else { 147 p->thread.acrs[0] = (unsigned int)(tls >> 32); 148 p->thread.acrs[1] = (unsigned int)tls; 149 } 150 } 151 return 0; 152 } 153 154 asmlinkage void execve_tail(void) 155 { 156 current->thread.fpu.fpc = 0; 157 asm volatile("sfpc %0" : : "d" (0)); 158 } 159 160 /* 161 * fill in the FPU structure for a core dump. 162 */ 163 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 164 { 165 save_fpu_regs(); 166 fpregs->fpc = current->thread.fpu.fpc; 167 fpregs->pad = 0; 168 if (MACHINE_HAS_VX) 169 convert_vx_to_fp((freg_t *)&fpregs->fprs, 170 current->thread.fpu.vxrs); 171 else 172 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 173 sizeof(fpregs->fprs)); 174 return 1; 175 } 176 EXPORT_SYMBOL(dump_fpu); 177 178 unsigned long get_wchan(struct task_struct *p) 179 { 180 struct stack_frame *sf, *low, *high; 181 unsigned long return_address; 182 int count; 183 184 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 185 return 0; 186 low = task_stack_page(p); 187 high = (struct stack_frame *) task_pt_regs(p); 188 sf = (struct stack_frame *) p->thread.ksp; 189 if (sf <= low || sf > high) 190 return 0; 191 for (count = 0; count < 16; count++) { 192 sf = (struct stack_frame *) sf->back_chain; 193 if (sf <= low || sf > high) 194 return 0; 195 return_address = sf->gprs[8]; 196 if (!in_sched_functions(return_address)) 197 return return_address; 198 } 199 return 0; 200 } 201 202 unsigned long arch_align_stack(unsigned long sp) 203 { 204 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 205 sp -= get_random_int() & ~PAGE_MASK; 206 return sp & ~0xf; 207 } 208 209 static inline unsigned long brk_rnd(void) 210 { 211 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 212 } 213 214 unsigned long arch_randomize_brk(struct mm_struct *mm) 215 { 216 unsigned long ret; 217 218 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 219 return (ret > mm->brk) ? ret : mm->brk; 220 } 221 222 void set_fs_fixup(void) 223 { 224 struct pt_regs *regs = current_pt_regs(); 225 static bool warned; 226 227 set_fs(USER_DS); 228 if (warned) 229 return; 230 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code); 231 show_registers(regs); 232 warned = true; 233 } 234