1 /* 2 * This file handles the architecture dependent parts of process handling. 3 * 4 * Copyright IBM Corp. 1999, 2009 5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, 6 * Hartmut Penner <hp@de.ibm.com>, 7 * Denis Joseph Barrow, 8 */ 9 10 #include <linux/elf-randomize.h> 11 #include <linux/compiler.h> 12 #include <linux/cpu.h> 13 #include <linux/sched.h> 14 #include <linux/sched/debug.h> 15 #include <linux/sched/task.h> 16 #include <linux/sched/task_stack.h> 17 #include <linux/kernel.h> 18 #include <linux/mm.h> 19 #include <linux/elfcore.h> 20 #include <linux/smp.h> 21 #include <linux/slab.h> 22 #include <linux/interrupt.h> 23 #include <linux/tick.h> 24 #include <linux/personality.h> 25 #include <linux/syscalls.h> 26 #include <linux/compat.h> 27 #include <linux/kprobes.h> 28 #include <linux/random.h> 29 #include <linux/export.h> 30 #include <linux/init_task.h> 31 #include <asm/io.h> 32 #include <asm/processor.h> 33 #include <asm/vtimer.h> 34 #include <asm/exec.h> 35 #include <asm/irq.h> 36 #include <asm/nmi.h> 37 #include <asm/smp.h> 38 #include <asm/switch_to.h> 39 #include <asm/runtime_instr.h> 40 #include "entry.h" 41 42 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 43 44 extern void kernel_thread_starter(void); 45 46 void flush_thread(void) 47 { 48 } 49 50 void arch_release_task_struct(struct task_struct *tsk) 51 { 52 runtime_instr_release(tsk); 53 guarded_storage_release(tsk); 54 } 55 56 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 57 { 58 /* 59 * Save the floating-point or vector register state of the current 60 * task and set the CIF_FPU flag to lazy restore the FPU register 61 * state when returning to user space. 62 */ 63 save_fpu_regs(); 64 65 memcpy(dst, src, arch_task_struct_size); 66 dst->thread.fpu.regs = dst->thread.fpu.fprs; 67 return 0; 68 } 69 70 int copy_thread_tls(unsigned long clone_flags, unsigned long new_stackp, 71 unsigned long arg, struct task_struct *p, unsigned long tls) 72 { 73 struct fake_frame 74 { 75 struct stack_frame sf; 76 struct pt_regs childregs; 77 } *frame; 78 79 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 80 p->thread.ksp = (unsigned long) frame; 81 /* Save access registers to new thread structure. */ 82 save_access_regs(&p->thread.acrs[0]); 83 /* start new process with ar4 pointing to the correct address space */ 84 p->thread.mm_segment = get_fs(); 85 /* Don't copy debug registers */ 86 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 87 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 88 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 89 /* Initialize per thread user and system timer values */ 90 p->thread.user_timer = 0; 91 p->thread.guest_timer = 0; 92 p->thread.system_timer = 0; 93 p->thread.hardirq_timer = 0; 94 p->thread.softirq_timer = 0; 95 96 frame->sf.back_chain = 0; 97 /* new return point is ret_from_fork */ 98 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 99 /* fake return stack for resume(), don't go back to schedule */ 100 frame->sf.gprs[9] = (unsigned long) frame; 101 102 /* Store access registers to kernel stack of new process. */ 103 if (unlikely(p->flags & PF_KTHREAD)) { 104 /* kernel thread */ 105 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 106 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 107 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 108 frame->childregs.psw.addr = 109 (unsigned long) kernel_thread_starter; 110 frame->childregs.gprs[9] = new_stackp; /* function */ 111 frame->childregs.gprs[10] = arg; 112 frame->childregs.gprs[11] = (unsigned long) do_exit; 113 frame->childregs.orig_gpr2 = -1; 114 115 return 0; 116 } 117 frame->childregs = *current_pt_regs(); 118 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 119 frame->childregs.flags = 0; 120 if (new_stackp) 121 frame->childregs.gprs[15] = new_stackp; 122 123 /* Don't copy runtime instrumentation info */ 124 p->thread.ri_cb = NULL; 125 frame->childregs.psw.mask &= ~PSW_MASK_RI; 126 /* Don't copy guarded storage control block */ 127 p->thread.gs_cb = NULL; 128 p->thread.gs_bc_cb = NULL; 129 130 /* Set a new TLS ? */ 131 if (clone_flags & CLONE_SETTLS) { 132 if (is_compat_task()) { 133 p->thread.acrs[0] = (unsigned int)tls; 134 } else { 135 p->thread.acrs[0] = (unsigned int)(tls >> 32); 136 p->thread.acrs[1] = (unsigned int)tls; 137 } 138 } 139 return 0; 140 } 141 142 asmlinkage void execve_tail(void) 143 { 144 current->thread.fpu.fpc = 0; 145 asm volatile("sfpc %0" : : "d" (0)); 146 } 147 148 /* 149 * fill in the FPU structure for a core dump. 150 */ 151 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 152 { 153 save_fpu_regs(); 154 fpregs->fpc = current->thread.fpu.fpc; 155 fpregs->pad = 0; 156 if (MACHINE_HAS_VX) 157 convert_vx_to_fp((freg_t *)&fpregs->fprs, 158 current->thread.fpu.vxrs); 159 else 160 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 161 sizeof(fpregs->fprs)); 162 return 1; 163 } 164 EXPORT_SYMBOL(dump_fpu); 165 166 unsigned long get_wchan(struct task_struct *p) 167 { 168 struct stack_frame *sf, *low, *high; 169 unsigned long return_address; 170 int count; 171 172 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 173 return 0; 174 low = task_stack_page(p); 175 high = (struct stack_frame *) task_pt_regs(p); 176 sf = (struct stack_frame *) p->thread.ksp; 177 if (sf <= low || sf > high) 178 return 0; 179 for (count = 0; count < 16; count++) { 180 sf = (struct stack_frame *) sf->back_chain; 181 if (sf <= low || sf > high) 182 return 0; 183 return_address = sf->gprs[8]; 184 if (!in_sched_functions(return_address)) 185 return return_address; 186 } 187 return 0; 188 } 189 190 unsigned long arch_align_stack(unsigned long sp) 191 { 192 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 193 sp -= get_random_int() & ~PAGE_MASK; 194 return sp & ~0xf; 195 } 196 197 static inline unsigned long brk_rnd(void) 198 { 199 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 200 } 201 202 unsigned long arch_randomize_brk(struct mm_struct *mm) 203 { 204 unsigned long ret; 205 206 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 207 return (ret > mm->brk) ? ret : mm->brk; 208 } 209 210 void set_fs_fixup(void) 211 { 212 struct pt_regs *regs = current_pt_regs(); 213 static bool warned; 214 215 set_fs(USER_DS); 216 if (warned) 217 return; 218 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code); 219 show_registers(regs); 220 warned = true; 221 } 222