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 /* 47 * Free current thread data structures etc.. 48 */ 49 void exit_thread(struct task_struct *tsk) 50 { 51 if (tsk == current) { 52 exit_thread_runtime_instr(); 53 exit_thread_gs(); 54 } 55 } 56 57 void flush_thread(void) 58 { 59 } 60 61 void release_thread(struct task_struct *dead_task) 62 { 63 } 64 65 void arch_release_task_struct(struct task_struct *tsk) 66 { 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_tls(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 p->thread.mm_segment = get_fs(); 98 /* Don't copy debug registers */ 99 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 100 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 101 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 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; 108 109 frame->sf.back_chain = 0; 110 /* new return point is ret_from_fork */ 111 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 112 /* fake return stack for resume(), don't go back to schedule */ 113 frame->sf.gprs[9] = (unsigned long) frame; 114 115 /* Store access registers to kernel stack of new process. */ 116 if (unlikely(p->flags & PF_KTHREAD)) { 117 /* kernel thread */ 118 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 119 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 120 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 121 frame->childregs.psw.addr = 122 (unsigned long) kernel_thread_starter; 123 frame->childregs.gprs[9] = new_stackp; /* function */ 124 frame->childregs.gprs[10] = arg; 125 frame->childregs.gprs[11] = (unsigned long) do_exit; 126 frame->childregs.orig_gpr2 = -1; 127 128 return 0; 129 } 130 frame->childregs = *current_pt_regs(); 131 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 132 frame->childregs.flags = 0; 133 if (new_stackp) 134 frame->childregs.gprs[15] = new_stackp; 135 136 /* Don't copy runtime instrumentation info */ 137 p->thread.ri_cb = NULL; 138 frame->childregs.psw.mask &= ~PSW_MASK_RI; 139 /* Don't copy guarded storage control block */ 140 p->thread.gs_cb = NULL; 141 p->thread.gs_bc_cb = NULL; 142 143 /* Set a new TLS ? */ 144 if (clone_flags & CLONE_SETTLS) { 145 if (is_compat_task()) { 146 p->thread.acrs[0] = (unsigned int)tls; 147 } else { 148 p->thread.acrs[0] = (unsigned int)(tls >> 32); 149 p->thread.acrs[1] = (unsigned int)tls; 150 } 151 } 152 return 0; 153 } 154 155 asmlinkage void execve_tail(void) 156 { 157 current->thread.fpu.fpc = 0; 158 asm volatile("sfpc %0" : : "d" (0)); 159 } 160 161 /* 162 * fill in the FPU structure for a core dump. 163 */ 164 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 165 { 166 save_fpu_regs(); 167 fpregs->fpc = current->thread.fpu.fpc; 168 fpregs->pad = 0; 169 if (MACHINE_HAS_VX) 170 convert_vx_to_fp((freg_t *)&fpregs->fprs, 171 current->thread.fpu.vxrs); 172 else 173 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 174 sizeof(fpregs->fprs)); 175 return 1; 176 } 177 EXPORT_SYMBOL(dump_fpu); 178 179 unsigned long get_wchan(struct task_struct *p) 180 { 181 struct stack_frame *sf, *low, *high; 182 unsigned long return_address; 183 int count; 184 185 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 186 return 0; 187 low = task_stack_page(p); 188 high = (struct stack_frame *) task_pt_regs(p); 189 sf = (struct stack_frame *) p->thread.ksp; 190 if (sf <= low || sf > high) 191 return 0; 192 for (count = 0; count < 16; count++) { 193 sf = (struct stack_frame *) sf->back_chain; 194 if (sf <= low || sf > high) 195 return 0; 196 return_address = sf->gprs[8]; 197 if (!in_sched_functions(return_address)) 198 return return_address; 199 } 200 return 0; 201 } 202 203 unsigned long arch_align_stack(unsigned long sp) 204 { 205 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 206 sp -= get_random_int() & ~PAGE_MASK; 207 return sp & ~0xf; 208 } 209 210 static inline unsigned long brk_rnd(void) 211 { 212 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 213 } 214 215 unsigned long arch_randomize_brk(struct mm_struct *mm) 216 { 217 unsigned long ret; 218 219 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 220 return (ret > mm->brk) ? ret : mm->brk; 221 } 222 223 void set_fs_fixup(void) 224 { 225 struct pt_regs *regs = current_pt_regs(); 226 static bool warned; 227 228 set_fs(USER_DS); 229 if (warned) 230 return; 231 WARN(1, "Unbalanced set_fs - int code: 0x%x\n", regs->int_code); 232 show_registers(regs); 233 warned = true; 234 } 235