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/kernel.h> 15 #include <linux/mm.h> 16 #include <linux/elfcore.h> 17 #include <linux/smp.h> 18 #include <linux/slab.h> 19 #include <linux/interrupt.h> 20 #include <linux/tick.h> 21 #include <linux/personality.h> 22 #include <linux/syscalls.h> 23 #include <linux/compat.h> 24 #include <linux/kprobes.h> 25 #include <linux/random.h> 26 #include <linux/export.h> 27 #include <linux/init_task.h> 28 #include <asm/io.h> 29 #include <asm/processor.h> 30 #include <asm/vtimer.h> 31 #include <asm/exec.h> 32 #include <asm/irq.h> 33 #include <asm/nmi.h> 34 #include <asm/smp.h> 35 #include <asm/switch_to.h> 36 #include <asm/runtime_instr.h> 37 #include "entry.h" 38 39 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 40 41 /* 42 * Return saved PC of a blocked thread. used in kernel/sched. 43 * resume in entry.S does not create a new stack frame, it 44 * just stores the registers %r6-%r15 to the frame given by 45 * schedule. We want to return the address of the caller of 46 * schedule, so we have to walk the backchain one time to 47 * find the frame schedule() store its return address. 48 */ 49 unsigned long thread_saved_pc(struct task_struct *tsk) 50 { 51 struct stack_frame *sf, *low, *high; 52 53 if (!tsk || !task_stack_page(tsk)) 54 return 0; 55 low = task_stack_page(tsk); 56 high = (struct stack_frame *) task_pt_regs(tsk); 57 sf = (struct stack_frame *) tsk->thread.ksp; 58 if (sf <= low || sf > high) 59 return 0; 60 sf = (struct stack_frame *) sf->back_chain; 61 if (sf <= low || sf > high) 62 return 0; 63 return sf->gprs[8]; 64 } 65 66 extern void kernel_thread_starter(void); 67 68 /* 69 * Free current thread data structures etc.. 70 */ 71 void exit_thread(struct task_struct *tsk) 72 { 73 if (tsk == current) 74 exit_thread_runtime_instr(); 75 } 76 77 void flush_thread(void) 78 { 79 } 80 81 void release_thread(struct task_struct *dead_task) 82 { 83 } 84 85 void arch_release_task_struct(struct task_struct *tsk) 86 { 87 } 88 89 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 90 { 91 /* 92 * Save the floating-point or vector register state of the current 93 * task and set the CIF_FPU flag to lazy restore the FPU register 94 * state when returning to user space. 95 */ 96 save_fpu_regs(); 97 98 memcpy(dst, src, arch_task_struct_size); 99 dst->thread.fpu.regs = dst->thread.fpu.fprs; 100 return 0; 101 } 102 103 int copy_thread(unsigned long clone_flags, unsigned long new_stackp, 104 unsigned long arg, struct task_struct *p) 105 { 106 struct fake_frame 107 { 108 struct stack_frame sf; 109 struct pt_regs childregs; 110 } *frame; 111 112 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 113 p->thread.ksp = (unsigned long) frame; 114 /* Save access registers to new thread structure. */ 115 save_access_regs(&p->thread.acrs[0]); 116 /* start new process with ar4 pointing to the correct address space */ 117 p->thread.mm_segment = get_fs(); 118 /* Don't copy debug registers */ 119 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 120 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 121 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 122 /* Initialize per thread user and system timer values */ 123 p->thread.user_timer = 0; 124 p->thread.system_timer = 0; 125 126 frame->sf.back_chain = 0; 127 /* new return point is ret_from_fork */ 128 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 129 /* fake return stack for resume(), don't go back to schedule */ 130 frame->sf.gprs[9] = (unsigned long) frame; 131 132 /* Store access registers to kernel stack of new process. */ 133 if (unlikely(p->flags & PF_KTHREAD)) { 134 /* kernel thread */ 135 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 136 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 137 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 138 frame->childregs.psw.addr = 139 (unsigned long) kernel_thread_starter; 140 frame->childregs.gprs[9] = new_stackp; /* function */ 141 frame->childregs.gprs[10] = arg; 142 frame->childregs.gprs[11] = (unsigned long) do_exit; 143 frame->childregs.orig_gpr2 = -1; 144 145 return 0; 146 } 147 frame->childregs = *current_pt_regs(); 148 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 149 frame->childregs.flags = 0; 150 if (new_stackp) 151 frame->childregs.gprs[15] = new_stackp; 152 153 /* Don't copy runtime instrumentation info */ 154 p->thread.ri_cb = NULL; 155 frame->childregs.psw.mask &= ~PSW_MASK_RI; 156 157 /* Set a new TLS ? */ 158 if (clone_flags & CLONE_SETTLS) { 159 unsigned long tls = frame->childregs.gprs[6]; 160 if (is_compat_task()) { 161 p->thread.acrs[0] = (unsigned int)tls; 162 } else { 163 p->thread.acrs[0] = (unsigned int)(tls >> 32); 164 p->thread.acrs[1] = (unsigned int)tls; 165 } 166 } 167 return 0; 168 } 169 170 asmlinkage void execve_tail(void) 171 { 172 current->thread.fpu.fpc = 0; 173 asm volatile("sfpc %0" : : "d" (0)); 174 } 175 176 /* 177 * fill in the FPU structure for a core dump. 178 */ 179 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 180 { 181 save_fpu_regs(); 182 fpregs->fpc = current->thread.fpu.fpc; 183 fpregs->pad = 0; 184 if (MACHINE_HAS_VX) 185 convert_vx_to_fp((freg_t *)&fpregs->fprs, 186 current->thread.fpu.vxrs); 187 else 188 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 189 sizeof(fpregs->fprs)); 190 return 1; 191 } 192 EXPORT_SYMBOL(dump_fpu); 193 194 unsigned long get_wchan(struct task_struct *p) 195 { 196 struct stack_frame *sf, *low, *high; 197 unsigned long return_address; 198 int count; 199 200 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 201 return 0; 202 low = task_stack_page(p); 203 high = (struct stack_frame *) task_pt_regs(p); 204 sf = (struct stack_frame *) p->thread.ksp; 205 if (sf <= low || sf > high) 206 return 0; 207 for (count = 0; count < 16; count++) { 208 sf = (struct stack_frame *) sf->back_chain; 209 if (sf <= low || sf > high) 210 return 0; 211 return_address = sf->gprs[8]; 212 if (!in_sched_functions(return_address)) 213 return return_address; 214 } 215 return 0; 216 } 217 218 unsigned long arch_align_stack(unsigned long sp) 219 { 220 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 221 sp -= get_random_int() & ~PAGE_MASK; 222 return sp & ~0xf; 223 } 224 225 static inline unsigned long brk_rnd(void) 226 { 227 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 228 } 229 230 unsigned long arch_randomize_brk(struct mm_struct *mm) 231 { 232 unsigned long ret; 233 234 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 235 return (ret > mm->brk) ? ret : mm->brk; 236 } 237