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/compiler.h> 11 #include <linux/cpu.h> 12 #include <linux/sched.h> 13 #include <linux/kernel.h> 14 #include <linux/mm.h> 15 #include <linux/elfcore.h> 16 #include <linux/smp.h> 17 #include <linux/slab.h> 18 #include <linux/interrupt.h> 19 #include <linux/tick.h> 20 #include <linux/personality.h> 21 #include <linux/syscalls.h> 22 #include <linux/compat.h> 23 #include <linux/kprobes.h> 24 #include <linux/random.h> 25 #include <linux/module.h> 26 #include <linux/init_task.h> 27 #include <asm/io.h> 28 #include <asm/processor.h> 29 #include <asm/vtimer.h> 30 #include <asm/exec.h> 31 #include <asm/irq.h> 32 #include <asm/nmi.h> 33 #include <asm/smp.h> 34 #include <asm/switch_to.h> 35 #include <asm/runtime_instr.h> 36 #include "entry.h" 37 38 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 39 40 /* FPU save area for the init task */ 41 __vector128 init_task_fpu_regs[__NUM_VXRS] __init_task_data; 42 43 /* 44 * Return saved PC of a blocked thread. used in kernel/sched. 45 * resume in entry.S does not create a new stack frame, it 46 * just stores the registers %r6-%r15 to the frame given by 47 * schedule. We want to return the address of the caller of 48 * schedule, so we have to walk the backchain one time to 49 * find the frame schedule() store its return address. 50 */ 51 unsigned long thread_saved_pc(struct task_struct *tsk) 52 { 53 struct stack_frame *sf, *low, *high; 54 55 if (!tsk || !task_stack_page(tsk)) 56 return 0; 57 low = task_stack_page(tsk); 58 high = (struct stack_frame *) task_pt_regs(tsk); 59 sf = (struct stack_frame *) tsk->thread.ksp; 60 if (sf <= low || sf > high) 61 return 0; 62 sf = (struct stack_frame *) sf->back_chain; 63 if (sf <= low || sf > high) 64 return 0; 65 return sf->gprs[8]; 66 } 67 68 extern void kernel_thread_starter(void); 69 70 /* 71 * Free current thread data structures etc.. 72 */ 73 void exit_thread(void) 74 { 75 exit_thread_runtime_instr(); 76 } 77 78 void flush_thread(void) 79 { 80 } 81 82 void release_thread(struct task_struct *dead_task) 83 { 84 } 85 86 void arch_release_task_struct(struct task_struct *tsk) 87 { 88 /* Free either the floating-point or the vector register save area */ 89 kfree(tsk->thread.fpu.regs); 90 } 91 92 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 93 { 94 size_t fpu_regs_size; 95 96 *dst = *src; 97 98 /* 99 * If the vector extension is available, it is enabled for all tasks, 100 * and, thus, the FPU register save area must be allocated accordingly. 101 */ 102 fpu_regs_size = MACHINE_HAS_VX ? sizeof(__vector128) * __NUM_VXRS 103 : sizeof(freg_t) * __NUM_FPRS; 104 dst->thread.fpu.regs = kzalloc(fpu_regs_size, GFP_KERNEL|__GFP_REPEAT); 105 if (!dst->thread.fpu.regs) 106 return -ENOMEM; 107 108 /* 109 * Save the floating-point or vector register state of the current 110 * task and set the CIF_FPU flag to lazy restore the FPU register 111 * state when returning to user space. 112 */ 113 save_fpu_regs(); 114 dst->thread.fpu.fpc = current->thread.fpu.fpc; 115 memcpy(dst->thread.fpu.regs, current->thread.fpu.regs, fpu_regs_size); 116 117 return 0; 118 } 119 120 int copy_thread(unsigned long clone_flags, unsigned long new_stackp, 121 unsigned long arg, struct task_struct *p) 122 { 123 struct thread_info *ti; 124 struct fake_frame 125 { 126 struct stack_frame sf; 127 struct pt_regs childregs; 128 } *frame; 129 130 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 131 p->thread.ksp = (unsigned long) frame; 132 /* Save access registers to new thread structure. */ 133 save_access_regs(&p->thread.acrs[0]); 134 /* start new process with ar4 pointing to the correct address space */ 135 p->thread.mm_segment = get_fs(); 136 /* Don't copy debug registers */ 137 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 138 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 139 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 140 /* Initialize per thread user and system timer values */ 141 ti = task_thread_info(p); 142 ti->user_timer = 0; 143 ti->system_timer = 0; 144 145 frame->sf.back_chain = 0; 146 /* new return point is ret_from_fork */ 147 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 148 /* fake return stack for resume(), don't go back to schedule */ 149 frame->sf.gprs[9] = (unsigned long) frame; 150 151 /* Store access registers to kernel stack of new process. */ 152 if (unlikely(p->flags & PF_KTHREAD)) { 153 /* kernel thread */ 154 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 155 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 156 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 157 frame->childregs.psw.addr = 158 (unsigned long) kernel_thread_starter; 159 frame->childregs.gprs[9] = new_stackp; /* function */ 160 frame->childregs.gprs[10] = arg; 161 frame->childregs.gprs[11] = (unsigned long) do_exit; 162 frame->childregs.orig_gpr2 = -1; 163 164 return 0; 165 } 166 frame->childregs = *current_pt_regs(); 167 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 168 frame->childregs.flags = 0; 169 if (new_stackp) 170 frame->childregs.gprs[15] = new_stackp; 171 172 /* Don't copy runtime instrumentation info */ 173 p->thread.ri_cb = NULL; 174 frame->childregs.psw.mask &= ~PSW_MASK_RI; 175 176 /* Set a new TLS ? */ 177 if (clone_flags & CLONE_SETTLS) { 178 unsigned long tls = frame->childregs.gprs[6]; 179 if (is_compat_task()) { 180 p->thread.acrs[0] = (unsigned int)tls; 181 } else { 182 p->thread.acrs[0] = (unsigned int)(tls >> 32); 183 p->thread.acrs[1] = (unsigned int)tls; 184 } 185 } 186 return 0; 187 } 188 189 asmlinkage void execve_tail(void) 190 { 191 current->thread.fpu.fpc = 0; 192 asm volatile("sfpc %0" : : "d" (0)); 193 } 194 195 /* 196 * fill in the FPU structure for a core dump. 197 */ 198 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 199 { 200 save_fpu_regs(); 201 fpregs->fpc = current->thread.fpu.fpc; 202 fpregs->pad = 0; 203 if (MACHINE_HAS_VX) 204 convert_vx_to_fp((freg_t *)&fpregs->fprs, 205 current->thread.fpu.vxrs); 206 else 207 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 208 sizeof(fpregs->fprs)); 209 return 1; 210 } 211 EXPORT_SYMBOL(dump_fpu); 212 213 unsigned long get_wchan(struct task_struct *p) 214 { 215 struct stack_frame *sf, *low, *high; 216 unsigned long return_address; 217 int count; 218 219 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 220 return 0; 221 low = task_stack_page(p); 222 high = (struct stack_frame *) task_pt_regs(p); 223 sf = (struct stack_frame *) p->thread.ksp; 224 if (sf <= low || sf > high) 225 return 0; 226 for (count = 0; count < 16; count++) { 227 sf = (struct stack_frame *) sf->back_chain; 228 if (sf <= low || sf > high) 229 return 0; 230 return_address = sf->gprs[8]; 231 if (!in_sched_functions(return_address)) 232 return return_address; 233 } 234 return 0; 235 } 236 237 unsigned long arch_align_stack(unsigned long sp) 238 { 239 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 240 sp -= get_random_int() & ~PAGE_MASK; 241 return sp & ~0xf; 242 } 243 244 static inline unsigned long brk_rnd(void) 245 { 246 return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; 247 } 248 249 unsigned long arch_randomize_brk(struct mm_struct *mm) 250 { 251 unsigned long ret; 252 253 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 254 return (ret > mm->brk) ? ret : mm->brk; 255 } 256