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 <asm/io.h> 27 #include <asm/processor.h> 28 #include <asm/vtimer.h> 29 #include <asm/exec.h> 30 #include <asm/irq.h> 31 #include <asm/nmi.h> 32 #include <asm/smp.h> 33 #include <asm/switch_to.h> 34 #include <asm/runtime_instr.h> 35 #include "entry.h" 36 37 asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); 38 39 /* 40 * Return saved PC of a blocked thread. used in kernel/sched. 41 * resume in entry.S does not create a new stack frame, it 42 * just stores the registers %r6-%r15 to the frame given by 43 * schedule. We want to return the address of the caller of 44 * schedule, so we have to walk the backchain one time to 45 * find the frame schedule() store its return address. 46 */ 47 unsigned long thread_saved_pc(struct task_struct *tsk) 48 { 49 struct stack_frame *sf, *low, *high; 50 51 if (!tsk || !task_stack_page(tsk)) 52 return 0; 53 low = task_stack_page(tsk); 54 high = (struct stack_frame *) task_pt_regs(tsk); 55 sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN); 56 if (sf <= low || sf > high) 57 return 0; 58 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 59 if (sf <= low || sf > high) 60 return 0; 61 return sf->gprs[8]; 62 } 63 64 extern void __kprobes kernel_thread_starter(void); 65 66 /* 67 * Free current thread data structures etc.. 68 */ 69 void exit_thread(void) 70 { 71 exit_thread_runtime_instr(); 72 } 73 74 void flush_thread(void) 75 { 76 } 77 78 void release_thread(struct task_struct *dead_task) 79 { 80 } 81 82 int copy_thread(unsigned long clone_flags, unsigned long new_stackp, 83 unsigned long arg, struct task_struct *p) 84 { 85 struct thread_info *ti; 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 ti = task_thread_info(p); 104 ti->user_timer = 0; 105 ti->system_timer = 0; 106 107 frame->sf.back_chain = 0; 108 /* new return point is ret_from_fork */ 109 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 110 /* fake return stack for resume(), don't go back to schedule */ 111 frame->sf.gprs[9] = (unsigned long) frame; 112 113 /* Store access registers to kernel stack of new process. */ 114 if (unlikely(p->flags & PF_KTHREAD)) { 115 /* kernel thread */ 116 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 117 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 118 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 119 frame->childregs.psw.addr = PSW_ADDR_AMODE | 120 (unsigned long) kernel_thread_starter; 121 frame->childregs.gprs[9] = new_stackp; /* function */ 122 frame->childregs.gprs[10] = arg; 123 frame->childregs.gprs[11] = (unsigned long) do_exit; 124 frame->childregs.orig_gpr2 = -1; 125 126 return 0; 127 } 128 frame->childregs = *current_pt_regs(); 129 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 130 frame->childregs.flags = 0; 131 if (new_stackp) 132 frame->childregs.gprs[15] = new_stackp; 133 134 /* Don't copy runtime instrumentation info */ 135 p->thread.ri_cb = NULL; 136 p->thread.ri_signum = 0; 137 frame->childregs.psw.mask &= ~PSW_MASK_RI; 138 139 #ifndef CONFIG_64BIT 140 /* 141 * save fprs to current->thread.fp_regs to merge them with 142 * the emulated registers and then copy the result to the child. 143 */ 144 save_fp_ctl(¤t->thread.fp_regs.fpc); 145 save_fp_regs(current->thread.fp_regs.fprs); 146 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 147 sizeof(s390_fp_regs)); 148 /* Set a new TLS ? */ 149 if (clone_flags & CLONE_SETTLS) 150 p->thread.acrs[0] = frame->childregs.gprs[6]; 151 #else /* CONFIG_64BIT */ 152 /* Save the fpu registers to new thread structure. */ 153 save_fp_ctl(&p->thread.fp_regs.fpc); 154 save_fp_regs(p->thread.fp_regs.fprs); 155 p->thread.fp_regs.pad = 0; 156 /* Set a new TLS ? */ 157 if (clone_flags & CLONE_SETTLS) { 158 unsigned long tls = frame->childregs.gprs[6]; 159 if (is_compat_task()) { 160 p->thread.acrs[0] = (unsigned int)tls; 161 } else { 162 p->thread.acrs[0] = (unsigned int)(tls >> 32); 163 p->thread.acrs[1] = (unsigned int)tls; 164 } 165 } 166 #endif /* CONFIG_64BIT */ 167 return 0; 168 } 169 170 asmlinkage void execve_tail(void) 171 { 172 current->thread.fp_regs.fpc = 0; 173 if (MACHINE_HAS_IEEE) 174 asm volatile("sfpc %0,%0" : : "d" (0)); 175 } 176 177 /* 178 * fill in the FPU structure for a core dump. 179 */ 180 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 181 { 182 #ifndef CONFIG_64BIT 183 /* 184 * save fprs to current->thread.fp_regs to merge them with 185 * the emulated registers and then copy the result to the dump. 186 */ 187 save_fp_ctl(¤t->thread.fp_regs.fpc); 188 save_fp_regs(current->thread.fp_regs.fprs); 189 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 190 #else /* CONFIG_64BIT */ 191 save_fp_ctl(&fpregs->fpc); 192 save_fp_regs(fpregs->fprs); 193 #endif /* CONFIG_64BIT */ 194 return 1; 195 } 196 EXPORT_SYMBOL(dump_fpu); 197 198 unsigned long get_wchan(struct task_struct *p) 199 { 200 struct stack_frame *sf, *low, *high; 201 unsigned long return_address; 202 int count; 203 204 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 205 return 0; 206 low = task_stack_page(p); 207 high = (struct stack_frame *) task_pt_regs(p); 208 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 209 if (sf <= low || sf > high) 210 return 0; 211 for (count = 0; count < 16; count++) { 212 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 213 if (sf <= low || sf > high) 214 return 0; 215 return_address = sf->gprs[8] & PSW_ADDR_INSN; 216 if (!in_sched_functions(return_address)) 217 return return_address; 218 } 219 return 0; 220 } 221 222 unsigned long arch_align_stack(unsigned long sp) 223 { 224 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 225 sp -= get_random_int() & ~PAGE_MASK; 226 return sp & ~0xf; 227 } 228 229 static inline unsigned long brk_rnd(void) 230 { 231 /* 8MB for 32bit, 1GB for 64bit */ 232 if (is_32bit_task()) 233 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; 234 else 235 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; 236 } 237 238 unsigned long arch_randomize_brk(struct mm_struct *mm) 239 { 240 unsigned long ret; 241 242 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 243 return (ret > mm->brk) ? ret : mm->brk; 244 } 245 246 unsigned long randomize_et_dyn(unsigned long base) 247 { 248 unsigned long ret; 249 250 if (!(current->flags & PF_RANDOMIZE)) 251 return base; 252 ret = PAGE_ALIGN(base + brk_rnd()); 253 return (ret > base) ? ret : base; 254 } 255