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 void arch_cpu_idle(void) 65 { 66 local_mcck_disable(); 67 if (test_thread_flag(TIF_MCCK_PENDING)) { 68 local_mcck_enable(); 69 local_irq_enable(); 70 return; 71 } 72 /* Halt the cpu and keep track of cpu time accounting. */ 73 vtime_stop_cpu(); 74 local_irq_enable(); 75 } 76 77 void arch_cpu_idle_exit(void) 78 { 79 if (test_thread_flag(TIF_MCCK_PENDING)) 80 s390_handle_mcck(); 81 } 82 83 void arch_cpu_idle_dead(void) 84 { 85 cpu_die(); 86 } 87 88 extern void __kprobes kernel_thread_starter(void); 89 90 /* 91 * Free current thread data structures etc.. 92 */ 93 void exit_thread(void) 94 { 95 exit_thread_runtime_instr(); 96 } 97 98 void flush_thread(void) 99 { 100 } 101 102 void release_thread(struct task_struct *dead_task) 103 { 104 } 105 106 int copy_thread(unsigned long clone_flags, unsigned long new_stackp, 107 unsigned long arg, struct task_struct *p) 108 { 109 struct thread_info *ti; 110 struct fake_frame 111 { 112 struct stack_frame sf; 113 struct pt_regs childregs; 114 } *frame; 115 116 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 117 p->thread.ksp = (unsigned long) frame; 118 /* Save access registers to new thread structure. */ 119 save_access_regs(&p->thread.acrs[0]); 120 /* start new process with ar4 pointing to the correct address space */ 121 p->thread.mm_segment = get_fs(); 122 /* Don't copy debug registers */ 123 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 124 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 125 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 126 clear_tsk_thread_flag(p, TIF_PER_TRAP); 127 /* Initialize per thread user and system timer values */ 128 ti = task_thread_info(p); 129 ti->user_timer = 0; 130 ti->system_timer = 0; 131 132 frame->sf.back_chain = 0; 133 /* new return point is ret_from_fork */ 134 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 135 /* fake return stack for resume(), don't go back to schedule */ 136 frame->sf.gprs[9] = (unsigned long) frame; 137 138 /* Store access registers to kernel stack of new process. */ 139 if (unlikely(p->flags & PF_KTHREAD)) { 140 /* kernel thread */ 141 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 142 frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | 143 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 144 frame->childregs.psw.addr = PSW_ADDR_AMODE | 145 (unsigned long) kernel_thread_starter; 146 frame->childregs.gprs[9] = new_stackp; /* function */ 147 frame->childregs.gprs[10] = arg; 148 frame->childregs.gprs[11] = (unsigned long) do_exit; 149 frame->childregs.orig_gpr2 = -1; 150 151 return 0; 152 } 153 frame->childregs = *current_pt_regs(); 154 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 155 if (new_stackp) 156 frame->childregs.gprs[15] = new_stackp; 157 158 /* Don't copy runtime instrumentation info */ 159 p->thread.ri_cb = NULL; 160 p->thread.ri_signum = 0; 161 frame->childregs.psw.mask &= ~PSW_MASK_RI; 162 163 #ifndef CONFIG_64BIT 164 /* 165 * save fprs to current->thread.fp_regs to merge them with 166 * the emulated registers and then copy the result to the child. 167 */ 168 save_fp_regs(¤t->thread.fp_regs); 169 memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, 170 sizeof(s390_fp_regs)); 171 /* Set a new TLS ? */ 172 if (clone_flags & CLONE_SETTLS) 173 p->thread.acrs[0] = frame->childregs.gprs[6]; 174 #else /* CONFIG_64BIT */ 175 /* Save the fpu registers to new thread structure. */ 176 save_fp_regs(&p->thread.fp_regs); 177 /* Set a new TLS ? */ 178 if (clone_flags & CLONE_SETTLS) { 179 unsigned long tls = frame->childregs.gprs[6]; 180 if (is_compat_task()) { 181 p->thread.acrs[0] = (unsigned int)tls; 182 } else { 183 p->thread.acrs[0] = (unsigned int)(tls >> 32); 184 p->thread.acrs[1] = (unsigned int)tls; 185 } 186 } 187 #endif /* CONFIG_64BIT */ 188 return 0; 189 } 190 191 asmlinkage void execve_tail(void) 192 { 193 current->thread.fp_regs.fpc = 0; 194 if (MACHINE_HAS_IEEE) 195 asm volatile("sfpc %0,%0" : : "d" (0)); 196 } 197 198 /* 199 * fill in the FPU structure for a core dump. 200 */ 201 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 202 { 203 #ifndef CONFIG_64BIT 204 /* 205 * save fprs to current->thread.fp_regs to merge them with 206 * the emulated registers and then copy the result to the dump. 207 */ 208 save_fp_regs(¤t->thread.fp_regs); 209 memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); 210 #else /* CONFIG_64BIT */ 211 save_fp_regs(fpregs); 212 #endif /* CONFIG_64BIT */ 213 return 1; 214 } 215 EXPORT_SYMBOL(dump_fpu); 216 217 unsigned long get_wchan(struct task_struct *p) 218 { 219 struct stack_frame *sf, *low, *high; 220 unsigned long return_address; 221 int count; 222 223 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 224 return 0; 225 low = task_stack_page(p); 226 high = (struct stack_frame *) task_pt_regs(p); 227 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 228 if (sf <= low || sf > high) 229 return 0; 230 for (count = 0; count < 16; count++) { 231 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 232 if (sf <= low || sf > high) 233 return 0; 234 return_address = sf->gprs[8] & PSW_ADDR_INSN; 235 if (!in_sched_functions(return_address)) 236 return return_address; 237 } 238 return 0; 239 } 240 241 unsigned long arch_align_stack(unsigned long sp) 242 { 243 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 244 sp -= get_random_int() & ~PAGE_MASK; 245 return sp & ~0xf; 246 } 247 248 static inline unsigned long brk_rnd(void) 249 { 250 /* 8MB for 32bit, 1GB for 64bit */ 251 if (is_32bit_task()) 252 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; 253 else 254 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; 255 } 256 257 unsigned long arch_randomize_brk(struct mm_struct *mm) 258 { 259 unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); 260 261 if (ret < mm->brk) 262 return mm->brk; 263 return ret; 264 } 265 266 unsigned long randomize_et_dyn(unsigned long base) 267 { 268 unsigned long ret = PAGE_ALIGN(base + brk_rnd()); 269 270 if (!(current->flags & PF_RANDOMIZE)) 271 return base; 272 if (ret < base) 273 return base; 274 return ret; 275 } 276