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