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 void arch_release_task_struct(struct task_struct *tsk) 83 { 84 /* Free either the floating-point or the vector register save area */ 85 kfree(tsk->thread.fpu.regs); 86 } 87 88 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 89 { 90 *dst = *src; 91 92 /* Set up a new floating-point register save area */ 93 dst->thread.fpu.fpc = 0; 94 dst->thread.fpu.flags = 0; /* Always start with VX disabled */ 95 dst->thread.fpu.fprs = kzalloc(sizeof(freg_t) * __NUM_FPRS, 96 GFP_KERNEL|__GFP_REPEAT); 97 if (!dst->thread.fpu.fprs) 98 return -ENOMEM; 99 100 /* 101 * Save the floating-point or vector register state of the current 102 * task. The state is not saved for early kernel threads, for example, 103 * the init_task, which do not have an allocated save area. 104 * The CIF_FPU flag is set in any case to lazy clear or restore a saved 105 * state when switching to a different task or returning to user space. 106 */ 107 save_fpu_regs(); 108 dst->thread.fpu.fpc = current->thread.fpu.fpc; 109 if (is_vx_task(current)) 110 convert_vx_to_fp(dst->thread.fpu.fprs, 111 current->thread.fpu.vxrs); 112 else 113 memcpy(dst->thread.fpu.fprs, current->thread.fpu.fprs, 114 sizeof(freg_t) * __NUM_FPRS); 115 return 0; 116 } 117 118 int copy_thread(unsigned long clone_flags, unsigned long new_stackp, 119 unsigned long arg, struct task_struct *p) 120 { 121 struct thread_info *ti; 122 struct fake_frame 123 { 124 struct stack_frame sf; 125 struct pt_regs childregs; 126 } *frame; 127 128 frame = container_of(task_pt_regs(p), struct fake_frame, childregs); 129 p->thread.ksp = (unsigned long) frame; 130 /* Save access registers to new thread structure. */ 131 save_access_regs(&p->thread.acrs[0]); 132 /* start new process with ar4 pointing to the correct address space */ 133 p->thread.mm_segment = get_fs(); 134 /* Don't copy debug registers */ 135 memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); 136 memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); 137 clear_tsk_thread_flag(p, TIF_SINGLE_STEP); 138 /* Initialize per thread user and system timer values */ 139 ti = task_thread_info(p); 140 ti->user_timer = 0; 141 ti->system_timer = 0; 142 143 frame->sf.back_chain = 0; 144 /* new return point is ret_from_fork */ 145 frame->sf.gprs[8] = (unsigned long) ret_from_fork; 146 /* fake return stack for resume(), don't go back to schedule */ 147 frame->sf.gprs[9] = (unsigned long) frame; 148 149 /* Store access registers to kernel stack of new process. */ 150 if (unlikely(p->flags & PF_KTHREAD)) { 151 /* kernel thread */ 152 memset(&frame->childregs, 0, sizeof(struct pt_regs)); 153 frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | 154 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 155 frame->childregs.psw.addr = PSW_ADDR_AMODE | 156 (unsigned long) kernel_thread_starter; 157 frame->childregs.gprs[9] = new_stackp; /* function */ 158 frame->childregs.gprs[10] = arg; 159 frame->childregs.gprs[11] = (unsigned long) do_exit; 160 frame->childregs.orig_gpr2 = -1; 161 162 return 0; 163 } 164 frame->childregs = *current_pt_regs(); 165 frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ 166 frame->childregs.flags = 0; 167 if (new_stackp) 168 frame->childregs.gprs[15] = new_stackp; 169 170 /* Don't copy runtime instrumentation info */ 171 p->thread.ri_cb = NULL; 172 p->thread.ri_signum = 0; 173 frame->childregs.psw.mask &= ~PSW_MASK_RI; 174 175 /* Set a new TLS ? */ 176 if (clone_flags & CLONE_SETTLS) { 177 unsigned long tls = frame->childregs.gprs[6]; 178 if (is_compat_task()) { 179 p->thread.acrs[0] = (unsigned int)tls; 180 } else { 181 p->thread.acrs[0] = (unsigned int)(tls >> 32); 182 p->thread.acrs[1] = (unsigned int)tls; 183 } 184 } 185 return 0; 186 } 187 188 asmlinkage void execve_tail(void) 189 { 190 current->thread.fpu.fpc = 0; 191 asm volatile("sfpc %0" : : "d" (0)); 192 } 193 194 /* 195 * fill in the FPU structure for a core dump. 196 */ 197 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) 198 { 199 save_fpu_regs(); 200 fpregs->fpc = current->thread.fpu.fpc; 201 fpregs->pad = 0; 202 if (is_vx_task(current)) 203 convert_vx_to_fp((freg_t *)&fpregs->fprs, 204 current->thread.fpu.vxrs); 205 else 206 memcpy(&fpregs->fprs, current->thread.fpu.fprs, 207 sizeof(fpregs->fprs)); 208 return 1; 209 } 210 EXPORT_SYMBOL(dump_fpu); 211 212 unsigned long get_wchan(struct task_struct *p) 213 { 214 struct stack_frame *sf, *low, *high; 215 unsigned long return_address; 216 int count; 217 218 if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) 219 return 0; 220 low = task_stack_page(p); 221 high = (struct stack_frame *) task_pt_regs(p); 222 sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); 223 if (sf <= low || sf > high) 224 return 0; 225 for (count = 0; count < 16; count++) { 226 sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); 227 if (sf <= low || sf > high) 228 return 0; 229 return_address = sf->gprs[8] & PSW_ADDR_INSN; 230 if (!in_sched_functions(return_address)) 231 return return_address; 232 } 233 return 0; 234 } 235 236 unsigned long arch_align_stack(unsigned long sp) 237 { 238 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 239 sp -= get_random_int() & ~PAGE_MASK; 240 return sp & ~0xf; 241 } 242 243 static inline unsigned long brk_rnd(void) 244 { 245 /* 8MB for 32bit, 1GB for 64bit */ 246 if (is_32bit_task()) 247 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; 248 else 249 return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; 250 } 251 252 unsigned long arch_randomize_brk(struct mm_struct *mm) 253 { 254 unsigned long ret; 255 256 ret = PAGE_ALIGN(mm->brk + brk_rnd()); 257 return (ret > mm->brk) ? ret : mm->brk; 258 } 259