/* * This file handles the architecture dependent parts of process handling. * * Copyright IBM Corp. 1999, 2009 * Author(s): Martin Schwidefsky , * Hartmut Penner , * Denis Joseph Barrow, */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "entry.h" asmlinkage void ret_from_fork(void) asm ("ret_from_fork"); /* * Return saved PC of a blocked thread. used in kernel/sched. * resume in entry.S does not create a new stack frame, it * just stores the registers %r6-%r15 to the frame given by * schedule. We want to return the address of the caller of * schedule, so we have to walk the backchain one time to * find the frame schedule() store its return address. */ unsigned long thread_saved_pc(struct task_struct *tsk) { struct stack_frame *sf, *low, *high; if (!tsk || !task_stack_page(tsk)) return 0; low = task_stack_page(tsk); high = (struct stack_frame *) task_pt_regs(tsk); sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN); if (sf <= low || sf > high) return 0; sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); if (sf <= low || sf > high) return 0; return sf->gprs[8]; } extern void kernel_thread_starter(void); /* * Free current thread data structures etc.. */ void exit_thread(void) { exit_thread_runtime_instr(); } void flush_thread(void) { } void release_thread(struct task_struct *dead_task) { } void arch_release_task_struct(struct task_struct *tsk) { /* Free either the floating-point or the vector register save area */ kfree(tsk->thread.fpu.regs); } int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { *dst = *src; /* Set up a new floating-point register save area */ dst->thread.fpu.fpc = 0; dst->thread.fpu.flags = 0; /* Always start with VX disabled */ dst->thread.fpu.fprs = kzalloc(sizeof(freg_t) * __NUM_FPRS, GFP_KERNEL|__GFP_REPEAT); if (!dst->thread.fpu.fprs) return -ENOMEM; /* * Save the floating-point or vector register state of the current * task. The state is not saved for early kernel threads, for example, * the init_task, which do not have an allocated save area. * The CIF_FPU flag is set in any case to lazy clear or restore a saved * state when switching to a different task or returning to user space. */ save_fpu_regs(¤t->thread.fpu); dst->thread.fpu.fpc = current->thread.fpu.fpc; if (is_vx_task(current)) convert_vx_to_fp(dst->thread.fpu.fprs, current->thread.fpu.vxrs); else memcpy(dst->thread.fpu.fprs, current->thread.fpu.fprs, sizeof(freg_t) * __NUM_FPRS); return 0; } int copy_thread(unsigned long clone_flags, unsigned long new_stackp, unsigned long arg, struct task_struct *p) { struct thread_info *ti; struct fake_frame { struct stack_frame sf; struct pt_regs childregs; } *frame; frame = container_of(task_pt_regs(p), struct fake_frame, childregs); p->thread.ksp = (unsigned long) frame; /* Save access registers to new thread structure. */ save_access_regs(&p->thread.acrs[0]); /* start new process with ar4 pointing to the correct address space */ p->thread.mm_segment = get_fs(); /* Don't copy debug registers */ memset(&p->thread.per_user, 0, sizeof(p->thread.per_user)); memset(&p->thread.per_event, 0, sizeof(p->thread.per_event)); clear_tsk_thread_flag(p, TIF_SINGLE_STEP); /* Initialize per thread user and system timer values */ ti = task_thread_info(p); ti->user_timer = 0; ti->system_timer = 0; frame->sf.back_chain = 0; /* new return point is ret_from_fork */ frame->sf.gprs[8] = (unsigned long) ret_from_fork; /* fake return stack for resume(), don't go back to schedule */ frame->sf.gprs[9] = (unsigned long) frame; /* Store access registers to kernel stack of new process. */ if (unlikely(p->flags & PF_KTHREAD)) { /* kernel thread */ memset(&frame->childregs, 0, sizeof(struct pt_regs)); frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; frame->childregs.psw.addr = PSW_ADDR_AMODE | (unsigned long) kernel_thread_starter; frame->childregs.gprs[9] = new_stackp; /* function */ frame->childregs.gprs[10] = arg; frame->childregs.gprs[11] = (unsigned long) do_exit; frame->childregs.orig_gpr2 = -1; return 0; } frame->childregs = *current_pt_regs(); frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ frame->childregs.flags = 0; if (new_stackp) frame->childregs.gprs[15] = new_stackp; /* Don't copy runtime instrumentation info */ p->thread.ri_cb = NULL; p->thread.ri_signum = 0; frame->childregs.psw.mask &= ~PSW_MASK_RI; /* Set a new TLS ? */ if (clone_flags & CLONE_SETTLS) { unsigned long tls = frame->childregs.gprs[6]; if (is_compat_task()) { p->thread.acrs[0] = (unsigned int)tls; } else { p->thread.acrs[0] = (unsigned int)(tls >> 32); p->thread.acrs[1] = (unsigned int)tls; } } return 0; } asmlinkage void execve_tail(void) { current->thread.fpu.fpc = 0; asm volatile("sfpc %0" : : "d" (0)); } /* * fill in the FPU structure for a core dump. */ int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) { save_fpu_regs(¤t->thread.fpu); fpregs->fpc = current->thread.fpu.fpc; fpregs->pad = 0; if (is_vx_task(current)) convert_vx_to_fp((freg_t *)&fpregs->fprs, current->thread.fpu.vxrs); else memcpy(&fpregs->fprs, current->thread.fpu.fprs, sizeof(fpregs->fprs)); return 1; } EXPORT_SYMBOL(dump_fpu); unsigned long get_wchan(struct task_struct *p) { struct stack_frame *sf, *low, *high; unsigned long return_address; int count; if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) return 0; low = task_stack_page(p); high = (struct stack_frame *) task_pt_regs(p); sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN); if (sf <= low || sf > high) return 0; for (count = 0; count < 16; count++) { sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN); if (sf <= low || sf > high) return 0; return_address = sf->gprs[8] & PSW_ADDR_INSN; if (!in_sched_functions(return_address)) return return_address; } return 0; } unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) sp -= get_random_int() & ~PAGE_MASK; return sp & ~0xf; } static inline unsigned long brk_rnd(void) { /* 8MB for 32bit, 1GB for 64bit */ if (is_32bit_task()) return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; else return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; } unsigned long arch_randomize_brk(struct mm_struct *mm) { unsigned long ret; ret = PAGE_ALIGN(mm->brk + brk_rnd()); return (ret > mm->brk) ? ret : mm->brk; }