| /* |
| * This file handles the architecture dependent parts of process handling. |
| * |
| * Copyright IBM Corp. 1999,2009 |
| * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, |
| * Hartmut Penner <hp@de.ibm.com>, |
| * Denis Joseph Barrow, |
| */ |
| |
| #include <linux/compiler.h> |
| #include <linux/cpu.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/elfcore.h> |
| #include <linux/smp.h> |
| #include <linux/slab.h> |
| #include <linux/interrupt.h> |
| #include <linux/tick.h> |
| #include <linux/personality.h> |
| #include <linux/syscalls.h> |
| #include <linux/compat.h> |
| #include <linux/kprobes.h> |
| #include <linux/random.h> |
| #include <linux/module.h> |
| #include <asm/system.h> |
| #include <asm/io.h> |
| #include <asm/processor.h> |
| #include <asm/irq.h> |
| #include <asm/timer.h> |
| #include <asm/nmi.h> |
| #include <asm/compat.h> |
| #include <asm/smp.h> |
| #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]; |
| } |
| |
| /* |
| * The idle loop on a S390... |
| */ |
| static void default_idle(void) |
| { |
| if (cpu_is_offline(smp_processor_id())) |
| cpu_die(); |
| local_irq_disable(); |
| if (need_resched()) { |
| local_irq_enable(); |
| return; |
| } |
| local_mcck_disable(); |
| if (test_thread_flag(TIF_MCCK_PENDING)) { |
| local_mcck_enable(); |
| local_irq_enable(); |
| return; |
| } |
| trace_hardirqs_on(); |
| /* Don't trace preempt off for idle. */ |
| stop_critical_timings(); |
| /* Stop virtual timer and halt the cpu. */ |
| vtime_stop_cpu(); |
| /* Reenable preemption tracer. */ |
| start_critical_timings(); |
| } |
| |
| void cpu_idle(void) |
| { |
| for (;;) { |
| tick_nohz_idle_enter(); |
| rcu_idle_enter(); |
| while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING)) |
| default_idle(); |
| rcu_idle_exit(); |
| tick_nohz_idle_exit(); |
| if (test_thread_flag(TIF_MCCK_PENDING)) |
| s390_handle_mcck(); |
| preempt_enable_no_resched(); |
| schedule(); |
| preempt_disable(); |
| } |
| } |
| |
| extern void __kprobes kernel_thread_starter(void); |
| |
| asm( |
| ".section .kprobes.text, \"ax\"\n" |
| ".global kernel_thread_starter\n" |
| "kernel_thread_starter:\n" |
| " la 2,0(10)\n" |
| " basr 14,9\n" |
| " la 2,0\n" |
| " br 11\n" |
| ".previous\n"); |
| |
| int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) |
| { |
| struct pt_regs regs; |
| |
| memset(®s, 0, sizeof(regs)); |
| regs.psw.mask = psw_kernel_bits | |
| PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; |
| regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE; |
| regs.gprs[9] = (unsigned long) fn; |
| regs.gprs[10] = (unsigned long) arg; |
| regs.gprs[11] = (unsigned long) do_exit; |
| regs.orig_gpr2 = -1; |
| |
| /* Ok, create the new process.. */ |
| return do_fork(flags | CLONE_VM | CLONE_UNTRACED, |
| 0, ®s, 0, NULL, NULL); |
| } |
| EXPORT_SYMBOL(kernel_thread); |
| |
| /* |
| * Free current thread data structures etc.. |
| */ |
| void exit_thread(void) |
| { |
| } |
| |
| void flush_thread(void) |
| { |
| } |
| |
| void release_thread(struct task_struct *dead_task) |
| { |
| } |
| |
| int copy_thread(unsigned long clone_flags, unsigned long new_stackp, |
| unsigned long unused, |
| struct task_struct *p, struct pt_regs *regs) |
| { |
| 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; |
| /* Store access registers to kernel stack of new process. */ |
| frame->childregs = *regs; |
| frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */ |
| frame->childregs.gprs[15] = new_stackp; |
| 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; |
| |
| /* Save access registers to new thread structure. */ |
| save_access_regs(&p->thread.acrs[0]); |
| |
| #ifndef CONFIG_64BIT |
| /* |
| * save fprs to current->thread.fp_regs to merge them with |
| * the emulated registers and then copy the result to the child. |
| */ |
| save_fp_regs(¤t->thread.fp_regs); |
| memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs, |
| sizeof(s390_fp_regs)); |
| /* Set a new TLS ? */ |
| if (clone_flags & CLONE_SETTLS) |
| p->thread.acrs[0] = regs->gprs[6]; |
| #else /* CONFIG_64BIT */ |
| /* Save the fpu registers to new thread structure. */ |
| save_fp_regs(&p->thread.fp_regs); |
| /* Set a new TLS ? */ |
| if (clone_flags & CLONE_SETTLS) { |
| if (is_compat_task()) { |
| p->thread.acrs[0] = (unsigned int) regs->gprs[6]; |
| } else { |
| p->thread.acrs[0] = (unsigned int)(regs->gprs[6] >> 32); |
| p->thread.acrs[1] = (unsigned int) regs->gprs[6]; |
| } |
| } |
| #endif /* CONFIG_64BIT */ |
| /* 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); |
| clear_tsk_thread_flag(p, TIF_PER_TRAP); |
| /* Initialize per thread user and system timer values */ |
| ti = task_thread_info(p); |
| ti->user_timer = 0; |
| ti->system_timer = 0; |
| return 0; |
| } |
| |
| SYSCALL_DEFINE0(fork) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| return do_fork(SIGCHLD, regs->gprs[15], regs, 0, NULL, NULL); |
| } |
| |
| SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags, |
| int __user *, parent_tidptr, int __user *, child_tidptr) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| |
| if (!newsp) |
| newsp = regs->gprs[15]; |
| return do_fork(clone_flags, newsp, regs, 0, |
| parent_tidptr, child_tidptr); |
| } |
| |
| /* |
| * This is trivial, and on the face of it looks like it |
| * could equally well be done in user mode. |
| * |
| * Not so, for quite unobvious reasons - register pressure. |
| * In user mode vfork() cannot have a stack frame, and if |
| * done by calling the "clone()" system call directly, you |
| * do not have enough call-clobbered registers to hold all |
| * the information you need. |
| */ |
| SYSCALL_DEFINE0(vfork) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, |
| regs->gprs[15], regs, 0, NULL, NULL); |
| } |
| |
| asmlinkage void execve_tail(void) |
| { |
| current->thread.fp_regs.fpc = 0; |
| if (MACHINE_HAS_IEEE) |
| asm volatile("sfpc %0,%0" : : "d" (0)); |
| } |
| |
| /* |
| * sys_execve() executes a new program. |
| */ |
| SYSCALL_DEFINE3(execve, const char __user *, name, |
| const char __user *const __user *, argv, |
| const char __user *const __user *, envp) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| char *filename; |
| long rc; |
| |
| filename = getname(name); |
| rc = PTR_ERR(filename); |
| if (IS_ERR(filename)) |
| return rc; |
| rc = do_execve(filename, argv, envp, regs); |
| if (rc) |
| goto out; |
| execve_tail(); |
| rc = regs->gprs[2]; |
| out: |
| putname(filename); |
| return rc; |
| } |
| |
| /* |
| * fill in the FPU structure for a core dump. |
| */ |
| int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs) |
| { |
| #ifndef CONFIG_64BIT |
| /* |
| * save fprs to current->thread.fp_regs to merge them with |
| * the emulated registers and then copy the result to the dump. |
| */ |
| save_fp_regs(¤t->thread.fp_regs); |
| memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs)); |
| #else /* CONFIG_64BIT */ |
| save_fp_regs(fpregs); |
| #endif /* CONFIG_64BIT */ |
| 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 = PAGE_ALIGN(mm->brk + brk_rnd()); |
| |
| if (ret < mm->brk) |
| return mm->brk; |
| return ret; |
| } |
| |
| unsigned long randomize_et_dyn(unsigned long base) |
| { |
| unsigned long ret = PAGE_ALIGN(base + brk_rnd()); |
| |
| if (!(current->flags & PF_RANDOMIZE)) |
| return base; |
| if (ret < base) |
| return base; |
| return ret; |
| } |