![Martin Schwidefsky](/assets/img/avatar_default.png)
The oi and ni instructions used in entry[64].S to set and clear bits in the thread-flags are not guaranteed to be atomic in regard to other CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific bits. Updates on the TIF bits are done with atomic instructions, updates on CPU and pt_regs bits are done with non-atomic instructions. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
279 lines
7.3 KiB
C
279 lines
7.3 KiB
C
/*
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* This file handles the architecture dependent parts of process handling.
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*
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* Copyright IBM Corp. 1999, 2009
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
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* Hartmut Penner <hp@de.ibm.com>,
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* Denis Joseph Barrow,
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*/
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#include <linux/compiler.h>
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#include <linux/cpu.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/smp.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/tick.h>
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#include <linux/personality.h>
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#include <linux/syscalls.h>
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#include <linux/compat.h>
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#include <linux/kprobes.h>
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#include <linux/random.h>
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#include <linux/module.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/vtimer.h>
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#include <asm/exec.h>
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#include <asm/irq.h>
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#include <asm/nmi.h>
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#include <asm/smp.h>
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#include <asm/switch_to.h>
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#include <asm/runtime_instr.h>
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#include "entry.h"
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asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
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/*
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* Return saved PC of a blocked thread. used in kernel/sched.
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* resume in entry.S does not create a new stack frame, it
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* just stores the registers %r6-%r15 to the frame given by
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* schedule. We want to return the address of the caller of
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* schedule, so we have to walk the backchain one time to
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* find the frame schedule() store its return address.
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*/
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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struct stack_frame *sf, *low, *high;
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if (!tsk || !task_stack_page(tsk))
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return 0;
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low = task_stack_page(tsk);
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high = (struct stack_frame *) task_pt_regs(tsk);
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sf = (struct stack_frame *) (tsk->thread.ksp & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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return sf->gprs[8];
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}
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void arch_cpu_idle(void)
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{
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local_mcck_disable();
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if (test_cpu_flag(CIF_MCCK_PENDING)) {
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local_mcck_enable();
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local_irq_enable();
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return;
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}
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/* Halt the cpu and keep track of cpu time accounting. */
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vtime_stop_cpu();
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local_irq_enable();
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}
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void arch_cpu_idle_exit(void)
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{
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if (test_cpu_flag(CIF_MCCK_PENDING))
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s390_handle_mcck();
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}
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void arch_cpu_idle_dead(void)
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{
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cpu_die();
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}
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extern void __kprobes kernel_thread_starter(void);
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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exit_thread_runtime_instr();
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}
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void flush_thread(void)
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{
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}
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void release_thread(struct task_struct *dead_task)
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{
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}
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int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
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unsigned long arg, struct task_struct *p)
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{
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struct thread_info *ti;
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struct fake_frame
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{
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struct stack_frame sf;
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struct pt_regs childregs;
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} *frame;
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frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
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p->thread.ksp = (unsigned long) frame;
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/* Save access registers to new thread structure. */
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save_access_regs(&p->thread.acrs[0]);
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/* start new process with ar4 pointing to the correct address space */
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p->thread.mm_segment = get_fs();
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/* Don't copy debug registers */
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memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
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memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
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clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
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/* Initialize per thread user and system timer values */
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ti = task_thread_info(p);
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ti->user_timer = 0;
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ti->system_timer = 0;
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frame->sf.back_chain = 0;
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/* new return point is ret_from_fork */
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frame->sf.gprs[8] = (unsigned long) ret_from_fork;
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/* fake return stack for resume(), don't go back to schedule */
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frame->sf.gprs[9] = (unsigned long) frame;
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/* Store access registers to kernel stack of new process. */
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if (unlikely(p->flags & PF_KTHREAD)) {
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/* kernel thread */
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memset(&frame->childregs, 0, sizeof(struct pt_regs));
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frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
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PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
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frame->childregs.psw.addr = PSW_ADDR_AMODE |
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(unsigned long) kernel_thread_starter;
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frame->childregs.gprs[9] = new_stackp; /* function */
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frame->childregs.gprs[10] = arg;
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frame->childregs.gprs[11] = (unsigned long) do_exit;
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frame->childregs.orig_gpr2 = -1;
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return 0;
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}
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frame->childregs = *current_pt_regs();
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frame->childregs.gprs[2] = 0; /* child returns 0 on fork. */
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frame->childregs.flags = 0;
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if (new_stackp)
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frame->childregs.gprs[15] = new_stackp;
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/* Don't copy runtime instrumentation info */
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p->thread.ri_cb = NULL;
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p->thread.ri_signum = 0;
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frame->childregs.psw.mask &= ~PSW_MASK_RI;
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#ifndef CONFIG_64BIT
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/*
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* save fprs to current->thread.fp_regs to merge them with
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* the emulated registers and then copy the result to the child.
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*/
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save_fp_ctl(¤t->thread.fp_regs.fpc);
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save_fp_regs(current->thread.fp_regs.fprs);
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memcpy(&p->thread.fp_regs, ¤t->thread.fp_regs,
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sizeof(s390_fp_regs));
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/* Set a new TLS ? */
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if (clone_flags & CLONE_SETTLS)
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p->thread.acrs[0] = frame->childregs.gprs[6];
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#else /* CONFIG_64BIT */
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/* Save the fpu registers to new thread structure. */
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save_fp_ctl(&p->thread.fp_regs.fpc);
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save_fp_regs(p->thread.fp_regs.fprs);
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p->thread.fp_regs.pad = 0;
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/* Set a new TLS ? */
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if (clone_flags & CLONE_SETTLS) {
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unsigned long tls = frame->childregs.gprs[6];
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if (is_compat_task()) {
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p->thread.acrs[0] = (unsigned int)tls;
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} else {
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p->thread.acrs[0] = (unsigned int)(tls >> 32);
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p->thread.acrs[1] = (unsigned int)tls;
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}
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}
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#endif /* CONFIG_64BIT */
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return 0;
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}
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asmlinkage void execve_tail(void)
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{
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current->thread.fp_regs.fpc = 0;
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if (MACHINE_HAS_IEEE)
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asm volatile("sfpc %0,%0" : : "d" (0));
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}
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/*
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* fill in the FPU structure for a core dump.
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*/
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int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
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{
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#ifndef CONFIG_64BIT
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/*
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* save fprs to current->thread.fp_regs to merge them with
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* the emulated registers and then copy the result to the dump.
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*/
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save_fp_ctl(¤t->thread.fp_regs.fpc);
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save_fp_regs(current->thread.fp_regs.fprs);
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memcpy(fpregs, ¤t->thread.fp_regs, sizeof(s390_fp_regs));
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#else /* CONFIG_64BIT */
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save_fp_ctl(&fpregs->fpc);
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save_fp_regs(fpregs->fprs);
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#endif /* CONFIG_64BIT */
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return 1;
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}
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EXPORT_SYMBOL(dump_fpu);
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unsigned long get_wchan(struct task_struct *p)
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{
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struct stack_frame *sf, *low, *high;
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unsigned long return_address;
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int count;
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if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p))
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return 0;
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low = task_stack_page(p);
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high = (struct stack_frame *) task_pt_regs(p);
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sf = (struct stack_frame *) (p->thread.ksp & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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for (count = 0; count < 16; count++) {
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sf = (struct stack_frame *) (sf->back_chain & PSW_ADDR_INSN);
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if (sf <= low || sf > high)
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return 0;
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return_address = sf->gprs[8] & PSW_ADDR_INSN;
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if (!in_sched_functions(return_address))
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return return_address;
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}
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return 0;
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}
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unsigned long arch_align_stack(unsigned long sp)
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{
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if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
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sp -= get_random_int() & ~PAGE_MASK;
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return sp & ~0xf;
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}
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static inline unsigned long brk_rnd(void)
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{
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/* 8MB for 32bit, 1GB for 64bit */
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if (is_32bit_task())
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return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
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else
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return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
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}
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unsigned long arch_randomize_brk(struct mm_struct *mm)
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{
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unsigned long ret;
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ret = PAGE_ALIGN(mm->brk + brk_rnd());
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return (ret > mm->brk) ? ret : mm->brk;
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}
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unsigned long randomize_et_dyn(unsigned long base)
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{
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unsigned long ret;
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if (!(current->flags & PF_RANDOMIZE))
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return base;
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ret = PAGE_ALIGN(base + brk_rnd());
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return (ret > base) ? ret : base;
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}
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