9bbafce2ee
Presently with preempt enabled there's the possibility to be preempted after the TIF_USEDFPU test and the register save, leading to bogus state post-__switch_to(). Use an explicit preempt_disable()/enable() pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86 change. Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
467 lines
10 KiB
C
467 lines
10 KiB
C
/*
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* arch/sh/kernel/process.c
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*
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* This file handles the architecture-dependent parts of process handling..
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*
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* Copyright (C) 1995 Linus Torvalds
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*
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* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
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* Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
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* Copyright (C) 2002 - 2007 Paul Mundt
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/pm.h>
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#include <linux/kallsyms.h>
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#include <linux/kexec.h>
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#include <linux/kdebug.h>
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#include <linux/tick.h>
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#include <linux/reboot.h>
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#include <linux/fs.h>
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#include <linux/preempt.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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#include <asm/system.h>
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#include <asm/ubc.h>
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#include <asm/fpu.h>
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static int hlt_counter;
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int ubc_usercnt = 0;
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void (*pm_idle)(void);
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void (*pm_power_off)(void);
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EXPORT_SYMBOL(pm_power_off);
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void disable_hlt(void)
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{
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hlt_counter++;
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}
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EXPORT_SYMBOL(disable_hlt);
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void enable_hlt(void)
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{
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hlt_counter--;
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}
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EXPORT_SYMBOL(enable_hlt);
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static int __init nohlt_setup(char *__unused)
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{
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hlt_counter = 1;
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return 1;
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}
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__setup("nohlt", nohlt_setup);
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static int __init hlt_setup(char *__unused)
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{
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hlt_counter = 0;
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return 1;
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}
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__setup("hlt", hlt_setup);
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void default_idle(void)
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{
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if (!hlt_counter) {
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb__after_clear_bit();
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set_bl_bit();
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while (!need_resched())
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cpu_sleep();
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clear_bl_bit();
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set_thread_flag(TIF_POLLING_NRFLAG);
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} else
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while (!need_resched())
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cpu_relax();
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}
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void cpu_idle(void)
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{
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set_thread_flag(TIF_POLLING_NRFLAG);
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/* endless idle loop with no priority at all */
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while (1) {
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void (*idle)(void) = pm_idle;
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if (!idle)
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idle = default_idle;
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tick_nohz_stop_sched_tick();
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while (!need_resched())
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idle();
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tick_nohz_restart_sched_tick();
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preempt_enable_no_resched();
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schedule();
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preempt_disable();
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check_pgt_cache();
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}
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}
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void machine_restart(char * __unused)
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{
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/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
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asm volatile("ldc %0, sr\n\t"
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"mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
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}
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void machine_halt(void)
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{
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local_irq_disable();
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while (1)
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cpu_sleep();
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}
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void machine_power_off(void)
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{
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if (pm_power_off)
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pm_power_off();
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}
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void show_regs(struct pt_regs * regs)
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{
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printk("\n");
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printk("Pid : %d, Comm: %20s\n", task_pid_nr(current), current->comm);
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print_symbol("PC is at %s\n", instruction_pointer(regs));
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printk("PC : %08lx SP : %08lx SR : %08lx ",
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regs->pc, regs->regs[15], regs->sr);
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#ifdef CONFIG_MMU
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printk("TEA : %08x ", ctrl_inl(MMU_TEA));
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#else
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printk(" ");
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#endif
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printk("%s\n", print_tainted());
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printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
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regs->regs[0],regs->regs[1],
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regs->regs[2],regs->regs[3]);
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printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
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regs->regs[4],regs->regs[5],
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regs->regs[6],regs->regs[7]);
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printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
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regs->regs[8],regs->regs[9],
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regs->regs[10],regs->regs[11]);
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printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
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regs->regs[12],regs->regs[13],
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regs->regs[14]);
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printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
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regs->mach, regs->macl, regs->gbr, regs->pr);
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show_trace(NULL, (unsigned long *)regs->regs[15], regs);
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}
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/*
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* Create a kernel thread
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*/
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/*
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* This is the mechanism for creating a new kernel thread.
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*
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*/
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extern void kernel_thread_helper(void);
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__asm__(".align 5\n"
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"kernel_thread_helper:\n\t"
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"jsr @r5\n\t"
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" nop\n\t"
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"mov.l 1f, r1\n\t"
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"jsr @r1\n\t"
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" mov r0, r4\n\t"
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".align 2\n\t"
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"1:.long do_exit");
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/* Don't use this in BL=1(cli). Or else, CPU resets! */
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int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.regs[4] = (unsigned long)arg;
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regs.regs[5] = (unsigned long)fn;
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regs.pc = (unsigned long)kernel_thread_helper;
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regs.sr = (1 << 30);
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/* Ok, create the new process.. */
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
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®s, 0, NULL, NULL);
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}
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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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if (current->thread.ubc_pc) {
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current->thread.ubc_pc = 0;
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ubc_usercnt -= 1;
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}
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}
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void flush_thread(void)
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{
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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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/* Forget lazy FPU state */
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clear_fpu(tsk, task_pt_regs(tsk));
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clear_used_math();
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#endif
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}
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void release_thread(struct task_struct *dead_task)
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{
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/* do nothing */
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}
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/* Fill in the fpu structure for a core dump.. */
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
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{
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int fpvalid = 0;
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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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fpvalid = !!tsk_used_math(tsk);
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if (fpvalid) {
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unlazy_fpu(tsk, regs);
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memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
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}
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#endif
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return fpvalid;
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}
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asmlinkage void ret_from_fork(void);
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int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct *p, struct pt_regs *regs)
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{
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struct thread_info *ti = task_thread_info(p);
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struct pt_regs *childregs;
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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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unlazy_fpu(tsk, regs);
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p->thread.fpu = tsk->thread.fpu;
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copy_to_stopped_child_used_math(p);
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#endif
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childregs = task_pt_regs(p);
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*childregs = *regs;
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if (user_mode(regs)) {
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childregs->regs[15] = usp;
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ti->addr_limit = USER_DS;
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} else {
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childregs->regs[15] = (unsigned long)childregs;
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ti->addr_limit = KERNEL_DS;
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}
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if (clone_flags & CLONE_SETTLS)
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childregs->gbr = childregs->regs[0];
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childregs->regs[0] = 0; /* Set return value for child */
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p->thread.sp = (unsigned long) childregs;
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p->thread.pc = (unsigned long) ret_from_fork;
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p->thread.ubc_pc = 0;
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return 0;
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}
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/* Tracing by user break controller. */
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static void ubc_set_tracing(int asid, unsigned long pc)
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{
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#if defined(CONFIG_CPU_SH4A)
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unsigned long val;
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val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
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val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
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ctrl_outl(val, UBC_CBR0);
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ctrl_outl(pc, UBC_CAR0);
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ctrl_outl(0x0, UBC_CAMR0);
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ctrl_outl(0x0, UBC_CBCR);
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val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
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ctrl_outl(val, UBC_CRR0);
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/* Read UBC register that we wrote last, for checking update */
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val = ctrl_inl(UBC_CRR0);
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#else /* CONFIG_CPU_SH4A */
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ctrl_outl(pc, UBC_BARA);
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#ifdef CONFIG_MMU
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ctrl_outb(asid, UBC_BASRA);
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#endif
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ctrl_outl(0, UBC_BAMRA);
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if (current_cpu_data.type == CPU_SH7729 ||
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current_cpu_data.type == CPU_SH7710 ||
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current_cpu_data.type == CPU_SH7712) {
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ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
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ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
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} else {
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ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
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ctrl_outw(BRCR_PCBA, UBC_BRCR);
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}
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#endif /* CONFIG_CPU_SH4A */
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}
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/*
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* switch_to(x,y) should switch tasks from x to y.
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*
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*/
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struct task_struct *__switch_to(struct task_struct *prev,
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struct task_struct *next)
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{
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#if defined(CONFIG_SH_FPU)
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unlazy_fpu(prev, task_pt_regs(prev));
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#endif
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#ifdef CONFIG_MMU
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/*
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* Restore the kernel mode register
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* k7 (r7_bank1)
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*/
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asm volatile("ldc %0, r7_bank"
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: /* no output */
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: "r" (task_thread_info(next)));
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#endif
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/* If no tasks are using the UBC, we're done */
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if (ubc_usercnt == 0)
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/* If no tasks are using the UBC, we're done */;
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else if (next->thread.ubc_pc && next->mm) {
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int asid = 0;
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#ifdef CONFIG_MMU
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asid |= cpu_asid(smp_processor_id(), next->mm);
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#endif
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ubc_set_tracing(asid, next->thread.ubc_pc);
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} else {
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#if defined(CONFIG_CPU_SH4A)
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ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
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ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
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#else
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ctrl_outw(0, UBC_BBRA);
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ctrl_outw(0, UBC_BBRB);
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#endif
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}
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return prev;
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}
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asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs __regs)
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{
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#ifdef CONFIG_MMU
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struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
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return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
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#else
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/* fork almost works, enough to trick you into looking elsewhere :-( */
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return -EINVAL;
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#endif
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}
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asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
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unsigned long parent_tidptr,
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unsigned long child_tidptr,
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struct pt_regs __regs)
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{
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struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
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if (!newsp)
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newsp = regs->regs[15];
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return do_fork(clone_flags, newsp, regs, 0,
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(int __user *)parent_tidptr,
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(int __user *)child_tidptr);
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}
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/*
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* This is trivial, and on the face of it looks like it
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* could equally well be done in user mode.
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*
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* Not so, for quite unobvious reasons - register pressure.
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* In user mode vfork() cannot have a stack frame, and if
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* done by calling the "clone()" system call directly, you
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* do not have enough call-clobbered registers to hold all
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* the information you need.
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*/
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asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs __regs)
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{
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struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
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0, NULL, NULL);
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}
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/*
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* sys_execve() executes a new program.
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*/
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asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
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char __user * __user *uenvp, unsigned long r7,
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struct pt_regs __regs)
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{
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struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
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int error;
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char *filename;
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filename = getname(ufilename);
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error = PTR_ERR(filename);
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if (IS_ERR(filename))
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goto out;
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error = do_execve(filename, uargv, uenvp, regs);
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if (error == 0) {
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task_lock(current);
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current->ptrace &= ~PT_DTRACE;
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task_unlock(current);
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}
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putname(filename);
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out:
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return error;
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}
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long pc;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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/*
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* The same comment as on the Alpha applies here, too ...
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*/
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pc = thread_saved_pc(p);
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#ifdef CONFIG_FRAME_POINTER
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if (in_sched_functions(pc)) {
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unsigned long schedule_frame = (unsigned long)p->thread.sp;
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return ((unsigned long *)schedule_frame)[21];
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}
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#endif
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return pc;
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}
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asmlinkage void break_point_trap(void)
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{
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/* Clear tracing. */
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#if defined(CONFIG_CPU_SH4A)
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ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
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ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
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#else
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ctrl_outw(0, UBC_BBRA);
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ctrl_outw(0, UBC_BBRB);
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#endif
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current->thread.ubc_pc = 0;
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ubc_usercnt -= 1;
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force_sig(SIGTRAP, current);
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}
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