process.c 32.2 KB
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/*
 *  Derived from "arch/i386/kernel/process.c"
 *    Copyright (C) 1995  Linus Torvalds
 *
 *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
 *  Paul Mackerras (paulus@cs.anu.edu.au)
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/prctl.h>
#include <linux/init_task.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/mqueue.h>
#include <linux/hardirq.h>
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#include <linux/utsname.h>
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#include <linux/ftrace.h>
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#include <linux/kernel_stat.h>
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#include <linux/personality.h>
#include <linux/random.h>
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#include <linux/hw_breakpoint.h>
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#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/prom.h>
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#include <asm/machdep.h>
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#include <asm/time.h>
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#include <asm/syscalls.h>
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#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#endif
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#include <linux/kprobes.h>
#include <linux/kdebug.h>
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extern unsigned long _get_SP(void);

#ifndef CONFIG_SMP
struct task_struct *last_task_used_math = NULL;
struct task_struct *last_task_used_altivec = NULL;
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struct task_struct *last_task_used_vsx = NULL;
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struct task_struct *last_task_used_spe = NULL;
#endif

/*
 * Make sure the floating-point register state in the
 * the thread_struct is up to date for task tsk.
 */
void flush_fp_to_thread(struct task_struct *tsk)
{
	if (tsk->thread.regs) {
		/*
		 * We need to disable preemption here because if we didn't,
		 * another process could get scheduled after the regs->msr
		 * test but before we have finished saving the FP registers
		 * to the thread_struct.  That process could take over the
		 * FPU, and then when we get scheduled again we would store
		 * bogus values for the remaining FP registers.
		 */
		preempt_disable();
		if (tsk->thread.regs->msr & MSR_FP) {
#ifdef CONFIG_SMP
			/*
			 * This should only ever be called for current or
			 * for a stopped child process.  Since we save away
			 * the FP register state on context switch on SMP,
			 * there is something wrong if a stopped child appears
			 * to still have its FP state in the CPU registers.
			 */
			BUG_ON(tsk != current);
#endif
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			giveup_fpu(tsk);
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		}
		preempt_enable();
	}
}

void enable_kernel_fp(void)
{
	WARN_ON(preemptible());

#ifdef CONFIG_SMP
	if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
		giveup_fpu(current);
	else
		giveup_fpu(NULL);	/* just enables FP for kernel */
#else
	giveup_fpu(last_task_used_math);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_fp);

#ifdef CONFIG_ALTIVEC
void enable_kernel_altivec(void)
{
	WARN_ON(preemptible());

#ifdef CONFIG_SMP
	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
		giveup_altivec(current);
	else
		giveup_altivec(NULL);	/* just enable AltiVec for kernel - force */
#else
	giveup_altivec(last_task_used_altivec);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_altivec);

/*
 * Make sure the VMX/Altivec register state in the
 * the thread_struct is up to date for task tsk.
 */
void flush_altivec_to_thread(struct task_struct *tsk)
{
	if (tsk->thread.regs) {
		preempt_disable();
		if (tsk->thread.regs->msr & MSR_VEC) {
#ifdef CONFIG_SMP
			BUG_ON(tsk != current);
#endif
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			giveup_altivec(tsk);
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		}
		preempt_enable();
	}
}
#endif /* CONFIG_ALTIVEC */

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#ifdef CONFIG_VSX
#if 0
/* not currently used, but some crazy RAID module might want to later */
void enable_kernel_vsx(void)
{
	WARN_ON(preemptible());

#ifdef CONFIG_SMP
	if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
		giveup_vsx(current);
	else
		giveup_vsx(NULL);	/* just enable vsx for kernel - force */
#else
	giveup_vsx(last_task_used_vsx);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_vsx);
#endif

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void giveup_vsx(struct task_struct *tsk)
{
	giveup_fpu(tsk);
	giveup_altivec(tsk);
	__giveup_vsx(tsk);
}

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void flush_vsx_to_thread(struct task_struct *tsk)
{
	if (tsk->thread.regs) {
		preempt_disable();
		if (tsk->thread.regs->msr & MSR_VSX) {
#ifdef CONFIG_SMP
			BUG_ON(tsk != current);
#endif
			giveup_vsx(tsk);
		}
		preempt_enable();
	}
}
#endif /* CONFIG_VSX */

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#ifdef CONFIG_SPE

void enable_kernel_spe(void)
{
	WARN_ON(preemptible());

#ifdef CONFIG_SMP
	if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
		giveup_spe(current);
	else
		giveup_spe(NULL);	/* just enable SPE for kernel - force */
#else
	giveup_spe(last_task_used_spe);
#endif /* __SMP __ */
}
EXPORT_SYMBOL(enable_kernel_spe);

void flush_spe_to_thread(struct task_struct *tsk)
{
	if (tsk->thread.regs) {
		preempt_disable();
		if (tsk->thread.regs->msr & MSR_SPE) {
#ifdef CONFIG_SMP
			BUG_ON(tsk != current);
#endif
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			giveup_spe(tsk);
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		}
		preempt_enable();
	}
}
#endif /* CONFIG_SPE */

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#ifndef CONFIG_SMP
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/*
 * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 * and the current task has some state, discard it.
 */
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void discard_lazy_cpu_state(void)
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{
	preempt_disable();
	if (last_task_used_math == current)
		last_task_used_math = NULL;
#ifdef CONFIG_ALTIVEC
	if (last_task_used_altivec == current)
		last_task_used_altivec = NULL;
#endif /* CONFIG_ALTIVEC */
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#ifdef CONFIG_VSX
	if (last_task_used_vsx == current)
		last_task_used_vsx = NULL;
#endif /* CONFIG_VSX */
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#ifdef CONFIG_SPE
	if (last_task_used_spe == current)
		last_task_used_spe = NULL;
#endif
	preempt_enable();
}
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#endif /* CONFIG_SMP */
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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
void do_send_trap(struct pt_regs *regs, unsigned long address,
		  unsigned long error_code, int signal_code, int breakpt)
{
	siginfo_t info;

	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
			11, SIGSEGV) == NOTIFY_STOP)
		return;

	/* Deliver the signal to userspace */
	info.si_signo = SIGTRAP;
	info.si_errno = breakpt;	/* breakpoint or watchpoint id */
	info.si_code = signal_code;
	info.si_addr = (void __user *)address;
	force_sig_info(SIGTRAP, &info, current);
}
#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
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void do_dabr(struct pt_regs *regs, unsigned long address,
		    unsigned long error_code)
{
	siginfo_t info;

	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
			11, SIGSEGV) == NOTIFY_STOP)
		return;

	if (debugger_dabr_match(regs))
		return;

	/* Clear the DABR */
	set_dabr(0);

	/* Deliver the signal to userspace */
	info.si_signo = SIGTRAP;
	info.si_errno = 0;
	info.si_code = TRAP_HWBKPT;
	info.si_addr = (void __user *)address;
	force_sig_info(SIGTRAP, &info, current);
}
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#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
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static DEFINE_PER_CPU(unsigned long, current_dabr);

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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/*
 * Set the debug registers back to their default "safe" values.
 */
static void set_debug_reg_defaults(struct thread_struct *thread)
{
	thread->iac1 = thread->iac2 = 0;
#if CONFIG_PPC_ADV_DEBUG_IACS > 2
	thread->iac3 = thread->iac4 = 0;
#endif
	thread->dac1 = thread->dac2 = 0;
#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
	thread->dvc1 = thread->dvc2 = 0;
#endif
	thread->dbcr0 = 0;
#ifdef CONFIG_BOOKE
	/*
	 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
	 */
	thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |	\
			DBCR1_IAC3US | DBCR1_IAC4US;
	/*
	 * Force Data Address Compare User/Supervisor bits to be User-only
	 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
	 */
	thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
#else
	thread->dbcr1 = 0;
#endif
}

static void prime_debug_regs(struct thread_struct *thread)
{
	mtspr(SPRN_IAC1, thread->iac1);
	mtspr(SPRN_IAC2, thread->iac2);
#if CONFIG_PPC_ADV_DEBUG_IACS > 2
	mtspr(SPRN_IAC3, thread->iac3);
	mtspr(SPRN_IAC4, thread->iac4);
#endif
	mtspr(SPRN_DAC1, thread->dac1);
	mtspr(SPRN_DAC2, thread->dac2);
#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
	mtspr(SPRN_DVC1, thread->dvc1);
	mtspr(SPRN_DVC2, thread->dvc2);
#endif
	mtspr(SPRN_DBCR0, thread->dbcr0);
	mtspr(SPRN_DBCR1, thread->dbcr1);
#ifdef CONFIG_BOOKE
	mtspr(SPRN_DBCR2, thread->dbcr2);
#endif
}
/*
 * Unless neither the old or new thread are making use of the
 * debug registers, set the debug registers from the values
 * stored in the new thread.
 */
static void switch_booke_debug_regs(struct thread_struct *new_thread)
{
	if ((current->thread.dbcr0 & DBCR0_IDM)
		|| (new_thread->dbcr0 & DBCR0_IDM))
			prime_debug_regs(new_thread);
}
#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
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#ifndef CONFIG_HAVE_HW_BREAKPOINT
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static void set_debug_reg_defaults(struct thread_struct *thread)
{
	if (thread->dabr) {
		thread->dabr = 0;
		set_dabr(0);
	}
}
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#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
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#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */

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int set_dabr(unsigned long dabr)
{
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	__get_cpu_var(current_dabr) = dabr;

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	if (ppc_md.set_dabr)
		return ppc_md.set_dabr(dabr);
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	/* XXX should we have a CPU_FTR_HAS_DABR ? */
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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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	mtspr(SPRN_DAC1, dabr);
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#ifdef CONFIG_PPC_47x
	isync();
#endif
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#elif defined(CONFIG_PPC_BOOK3S)
	mtspr(SPRN_DABR, dabr);
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#endif

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	return 0;
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}

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#ifdef CONFIG_PPC64
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
#endif
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struct task_struct *__switch_to(struct task_struct *prev,
	struct task_struct *new)
{
	struct thread_struct *new_thread, *old_thread;
	unsigned long flags;
	struct task_struct *last;

#ifdef CONFIG_SMP
	/* avoid complexity of lazy save/restore of fpu
	 * by just saving it every time we switch out if
	 * this task used the fpu during the last quantum.
	 *
	 * If it tries to use the fpu again, it'll trap and
	 * reload its fp regs.  So we don't have to do a restore
	 * every switch, just a save.
	 *  -- Cort
	 */
	if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
		giveup_fpu(prev);
#ifdef CONFIG_ALTIVEC
	/*
	 * If the previous thread used altivec in the last quantum
	 * (thus changing altivec regs) then save them.
	 * We used to check the VRSAVE register but not all apps
	 * set it, so we don't rely on it now (and in fact we need
	 * to save & restore VSCR even if VRSAVE == 0).  -- paulus
	 *
	 * On SMP we always save/restore altivec regs just to avoid the
	 * complexity of changing processors.
	 *  -- Cort
	 */
	if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
		giveup_altivec(prev);
#endif /* CONFIG_ALTIVEC */
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#ifdef CONFIG_VSX
	if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
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		/* VMX and FPU registers are already save here */
		__giveup_vsx(prev);
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#endif /* CONFIG_VSX */
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#ifdef CONFIG_SPE
	/*
	 * If the previous thread used spe in the last quantum
	 * (thus changing spe regs) then save them.
	 *
	 * On SMP we always save/restore spe regs just to avoid the
	 * complexity of changing processors.
	 */
	if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
		giveup_spe(prev);
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#endif /* CONFIG_SPE */

#else  /* CONFIG_SMP */
#ifdef CONFIG_ALTIVEC
	/* Avoid the trap.  On smp this this never happens since
	 * we don't set last_task_used_altivec -- Cort
	 */
	if (new->thread.regs && last_task_used_altivec == new)
		new->thread.regs->msr |= MSR_VEC;
#endif /* CONFIG_ALTIVEC */
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#ifdef CONFIG_VSX
	if (new->thread.regs && last_task_used_vsx == new)
		new->thread.regs->msr |= MSR_VSX;
#endif /* CONFIG_VSX */
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#ifdef CONFIG_SPE
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	/* Avoid the trap.  On smp this this never happens since
	 * we don't set last_task_used_spe
	 */
	if (new->thread.regs && last_task_used_spe == new)
		new->thread.regs->msr |= MSR_SPE;
#endif /* CONFIG_SPE */
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#endif /* CONFIG_SMP */

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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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	switch_booke_debug_regs(&new->thread);
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#else
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/*
 * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
 * schedule DABR
 */
#ifndef CONFIG_HAVE_HW_BREAKPOINT
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	if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
		set_dabr(new->thread.dabr);
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#endif /* CONFIG_HAVE_HW_BREAKPOINT */
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#endif

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	new_thread = &new->thread;
	old_thread = &current->thread;
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#if defined(CONFIG_PPC_BOOK3E_64)
	/* XXX Current Book3E code doesn't deal with kernel side DBCR0,
	 * we always hold the user values, so we set it now.
	 *
	 * However, we ensure the kernel MSR:DE is appropriately cleared too
	 * to avoid spurrious single step exceptions in the kernel.
	 *
	 * This will have to change to merge with the ppc32 code at some point,
	 * but I don't like much what ppc32 is doing today so there's some
	 * thinking needed there
	 */
	if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) {
		u32 dbcr0;

		mtmsr(mfmsr() & ~MSR_DE);
		isync();
		dbcr0 = mfspr(SPRN_DBCR0);
		dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0;
		mtspr(SPRN_DBCR0, dbcr0);
	}
#endif /* CONFIG_PPC64_BOOK3E */

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#ifdef CONFIG_PPC64
	/*
	 * Collect processor utilization data per process
	 */
	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
		struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
		long unsigned start_tb, current_tb;
		start_tb = old_thread->start_tb;
		cu->current_tb = current_tb = mfspr(SPRN_PURR);
		old_thread->accum_tb += (current_tb - start_tb);
		new_thread->start_tb = current_tb;
	}
#endif

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	local_irq_save(flags);
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	account_system_vtime(current);
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	account_process_vtime(current);
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	/*
	 * We can't take a PMU exception inside _switch() since there is a
	 * window where the kernel stack SLB and the kernel stack are out
	 * of sync. Hard disable here.
	 */
	hard_irq_disable();
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	last = _switch(old_thread, new_thread);

	local_irq_restore(flags);

	return last;
}

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static int instructions_to_print = 16;

static void show_instructions(struct pt_regs *regs)
{
	int i;
	unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
			sizeof(int));

	printk("Instruction dump:");

	for (i = 0; i < instructions_to_print; i++) {
		int instr;

		if (!(i % 8))
			printk("\n");

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#if !defined(CONFIG_BOOKE)
		/* If executing with the IMMU off, adjust pc rather
		 * than print XXXXXXXX.
		 */
		if (!(regs->msr & MSR_IR))
			pc = (unsigned long)phys_to_virt(pc);
#endif

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		/* We use __get_user here *only* to avoid an OOPS on a
		 * bad address because the pc *should* only be a
		 * kernel address.
		 */
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		if (!__kernel_text_address(pc) ||
		     __get_user(instr, (unsigned int __user *)pc)) {
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			printk("XXXXXXXX ");
		} else {
			if (regs->nip == pc)
				printk("<%08x> ", instr);
			else
				printk("%08x ", instr);
		}

		pc += sizeof(int);
	}

	printk("\n");
}

static struct regbit {
	unsigned long bit;
	const char *name;
} msr_bits[] = {
	{MSR_EE,	"EE"},
	{MSR_PR,	"PR"},
	{MSR_FP,	"FP"},
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	{MSR_VEC,	"VEC"},
	{MSR_VSX,	"VSX"},
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	{MSR_ME,	"ME"},
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	{MSR_CE,	"CE"},
	{MSR_DE,	"DE"},
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	{MSR_IR,	"IR"},
	{MSR_DR,	"DR"},
	{0,		NULL}
};

static void printbits(unsigned long val, struct regbit *bits)
{
	const char *sep = "";

	printk("<");
	for (; bits->bit; ++bits)
		if (val & bits->bit) {
			printk("%s%s", sep, bits->name);
			sep = ",";
		}
	printk(">");
}

#ifdef CONFIG_PPC64
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#define REG		"%016lx"
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#define REGS_PER_LINE	4
#define LAST_VOLATILE	13
#else
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#define REG		"%08lx"
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#define REGS_PER_LINE	8
#define LAST_VOLATILE	12
#endif

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void show_regs(struct pt_regs * regs)
{
	int i, trap;

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	printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
	       regs->nip, regs->link, regs->ctr);
	printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
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	       regs, regs->trap, print_tainted(), init_utsname()->release);
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	printk("MSR: "REG" ", regs->msr);
	printbits(regs->msr, msr_bits);
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	printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
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	trap = TRAP(regs);
	if (trap == 0x300 || trap == 0x600)
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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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		printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
#else
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		printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
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#endif
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	printk("TASK = %p[%d] '%s' THREAD: %p",
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	       current, task_pid_nr(current), current->comm, task_thread_info(current));
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#ifdef CONFIG_SMP
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	printk(" CPU: %d", raw_smp_processor_id());
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#endif /* CONFIG_SMP */

	for (i = 0;  i < 32;  i++) {
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		if ((i % REGS_PER_LINE) == 0)
K
Kumar Gala 已提交
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			printk("\nGPR%02d: ", i);
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		printk(REG " ", regs->gpr[i]);
		if (i == LAST_VOLATILE && !FULL_REGS(regs))
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			break;
	}
	printk("\n");
#ifdef CONFIG_KALLSYMS
	/*
	 * Lookup NIP late so we have the best change of getting the
	 * above info out without failing
	 */
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	printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
	printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
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#endif
	show_stack(current, (unsigned long *) regs->gpr[1]);
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	if (!user_mode(regs))
		show_instructions(regs);
664 665 666 667
}

void exit_thread(void)
{
668
	discard_lazy_cpu_state();
669 670 671 672
}

void flush_thread(void)
{
673
	discard_lazy_cpu_state();
674

675
#ifdef CONFIG_HAVE_HW_BREAKPOINT
676
	flush_ptrace_hw_breakpoint(current);
677
#else /* CONFIG_HAVE_HW_BREAKPOINT */
678
	set_debug_reg_defaults(&current->thread);
679
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
680 681 682 683 684 685 686 687 688 689 690 691 692 693 694
}

void
release_thread(struct task_struct *t)
{
}

/*
 * This gets called before we allocate a new thread and copy
 * the current task into it.
 */
void prepare_to_copy(struct task_struct *tsk)
{
	flush_fp_to_thread(current);
	flush_altivec_to_thread(current);
695
	flush_vsx_to_thread(current);
696
	flush_spe_to_thread(current);
697 698 699
#ifdef CONFIG_HAVE_HW_BREAKPOINT
	flush_ptrace_hw_breakpoint(tsk);
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
700 701 702 703 704
}

/*
 * Copy a thread..
 */
705 706
extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */

A
Alexey Dobriyan 已提交
707
int copy_thread(unsigned long clone_flags, unsigned long usp,
708 709
		unsigned long unused, struct task_struct *p,
		struct pt_regs *regs)
710 711 712
{
	struct pt_regs *childregs, *kregs;
	extern void ret_from_fork(void);
A
Al Viro 已提交
713
	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
714 715 716 717 718 719 720 721 722

	CHECK_FULL_REGS(regs);
	/* Copy registers */
	sp -= sizeof(struct pt_regs);
	childregs = (struct pt_regs *) sp;
	*childregs = *regs;
	if ((childregs->msr & MSR_PR) == 0) {
		/* for kernel thread, set `current' and stackptr in new task */
		childregs->gpr[1] = sp + sizeof(struct pt_regs);
723
#ifdef CONFIG_PPC32
724
		childregs->gpr[2] = (unsigned long) p;
725
#else
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Al Viro 已提交
726
		clear_tsk_thread_flag(p, TIF_32BIT);
727
#endif
728 729 730 731
		p->thread.regs = NULL;	/* no user register state */
	} else {
		childregs->gpr[1] = usp;
		p->thread.regs = childregs;
732 733
		if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_PPC64
734
			if (!is_32bit_task())
735 736 737 738 739
				childregs->gpr[13] = childregs->gpr[6];
			else
#endif
				childregs->gpr[2] = childregs->gpr[6];
		}
740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755
	}
	childregs->gpr[3] = 0;  /* Result from fork() */
	sp -= STACK_FRAME_OVERHEAD;

	/*
	 * The way this works is that at some point in the future
	 * some task will call _switch to switch to the new task.
	 * That will pop off the stack frame created below and start
	 * the new task running at ret_from_fork.  The new task will
	 * do some house keeping and then return from the fork or clone
	 * system call, using the stack frame created above.
	 */
	sp -= sizeof(struct pt_regs);
	kregs = (struct pt_regs *) sp;
	sp -= STACK_FRAME_OVERHEAD;
	p->thread.ksp = sp;
756 757
	p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
				_ALIGN_UP(sizeof(struct thread_info), 16);
758

759
#ifdef CONFIG_PPC_STD_MMU_64
760
	if (cpu_has_feature(CPU_FTR_SLB)) {
P
Paul Mackerras 已提交
761
		unsigned long sp_vsid;
762
		unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
763

P
Paul Mackerras 已提交
764 765 766 767 768 769
		if (cpu_has_feature(CPU_FTR_1T_SEGMENT))
			sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
				<< SLB_VSID_SHIFT_1T;
		else
			sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
				<< SLB_VSID_SHIFT;
770
		sp_vsid |= SLB_VSID_KERNEL | llp;
771 772
		p->thread.ksp_vsid = sp_vsid;
	}
773
#endif /* CONFIG_PPC_STD_MMU_64 */
774 775 776 777 778 779 780 781 782 783 784 785 786 787
#ifdef CONFIG_PPC64 
	if (cpu_has_feature(CPU_FTR_DSCR)) {
		if (current->thread.dscr_inherit) {
			p->thread.dscr_inherit = 1;
			p->thread.dscr = current->thread.dscr;
		} else if (0 != dscr_default) {
			p->thread.dscr_inherit = 1;
			p->thread.dscr = dscr_default;
		} else {
			p->thread.dscr_inherit = 0;
			p->thread.dscr = 0;
		}
	}
#endif
788 789 790 791 792 793 794

	/*
	 * The PPC64 ABI makes use of a TOC to contain function 
	 * pointers.  The function (ret_from_except) is actually a pointer
	 * to the TOC entry.  The first entry is a pointer to the actual
	 * function.
 	 */
795
#ifdef CONFIG_PPC64
796 797 798 799
	kregs->nip = *((unsigned long *)ret_from_fork);
#else
	kregs->nip = (unsigned long)ret_from_fork;
#endif
800 801 802 803 804 805 806

	return 0;
}

/*
 * Set up a thread for executing a new program
 */
807
void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
808
{
809 810 811 812
#ifdef CONFIG_PPC64
	unsigned long load_addr = regs->gpr[2];	/* saved by ELF_PLAT_INIT */
#endif

813
	set_fs(USER_DS);
814 815 816 817 818 819

	/*
	 * If we exec out of a kernel thread then thread.regs will not be
	 * set.  Do it now.
	 */
	if (!current->thread.regs) {
A
Al Viro 已提交
820 821
		struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
		current->thread.regs = regs - 1;
822 823
	}

824 825 826 827 828 829
	memset(regs->gpr, 0, sizeof(regs->gpr));
	regs->ctr = 0;
	regs->link = 0;
	regs->xer = 0;
	regs->ccr = 0;
	regs->gpr[1] = sp;
830

831 832 833 834 835 836 837
	/*
	 * We have just cleared all the nonvolatile GPRs, so make
	 * FULL_REGS(regs) return true.  This is necessary to allow
	 * ptrace to examine the thread immediately after exec.
	 */
	regs->trap &= ~1UL;

838 839 840
#ifdef CONFIG_PPC32
	regs->mq = 0;
	regs->nip = start;
841
	regs->msr = MSR_USER;
842
#else
843
	if (!is_32bit_task()) {
844
		unsigned long entry, toc;
845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863

		/* start is a relocated pointer to the function descriptor for
		 * the elf _start routine.  The first entry in the function
		 * descriptor is the entry address of _start and the second
		 * entry is the TOC value we need to use.
		 */
		__get_user(entry, (unsigned long __user *)start);
		__get_user(toc, (unsigned long __user *)start+1);

		/* Check whether the e_entry function descriptor entries
		 * need to be relocated before we can use them.
		 */
		if (load_addr != 0) {
			entry += load_addr;
			toc   += load_addr;
		}
		regs->nip = entry;
		regs->gpr[2] = toc;
		regs->msr = MSR_USER64;
S
Stephen Rothwell 已提交
864 865 866 867
	} else {
		regs->nip = start;
		regs->gpr[2] = 0;
		regs->msr = MSR_USER32;
868 869 870
	}
#endif

871
	discard_lazy_cpu_state();
872 873 874
#ifdef CONFIG_VSX
	current->thread.used_vsr = 0;
#endif
875
	memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
876
	current->thread.fpscr.val = 0;
877 878 879
#ifdef CONFIG_ALTIVEC
	memset(current->thread.vr, 0, sizeof(current->thread.vr));
	memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
880
	current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
	current->thread.vrsave = 0;
	current->thread.used_vr = 0;
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
	memset(current->thread.evr, 0, sizeof(current->thread.evr));
	current->thread.acc = 0;
	current->thread.spefscr = 0;
	current->thread.used_spe = 0;
#endif /* CONFIG_SPE */
}

#define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
		| PR_FP_EXC_RES | PR_FP_EXC_INV)

int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
{
	struct pt_regs *regs = tsk->thread.regs;

	/* This is a bit hairy.  If we are an SPE enabled  processor
	 * (have embedded fp) we store the IEEE exception enable flags in
	 * fpexc_mode.  fpexc_mode is also used for setting FP exception
	 * mode (asyn, precise, disabled) for 'Classic' FP. */
	if (val & PR_FP_EXC_SW_ENABLE) {
#ifdef CONFIG_SPE
905 906 907 908 909 910 911
		if (cpu_has_feature(CPU_FTR_SPE)) {
			tsk->thread.fpexc_mode = val &
				(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
			return 0;
		} else {
			return -EINVAL;
		}
912 913 914 915
#else
		return -EINVAL;
#endif
	}
916 917 918 919 920 921 922 923 924 925 926 927

	/* on a CONFIG_SPE this does not hurt us.  The bits that
	 * __pack_fe01 use do not overlap with bits used for
	 * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
	 * on CONFIG_SPE implementations are reserved so writing to
	 * them does not change anything */
	if (val > PR_FP_EXC_PRECISE)
		return -EINVAL;
	tsk->thread.fpexc_mode = __pack_fe01(val);
	if (regs != NULL && (regs->msr & MSR_FP) != 0)
		regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
			| tsk->thread.fpexc_mode;
928 929 930 931 932 933 934 935 936
	return 0;
}

int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
{
	unsigned int val;

	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
#ifdef CONFIG_SPE
937 938 939 940
		if (cpu_has_feature(CPU_FTR_SPE))
			val = tsk->thread.fpexc_mode;
		else
			return -EINVAL;
941 942 943 944 945 946 947 948
#else
		return -EINVAL;
#endif
	else
		val = __unpack_fe01(tsk->thread.fpexc_mode);
	return put_user(val, (unsigned int __user *) adr);
}

949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992
int set_endian(struct task_struct *tsk, unsigned int val)
{
	struct pt_regs *regs = tsk->thread.regs;

	if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
	    (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
		return -EINVAL;

	if (regs == NULL)
		return -EINVAL;

	if (val == PR_ENDIAN_BIG)
		regs->msr &= ~MSR_LE;
	else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
		regs->msr |= MSR_LE;
	else
		return -EINVAL;

	return 0;
}

int get_endian(struct task_struct *tsk, unsigned long adr)
{
	struct pt_regs *regs = tsk->thread.regs;
	unsigned int val;

	if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
	    !cpu_has_feature(CPU_FTR_REAL_LE))
		return -EINVAL;

	if (regs == NULL)
		return -EINVAL;

	if (regs->msr & MSR_LE) {
		if (cpu_has_feature(CPU_FTR_REAL_LE))
			val = PR_ENDIAN_LITTLE;
		else
			val = PR_ENDIAN_PPC_LITTLE;
	} else
		val = PR_ENDIAN_BIG;

	return put_user(val, (unsigned int __user *)adr);
}

993 994 995 996 997 998 999 1000 1001 1002 1003
int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
{
	tsk->thread.align_ctl = val;
	return 0;
}

int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
{
	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
}

1004 1005
#define TRUNC_PTR(x)	((typeof(x))(((unsigned long)(x)) & 0xffffffff))

1006 1007 1008 1009 1010 1011 1012 1013
int sys_clone(unsigned long clone_flags, unsigned long usp,
	      int __user *parent_tidp, void __user *child_threadptr,
	      int __user *child_tidp, int p6,
	      struct pt_regs *regs)
{
	CHECK_FULL_REGS(regs);
	if (usp == 0)
		usp = regs->gpr[1];	/* stack pointer for child */
1014
#ifdef CONFIG_PPC64
1015
	if (is_32bit_task()) {
1016 1017 1018 1019
		parent_tidp = TRUNC_PTR(parent_tidp);
		child_tidp = TRUNC_PTR(child_tidp);
	}
#endif
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
 	return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
}

int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
	     unsigned long p4, unsigned long p5, unsigned long p6,
	     struct pt_regs *regs)
{
	CHECK_FULL_REGS(regs);
	return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
}

int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
	      unsigned long p4, unsigned long p5, unsigned long p6,
	      struct pt_regs *regs)
{
	CHECK_FULL_REGS(regs);
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
			regs, 0, NULL, NULL);
}

int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
	       unsigned long a3, unsigned long a4, unsigned long a5,
	       struct pt_regs *regs)
{
	int error;
1045
	char *filename;
1046

1047
	filename = getname((const char __user *) a0);
1048 1049 1050 1051 1052 1053
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	flush_fp_to_thread(current);
	flush_altivec_to_thread(current);
	flush_spe_to_thread(current);
1054 1055 1056
	error = do_execve(filename,
			  (const char __user *const __user *) a1,
			  (const char __user *const __user *) a2, regs);
1057 1058 1059 1060 1061
	putname(filename);
out:
	return error;
}

1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085
static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
				  unsigned long nbytes)
{
	unsigned long stack_page;
	unsigned long cpu = task_cpu(p);

	/*
	 * Avoid crashing if the stack has overflowed and corrupted
	 * task_cpu(p), which is in the thread_info struct.
	 */
	if (cpu < NR_CPUS && cpu_possible(cpu)) {
		stack_page = (unsigned long) hardirq_ctx[cpu];
		if (sp >= stack_page + sizeof(struct thread_struct)
		    && sp <= stack_page + THREAD_SIZE - nbytes)
			return 1;

		stack_page = (unsigned long) softirq_ctx[cpu];
		if (sp >= stack_page + sizeof(struct thread_struct)
		    && sp <= stack_page + THREAD_SIZE - nbytes)
			return 1;
	}
	return 0;
}

1086
int validate_sp(unsigned long sp, struct task_struct *p,
1087 1088
		       unsigned long nbytes)
{
A
Al Viro 已提交
1089
	unsigned long stack_page = (unsigned long)task_stack_page(p);
1090 1091 1092 1093 1094

	if (sp >= stack_page + sizeof(struct thread_struct)
	    && sp <= stack_page + THREAD_SIZE - nbytes)
		return 1;

1095
	return valid_irq_stack(sp, p, nbytes);
1096 1097
}

1098 1099
EXPORT_SYMBOL(validate_sp);

1100 1101 1102 1103 1104 1105 1106 1107 1108
unsigned long get_wchan(struct task_struct *p)
{
	unsigned long ip, sp;
	int count = 0;

	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	sp = p->thread.ksp;
1109
	if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1110 1111 1112 1113
		return 0;

	do {
		sp = *(unsigned long *)sp;
1114
		if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1115 1116
			return 0;
		if (count > 0) {
1117
			ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1118 1119 1120 1121 1122 1123
			if (!in_sched_functions(ip))
				return ip;
		}
	} while (count++ < 16);
	return 0;
}
1124

1125
static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1126 1127 1128 1129 1130 1131

void show_stack(struct task_struct *tsk, unsigned long *stack)
{
	unsigned long sp, ip, lr, newsp;
	int count = 0;
	int firstframe = 1;
1132 1133 1134
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	int curr_frame = current->curr_ret_stack;
	extern void return_to_handler(void);
1135 1136
	unsigned long rth = (unsigned long)return_to_handler;
	unsigned long mrth = -1;
1137
#ifdef CONFIG_PPC64
1138 1139 1140 1141
	extern void mod_return_to_handler(void);
	rth = *(unsigned long *)rth;
	mrth = (unsigned long)mod_return_to_handler;
	mrth = *(unsigned long *)mrth;
1142 1143
#endif
#endif
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157

	sp = (unsigned long) stack;
	if (tsk == NULL)
		tsk = current;
	if (sp == 0) {
		if (tsk == current)
			asm("mr %0,1" : "=r" (sp));
		else
			sp = tsk->thread.ksp;
	}

	lr = 0;
	printk("Call Trace:\n");
	do {
1158
		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1159 1160 1161 1162
			return;

		stack = (unsigned long *) sp;
		newsp = stack[0];
1163
		ip = stack[STACK_FRAME_LR_SAVE];
1164
		if (!firstframe || ip != lr) {
1165
			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1166
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1167
			if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1168 1169 1170 1171 1172
				printk(" (%pS)",
				       (void *)current->ret_stack[curr_frame].ret);
				curr_frame--;
			}
#endif
1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
			if (firstframe)
				printk(" (unreliable)");
			printk("\n");
		}
		firstframe = 0;

		/*
		 * See if this is an exception frame.
		 * We look for the "regshere" marker in the current frame.
		 */
1183 1184
		if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
		    && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1185 1186 1187
			struct pt_regs *regs = (struct pt_regs *)
				(sp + STACK_FRAME_OVERHEAD);
			lr = regs->link;
1188 1189
			printk("--- Exception: %lx at %pS\n    LR = %pS\n",
			       regs->trap, (void *)regs->nip, (void *)lr);
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201
			firstframe = 1;
		}

		sp = newsp;
	} while (count++ < kstack_depth_to_print);
}

void dump_stack(void)
{
	show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218

#ifdef CONFIG_PPC64
void ppc64_runlatch_on(void)
{
	unsigned long ctrl;

	if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
		HMT_medium();

		ctrl = mfspr(SPRN_CTRLF);
		ctrl |= CTRL_RUNLATCH;
		mtspr(SPRN_CTRLT, ctrl);

		set_thread_flag(TIF_RUNLATCH);
	}
}

1219
void __ppc64_runlatch_off(void)
1220 1221 1222
{
	unsigned long ctrl;

1223
	HMT_medium();
1224

1225
	clear_thread_flag(TIF_RUNLATCH);
1226

1227 1228 1229
	ctrl = mfspr(SPRN_CTRLF);
	ctrl &= ~CTRL_RUNLATCH;
	mtspr(SPRN_CTRLT, ctrl);
1230 1231
}
#endif
1232 1233 1234 1235 1236

#if THREAD_SHIFT < PAGE_SHIFT

static struct kmem_cache *thread_info_cache;

1237
struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
1238 1239 1240
{
	struct thread_info *ti;

1241
	ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262
	if (unlikely(ti == NULL))
		return NULL;
#ifdef CONFIG_DEBUG_STACK_USAGE
	memset(ti, 0, THREAD_SIZE);
#endif
	return ti;
}

void free_thread_info(struct thread_info *ti)
{
	kmem_cache_free(thread_info_cache, ti);
}

void thread_info_cache_init(void)
{
	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
					      THREAD_SIZE, 0, NULL);
	BUG_ON(thread_info_cache == NULL);
}

#endif /* THREAD_SHIFT < PAGE_SHIFT */
1263 1264 1265 1266 1267 1268 1269

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;
}
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285

static inline unsigned long brk_rnd(void)
{
        unsigned long rnd = 0;

	/* 8MB for 32bit, 1GB for 64bit */
	if (is_32bit_task())
		rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
	else
		rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));

	return rnd << PAGE_SHIFT;
}

unsigned long arch_randomize_brk(struct mm_struct *mm)
{
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	unsigned long base = mm->brk;
	unsigned long ret;

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#ifdef CONFIG_PPC_STD_MMU_64
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	/*
	 * If we are using 1TB segments and we are allowed to randomise
	 * the heap, we can put it above 1TB so it is backed by a 1TB
	 * segment. Otherwise the heap will be in the bottom 1TB
	 * which always uses 256MB segments and this may result in a
	 * performance penalty.
	 */
	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
#endif

	ret = PAGE_ALIGN(base + brk_rnd());
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	if (ret < mm->brk)
		return mm->brk;

	return ret;
}
A
Anton Blanchard 已提交
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unsigned long randomize_et_dyn(unsigned long base)
{
	unsigned long ret = PAGE_ALIGN(base + brk_rnd());

	if (ret < base)
		return base;

	return ret;
}