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process.c

/*
 *  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>
#include <linux/utsname.h>

#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>
#include <asm/machdep.h>
#include <asm/time.h>
#include <asm/syscalls.h>
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#endif

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;
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
                  giveup_fpu(tsk);
            }
            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);

int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
{
      if (!tsk->thread.regs)
            return 0;
      flush_fp_to_thread(current);

      memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));

      return 1;
}

#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
                  giveup_altivec(tsk);
            }
            preempt_enable();
      }
}

int dump_task_altivec(struct task_struct *tsk, elf_vrregset_t *vrregs)
{
      /* ELF_NVRREG includes the VSCR and VRSAVE which we need to save
       * separately, see below */
      const int nregs = ELF_NVRREG - 2;
      elf_vrreg_t *reg;
      u32 *dest;

      if (tsk == current)
            flush_altivec_to_thread(tsk);

      reg = (elf_vrreg_t *)vrregs;

      /* copy the 32 vr registers */
      memcpy(reg, &tsk->thread.vr[0], nregs * sizeof(*reg));
      reg += nregs;

      /* copy the vscr */
      memcpy(reg, &tsk->thread.vscr, sizeof(*reg));
      reg++;

      /* vrsave is stored in the high 32bit slot of the final 128bits */
      memset(reg, 0, sizeof(*reg));
      dest = (u32 *)reg;
      *dest = tsk->thread.vrsave;

      return 1;
}
#endif /* CONFIG_ALTIVEC */

#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
                  giveup_spe(tsk);
            }
            preempt_enable();
      }
}

int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
{
      flush_spe_to_thread(current);
      /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
      memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
      return 1;
}
#endif /* CONFIG_SPE */

#ifndef CONFIG_SMP
/*
 * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 * and the current task has some state, discard it.
 */
void discard_lazy_cpu_state(void)
{
      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 */
#ifdef CONFIG_SPE
      if (last_task_used_spe == current)
            last_task_used_spe = NULL;
#endif
      preempt_enable();
}
#endif /* CONFIG_SMP */

int set_dabr(unsigned long dabr)
{
#ifdef CONFIG_PPC_MERGE       /* XXX for now */
      if (ppc_md.set_dabr)
            return ppc_md.set_dabr(dabr);
#endif

      /* XXX should we have a CPU_FTR_HAS_DABR ? */
#if defined(CONFIG_PPC64) || defined(CONFIG_6xx)
      mtspr(SPRN_DABR, dabr);
#endif
      return 0;
}

#ifdef CONFIG_PPC64
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
#endif

static DEFINE_PER_CPU(unsigned long, current_dabr);

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 */
#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);
#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 */
#ifdef CONFIG_SPE
      /* 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 */

#endif /* CONFIG_SMP */

      if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
            set_dabr(new->thread.dabr);
            __get_cpu_var(current_dabr) = new->thread.dabr;
      }

      new_thread = &new->thread;
      old_thread = &current->thread;

#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

      local_irq_save(flags);

      account_system_vtime(current);
      account_process_vtime(current);
      calculate_steal_time();

      last = _switch(old_thread, new_thread);

      local_irq_restore(flags);

      return last;
}

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");

#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

            /* We use __get_user here *only* to avoid an OOPS on a
             * bad address because the pc *should* only be a
             * kernel address.
             */
            if (!__kernel_text_address(pc) ||
                 __get_user(instr, (unsigned int __user *)pc)) {
                  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"},
      {MSR_ME,    "ME"},
      {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
#define REG       "%016lx"
#define REGS_PER_LINE   4
#define LAST_VOLATILE   13
#else
#define REG       "%08lx"
#define REGS_PER_LINE   8
#define LAST_VOLATILE   12
#endif

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

      printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
             regs->nip, regs->link, regs->ctr);
      printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
             regs, regs->trap, print_tainted(), init_utsname()->release);
      printk("MSR: "REG" ", regs->msr);
      printbits(regs->msr, msr_bits);
      printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
      trap = TRAP(regs);
      if (trap == 0x300 || trap == 0x600)
#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
            printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
#else
            printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
#endif
      printk("TASK = %p[%d] '%s' THREAD: %p",
             current, task_pid_nr(current), current->comm, task_thread_info(current));

#ifdef CONFIG_SMP
      printk(" CPU: %d", smp_processor_id());
#endif /* CONFIG_SMP */

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

void exit_thread(void)
{
      discard_lazy_cpu_state();
}

void flush_thread(void)
{
#ifdef CONFIG_PPC64
      struct thread_info *t = current_thread_info();

      if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
            clear_ti_thread_flag(t, TIF_ABI_PENDING);
            if (test_ti_thread_flag(t, TIF_32BIT))
                  clear_ti_thread_flag(t, TIF_32BIT);
            else
                  set_ti_thread_flag(t, TIF_32BIT);
      }
#endif

      discard_lazy_cpu_state();

      if (current->thread.dabr) {
            current->thread.dabr = 0;
            set_dabr(0);
      }
}

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);
      flush_spe_to_thread(current);
}

/*
 * Copy a thread..
 */
int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
            unsigned long unused, struct task_struct *p,
            struct pt_regs *regs)
{
      struct pt_regs *childregs, *kregs;
      extern void ret_from_fork(void);
      unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

      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);
#ifdef CONFIG_PPC32
            childregs->gpr[2] = (unsigned long) p;
#else
            clear_tsk_thread_flag(p, TIF_32BIT);
#endif
            p->thread.regs = NULL;  /* no user register state */
      } else {
            childregs->gpr[1] = usp;
            p->thread.regs = childregs;
            if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_PPC64
                  if (!test_thread_flag(TIF_32BIT))
                        childregs->gpr[13] = childregs->gpr[6];
                  else
#endif
                        childregs->gpr[2] = childregs->gpr[6];
            }
      }
      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;

#ifdef CONFIG_PPC64
      if (cpu_has_feature(CPU_FTR_SLB)) {
            unsigned long sp_vsid;
            unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;

            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;
            sp_vsid |= SLB_VSID_KERNEL | llp;
            p->thread.ksp_vsid = sp_vsid;
      }

      /*
       * 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.
       */
      kregs->nip = *((unsigned long *)ret_from_fork);
#else
      kregs->nip = (unsigned long)ret_from_fork;
#endif

      return 0;
}

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

      set_fs(USER_DS);

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

      memset(regs->gpr, 0, sizeof(regs->gpr));
      regs->ctr = 0;
      regs->link = 0;
      regs->xer = 0;
      regs->ccr = 0;
      regs->gpr[1] = sp;

      /*
       * 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;

#ifdef CONFIG_PPC32
      regs->mq = 0;
      regs->nip = start;
      regs->msr = MSR_USER;
#else
      if (!test_thread_flag(TIF_32BIT)) {
            unsigned long entry, toc;

            /* 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;
      } else {
            regs->nip = start;
            regs->gpr[2] = 0;
            regs->msr = MSR_USER32;
      }
#endif

      discard_lazy_cpu_state();
      memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
      current->thread.fpscr.val = 0;
#ifdef CONFIG_ALTIVEC
      memset(current->thread.vr, 0, sizeof(current->thread.vr));
      memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
      current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
      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
            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;
            }
#else
            return -EINVAL;
#endif
      }

      /* 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;
      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
            if (cpu_has_feature(CPU_FTR_SPE))
                  val = tsk->thread.fpexc_mode;
            else
                  return -EINVAL;
#else
            return -EINVAL;
#endif
      else
            val = __unpack_fe01(tsk->thread.fpexc_mode);
      return put_user(val, (unsigned int __user *) adr);
}

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);
}

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);
}

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

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 */
#ifdef CONFIG_PPC64
      if (test_thread_flag(TIF_32BIT)) {
            parent_tidp = TRUNC_PTR(parent_tidp);
            child_tidp = TRUNC_PTR(child_tidp);
      }
#endif
      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;
      char *filename;

      filename = getname((char __user *) a0);
      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);
      error = do_execve(filename, (char __user * __user *) a1,
                    (char __user * __user *) a2, regs);
      if (error == 0) {
            task_lock(current);
            current->ptrace &= ~PT_DTRACE;
            task_unlock(current);
      }
      putname(filename);
out:
      return error;
}

#ifdef CONFIG_IRQSTACKS
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;
}

#else
#define valid_irq_stack(sp, p, nb)  0
#endif /* CONFIG_IRQSTACKS */

int validate_sp(unsigned long sp, struct task_struct *p,
                   unsigned long nbytes)
{
      unsigned long stack_page = (unsigned long)task_stack_page(p);

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

      return valid_irq_stack(sp, p, nbytes);
}

#ifdef CONFIG_PPC64
#define MIN_STACK_FRAME 112   /* same as STACK_FRAME_OVERHEAD, in fact */
#define FRAME_LR_SAVE   2
#define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
#define REGS_MARKER     0x7265677368657265ul
#define FRAME_MARKER    12
#else
#define MIN_STACK_FRAME 16
#define FRAME_LR_SAVE   1
#define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
#define REGS_MARKER     0x72656773ul
#define FRAME_MARKER    2
#endif

EXPORT_SYMBOL(validate_sp);

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;
      if (!validate_sp(sp, p, MIN_STACK_FRAME))
            return 0;

      do {
            sp = *(unsigned long *)sp;
            if (!validate_sp(sp, p, MIN_STACK_FRAME))
                  return 0;
            if (count > 0) {
                  ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
                  if (!in_sched_functions(ip))
                        return ip;
            }
      } while (count++ < 16);
      return 0;
}

static int kstack_depth_to_print = 64;

void show_stack(struct task_struct *tsk, unsigned long *stack)
{
      unsigned long sp, ip, lr, newsp;
      int count = 0;
      int firstframe = 1;

      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 {
            if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
                  return;

            stack = (unsigned long *) sp;
            newsp = stack[0];
            ip = stack[FRAME_LR_SAVE];
            if (!firstframe || ip != lr) {
                  printk("["REG"] ["REG"] ", sp, ip);
                  print_symbol("%s", ip);
                  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.
             */
            if (validate_sp(sp, tsk, INT_FRAME_SIZE)
                && stack[FRAME_MARKER] == REGS_MARKER) {
                  struct pt_regs *regs = (struct pt_regs *)
                        (sp + STACK_FRAME_OVERHEAD);
                  printk("--- Exception: %lx", regs->trap);
                  print_symbol(" at %s\n", regs->nip);
                  lr = regs->link;
                  print_symbol("    LR = %s\n", lr);
                  firstframe = 1;
            }

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

void dump_stack(void)
{
      show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);

#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);
      }
}

void ppc64_runlatch_off(void)
{
      unsigned long ctrl;

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

            clear_thread_flag(TIF_RUNLATCH);

            ctrl = mfspr(SPRN_CTRLF);
            ctrl &= ~CTRL_RUNLATCH;
            mtspr(SPRN_CTRLT, ctrl);
      }
}
#endif

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