Linux-2.6.12-rc2

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / sh64 / mm / fault.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * arch/sh64/mm/fault.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Richard Curnow (/proc/tlb, bug fixes)
 * Copyright (C) 2003  Paul Mundt
 *
 */

#include <linux/signal.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/tlb.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/registers.h>              /* required by inline asm statements */

#if defined(CONFIG_SH64_PROC_TLB)
#include <linux/init.h>
#include <linux/proc_fs.h>
/* Count numbers of tlb refills in each region */
static unsigned long long calls_to_update_mmu_cache = 0ULL;
static unsigned long long calls_to_flush_tlb_page   = 0ULL;
static unsigned long long calls_to_flush_tlb_range  = 0ULL;
static unsigned long long calls_to_flush_tlb_mm     = 0ULL;
static unsigned long long calls_to_flush_tlb_all    = 0ULL;
unsigned long long calls_to_do_slow_page_fault = 0ULL;
unsigned long long calls_to_do_fast_page_fault = 0ULL;

/* Count size of ranges for flush_tlb_range */
static unsigned long long flush_tlb_range_1         = 0ULL;
static unsigned long long flush_tlb_range_2         = 0ULL;
static unsigned long long flush_tlb_range_3_4       = 0ULL;
static unsigned long long flush_tlb_range_5_7       = 0ULL;
static unsigned long long flush_tlb_range_8_11      = 0ULL;
static unsigned long long flush_tlb_range_12_15     = 0ULL;
static unsigned long long flush_tlb_range_16_up     = 0ULL;

static unsigned long long page_not_present          = 0ULL;

#endif

extern void die(const char *,struct pt_regs *,long);

#define PFLAG(val,flag)   (( (val) & (flag) ) ? #flag : "" )
#define PPROT(flag) PFLAG(pgprot_val(prot),flag)

static inline void print_prots(pgprot_t prot)
{
        printk("prot is 0x%08lx\n",pgprot_val(prot));

        printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
               PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
}

static inline void print_vma(struct vm_area_struct *vma)
{
        printk("vma start 0x%08lx\n", vma->vm_start);
        printk("vma end   0x%08lx\n", vma->vm_end);

        print_prots(vma->vm_page_prot);
        printk("vm_flags 0x%08lx\n", vma->vm_flags);
}

static inline void print_task(struct task_struct *tsk)
{
        printk("Task pid %d\n", tsk->pid);
}

static pte_t *lookup_pte(struct mm_struct *mm, unsigned long address)
{
        pgd_t *dir;
        pmd_t *pmd;
        pte_t *pte;
        pte_t entry;

        dir = pgd_offset(mm, address);
        if (pgd_none(*dir)) {
                return NULL;
        }

        pmd = pmd_offset(dir, address);
        if (pmd_none(*pmd)) {
                return NULL;
        }

        pte = pte_offset_kernel(pmd, address);
        entry = *pte;

        if (pte_none(entry)) {
                return NULL;
        }
        if (!pte_present(entry)) {
                return NULL;
        }

        return pte;
}

/*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 */
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
                              unsigned long textaccess, unsigned long address)
{
        struct task_struct *tsk;
        struct mm_struct *mm;
        struct vm_area_struct * vma;
        const struct exception_table_entry *fixup;
        pte_t *pte;

#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_do_slow_page_fault;
#endif

        /* SIM
         * Note this is now called with interrupts still disabled
         * This is to cope with being called for a missing IO port
         * address with interupts disabled. This should be fixed as
         * soon as we have a better 'fast path' miss handler.
         *
         * Plus take care how you try and debug this stuff.
         * For example, writing debug data to a port which you
         * have just faulted on is not going to work.
         */

        tsk = current;
        mm = tsk->mm;

        /* Not an IO address, so reenable interrupts */
        local_irq_enable();

        /*
         * If we're in an interrupt or have no user
         * context, we must not take the fault..
         */
        if (in_interrupt() || !mm)
                goto no_context;

        /* TLB misses upon some cache flushes get done under cli() */
        down_read(&mm->mmap_sem);

        vma = find_vma(mm, address);

        if (!vma) {
#ifdef DEBUG_FAULT
                print_task(tsk);
                printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
                       __FUNCTION__,__LINE__,
                       address,regs->pc,textaccess,writeaccess);
                show_regs(regs);
#endif
                goto bad_area;
        }
        if (vma->vm_start <= address) {
                goto good_area;
        }

        if (!(vma->vm_flags & VM_GROWSDOWN)) {
#ifdef DEBUG_FAULT
                print_task(tsk);
                printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
                       __FUNCTION__,__LINE__,
                       address,regs->pc,textaccess,writeaccess);
                show_regs(regs);

                print_vma(vma);
#endif
                goto bad_area;
        }
        if (expand_stack(vma, address)) {
#ifdef DEBUG_FAULT
                print_task(tsk);
                printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
                       __FUNCTION__,__LINE__,
                       address,regs->pc,textaccess,writeaccess);
                show_regs(regs);
#endif
                goto bad_area;
        }
/*
 * Ok, we have a good vm_area for this memory access, so
 * we can handle it..
 */
good_area:
        if (textaccess) {
                if (!(vma->vm_flags & VM_EXEC))
                        goto bad_area;
        } else {
                if (writeaccess) {
                        if (!(vma->vm_flags & VM_WRITE))
                                goto bad_area;
                } else {
                        if (!(vma->vm_flags & VM_READ))
                                goto bad_area;
                }
        }

        /*
         * If for any reason at all we couldn't handle the fault,
         * make sure we exit gracefully rather than endlessly redo
         * the fault.
         */
survive:
        switch (handle_mm_fault(mm, vma, address, writeaccess)) {
        case 1:
                tsk->min_flt++;
                break;
        case 2:
                tsk->maj_flt++;
                break;
        case 0:
                goto do_sigbus;
        default:
                goto out_of_memory;
        }
        /* If we get here, the page fault has been handled.  Do the TLB refill
           now from the newly-setup PTE, to avoid having to fault again right
           away on the same instruction. */
        pte = lookup_pte (mm, address);
        if (!pte) {
                /* From empirical evidence, we can get here, due to
                   !pte_present(pte).  (e.g. if a swap-in occurs, and the page
                   is swapped back out again before the process that wanted it
                   gets rescheduled?) */
                goto no_pte;
        }

        __do_tlb_refill(address, textaccess, pte);

no_pte:

        up_read(&mm->mmap_sem);
        return;

/*
 * Something tried to access memory that isn't in our memory map..
 * Fix it, but check if it's kernel or user first..
 */
bad_area:
#ifdef DEBUG_FAULT
        printk("fault:bad area\n");
#endif
        up_read(&mm->mmap_sem);

        if (user_mode(regs)) {
                static int count=0;
                siginfo_t info;
                if (count < 4) {
                        /* This is really to help debug faults when starting
                         * usermode, so only need a few */
                        count++;
                        printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
                                address, current->pid, current->comm,
                                (unsigned long) regs->pc);
#if 0
                        show_regs(regs);
#endif
                }
                if (tsk->pid == 1) {
                        panic("INIT had user mode bad_area\n");
                }
                tsk->thread.address = address;
                tsk->thread.error_code = writeaccess;
                info.si_signo = SIGSEGV;
                info.si_errno = 0;
                info.si_addr = (void *) address;
                force_sig_info(SIGSEGV, &info, tsk);
                return;
        }

no_context:
#ifdef DEBUG_FAULT
        printk("fault:No context\n");
#endif
        /* Are we prepared to handle this kernel fault?  */
        fixup = search_exception_tables(regs->pc);
        if (fixup) {
                regs->pc = fixup->fixup;
                return;
        }

/*
 * Oops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 *
 */
        if (address < PAGE_SIZE)
                printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
        else
                printk(KERN_ALERT "Unable to handle kernel paging request");
        printk(" at virtual address %08lx\n", address);
        printk(KERN_ALERT "pc = %08Lx%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
        die("Oops", regs, writeaccess);
        do_exit(SIGKILL);

/*
 * We ran out of memory, or some other thing happened to us that made
 * us unable to handle the page fault gracefully.
 */
out_of_memory:
        if (current->pid == 1) {
                panic("INIT out of memory\n");
                yield();
                goto survive;
        }
        printk("fault:Out of memory\n");
        up_read(&mm->mmap_sem);
        if (current->pid == 1) {
                yield();
                down_read(&mm->mmap_sem);
                goto survive;
        }
        printk("VM: killing process %s\n", tsk->comm);
        if (user_mode(regs))
                do_exit(SIGKILL);
        goto no_context;

do_sigbus:
        printk("fault:Do sigbus\n");
        up_read(&mm->mmap_sem);

        /*
         * Send a sigbus, regardless of whether we were in kernel
         * or user mode.
         */
        tsk->thread.address = address;
        tsk->thread.error_code = writeaccess;
        tsk->thread.trap_no = 14;
        force_sig(SIGBUS, tsk);

        /* Kernel mode? Handle exceptions or die */
        if (!user_mode(regs))
                goto no_context;
}


void flush_tlb_all(void);

void update_mmu_cache(struct vm_area_struct * vma,
                        unsigned long address, pte_t pte)
{
#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_update_mmu_cache;
#endif

        /*
         * This appears to get called once for every pte entry that gets
         * established => I don't think it's efficient to try refilling the
         * TLBs with the pages - some may not get accessed even.  Also, for
         * executable pages, it is impossible to determine reliably here which
         * TLB they should be mapped into (or both even).
         *
         * So, just do nothing here and handle faults on demand.  In the
         * TLBMISS handling case, the refill is now done anyway after the pte
         * has been fixed up, so that deals with most useful cases.
         */
}

static void __flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
        unsigned long long match, pteh=0, lpage;
        unsigned long tlb;
        struct mm_struct *mm;

        mm = vma->vm_mm;

        if (mm->context == NO_CONTEXT)
                return;

        /*
         * Sign-extend based on neff.
         */
        lpage = (page & NEFF_SIGN) ? (page | NEFF_MASK) : page;
        match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;
        match |= lpage;

        /* Do ITLB : don't bother for pages in non-exectutable VMAs */
        if (vma->vm_flags & VM_EXEC) {
                for_each_itlb_entry(tlb) {
                        asm volatile ("getcfg   %1, 0, %0"
                                      : "=r" (pteh)
                                      : "r" (tlb) );

                        if (pteh == match) {
                                __flush_tlb_slot(tlb);
                                break;
                        }

                }
        }

        /* Do DTLB : any page could potentially be in here. */
        for_each_dtlb_entry(tlb) {
                asm volatile ("getcfg   %1, 0, %0"
                              : "=r" (pteh)
                              : "r" (tlb) );

                if (pteh == match) {
                        __flush_tlb_slot(tlb);
                        break;
                }

        }
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
        unsigned long flags;

#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_flush_tlb_page;
#endif

        if (vma->vm_mm) {
                page &= PAGE_MASK;
                local_irq_save(flags);
                __flush_tlb_page(vma, page);
                local_irq_restore(flags);
        }
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
                     unsigned long end)
{
        unsigned long flags;
        unsigned long long match, pteh=0, pteh_epn, pteh_low;
        unsigned long tlb;
        struct mm_struct *mm;

        mm = vma->vm_mm;

#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_flush_tlb_range;

        {
                unsigned long size = (end - 1) - start;
                size >>= 12; /* divide by PAGE_SIZE */
                size++; /* end=start+4096 => 1 page */
                switch (size) {
                  case  1        : flush_tlb_range_1++;     break;
                  case  2        : flush_tlb_range_2++;     break;
                  case  3 ...  4 : flush_tlb_range_3_4++;   break;
                  case  5 ...  7 : flush_tlb_range_5_7++;   break;
                  case  8 ... 11 : flush_tlb_range_8_11++;  break;
                  case 12 ... 15 : flush_tlb_range_12_15++; break;
                  default        : flush_tlb_range_16_up++; break;
                }
        }
#endif

        if (mm->context == NO_CONTEXT)
                return;

        local_irq_save(flags);

        start &= PAGE_MASK;
        end &= PAGE_MASK;

        match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;

        /* Flush ITLB */
        for_each_itlb_entry(tlb) {
                asm volatile ("getcfg   %1, 0, %0"
                              : "=r" (pteh)
                              : "r" (tlb) );

                pteh_epn = pteh & PAGE_MASK;
                pteh_low = pteh & ~PAGE_MASK;

                if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
                        __flush_tlb_slot(tlb);
        }

        /* Flush DTLB */
        for_each_dtlb_entry(tlb) {
                asm volatile ("getcfg   %1, 0, %0"
                              : "=r" (pteh)
                              : "r" (tlb) );

                pteh_epn = pteh & PAGE_MASK;
                pteh_low = pteh & ~PAGE_MASK;

                if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
                        __flush_tlb_slot(tlb);
        }

        local_irq_restore(flags);
}

void flush_tlb_mm(struct mm_struct *mm)
{
        unsigned long flags;

#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_flush_tlb_mm;
#endif

        if (mm->context == NO_CONTEXT)
                return;

        local_irq_save(flags);

        mm->context=NO_CONTEXT;
        if(mm==current->mm)
                activate_context(mm);

        local_irq_restore(flags);

}

void flush_tlb_all(void)
{
        /* Invalidate all, including shared pages, excluding fixed TLBs */

        unsigned long flags, tlb;

#if defined(CONFIG_SH64_PROC_TLB)
        ++calls_to_flush_tlb_all;
#endif

        local_irq_save(flags);

        /* Flush each ITLB entry */
        for_each_itlb_entry(tlb) {
                __flush_tlb_slot(tlb);
        }

        /* Flush each DTLB entry */
        for_each_dtlb_entry(tlb) {
                __flush_tlb_slot(tlb);
        }

        local_irq_restore(flags);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
        /* FIXME: Optimize this later.. */
        flush_tlb_all();
}

#if defined(CONFIG_SH64_PROC_TLB)
/* Procfs interface to read the performance information */

static int
tlb_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
{
  int len=0;
  len += sprintf(buf+len, "do_fast_page_fault   called %12lld times\n", calls_to_do_fast_page_fault);
  len += sprintf(buf+len, "do_slow_page_fault   called %12lld times\n", calls_to_do_slow_page_fault);
  len += sprintf(buf+len, "update_mmu_cache     called %12lld times\n", calls_to_update_mmu_cache);
  len += sprintf(buf+len, "flush_tlb_page       called %12lld times\n", calls_to_flush_tlb_page);
  len += sprintf(buf+len, "flush_tlb_range      called %12lld times\n", calls_to_flush_tlb_range);
  len += sprintf(buf+len, "flush_tlb_mm         called %12lld times\n", calls_to_flush_tlb_mm);
  len += sprintf(buf+len, "flush_tlb_all        called %12lld times\n", calls_to_flush_tlb_all);
  len += sprintf(buf+len, "flush_tlb_range_sizes\n"
                          " 1      : %12lld\n"
                          " 2      : %12lld\n"
                          " 3 -  4 : %12lld\n"
                          " 5 -  7 : %12lld\n"
                          " 8 - 11 : %12lld\n"
                          "12 - 15 : %12lld\n"
                          "16+     : %12lld\n",
                          flush_tlb_range_1, flush_tlb_range_2, flush_tlb_range_3_4,
                          flush_tlb_range_5_7, flush_tlb_range_8_11, flush_tlb_range_12_15,
                          flush_tlb_range_16_up);
  len += sprintf(buf+len, "page not present           %12lld times\n", page_not_present);
  *eof = 1;
  return len;
}

static int __init register_proc_tlb(void)
{
  create_proc_read_entry("tlb", 0, NULL, tlb_proc_info, NULL);
  return 0;
}

__initcall(register_proc_tlb);

#endif