fault.c

来自「linux 内核源代码」· C语言 代码 · 共 603 行 · 第 1/2 页

/*
 * 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 (is_global_init(current)) {
		panic("INIT out of memory\n");
		yield();
		goto survive;
	}
	printk("fault:Out of memory\n");
	up_read(&mm->mmap_sem);
	if (is_global_init(current)) {
		yield();
		down_read(&mm->mmap_sem);
		goto survive;
	}
	printk("VM: killing process %s\n", tsk->comm);
	if (user_mode(regs))
		do_group_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