[linux-block.git] / arch / m32r / mm / fault.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/arch/m32r/mm/fault.c
 *
 *  Copyright (c) 2001, 2002  Hitoshi Yamamoto, and H. Kondo
 *  Copyright (c) 2004  Naoto Sugai, NIIBE Yutaka
 *
 *  Some code taken from i386 version.
 *    Copyright (C) 1995  Linus Torvalds
 */

#include <linux/signal.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/interrupt.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/vt_kern.h>		/* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/extable.h>
#include <linux/uaccess.h>

#include <asm/m32r.h>
#include <asm/hardirq.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>

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

#ifndef CONFIG_SMP
asmlinkage unsigned int tlb_entry_i_dat;
asmlinkage unsigned int tlb_entry_d_dat;
#define tlb_entry_i tlb_entry_i_dat
#define tlb_entry_d tlb_entry_d_dat
#else
unsigned int tlb_entry_i_dat[NR_CPUS];
unsigned int tlb_entry_d_dat[NR_CPUS];
#define tlb_entry_i tlb_entry_i_dat[smp_processor_id()]
#define tlb_entry_d tlb_entry_d_dat[smp_processor_id()]
#endif

extern void init_tlb(void);

/*======================================================================*
 * do_page_fault()
 *======================================================================*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 *
 * ARGUMENT:
 *  regs       : M32R SP reg.
 *  error_code : See below
 *  address    : M32R MMU MDEVA reg. (Operand ACE)
 *             : M32R BPC reg. (Instruction ACE)
 *
 * error_code :
 *  bit 0 == 0 means no page found, 1 means protection fault
 *  bit 1 == 0 means read, 1 means write
 *  bit 2 == 0 means kernel, 1 means user-mode
 *  bit 3 == 0 means data, 1 means instruction
 *======================================================================*/
#define ACE_PROTECTION		1
#define ACE_WRITE		2
#define ACE_USERMODE		4
#define ACE_INSTRUCTION		8

asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code,
  unsigned long address)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	struct vm_area_struct * vma;
	unsigned long page, addr;
	unsigned long flags = 0;
	int fault;
	siginfo_t info;

	/*
	 * If BPSW IE bit enable --> set PSW IE bit
	 */
	if (regs->psw & M32R_PSW_BIE)
		local_irq_enable();

	tsk = current;

	info.si_code = SEGV_MAPERR;

	/*
	 * We fault-in kernel-space virtual memory on-demand. The
	 * 'reference' page table is init_mm.pgd.
	 *
	 * NOTE! We MUST NOT take any locks for this case. We may
	 * be in an interrupt or a critical region, and should
	 * only copy the information from the master page table,
	 * nothing more.
	 *
	 * This verifies that the fault happens in kernel space
	 * (error_code & ACE_USERMODE) == 0, and that the fault was not a
	 * protection error (error_code & ACE_PROTECTION) == 0.
	 */
	if (address >= TASK_SIZE && !(error_code & ACE_USERMODE))
		goto vmalloc_fault;

	mm = tsk->mm;

	/*
	 * If we're in an interrupt or have no user context or have pagefaults
	 * disabled then we must not take the fault.
	 */
	if (faulthandler_disabled() || !mm)
		goto bad_area_nosemaphore;

	if (error_code & ACE_USERMODE)
		flags |= FAULT_FLAG_USER;

	/* When running in the kernel we expect faults to occur only to
	 * addresses in user space.  All other faults represent errors in the
	 * kernel and should generate an OOPS.  Unfortunately, in the case of an
	 * erroneous fault occurring in a code path which already holds mmap_sem
	 * we will deadlock attempting to validate the fault against the
	 * address space.  Luckily the kernel only validly references user
	 * space from well defined areas of code, which are listed in the
	 * exceptions table.
	 *
	 * As the vast majority of faults will be valid we will only perform
	 * the source reference check when there is a possibility of a deadlock.
	 * Attempt to lock the address space, if we cannot we then validate the
	 * source.  If this is invalid we can skip the address space check,
	 * thus avoiding the deadlock.
	 */
	if (!down_read_trylock(&mm->mmap_sem)) {
		if ((error_code & ACE_USERMODE) == 0 &&
		    !search_exception_tables(regs->psw))
			goto bad_area_nosemaphore;
		down_read(&mm->mmap_sem);
	}

	vma = find_vma(mm, address);
	if (!vma)
		goto bad_area;
	if (vma->vm_start <= address)
		goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
		goto bad_area;

	if (error_code & ACE_USERMODE) {
		/*
		 * accessing the stack below "spu" is always a bug.
		 * The "+ 4" is there due to the push instruction
		 * doing pre-decrement on the stack and that
		 * doesn't show up until later..
		 */
		if (address + 4 < regs->spu)
			goto bad_area;
	}

	if (expand_stack(vma, address))
		goto bad_area;
/*
 * Ok, we have a good vm_area for this memory access, so
 * we can handle it..
 */
good_area:
	info.si_code = SEGV_ACCERR;
	switch (error_code & (ACE_WRITE|ACE_PROTECTION)) {
		default:	/* 3: write, present */
			/* fall through */
		case ACE_WRITE:	/* write, not present */
			if (!(vma->vm_flags & VM_WRITE))
				goto bad_area;
			flags |= FAULT_FLAG_WRITE;
			break;
		case ACE_PROTECTION:	/* read, present */
		case 0:		/* read, not present */
			if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
				goto bad_area;
	}

	/*
	 * For instruction access exception, check if the area is executable
	 */
	if ((error_code & ACE_INSTRUCTION) && !(vma->vm_flags & VM_EXEC))
	  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.
	 */
	addr = (address & PAGE_MASK);
	set_thread_fault_code(error_code);
	fault = handle_mm_fault(vma, addr, flags);
	if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM)
			goto out_of_memory;
		else if (fault & VM_FAULT_SIGSEGV)
			goto bad_area;
		else if (fault & VM_FAULT_SIGBUS)
			goto do_sigbus;
		BUG();
	}
	if (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;
	set_thread_fault_code(0);
	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:
	up_read(&mm->mmap_sem);

bad_area_nosemaphore:
	/* User mode accesses just cause a SIGSEGV */
	if (error_code & ACE_USERMODE) {
		tsk->thread.address = address;
		tsk->thread.error_code = error_code | (address >= TASK_SIZE);
		tsk->thread.trap_no = 14;
		info.si_signo = SIGSEGV;
		info.si_errno = 0;
		/* info.si_code has been set above */
		info.si_addr = (void __user *)address;
		force_sig_info(SIGSEGV, &info, tsk);
		return;
	}

no_context:
	/* Are we prepared to handle this kernel fault?  */
	if (fixup_exception(regs))
		return;

/*
 * Oops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 */

	bust_spinlocks(1);

	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 " printing bpc:\n");
	printk("%08lx\n", regs->bpc);
	page = *(unsigned long *)MPTB;
	page = ((unsigned long *) page)[address >> PGDIR_SHIFT];
	printk(KERN_ALERT "*pde = %08lx\n", page);
	if (page & _PAGE_PRESENT) {
		page &= PAGE_MASK;
		address &= 0x003ff000;
		page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
		printk(KERN_ALERT "*pte = %08lx\n", page);
	}
	die("Oops", regs, error_code);
	bust_spinlocks(0);
	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:
	up_read(&mm->mmap_sem);
	if (!(error_code & ACE_USERMODE))
		goto no_context;
	pagefault_out_of_memory();
	return;

do_sigbus:
	up_read(&mm->mmap_sem);

	/* Kernel mode? Handle exception or die */
	if (!(error_code & ACE_USERMODE))
		goto no_context;

	tsk->thread.address = address;
	tsk->thread.error_code = error_code;
	tsk->thread.trap_no = 14;
	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code = BUS_ADRERR;
	info.si_addr = (void __user *)address;
	force_sig_info(SIGBUS, &info, tsk);
	return;

vmalloc_fault:
	{
		/*
		 * Synchronize this task's top level page-table
		 * with the 'reference' page table.
		 *
		 * Do _not_ use "tsk" here. We might be inside
		 * an interrupt in the middle of a task switch..
		 */
		int offset = pgd_index(address);
		pgd_t *pgd, *pgd_k;
		pmd_t *pmd, *pmd_k;
		pte_t *pte_k;

		pgd = (pgd_t *)*(unsigned long *)MPTB;
		pgd = offset + (pgd_t *)pgd;
		pgd_k = init_mm.pgd + offset;

		if (!pgd_present(*pgd_k))
			goto no_context;

		/*
		 * set_pgd(pgd, *pgd_k); here would be useless on PAE
		 * and redundant with the set_pmd() on non-PAE.
		 */

		pmd = pmd_offset(pgd, address);
		pmd_k = pmd_offset(pgd_k, address);
		if (!pmd_present(*pmd_k))
			goto no_context;
		set_pmd(pmd, *pmd_k);

		pte_k = pte_offset_kernel(pmd_k, address);
		if (!pte_present(*pte_k))
			goto no_context;

		addr = (address & PAGE_MASK);
		set_thread_fault_code(error_code);
		update_mmu_cache(NULL, addr, pte_k);
		set_thread_fault_code(0);
		return;
	}
}

/*======================================================================*
 * update_mmu_cache()
 *======================================================================*/
#define TLB_MASK	(NR_TLB_ENTRIES - 1)
#define ITLB_END	(unsigned long *)(ITLB_BASE + (NR_TLB_ENTRIES * 8))
#define DTLB_END	(unsigned long *)(DTLB_BASE + (NR_TLB_ENTRIES * 8))
void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr,
	pte_t *ptep)
{
	volatile unsigned long *entry1, *entry2;
	unsigned long pte_data, flags;
	unsigned int *entry_dat;
	int inst = get_thread_fault_code() & ACE_INSTRUCTION;
	int i;

	/* Ptrace may call this routine. */
	if (vma && current->active_mm != vma->vm_mm)
		return;

	local_irq_save(flags);

	vaddr = (vaddr & PAGE_MASK) | get_asid();

	pte_data = pte_val(*ptep);

#ifdef CONFIG_CHIP_OPSP
	entry1 = (unsigned long *)ITLB_BASE;
	for (i = 0; i < NR_TLB_ENTRIES; i++) {
		if (*entry1++ == vaddr) {
			set_tlb_data(entry1, pte_data);
			break;
		}
		entry1++;
	}
	entry2 = (unsigned long *)DTLB_BASE;
	for (i = 0; i < NR_TLB_ENTRIES; i++) {
		if (*entry2++ == vaddr) {
			set_tlb_data(entry2, pte_data);
			break;
		}
		entry2++;
	}
#else
	/*
	 * Update TLB entries
	 *  entry1: ITLB entry address
	 *  entry2: DTLB entry address
	 */
	__asm__ __volatile__ (
		"seth	%0, #high(%4)	\n\t"
		"st	%2, @(%5, %0)	\n\t"
		"ldi	%1, #1		\n\t"
		"st	%1, @(%6, %0)	\n\t"
		"add3	r4, %0, %7	\n\t"
		".fillinsn		\n"
		"1:			\n\t"
		"ld	%1, @(%6, %0)	\n\t"
		"bnez	%1, 1b		\n\t"
		"ld	%0, @r4+	\n\t"
		"ld	%1, @r4		\n\t"
		"st	%3, @+%0	\n\t"
		"st	%3, @+%1	\n\t"
		: "=&r" (entry1), "=&r" (entry2)
		: "r" (vaddr), "r" (pte_data), "i" (MMU_REG_BASE),
		"i" (MSVA_offset), "i" (MTOP_offset), "i" (MIDXI_offset)
		: "r4", "memory"
	);
#endif

	if ((!inst && entry2 >= DTLB_END) || (inst && entry1 >= ITLB_END))
		goto notfound;

found:
	local_irq_restore(flags);

	return;

	/* Valid entry not found */
notfound:
	/*
	 * Update ITLB or DTLB entry
	 *  entry1: TLB entry address
	 *  entry2: TLB base address
	 */
	if (!inst) {
		entry2 = (unsigned long *)DTLB_BASE;
		entry_dat = &tlb_entry_d;
	} else {
		entry2 = (unsigned long *)ITLB_BASE;
		entry_dat = &tlb_entry_i;
	}
	entry1 = entry2 + (((*entry_dat - 1) & TLB_MASK) << 1);

	for (i = 0 ; i < NR_TLB_ENTRIES ; i++) {
		if (!(entry1[1] & 2))	/* Valid bit check */
			break;

		if (entry1 != entry2)
			entry1 -= 2;
		else
			entry1 += TLB_MASK << 1;
	}

	if (i >= NR_TLB_ENTRIES) {	/* Empty entry not found */
		entry1 = entry2 + (*entry_dat << 1);
		*entry_dat = (*entry_dat + 1) & TLB_MASK;
	}
	*entry1++ = vaddr;	/* Set TLB tag */
	set_tlb_data(entry1, pte_data);

	goto found;
}

/*======================================================================*
 * flush_tlb_page() : flushes one page
 *======================================================================*/
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
	if (vma->vm_mm && mm_context(vma->vm_mm) != NO_CONTEXT) {
		unsigned long flags;

		local_irq_save(flags);
		page &= PAGE_MASK;
		page |= (mm_context(vma->vm_mm) & MMU_CONTEXT_ASID_MASK);
		__flush_tlb_page(page);
		local_irq_restore(flags);
	}
}

/*======================================================================*
 * flush_tlb_range() : flushes a range of pages
 *======================================================================*/
void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
	unsigned long end)
{
	struct mm_struct *mm;

	mm = vma->vm_mm;
	if (mm_context(mm) != NO_CONTEXT) {
		unsigned long flags;
		int size;

		local_irq_save(flags);
		size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
		if (size > (NR_TLB_ENTRIES / 4)) { /* Too many TLB to flush */
			mm_context(mm) = NO_CONTEXT;
			if (mm == current->mm)
				activate_context(mm);
		} else {
			unsigned long asid;

			asid = mm_context(mm) & MMU_CONTEXT_ASID_MASK;
			start &= PAGE_MASK;
			end += (PAGE_SIZE - 1);
			end &= PAGE_MASK;

			start |= asid;
			end   |= asid;
			while (start < end) {
				__flush_tlb_page(start);
				start += PAGE_SIZE;
			}
		}
		local_irq_restore(flags);
	}
}

/*======================================================================*
 * flush_tlb_mm() : flushes the specified mm context TLB's
 *======================================================================*/
void local_flush_tlb_mm(struct mm_struct *mm)
{
	/* Invalidate all TLB of this process. */
	/* Instead of invalidating each TLB, we get new MMU context. */
	if (mm_context(mm) != NO_CONTEXT) {
		unsigned long flags;

		local_irq_save(flags);
		mm_context(mm) = NO_CONTEXT;
		if (mm == current->mm)
			activate_context(mm);
		local_irq_restore(flags);
	}
}

/*======================================================================*
 * flush_tlb_all() : flushes all processes TLBs
 *======================================================================*/
void local_flush_tlb_all(void)
{
	unsigned long flags;

	local_irq_save(flags);
	__flush_tlb_all();
	local_irq_restore(flags);
}

/*======================================================================*
 * init_mmu()
 *======================================================================*/
void __init init_mmu(void)
{
	tlb_entry_i = 0;
	tlb_entry_d = 0;
	mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
	set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
	*(volatile unsigned long *)MPTB = (unsigned long)swapper_pg_dir;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/arch/m32r/mm/fault.c
	4	*
	5	* Copyright (c) 2001, 2002 Hitoshi Yamamoto, and H. Kondo
	6	* Copyright (c) 2004 Naoto Sugai, NIIBE Yutaka
	7	*
	8	* Some code taken from i386 version.
	9	* Copyright (C) 1995 Linus Torvalds
	10	*/
	11
1da177e4 LT	12	#include <linux/signal.h>
	13	#include <linux/sched.h>
	14	#include <linux/kernel.h>
	15	#include <linux/errno.h>
	16	#include <linux/string.h>
	17	#include <linux/types.h>
	18	#include <linux/ptrace.h>
	19	#include <linux/mman.h>
	20	#include <linux/mm.h>
	21	#include <linux/smp.h>
1da177e4 LT	22	#include <linux/interrupt.h>
	23	#include <linux/init.h>
	24	#include <linux/tty.h>
	25	#include <linux/vt_kern.h> /* For unblank_screen() */
	26	#include <linux/highmem.h>
ae26cdae	27	#include <linux/extable.h>
70ffdb93	28	#include <linux/uaccess.h>
1da177e4 LT	29
1da177e4 LT	30	#include <asm/m32r.h>
1da177e4 LT	31	#include <asm/hardirq.h>
	32	#include <asm/mmu_context.h>
	33	#include <asm/tlbflush.h>
	34
	35	extern void die(const char , struct pt_regs , long);
	36
	37	#ifndef CONFIG_SMP
	38	asmlinkage unsigned int tlb_entry_i_dat;
	39	asmlinkage unsigned int tlb_entry_d_dat;
	40	#define tlb_entry_i tlb_entry_i_dat
	41	#define tlb_entry_d tlb_entry_d_dat
	42	#else
	43	unsigned int tlb_entry_i_dat[NR_CPUS];
	44	unsigned int tlb_entry_d_dat[NR_CPUS];
	45	#define tlb_entry_i tlb_entry_i_dat[smp_processor_id()]
	46	#define tlb_entry_d tlb_entry_d_dat[smp_processor_id()]
	47	#endif
	48
	49	extern void init_tlb(void);
	50
1da177e4 LT	51	/======================================================================
	52	* do_page_fault()
	53	======================================================================
	54	* This routine handles page faults. It determines the address,
	55	* and the problem, and then passes it off to one of the appropriate
	56	* routines.
	57	*
	58	* ARGUMENT:
	59	* regs : M32R SP reg.
	60	* error_code : See below
	61	* address : M32R MMU MDEVA reg. (Operand ACE)
	62	* : M32R BPC reg. (Instruction ACE)
	63	*
	64	* error_code :
	65	* bit 0 == 0 means no page found, 1 means protection fault
	66	* bit 1 == 0 means read, 1 means write
	67	* bit 2 == 0 means kernel, 1 means user-mode
	68	* bit 3 == 0 means data, 1 means instruction
	69	======================================================================/
	70	#define ACE_PROTECTION 1
	71	#define ACE_WRITE 2
	72	#define ACE_USERMODE 4
	73	#define ACE_INSTRUCTION 8
	74
	75	asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code,
	76	unsigned long address)
	77	{
	78	struct task_struct *tsk;
	79	struct mm_struct *mm;
	80	struct vm_area_struct * vma;
	81	unsigned long page, addr;
759496ba	82	unsigned long flags = 0;
83c54070	83	int fault;
1da177e4 LT	84	siginfo_t info;
	85
	86	/*
	87	* If BPSW IE bit enable --> set PSW IE bit
	88	*/
	89	if (regs->psw & M32R_PSW_BIE)
	90	local_irq_enable();
	91
	92	tsk = current;
	93
	94	info.si_code = SEGV_MAPERR;
	95
	96	/*
	97	* We fault-in kernel-space virtual memory on-demand. The
	98	* 'reference' page table is init_mm.pgd.
	99	*
	100	* NOTE! We MUST NOT take any locks for this case. We may
	101	* be in an interrupt or a critical region, and should
	102	* only copy the information from the master page table,
	103	* nothing more.
	104	*
	105	* This verifies that the fault happens in kernel space
	106	* (error_code & ACE_USERMODE) == 0, and that the fault was not a
	107	* protection error (error_code & ACE_PROTECTION) == 0.
	108	*/
	109	if (address >= TASK_SIZE && !(error_code & ACE_USERMODE))
	110	goto vmalloc_fault;
	111
	112	mm = tsk->mm;
	113
	114	/*
70ffdb93 DH	115	* If we're in an interrupt or have no user context or have pagefaults
70ffdb93 DH	116	* disabled then we must not take the fault.
1da177e4	117	*/
70ffdb93	118	if (faulthandler_disabled() \|\| !mm)
1da177e4 LT	119	goto bad_area_nosemaphore;
1da177e4 LT	120
759496ba JW	121	if (error_code & ACE_USERMODE)
	122	flags \|= FAULT_FLAG_USER;
	123
1da177e4 LT	124	/* When running in the kernel we expect faults to occur only to
1da177e4 LT	125	* addresses in user space. All other faults represent errors in the
25985edc	126	* kernel and should generate an OOPS. Unfortunately, in the case of an
80f7228b	127	* erroneous fault occurring in a code path which already holds mmap_sem
1da177e4 LT	128	* we will deadlock attempting to validate the fault against the
	129	* address space. Luckily the kernel only validly references user
	130	* space from well defined areas of code, which are listed in the
	131	* exceptions table.
	132	*
	133	* As the vast majority of faults will be valid we will only perform
25985edc	134	* the source reference check when there is a possibility of a deadlock.
1da177e4 LT	135	* Attempt to lock the address space, if we cannot we then validate the
	136	* source. If this is invalid we can skip the address space check,
	137	* thus avoiding the deadlock.
	138	*/
	139	if (!down_read_trylock(&mm->mmap_sem)) {
	140	if ((error_code & ACE_USERMODE) == 0 &&
	141	!search_exception_tables(regs->psw))
	142	goto bad_area_nosemaphore;
	143	down_read(&mm->mmap_sem);
	144	}
	145
	146	vma = find_vma(mm, address);
	147	if (!vma)
	148	goto bad_area;
	149	if (vma->vm_start <= address)
	150	goto good_area;
	151	if (!(vma->vm_flags & VM_GROWSDOWN))
	152	goto bad_area;
6b8bd3f4	153
1da177e4 LT	154	if (error_code & ACE_USERMODE) {
	155	/*
	156	* accessing the stack below "spu" is always a bug.
	157	* The "+ 4" is there due to the push instruction
	158	* doing pre-decrement on the stack and that
	159	* doesn't show up until later..
	160	*/
	161	if (address + 4 < regs->spu)
	162	goto bad_area;
	163	}
6b8bd3f4	164
1da177e4 LT	165	if (expand_stack(vma, address))
	166	goto bad_area;
	167	/*
	168	* Ok, we have a good vm_area for this memory access, so
	169	* we can handle it..
	170	*/
	171	good_area:
	172	info.si_code = SEGV_ACCERR;
1da177e4 LT	173	switch (error_code & (ACE_WRITE\|ACE_PROTECTION)) {
	174	default: /* 3: write, present */
	175	/* fall through */
	176	case ACE_WRITE: /* write, not present */
	177	if (!(vma->vm_flags & VM_WRITE))
	178	goto bad_area;
759496ba	179	flags \|= FAULT_FLAG_WRITE;
1da177e4 LT	180	break;
	181	case ACE_PROTECTION: /* read, present */
	182	case 0: /* read, not present */
	183	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	184	goto bad_area;
	185	}
	186
	187	/*
	188	* For instruction access exception, check if the area is executable
	189	*/
	190	if ((error_code & ACE_INSTRUCTION) && !(vma->vm_flags & VM_EXEC))
	191	goto bad_area;
	192
1da177e4 LT	193	/*
	194	* If for any reason at all we couldn't handle the fault,
	195	* make sure we exit gracefully rather than endlessly redo
	196	* the fault.
	197	*/
	198	addr = (address & PAGE_MASK);
	199	set_thread_fault_code(error_code);
dcddffd4	200	fault = handle_mm_fault(vma, addr, flags);
83c54070 NP	201	if (unlikely(fault & VM_FAULT_ERROR)) {
83c54070 NP	202	if (fault & VM_FAULT_OOM)
1da177e4	203	goto out_of_memory;
33692f27 LT	204	else if (fault & VM_FAULT_SIGSEGV)
33692f27 LT	205	goto bad_area;
83c54070 NP	206	else if (fault & VM_FAULT_SIGBUS)
	207	goto do_sigbus;
	208	BUG();
1da177e4	209	}
83c54070 NP	210	if (fault & VM_FAULT_MAJOR)
	211	tsk->maj_flt++;
	212	else
	213	tsk->min_flt++;
1da177e4 LT	214	set_thread_fault_code(0);
	215	up_read(&mm->mmap_sem);
	216	return;
	217
	218	/*
	219	* Something tried to access memory that isn't in our memory map..
	220	* Fix it, but check if it's kernel or user first..
	221	*/
	222	bad_area:
	223	up_read(&mm->mmap_sem);
	224
	225	bad_area_nosemaphore:
	226	/* User mode accesses just cause a SIGSEGV */
	227	if (error_code & ACE_USERMODE) {
	228	tsk->thread.address = address;
	229	tsk->thread.error_code = error_code \| (address >= TASK_SIZE);
	230	tsk->thread.trap_no = 14;
	231	info.si_signo = SIGSEGV;
	232	info.si_errno = 0;
	233	/* info.si_code has been set above */
	234	info.si_addr = (void __user *)address;
	235	force_sig_info(SIGSEGV, &info, tsk);
	236	return;
	237	}
	238
	239	no_context:
	240	/* Are we prepared to handle this kernel fault? */
	241	if (fixup_exception(regs))
	242	return;
	243
	244	/*
	245	* Oops. The kernel tried to access some bad page. We'll have to
	246	* terminate things with extreme prejudice.
	247	*/
	248
	249	bust_spinlocks(1);
	250
	251	if (address < PAGE_SIZE)
	252	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	253	else
	254	printk(KERN_ALERT "Unable to handle kernel paging request");
	255	printk(" at virtual address %08lx\n",address);
	256	printk(KERN_ALERT " printing bpc:\n");
	257	printk("%08lx\n", regs->bpc);
	258	page = (unsigned long )MPTB;
	259	page = ((unsigned long *) page)[address >> PGDIR_SHIFT];
	260	printk(KERN_ALERT "*pde = %08lx\n", page);
	261	if (page & _PAGE_PRESENT) {
	262	page &= PAGE_MASK;
	263	address &= 0x003ff000;
	264	page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
	265	printk(KERN_ALERT "*pte = %08lx\n", page);
	266	}
	267	die("Oops", regs, error_code);
	268	bust_spinlocks(0);
	269	do_exit(SIGKILL);
	270
	271	/*
	272	* We ran out of memory, or some other thing happened to us that made
	273	* us unable to handle the page fault gracefully.
	274	*/
	275	out_of_memory:
	276	up_read(&mm->mmap_sem);
68db30ce NP	277	if (!(error_code & ACE_USERMODE))
	278	goto no_context;
	279	pagefault_out_of_memory();
	280	return;
1da177e4 LT	281
	282	do_sigbus:
	283	up_read(&mm->mmap_sem);
	284
	285	/* Kernel mode? Handle exception or die */
	286	if (!(error_code & ACE_USERMODE))
	287	goto no_context;
	288
	289	tsk->thread.address = address;
	290	tsk->thread.error_code = error_code;
	291	tsk->thread.trap_no = 14;
	292	info.si_signo = SIGBUS;
	293	info.si_errno = 0;
	294	info.si_code = BUS_ADRERR;
	295	info.si_addr = (void __user *)address;
	296	force_sig_info(SIGBUS, &info, tsk);
	297	return;
	298
	299	vmalloc_fault:
	300	{
	301	/*
	302	* Synchronize this task's top level page-table
	303	* with the 'reference' page table.
	304	*
	305	* Do _not_ use "tsk" here. We might be inside
	306	* an interrupt in the middle of a task switch..
	307	*/
	308	int offset = pgd_index(address);
	309	pgd_t pgd, pgd_k;
	310	pmd_t pmd, pmd_k;
	311	pte_t *pte_k;
	312
	313	pgd = (pgd_t )(unsigned long *)MPTB;
	314	pgd = offset + (pgd_t *)pgd;
	315	pgd_k = init_mm.pgd + offset;
	316
	317	if (!pgd_present(*pgd_k))
	318	goto no_context;
	319
	320	/*
	321	* set_pgd(pgd, *pgd_k); here would be useless on PAE
	322	* and redundant with the set_pmd() on non-PAE.
	323	*/
	324
	325	pmd = pmd_offset(pgd, address);
	326	pmd_k = pmd_offset(pgd_k, address);
	327	if (!pmd_present(*pmd_k))
	328	goto no_context;
	329	set_pmd(pmd, *pmd_k);
	330
	331	pte_k = pte_offset_kernel(pmd_k, address);
	332	if (!pte_present(*pte_k))
	333	goto no_context;
	334
9b87ed79 HT	335	addr = (address & PAGE_MASK);
9b87ed79 HT	336	set_thread_fault_code(error_code);
4b3073e1	337	update_mmu_cache(NULL, addr, pte_k);
9b87ed79	338	set_thread_fault_code(0);
1da177e4 LT	339	return;
	340	}
	341	}
	342
	343	/======================================================================
	344	* update_mmu_cache()
	345	======================================================================/
	346	#define TLB_MASK (NR_TLB_ENTRIES - 1)
	347	#define ITLB_END (unsigned long )(ITLB_BASE + (NR_TLB_ENTRIES 8))
	348	#define DTLB_END (unsigned long )(DTLB_BASE + (NR_TLB_ENTRIES 8))
	349	void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr,
4b3073e1	350	pte_t *ptep)
1da177e4	351	{
9b87ed79	352	volatile unsigned long entry1, entry2;
1da177e4 LT	353	unsigned long pte_data, flags;
	354	unsigned int *entry_dat;
	355	int inst = get_thread_fault_code() & ACE_INSTRUCTION;
	356	int i;
	357
	358	/* Ptrace may call this routine. */
	359	if (vma && current->active_mm != vma->vm_mm)
	360	return;
	361
	362	local_irq_save(flags);
	363
	364	vaddr = (vaddr & PAGE_MASK) \| get_asid();
	365
4b3073e1	366	pte_data = pte_val(*ptep);
9b87ed79	367
1da177e4 LT	368	#ifdef CONFIG_CHIP_OPSP
1da177e4 LT	369	entry1 = (unsigned long *)ITLB_BASE;
9b87ed79 HT	370	for (i = 0; i < NR_TLB_ENTRIES; i++) {
	371	if (*entry1++ == vaddr) {
	372	set_tlb_data(entry1, pte_data);
	373	break;
	374	}
	375	entry1++;
1da177e4 LT	376	}
1da177e4 LT	377	entry2 = (unsigned long *)DTLB_BASE;
9b87ed79 HT	378	for (i = 0; i < NR_TLB_ENTRIES; i++) {
	379	if (*entry2++ == vaddr) {
	380	set_tlb_data(entry2, pte_data);
	381	break;
	382	}
	383	entry2++;
1da177e4	384	}
1da177e4	385	#else
1da177e4 LT	386	/*
	387	* Update TLB entries
	388	* entry1: ITLB entry address
	389	* entry2: DTLB entry address
	390	*/
	391	__asm__ __volatile__ (
	392	"seth %0, #high(%4) \n\t"
	393	"st %2, @(%5, %0) \n\t"
	394	"ldi %1, #1 \n\t"
	395	"st %1, @(%6, %0) \n\t"
	396	"add3 r4, %0, %7 \n\t"
	397	".fillinsn \n"
	398	"1: \n\t"
	399	"ld %1, @(%6, %0) \n\t"
	400	"bnez %1, 1b \n\t"
	401	"ld %0, @r4+ \n\t"
	402	"ld %1, @r4 \n\t"
	403	"st %3, @+%0 \n\t"
	404	"st %3, @+%1 \n\t"
	405	: "=&r" (entry1), "=&r" (entry2)
	406	: "r" (vaddr), "r" (pte_data), "i" (MMU_REG_BASE),
	407	"i" (MSVA_offset), "i" (MTOP_offset), "i" (MIDXI_offset)
	408	: "r4", "memory"
	409	);
9b87ed79	410	#endif
1da177e4 LT	411
	412	if ((!inst && entry2 >= DTLB_END) \|\| (inst && entry1 >= ITLB_END))
	413	goto notfound;
	414
	415	found:
	416	local_irq_restore(flags);
	417
	418	return;
	419
	420	/* Valid entry not found */
	421	notfound:
	422	/*
	423	* Update ITLB or DTLB entry
	424	* entry1: TLB entry address
	425	* entry2: TLB base address
	426	*/
	427	if (!inst) {
	428	entry2 = (unsigned long *)DTLB_BASE;
	429	entry_dat = &tlb_entry_d;
	430	} else {
	431	entry2 = (unsigned long *)ITLB_BASE;
	432	entry_dat = &tlb_entry_i;
	433	}
	434	entry1 = entry2 + (((*entry_dat - 1) & TLB_MASK) << 1);
	435
	436	for (i = 0 ; i < NR_TLB_ENTRIES ; i++) {
	437	if (!(entry1[1] & 2)) /* Valid bit check */
	438	break;
	439
	440	if (entry1 != entry2)
	441	entry1 -= 2;
	442	else
	443	entry1 += TLB_MASK << 1;
	444	}
	445
	446	if (i >= NR_TLB_ENTRIES) { /* Empty entry not found */
	447	entry1 = entry2 + (*entry_dat << 1);
	448	entry_dat = (entry_dat + 1) & TLB_MASK;
	449	}
	450	entry1++ = vaddr; / Set TLB tag */
	451	set_tlb_data(entry1, pte_data);
	452
	453	goto found;
1da177e4 LT	454	}
	455
	456	/======================================================================
	457	* flush_tlb_page() : flushes one page
	458	======================================================================/
	459	void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
	460	{
	461	if (vma->vm_mm && mm_context(vma->vm_mm) != NO_CONTEXT) {
	462	unsigned long flags;
	463
	464	local_irq_save(flags);
	465	page &= PAGE_MASK;
	466	page \|= (mm_context(vma->vm_mm) & MMU_CONTEXT_ASID_MASK);
	467	__flush_tlb_page(page);
	468	local_irq_restore(flags);
	469	}
	470	}
	471
	472	/======================================================================
	473	* flush_tlb_range() : flushes a range of pages
	474	======================================================================/
	475	void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
	476	unsigned long end)
	477	{
	478	struct mm_struct *mm;
	479
	480	mm = vma->vm_mm;
	481	if (mm_context(mm) != NO_CONTEXT) {
	482	unsigned long flags;
	483	int size;
	484
	485	local_irq_save(flags);
	486	size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
	487	if (size > (NR_TLB_ENTRIES / 4)) { /* Too many TLB to flush */
	488	mm_context(mm) = NO_CONTEXT;
	489	if (mm == current->mm)
	490	activate_context(mm);
	491	} else {
	492	unsigned long asid;
	493
	494	asid = mm_context(mm) & MMU_CONTEXT_ASID_MASK;
	495	start &= PAGE_MASK;
	496	end += (PAGE_SIZE - 1);
	497	end &= PAGE_MASK;
	498
	499	start \|= asid;
	500	end \|= asid;
	501	while (start < end) {
	502	__flush_tlb_page(start);
	503	start += PAGE_SIZE;
	504	}
	505	}
	506	local_irq_restore(flags);
	507	}
	508	}
	509
	510	/======================================================================
	511	* flush_tlb_mm() : flushes the specified mm context TLB's
	512	======================================================================/
	513	void local_flush_tlb_mm(struct mm_struct *mm)
	514	{
	515	/* Invalidate all TLB of this process. */
	516	/* Instead of invalidating each TLB, we get new MMU context. */
	517	if (mm_context(mm) != NO_CONTEXT) {
518	unsigned long flags;
519
520	local_irq_save(flags);
521	mm_context(mm) = NO_CONTEXT;
522	if (mm == current->mm)
523	activate_context(mm);
524	local_irq_restore(flags);
525	}
526	}
527
528	/======================================================================
529	* flush_tlb_all() : flushes all processes TLBs
530	======================================================================/
531	void local_flush_tlb_all(void)
532	{
533	unsigned long flags;
534
535	local_irq_save(flags);
536	__flush_tlb_all();
537	local_irq_restore(flags);
538	}
539
540	/======================================================================
541	* init_mmu()
542	======================================================================/
543	void __init init_mmu(void)
544	{
545	tlb_entry_i = 0;
546	tlb_entry_d = 0;
547	mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
548	set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
549	(volatile unsigned long )MPTB = (unsigned long)swapper_pg_dir;
550	}