arch/frv/mm/fault.c - kernel/prism - Git at Google

 /*
  *  linux/arch/frv/mm/fault.c
  *
  * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
  * - Written by David Howells (dhowells@redhat.com)
  * - Derived from arch/m68knommu/mm/fault.c
  *   - Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
  *   - Copyright (C) 2000  Lineo, Inc.  (www.lineo.com)
  *
  *  Based on:
  *
  *  linux/arch/m68k/mm/fault.c
  *
  *  Copyright (C) 1995  Hamish Macdonald
  */

 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
 #include <linux/hardirq.h>

 #include <asm/system.h>
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/gdb-stub.h>

 /*****************************************************************************/
 /*
  * This routine handles page faults.  It determines the problem, and
  * then passes it off to one of the appropriate routines.
  */
 asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm;
 	unsigned long _pme, lrai, lrad, fixup;
 	siginfo_t info;
 	pgd_t *pge;
 	pud_t *pue;
 	pte_t *pte;
 	int write;
 	int fault;

 #if 0
 	const char *atxc[16] = {
 		[0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
 		[0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
 	};

 	printk("do_page_fault(%d,%lx [%s],%lx)\n",
 	       datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
 #endif

 	mm = current->mm;

 	/*
 	 * 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
 	 * and that the fault was a page not present (invalid) error
 	 */
 	if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
 		if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
 			goto kernel_pte_fault;
 		if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
 			goto kernel_pte_fault;
 	}

 	info.si_code = SEGV_MAPERR;

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

 	down_read(&mm->mmap_sem);

 	vma = find_vma(mm, ear0);
 	if (!vma)
 		goto bad_area;
 	if (vma->vm_start <= ear0)
 		goto good_area;
 	if (!(vma->vm_flags & VM_GROWSDOWN))
 		goto bad_area;

 	if (user_mode(__frame)) {
 		/*
 		 * accessing the stack below %esp is always a bug.
 		 * The "+ 32" is there due to some instructions (like
 		 * pusha) doing post-decrement on the stack and that
 		 * doesn't show up until later..
 		 */
 		if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
 #if 0
 			printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
 			       current->pid, ear0, __frame->sp);
 			show_registers(__frame);
 			printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
 			       current->pid,
 			       __frame->pc,
 			       ((u8*)__frame->pc)[0],
 			       ((u8*)__frame->pc)[1],
 			       ((u8*)__frame->pc)[2],
 			       ((u8*)__frame->pc)[3],
 			       ((u8*)__frame->pc)[4],
 			       ((u8*)__frame->pc)[5],
 			       ((u8*)__frame->pc)[6],
 			       ((u8*)__frame->pc)[7]
 			       );
 #endif
 			goto bad_area;
 		}
 	}

 	if (expand_stack(vma, ear0))
 		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;
 	write = 0;
 	switch (esr0 & ESR0_ATXC) {
 	default:
 		/* handle write to write protected page */
 	case ESR0_ATXC_WP_EXCEP:
 #ifdef TEST_VERIFY_AREA
 		if (!(user_mode(__frame)))
 			printk("WP fault at %08lx\n", __frame->pc);
 #endif
 		if (!(vma->vm_flags & VM_WRITE))
 			goto bad_area;
 		write = 1;
 		break;

 		 /* handle read from protected page */
 	case ESR0_ATXC_PRIV_EXCEP:
 		goto bad_area;

 		 /* handle read, write or exec on absent page
 		  * - can't support write without permitting read
 		  * - don't support execute without permitting read and vice-versa
 		  */
 	case ESR0_ATXC_AMRTLB_MISS:
 		if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
 			goto bad_area;
 		break;
 	}

 	/*
 	 * If for any reason at all we couldn't handle the fault,
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
 	fault = handle_mm_fault(mm, vma, ear0, write ? FAULT_FLAG_WRITE : 0);
 	if (unlikely(fault & VM_FAULT_ERROR)) {
 		if (fault & VM_FAULT_OOM)
 			goto out_of_memory;
 		else if (fault & VM_FAULT_SIGBUS)
 			goto do_sigbus;
 		BUG();
 	}
 	if (fault & VM_FAULT_MAJOR)
 		current->maj_flt++;
 	else
 		current->min_flt++;

 	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);

 	/* User mode accesses just cause a SIGSEGV */
 	if (user_mode(__frame)) {
 		info.si_signo = SIGSEGV;
 		info.si_errno = 0;
 		/* info.si_code has been set above */
 		info.si_addr = (void *) ear0;
 		force_sig_info(SIGSEGV, &info, current);
 		return;
 	}

  no_context:
 	/* are we prepared to handle this kernel fault? */
 	if ((fixup = search_exception_table(__frame->pc)) != 0) {
 		__frame->pc = fixup;
 		return;
 	}

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

 	bust_spinlocks(1);

 	if (ear0 < 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 addr %08lx\n", ear0);
 	printk("  PC  : %08lx\n", __frame->pc);
 	printk("  EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);

 	asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
 	asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));

 	printk(KERN_ALERT "  LRAI: %08lx\n", lrai);
 	printk(KERN_ALERT "  LRAD: %08lx\n", lrad);

 	__break_hijack_kernel_event();

 	pge = pgd_offset(current->mm, ear0);
 	pue = pud_offset(pge, ear0);
 	_pme = pue->pue[0].ste[0];

 	printk(KERN_ALERT "  PGE : %8p { PME %08lx }\n", pge, _pme);

 	if (_pme & xAMPRx_V) {
 		unsigned long dampr, damlr, val;

 		asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
 			     : "=&r"(dampr), "=r"(damlr)
 			     : "r" (_pme | xAMPRx_L|xAMPRx_SS_16Kb|xAMPRx_S|xAMPRx_C|xAMPRx_V)
 			     );

 		pte = (pte_t *) damlr + __pte_index(ear0);
 		val = pte_val(*pte);

 		asm volatile("movgs %0,dampr2" :: "r" (dampr));

 		printk(KERN_ALERT "  PTE : %8p { %08lx }\n", pte, val);
 	}

 	die_if_kernel("Oops\n");
 	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);
 	printk("VM: killing process %s\n", current->comm);
 	if (user_mode(__frame))
 		do_group_exit(SIGKILL);
 	goto no_context;

  do_sigbus:
 	up_read(&mm->mmap_sem);

 	/*
 	 * Send a sigbus, regardless of whether we were in kernel
 	 * or user mode.
 	 */
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRERR;
 	info.si_addr = (void *) ear0;
 	force_sig_info(SIGBUS, &info, current);

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

 /*
  * The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
  */
  kernel_pte_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 index = pgd_index(ear0);
 		pgd_t *pgd, *pgd_k;
 		pud_t *pud, *pud_k;
 		pmd_t *pmd, *pmd_k;
 		pte_t *pte_k;

 		pgd = (pgd_t *) __get_TTBR();
 		pgd = (pgd_t *)__va(pgd) + index;
 		pgd_k = ((pgd_t *)(init_mm.pgd)) + index;

 		if (!pgd_present(*pgd_k))
 			goto no_context;
 		//set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line

 		pud_k = pud_offset(pgd_k, ear0);
 		if (!pud_present(*pud_k))
 			goto no_context;

 		pmd_k = pmd_offset(pud_k, ear0);
 		if (!pmd_present(*pmd_k))
 			goto no_context;

 		pud = pud_offset(pgd, ear0);
 		pmd = pmd_offset(pud, ear0);
 		set_pmd(pmd, *pmd_k);

 		pte_k = pte_offset_kernel(pmd_k, ear0);
 		if (!pte_present(*pte_k))
 			goto no_context;
 		return;
 	}
 } /* end do_page_fault() */
	/*
	* linux/arch/frv/mm/fault.c
	*
	* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
	* - Written by David Howells (dhowells@redhat.com)
	* - Derived from arch/m68knommu/mm/fault.c
	* - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
	* - Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
	*
	* Based on:
	*
	* linux/arch/m68k/mm/fault.c
	*
	* Copyright (C) 1995 Hamish Macdonald
	*/

	#include <linux/mman.h>
	#include <linux/mm.h>
	#include <linux/kernel.h>
	#include <linux/ptrace.h>
	#include <linux/hardirq.h>

	#include <asm/system.h>
	#include <asm/pgtable.h>
	#include <asm/uaccess.h>
	#include <asm/gdb-stub.h>

	/*****************************************************************************/
	/*
	* This routine handles page faults. It determines the problem, and
	* then passes it off to one of the appropriate routines.
	*/
	asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
	{
	struct vm_area_struct *vma;
	struct mm_struct *mm;
	unsigned long _pme, lrai, lrad, fixup;
	siginfo_t info;
	pgd_t *pge;
	pud_t *pue;
	pte_t *pte;
	int write;
	int fault;

	#if 0
	const char *atxc[16] = {
	[0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
	[0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
	};

	printk("do_page_fault(%d,%lx [%s],%lx)\n",
	datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
	#endif

	mm = current->mm;

	/*
	* 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
	* and that the fault was a page not present (invalid) error
	*/
	if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
	if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
	goto kernel_pte_fault;
	if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
	goto kernel_pte_fault;
	}

	info.si_code = SEGV_MAPERR;

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

	down_read(&mm->mmap_sem);

	vma = find_vma(mm, ear0);
	if (!vma)
	goto bad_area;
	if (vma->vm_start <= ear0)
	goto good_area;
	if (!(vma->vm_flags & VM_GROWSDOWN))
	goto bad_area;

	if (user_mode(__frame)) {
	/*
	* accessing the stack below %esp is always a bug.
	* The "+ 32" is there due to some instructions (like
	* pusha) doing post-decrement on the stack and that
	* doesn't show up until later..
	*/
	if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
	#if 0
	printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
	current->pid, ear0, __frame->sp);
	show_registers(__frame);
	printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
	current->pid,
	__frame->pc,
	((u8*)__frame->pc)[0],
	((u8*)__frame->pc)[1],
	((u8*)__frame->pc)[2],
	((u8*)__frame->pc)[3],
	((u8*)__frame->pc)[4],
	((u8*)__frame->pc)[5],
	((u8*)__frame->pc)[6],
	((u8*)__frame->pc)[7]
	);
	#endif
	goto bad_area;
	}
	}

	if (expand_stack(vma, ear0))
	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;
	write = 0;
	switch (esr0 & ESR0_ATXC) {
	default:
	/* handle write to write protected page */
	case ESR0_ATXC_WP_EXCEP:
	#ifdef TEST_VERIFY_AREA
	if (!(user_mode(__frame)))
	printk("WP fault at %08lx\n", __frame->pc);
	#endif
	if (!(vma->vm_flags & VM_WRITE))
	goto bad_area;
	write = 1;
	break;

	/* handle read from protected page */
	case ESR0_ATXC_PRIV_EXCEP:
	goto bad_area;

	/* handle read, write or exec on absent page
	* - can't support write without permitting read
	* - don't support execute without permitting read and vice-versa
	*/
	case ESR0_ATXC_AMRTLB_MISS:
	if (!(vma->vm_flags & (VM_READ \| VM_WRITE \| VM_EXEC)))
	goto bad_area;
	break;
	}

	/*
	* If for any reason at all we couldn't handle the fault,
	* make sure we exit gracefully rather than endlessly redo
	* the fault.
	*/
	fault = handle_mm_fault(mm, vma, ear0, write ? FAULT_FLAG_WRITE : 0);
	if (unlikely(fault & VM_FAULT_ERROR)) {
	if (fault & VM_FAULT_OOM)
	goto out_of_memory;
	else if (fault & VM_FAULT_SIGBUS)
	goto do_sigbus;
	BUG();
	}
	if (fault & VM_FAULT_MAJOR)
	current->maj_flt++;
	else
	current->min_flt++;

	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);

	/* User mode accesses just cause a SIGSEGV */
	if (user_mode(__frame)) {
	info.si_signo = SIGSEGV;
	info.si_errno = 0;
	/* info.si_code has been set above */
	info.si_addr = (void *) ear0;
	force_sig_info(SIGSEGV, &info, current);
	return;
	}

	no_context:
	/* are we prepared to handle this kernel fault? */
	if ((fixup = search_exception_table(__frame->pc)) != 0) {
	__frame->pc = fixup;
	return;
	}

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

	bust_spinlocks(1);

	if (ear0 < 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 addr %08lx\n", ear0);
	printk(" PC : %08lx\n", __frame->pc);
	printk(" EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);

	asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
	asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));

	printk(KERN_ALERT " LRAI: %08lx\n", lrai);
	printk(KERN_ALERT " LRAD: %08lx\n", lrad);

	__break_hijack_kernel_event();

	pge = pgd_offset(current->mm, ear0);
	pue = pud_offset(pge, ear0);
	_pme = pue->pue[0].ste[0];

	printk(KERN_ALERT " PGE : %8p { PME %08lx }\n", pge, _pme);

	if (_pme & xAMPRx_V) {
	unsigned long dampr, damlr, val;

	asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
	: "=&r"(dampr), "=r"(damlr)
	: "r" (_pme \| xAMPRx_L\|xAMPRx_SS_16Kb\|xAMPRx_S\|xAMPRx_C\|xAMPRx_V)
	);

	pte = (pte_t *) damlr + __pte_index(ear0);
	val = pte_val(*pte);

	asm volatile("movgs %0,dampr2" :: "r" (dampr));

	printk(KERN_ALERT " PTE : %8p { %08lx }\n", pte, val);
	}

	die_if_kernel("Oops\n");
	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);
	printk("VM: killing process %s\n", current->comm);
	if (user_mode(__frame))
	do_group_exit(SIGKILL);
	goto no_context;

	do_sigbus:
	up_read(&mm->mmap_sem);

	/*
	* Send a sigbus, regardless of whether we were in kernel
	* or user mode.
	*/
	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code = BUS_ADRERR;
	info.si_addr = (void *) ear0;
	force_sig_info(SIGBUS, &info, current);

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

	/*
	* The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
	*/
	kernel_pte_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 index = pgd_index(ear0);
	pgd_t pgd, pgd_k;
	pud_t pud, pud_k;
	pmd_t pmd, pmd_k;
	pte_t *pte_k;

	pgd = (pgd_t *) __get_TTBR();
	pgd = (pgd_t *)__va(pgd) + index;
	pgd_k = ((pgd_t *)(init_mm.pgd)) + index;

	if (!pgd_present(*pgd_k))
	goto no_context;
	//set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line

	pud_k = pud_offset(pgd_k, ear0);
	if (!pud_present(*pud_k))
	goto no_context;

	pmd_k = pmd_offset(pud_k, ear0);
	if (!pmd_present(*pmd_k))
	goto no_context;

	pud = pud_offset(pgd, ear0);
	pmd = pmd_offset(pud, ear0);
	set_pmd(pmd, *pmd_k);

	pte_k = pte_offset_kernel(pmd_k, ear0);
	if (!pte_present(*pte_k))
	goto no_context;
	return;
	}
	} /* end do_page_fault() */