[net-next-2.6.git] / arch / frv / mm / fault.c

/*
 *  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);
	if (!user_mode(__frame))
		goto no_context;
	pagefault_out_of_memory();
	return;

 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() */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/frv/mm/fault.c
	3	*
	4	* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
	5	* - Written by David Howells (dhowells@redhat.com)
	6	* - Derived from arch/m68knommu/mm/fault.c
	7	* - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
	8	* - Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
	9	*
	10	* Based on:
	11	*
	12	* linux/arch/m68k/mm/fault.c
	13	*
	14	* Copyright (C) 1995 Hamish Macdonald
	15	*/
	16
	17	#include <linux/mman.h>
	18	#include <linux/mm.h>
	19	#include <linux/kernel.h>
	20	#include <linux/ptrace.h>
	21	#include <linux/hardirq.h>
	22
	23	#include <asm/system.h>
	24	#include <asm/pgtable.h>
	25	#include <asm/uaccess.h>
	26	#include <asm/gdb-stub.h>
	27
	28	/*****************************************************************************/
	29	/*
	30	* This routine handles page faults. It determines the problem, and
	31	* then passes it off to one of the appropriate routines.
	32	*/
	33	asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear0)
	34	{
	35	struct vm_area_struct *vma;
	36	struct mm_struct *mm;
	37	unsigned long _pme, lrai, lrad, fixup;
	38	siginfo_t info;
	39	pgd_t *pge;
	40	pud_t *pue;
	41	pte_t *pte;
	42	int write;
83c54070	43	int fault;
1da177e4 LT	44
	45	#if 0
	46	const char *atxc[16] = {
	47	[0x0] = "mmu-miss", [0x8] = "multi-dat", [0x9] = "multi-sat",
	48	[0xa] = "tlb-miss", [0xc] = "privilege", [0xd] = "write-prot",
	49	};
	50
	51	printk("do_page_fault(%d,%lx [%s],%lx)\n",
	52	datammu, esr0, atxc[esr0 >> 20 & 0xf], ear0);
	53	#endif
	54
	55	mm = current->mm;
	56
	57	/*
	58	* We fault-in kernel-space virtual memory on-demand. The
	59	* 'reference' page table is init_mm.pgd.
	60	*
	61	* NOTE! We MUST NOT take any locks for this case. We may
	62	* be in an interrupt or a critical region, and should
	63	* only copy the information from the master page table,
	64	* nothing more.
	65	*
	66	* This verifies that the fault happens in kernel space
	67	* and that the fault was a page not present (invalid) error
	68	*/
	69	if (!user_mode(__frame) && (esr0 & ESR0_ATXC) == ESR0_ATXC_AMRTLB_MISS) {
	70	if (ear0 >= VMALLOC_START && ear0 < VMALLOC_END)
	71	goto kernel_pte_fault;
	72	if (ear0 >= PKMAP_BASE && ear0 < PKMAP_END)
	73	goto kernel_pte_fault;
	74	}
	75
	76	info.si_code = SEGV_MAPERR;
	77
	78	/*
	79	* If we're in an interrupt or have no user
	80	* context, we must not take the fault..
	81	*/
6edaf68a	82	if (in_atomic() \|\| !mm)
1da177e4 LT	83	goto no_context;
	84
	85	down_read(&mm->mmap_sem);
	86
	87	vma = find_vma(mm, ear0);
	88	if (!vma)
	89	goto bad_area;
	90	if (vma->vm_start <= ear0)
	91	goto good_area;
	92	if (!(vma->vm_flags & VM_GROWSDOWN))
	93	goto bad_area;
	94
	95	if (user_mode(__frame)) {
	96	/*
	97	* accessing the stack below %esp is always a bug.
	98	* The "+ 32" is there due to some instructions (like
	99	* pusha) doing post-decrement on the stack and that
	100	* doesn't show up until later..
	101	*/
	102	if ((ear0 & PAGE_MASK) + 2 * PAGE_SIZE < __frame->sp) {
	103	#if 0
	104	printk("[%d] ### Access below stack @%lx (sp=%lx)\n",
	105	current->pid, ear0, __frame->sp);
	106	show_registers(__frame);
	107	printk("[%d] ### Code: [%08lx] %02x %02x %02x %02x %02x %02x %02x %02x\n",
	108	current->pid,
	109	__frame->pc,
	110	((u8*)__frame->pc)[0],
	111	((u8*)__frame->pc)[1],
	112	((u8*)__frame->pc)[2],
	113	((u8*)__frame->pc)[3],
	114	((u8*)__frame->pc)[4],
	115	((u8*)__frame->pc)[5],
	116	((u8*)__frame->pc)[6],
	117	((u8*)__frame->pc)[7]
	118	);
	119	#endif
	120	goto bad_area;
	121	}
	122	}
	123
	124	if (expand_stack(vma, ear0))
	125	goto bad_area;
	126
	127	/*
	128	* Ok, we have a good vm_area for this memory access, so
	129	* we can handle it..
	130	*/
	131	good_area:
	132	info.si_code = SEGV_ACCERR;
	133	write = 0;
	134	switch (esr0 & ESR0_ATXC) {
	135	default:
	136	/* handle write to write protected page */
	137	case ESR0_ATXC_WP_EXCEP:
	138	#ifdef TEST_VERIFY_AREA
	139	if (!(user_mode(__frame)))
	140	printk("WP fault at %08lx\n", __frame->pc);
	141	#endif
	142	if (!(vma->vm_flags & VM_WRITE))
	143	goto bad_area;
	144	write = 1;
	145	break;
	146
147	/* handle read from protected page */
148	case ESR0_ATXC_PRIV_EXCEP:
149	goto bad_area;
150
151	/* handle read, write or exec on absent page
152	* - can't support write without permitting read
153	* - don't support execute without permitting read and vice-versa
154	*/
155	case ESR0_ATXC_AMRTLB_MISS:
156	if (!(vma->vm_flags & (VM_READ \| VM_WRITE \| VM_EXEC)))
157	goto bad_area;
158	break;
159	}
160
161	/*
162	* If for any reason at all we couldn't handle the fault,
163	* make sure we exit gracefully rather than endlessly redo
164	* the fault.
165	*/
d06063cc	166	fault = handle_mm_fault(mm, vma, ear0, write ? FAULT_FLAG_WRITE : 0);
83c54070 NP	167	if (unlikely(fault & VM_FAULT_ERROR)) {
	168	if (fault & VM_FAULT_OOM)
	169	goto out_of_memory;
	170	else if (fault & VM_FAULT_SIGBUS)
	171	goto do_sigbus;
	172	BUG();
1da177e4	173	}
83c54070 NP	174	if (fault & VM_FAULT_MAJOR)
	175	current->maj_flt++;
	176	else
	177	current->min_flt++;
1da177e4 LT	178
	179	up_read(&mm->mmap_sem);
	180	return;
	181
	182	/*
	183	* Something tried to access memory that isn't in our memory map..
	184	* Fix it, but check if it's kernel or user first..
	185	*/
	186	bad_area:
	187	up_read(&mm->mmap_sem);
	188
	189	/* User mode accesses just cause a SIGSEGV */
	190	if (user_mode(__frame)) {
	191	info.si_signo = SIGSEGV;
	192	info.si_errno = 0;
	193	/* info.si_code has been set above */
	194	info.si_addr = (void *) ear0;
	195	force_sig_info(SIGSEGV, &info, current);
	196	return;
	197	}
	198
	199	no_context:
	200	/* are we prepared to handle this kernel fault? */
	201	if ((fixup = search_exception_table(__frame->pc)) != 0) {
	202	__frame->pc = fixup;
	203	return;
	204	}
	205
	206	/*
	207	* Oops. The kernel tried to access some bad page. We'll have to
	208	* terminate things with extreme prejudice.
	209	*/
	210
	211	bust_spinlocks(1);
	212
	213	if (ear0 < PAGE_SIZE)
	214	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	215	else
	216	printk(KERN_ALERT "Unable to handle kernel paging request");
	217	printk(" at virtual addr %08lx\n", ear0);
	218	printk(" PC : %08lx\n", __frame->pc);
	219	printk(" EXC : esr0=%08lx ear0=%08lx\n", esr0, ear0);
	220
	221	asm("lrai %1,%0,#1,#0,#0" : "=&r"(lrai) : "r"(ear0));
	222	asm("lrad %1,%0,#1,#0,#0" : "=&r"(lrad) : "r"(ear0));
	223
	224	printk(KERN_ALERT " LRAI: %08lx\n", lrai);
	225	printk(KERN_ALERT " LRAD: %08lx\n", lrad);
	226
	227	__break_hijack_kernel_event();
	228
	229	pge = pgd_offset(current->mm, ear0);
	230	pue = pud_offset(pge, ear0);
	231	_pme = pue->pue[0].ste[0];
	232
	233	printk(KERN_ALERT " PGE : %8p { PME %08lx }\n", pge, _pme);
	234
	235	if (_pme & xAMPRx_V) {
	236	unsigned long dampr, damlr, val;
	237
	238	asm volatile("movsg dampr2,%0 ! movgs %2,dampr2 ! movsg damlr2,%1"
	239	: "=&r"(dampr), "=r"(damlr)
	240	: "r" (_pme \| xAMPRx_L\|xAMPRx_SS_16Kb\|xAMPRx_S\|xAMPRx_C\|xAMPRx_V)
	241	);
242
243	pte = (pte_t *) damlr + __pte_index(ear0);
244	val = pte_val(*pte);
245
246	asm volatile("movgs %0,dampr2" :: "r" (dampr));
247
248	printk(KERN_ALERT " PTE : %8p { %08lx }\n", pte, val);
249	}
250
251	die_if_kernel("Oops\n");
252	do_exit(SIGKILL);
253
254	/*
255	* We ran out of memory, or some other thing happened to us that made
256	* us unable to handle the page fault gracefully.
257	*/
258	out_of_memory:
259	up_read(&mm->mmap_sem);
f9c497c4 NP	260	if (!user_mode(__frame))
	261	goto no_context;
	262	pagefault_out_of_memory();
	263	return;
1da177e4 LT	264
	265	do_sigbus:
	266	up_read(&mm->mmap_sem);
	267
	268	/*
	269	* Send a sigbus, regardless of whether we were in kernel
	270	* or user mode.
	271	*/
	272	info.si_signo = SIGBUS;
	273	info.si_errno = 0;
	274	info.si_code = BUS_ADRERR;
	275	info.si_addr = (void *) ear0;
	276	force_sig_info(SIGBUS, &info, current);
	277
	278	/* Kernel mode? Handle exceptions or die */
	279	if (!user_mode(__frame))
	280	goto no_context;
	281	return;
	282
	283	/*
	284	* The fault was caused by a kernel PTE (such as installed by vmalloc or kmap)
	285	*/
	286	kernel_pte_fault:
	287	{
	288	/*
	289	* Synchronize this task's top level page-table
	290	* with the 'reference' page table.
	291	*
	292	* Do _not_ use "tsk" here. We might be inside
	293	* an interrupt in the middle of a task switch..
	294	*/
	295	int index = pgd_index(ear0);
	296	pgd_t pgd, pgd_k;
	297	pud_t pud, pud_k;
	298	pmd_t pmd, pmd_k;
	299	pte_t *pte_k;
	300
	301	pgd = (pgd_t *) __get_TTBR();
	302	pgd = (pgd_t *)__va(pgd) + index;
	303	pgd_k = ((pgd_t *)(init_mm.pgd)) + index;
	304
	305	if (!pgd_present(*pgd_k))
	306	goto no_context;
	307	//set_pgd(pgd, *pgd_k); /////// gcc ICE's on this line
	308
	309	pud_k = pud_offset(pgd_k, ear0);
	310	if (!pud_present(*pud_k))
	311	goto no_context;
	312
	313	pmd_k = pmd_offset(pud_k, ear0);
	314	if (!pmd_present(*pmd_k))
	315	goto no_context;
	316
	317	pud = pud_offset(pgd, ear0);
	318	pmd = pmd_offset(pud, ear0);
	319	set_pmd(pmd, *pmd_k);
	320
	321	pte_k = pte_offset_kernel(pmd_k, ear0);
	322	if (!pte_present(*pte_k))
	323	goto no_context;
	324	return;
	325	}
	326	} /* end do_page_fault() */