[deliverable/linux.git] / arch / unicore32 / mm / fault.c

/*
 * linux/arch/unicore32/mm/fault.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/page-flags.h>
#include <linux/sched.h>
#include <linux/io.h>

#include <asm/pgtable.h>
#include <asm/tlbflush.h>

/*
 * Fault status register encodings.  We steal bit 31 for our own purposes.
 */
#define FSR_LNX_PF		(1 << 31)

static inline int fsr_fs(unsigned int fsr)
{
	/* xyabcde will be abcde+xy */
	return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
}

/*
 * This is useful to dump out the page tables associated with
 * 'addr' in mm 'mm'.
 */
void show_pte(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;

	if (!mm)
		mm = &init_mm;

	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	pgd = pgd_offset(mm, addr);
	printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));

	do {
		pmd_t *pmd;
		pte_t *pte;

		if (pgd_none(*pgd))
			break;

		if (pgd_bad(*pgd)) {
			printk("(bad)");
			break;
		}

		pmd = pmd_offset((pud_t *) pgd, addr);
		if (PTRS_PER_PMD != 1)
			printk(", *pmd=%08lx", pmd_val(*pmd));

		if (pmd_none(*pmd))
			break;

		if (pmd_bad(*pmd)) {
			printk("(bad)");
			break;
		}

		/* We must not map this if we have highmem enabled */
		if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
			break;

		pte = pte_offset_map(pmd, addr);
		printk(", *pte=%08lx", pte_val(*pte));
		pte_unmap(pte);
	} while (0);

	printk("\n");
}

/*
 * Oops.  The kernel tried to access some page that wasn't present.
 */
static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
		unsigned int fsr, struct pt_regs *regs)
{
	/*
	 * Are we prepared to handle this kernel fault?
	 */
	if (fixup_exception(regs))
		return;

	/*
	 * No handler, we'll have to terminate things with extreme prejudice.
	 */
	bust_spinlocks(1);
	printk(KERN_ALERT
	       "Unable to handle kernel %s at virtual address %08lx\n",
	       (addr < PAGE_SIZE) ? "NULL pointer dereference" :
	       "paging request", addr);

	show_pte(mm, addr);
	die("Oops", regs, fsr);
	bust_spinlocks(0);
	do_exit(SIGKILL);
}

/*
 * Something tried to access memory that isn't in our memory map..
 * User mode accesses just cause a SIGSEGV
 */
static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
		unsigned int fsr, unsigned int sig, int code,
		struct pt_regs *regs)
{
	struct siginfo si;

	tsk->thread.address = addr;
	tsk->thread.error_code = fsr;
	tsk->thread.trap_no = 14;
	si.si_signo = sig;
	si.si_errno = 0;
	si.si_code = code;
	si.si_addr = (void __user *)addr;
	force_sig_info(sig, &si, tsk);
}

void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->active_mm;

	/*
	 * If we are in kernel mode at this point, we
	 * have no context to handle this fault with.
	 */
	if (user_mode(regs))
		__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
	else
		__do_kernel_fault(mm, addr, fsr, regs);
}

#define VM_FAULT_BADMAP		0x010000
#define VM_FAULT_BADACCESS	0x020000

/*
 * Check that the permissions on the VMA allow for the fault which occurred.
 * If we encountered a write fault, we must have write permission, otherwise
 * we allow any permission.
 */
static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
{
	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;

	if (!(fsr ^ 0x12))	/* write? */
		mask = VM_WRITE;
	if (fsr & FSR_LNX_PF)
		mask = VM_EXEC;

	return vma->vm_flags & mask ? false : true;
}

static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
		struct task_struct *tsk)
{
	struct vm_area_struct *vma;
	int fault;

	vma = find_vma(mm, addr);
	fault = VM_FAULT_BADMAP;
	if (unlikely(!vma))
		goto out;
	if (unlikely(vma->vm_start > addr))
		goto check_stack;

	/*
	 * Ok, we have a good vm_area for this
	 * memory access, so we can handle it.
	 */
good_area:
	if (access_error(fsr, vma)) {
		fault = VM_FAULT_BADACCESS;
		goto out;
	}

	/*
	 * 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, addr & PAGE_MASK,
			    (!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
	if (unlikely(fault & VM_FAULT_ERROR))
		return fault;
	if (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;
	return fault;

check_stack:
	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
		goto good_area;
out:
	return fault;
}

static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	int fault, sig, code;

	tsk = current;
	mm = tsk->mm;

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

	/*
	 * As per x86, we may deadlock here.  However, since the kernel only
	 * validly references user space from well defined areas of the code,
	 * we can bug out early if this is from code which shouldn't.
	 */
	if (!down_read_trylock(&mm->mmap_sem)) {
		if (!user_mode(regs)
		    && !search_exception_tables(regs->UCreg_pc))
			goto no_context;
		down_read(&mm->mmap_sem);
	} else {
		/*
		 * The above down_read_trylock() might have succeeded in
		 * which case, we'll have missed the might_sleep() from
		 * down_read()
		 */
		might_sleep();
#ifdef CONFIG_DEBUG_VM
		if (!user_mode(regs) &&
		    !search_exception_tables(regs->UCreg_pc))
			goto no_context;
#endif
	}

	fault = __do_pf(mm, addr, fsr, tsk);
	up_read(&mm->mmap_sem);

	/*
	 * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
	 */
	if (likely(!(fault &
	       (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
		return 0;

	if (fault & VM_FAULT_OOM) {
		/*
		 * We ran out of memory, call the OOM killer, and return to
		 * userspace (which will retry the fault, or kill us if we
		 * got oom-killed)
		 */
		pagefault_out_of_memory();
		return 0;
	}

	/*
	 * If we are in kernel mode at this point, we
	 * have no context to handle this fault with.
	 */
	if (!user_mode(regs))
		goto no_context;

	if (fault & VM_FAULT_SIGBUS) {
		/*
		 * We had some memory, but were unable to
		 * successfully fix up this page fault.
		 */
		sig = SIGBUS;
		code = BUS_ADRERR;
	} else {
		/*
		 * Something tried to access memory that
		 * isn't in our memory map..
		 */
		sig = SIGSEGV;
		code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR;
	}

	__do_user_fault(tsk, addr, fsr, sig, code, regs);
	return 0;

no_context:
	__do_kernel_fault(mm, addr, fsr, regs);
	return 0;
}

/*
 * First Level Translation Fault Handler
 *
 * We enter here because the first level page table doesn't contain
 * a valid entry for the address.
 *
 * If the address is in kernel space (>= TASK_SIZE), then we are
 * probably faulting in the vmalloc() area.
 *
 * If the init_task's first level page tables contains the relevant
 * entry, we copy the it to this task.  If not, we send the process
 * a signal, fixup the exception, or oops the kernel.
 *
 * 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.
 */
static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	unsigned int index;
	pgd_t *pgd, *pgd_k;
	pmd_t *pmd, *pmd_k;

	if (addr < TASK_SIZE)
		return do_pf(addr, fsr, regs);

	if (user_mode(regs))
		goto bad_area;

	index = pgd_index(addr);

	pgd = cpu_get_pgd() + index;
	pgd_k = init_mm.pgd + index;

	if (pgd_none(*pgd_k))
		goto bad_area;

	pmd_k = pmd_offset((pud_t *) pgd_k, addr);
	pmd = pmd_offset((pud_t *) pgd, addr);

	if (pmd_none(*pmd_k))
		goto bad_area;

	set_pmd(pmd, *pmd_k);
	flush_pmd_entry(pmd);
	return 0;

bad_area:
	do_bad_area(addr, fsr, regs);
	return 0;
}

/*
 * This abort handler always returns "fault".
 */
static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	return 1;
}

static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	unsigned int res1, res2;

	printk("dabt exception but no error!\n");

	__asm__ __volatile__(
			"mff %0,f0\n"
			"mff %1,f1\n"
			: "=r"(res1), "=r"(res2)
			:
			: "memory");

	printk(KERN_EMERG "r0 :%08x  r1 :%08x\n", res1, res2);
	panic("shut up\n");
	return 0;
}

static struct fsr_info {
	int (*fn) (unsigned long addr, unsigned int fsr, struct pt_regs *regs);
	int sig;
	int code;
	const char *name;
} fsr_info[] = {
	/*
	 * The following are the standard Unicore-I and UniCore-II aborts.
	 */
	{ do_good,	SIGBUS,  0,		"no error"		},
	{ do_bad,	SIGBUS,  BUS_ADRALN,	"alignment exception"	},
	{ do_bad,	SIGBUS,  BUS_OBJERR,	"external exception"	},
	{ do_bad,	SIGBUS,  0,		"burst operation"	},
	{ do_bad,	SIGBUS,  0,		"unknown 00100"		},
	{ do_ifault,	SIGSEGV, SEGV_MAPERR,	"2nd level pt non-exist"},
	{ do_bad,	SIGBUS,  0,		"2nd lvl large pt non-exist" },
	{ do_bad,	SIGBUS,  0,		"invalid pte"		},
	{ do_pf,	SIGSEGV, SEGV_MAPERR,	"page miss"		},
	{ do_bad,	SIGBUS,  0,		"middle page miss"	},
	{ do_bad,	SIGBUS,	 0,		"large page miss"	},
	{ do_pf,	SIGSEGV, SEGV_MAPERR,	"super page (section) miss" },
	{ do_bad,	SIGBUS,  0,		"unknown 01100"		},
	{ do_bad,	SIGBUS,  0,		"unknown 01101"		},
	{ do_bad,	SIGBUS,  0,		"unknown 01110"		},
	{ do_bad,	SIGBUS,  0,		"unknown 01111"		},
	{ do_bad,	SIGBUS,  0,		"addr: up 3G or IO"	},
	{ do_pf,	SIGSEGV, SEGV_ACCERR,	"read unreadable addr"	},
	{ do_pf,	SIGSEGV, SEGV_ACCERR,	"write unwriteable addr"},
	{ do_pf,	SIGSEGV, SEGV_ACCERR,	"exec unexecutable addr"},
	{ do_bad,	SIGBUS,  0,		"unknown 10100"		},
	{ do_bad,	SIGBUS,  0,		"unknown 10101"		},
	{ do_bad,	SIGBUS,  0,		"unknown 10110"		},
	{ do_bad,	SIGBUS,  0,		"unknown 10111"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11000"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11001"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11010"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11011"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11100"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11101"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11110"		},
	{ do_bad,	SIGBUS,  0,		"unknown 11111"		}
};

void __init hook_fault_code(int nr,
		int (*fn) (unsigned long, unsigned int, struct pt_regs *),
		int sig, int code, const char *name)
{
	if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
		BUG();

	fsr_info[nr].fn   = fn;
	fsr_info[nr].sig  = sig;
	fsr_info[nr].code = code;
	fsr_info[nr].name = name;
}

/*
 * Dispatch a data abort to the relevant handler.
 */
asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
			struct pt_regs *regs)
{
	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
	struct siginfo info;

	if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
		return;

	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
	       inf->name, fsr, addr);

	info.si_signo = inf->sig;
	info.si_errno = 0;
	info.si_code = inf->code;
	info.si_addr = (void __user *)addr;
	uc32_notify_die("", regs, &info, fsr, 0);
}

asmlinkage void do_PrefetchAbort(unsigned long addr,
			unsigned int ifsr, struct pt_regs *regs)
{
	const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
	struct siginfo info;

	if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
		return;

	printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
	       inf->name, ifsr, addr);

	info.si_signo = inf->sig;
	info.si_errno = 0;
	info.si_code = inf->code;
	info.si_addr = (void __user *)addr;
	uc32_notify_die("", regs, &info, ifsr, 0);
}
Commit	Line	Data
56372b0b G	1	/*
	2	* linux/arch/unicore32/mm/fault.c
	3	*
	4	* Code specific to PKUnity SoC and UniCore ISA
	5	*
	6	* Copyright (C) 2001-2010 GUAN Xue-tao
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12	#include <linux/module.h>
	13	#include <linux/signal.h>
	14	#include <linux/mm.h>
	15	#include <linux/hardirq.h>
	16	#include <linux/init.h>
	17	#include <linux/kprobes.h>
	18	#include <linux/uaccess.h>
	19	#include <linux/page-flags.h>
	20	#include <linux/sched.h>
	21	#include <linux/io.h>
	22
56372b0b G	23	#include <asm/pgtable.h>
	24	#include <asm/tlbflush.h>
	25
	26	/*
	27	* Fault status register encodings. We steal bit 31 for our own purposes.
	28	*/
	29	#define FSR_LNX_PF (1 << 31)
	30
	31	static inline int fsr_fs(unsigned int fsr)
	32	{
	33	/* xyabcde will be abcde+xy */
	34	return (fsr & 31) + ((fsr & (3 << 5)) >> 5);
	35	}
	36
	37	/*
	38	* This is useful to dump out the page tables associated with
	39	* 'addr' in mm 'mm'.
	40	*/
	41	void show_pte(struct mm_struct *mm, unsigned long addr)
	42	{
	43	pgd_t *pgd;
	44
	45	if (!mm)
	46	mm = &init_mm;
	47
	48	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	49	pgd = pgd_offset(mm, addr);
	50	printk(KERN_ALERT "[%08lx] pgd=%08lx", addr, pgd_val(pgd));
	51
	52	do {
	53	pmd_t *pmd;
	54	pte_t *pte;
	55
	56	if (pgd_none(*pgd))
	57	break;
	58
	59	if (pgd_bad(*pgd)) {
	60	printk("(bad)");
	61	break;
	62	}
	63
	64	pmd = pmd_offset((pud_t *) pgd, addr);
	65	if (PTRS_PER_PMD != 1)
	66	printk(", pmd=%08lx", pmd_val(pmd));
	67
	68	if (pmd_none(*pmd))
	69	break;
	70
	71	if (pmd_bad(*pmd)) {
	72	printk("(bad)");
	73	break;
	74	}
	75
	76	/* We must not map this if we have highmem enabled */
	77	if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
	78	break;
	79
	80	pte = pte_offset_map(pmd, addr);
	81	printk(", pte=%08lx", pte_val(pte));
	82	pte_unmap(pte);
	83	} while (0);
	84
	85	printk("\n");
	86	}
87
88	/*
89	* Oops. The kernel tried to access some page that wasn't present.
90	*/
91	static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
92	unsigned int fsr, struct pt_regs *regs)
93	{
94	/*
95	* Are we prepared to handle this kernel fault?
96	*/
97	if (fixup_exception(regs))
98	return;
99
100	/*
101	* No handler, we'll have to terminate things with extreme prejudice.
102	*/
103	bust_spinlocks(1);
104	printk(KERN_ALERT
105	"Unable to handle kernel %s at virtual address %08lx\n",
106	(addr < PAGE_SIZE) ? "NULL pointer dereference" :
107	"paging request", addr);
108
109	show_pte(mm, addr);
110	die("Oops", regs, fsr);
111	bust_spinlocks(0);
112	do_exit(SIGKILL);
113	}
114
115	/*
116	* Something tried to access memory that isn't in our memory map..
117	* User mode accesses just cause a SIGSEGV
118	*/
119	static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
120	unsigned int fsr, unsigned int sig, int code,
121	struct pt_regs *regs)
122	{
123	struct siginfo si;
124
125	tsk->thread.address = addr;
126	tsk->thread.error_code = fsr;
127	tsk->thread.trap_no = 14;
128	si.si_signo = sig;
129	si.si_errno = 0;
130	si.si_code = code;
131	si.si_addr = (void __user *)addr;
132	force_sig_info(sig, &si, tsk);
133	}
134
135	void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
136	{
137	struct task_struct *tsk = current;
138	struct mm_struct *mm = tsk->active_mm;
139
140	/*
141	* If we are in kernel mode at this point, we
142	* have no context to handle this fault with.
143	*/
144	if (user_mode(regs))
145	__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
146	else
147	__do_kernel_fault(mm, addr, fsr, regs);
148	}
149
150	#define VM_FAULT_BADMAP 0x010000
151	#define VM_FAULT_BADACCESS 0x020000
152
153	/*
154	* Check that the permissions on the VMA allow for the fault which occurred.
155	* If we encountered a write fault, we must have write permission, otherwise
156	* we allow any permission.
157	*/
158	static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
159	{
160	unsigned int mask = VM_READ \| VM_WRITE \| VM_EXEC;
161
162	if (!(fsr ^ 0x12)) /* write? */
163	mask = VM_WRITE;
164	if (fsr & FSR_LNX_PF)
165	mask = VM_EXEC;
166
167	return vma->vm_flags & mask ? false : true;
168	}
169
170	static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
171	struct task_struct *tsk)
172	{
173	struct vm_area_struct *vma;
174	int fault;
175
176	vma = find_vma(mm, addr);
177	fault = VM_FAULT_BADMAP;
178	if (unlikely(!vma))
179	goto out;
180	if (unlikely(vma->vm_start > addr))
181	goto check_stack;
182
183	/*
184	* Ok, we have a good vm_area for this
185	* memory access, so we can handle it.
186	*/
187	good_area:
188	if (access_error(fsr, vma)) {
189	fault = VM_FAULT_BADACCESS;
190	goto out;
191	}
192
193	/*
194	* If for any reason at all we couldn't handle the fault, make
195	* sure we exit gracefully rather than endlessly redo the fault.
196	*/
197	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK,
198	(!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
199	if (unlikely(fault & VM_FAULT_ERROR))
200	return fault;
201	if (fault & VM_FAULT_MAJOR)
202	tsk->maj_flt++;
203	else
204	tsk->min_flt++;
205	return fault;
206
207	check_stack:
208	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
209	goto good_area;
210	out:
211	return fault;
212	}
213
214	static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
215	{
216	struct task_struct *tsk;
217	struct mm_struct *mm;
218	int fault, sig, code;
219
220	tsk = current;
221	mm = tsk->mm;
222
223	/*
224	* If we're in an interrupt or have no user
225	* context, we must not take the fault..
226	*/
227	if (in_atomic() \|\| !mm)
228	goto no_context;
229
230	/*
231	* As per x86, we may deadlock here. However, since the kernel only
232	* validly references user space from well defined areas of the code,
233	* we can bug out early if this is from code which shouldn't.
234	*/
235	if (!down_read_trylock(&mm->mmap_sem)) {
236	if (!user_mode(regs)
237	&& !search_exception_tables(regs->UCreg_pc))
238	goto no_context;
239	down_read(&mm->mmap_sem);
240	} else {
241	/*
242	* The above down_read_trylock() might have succeeded in
243	* which case, we'll have missed the might_sleep() from
244	* down_read()
245	*/
246	might_sleep();
247	#ifdef CONFIG_DEBUG_VM
248	if (!user_mode(regs) &&
249	!search_exception_tables(regs->UCreg_pc))
250	goto no_context;
251	#endif
252	}
253
254	fault = __do_pf(mm, addr, fsr, tsk);
255	up_read(&mm->mmap_sem);
256
257	/*
258	* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
259	*/
260	if (likely(!(fault &
261	(VM_FAULT_ERROR \| VM_FAULT_BADMAP \| VM_FAULT_BADACCESS))))
262	return 0;
263
264	if (fault & VM_FAULT_OOM) {
265	/*
266	* We ran out of memory, call the OOM killer, and return to
267	* userspace (which will retry the fault, or kill us if we
268	* got oom-killed)
269	*/
270	pagefault_out_of_memory();
271	return 0;
272	}
273
274	/*
275	* If we are in kernel mode at this point, we
276	* have no context to handle this fault with.
277	*/
278	if (!user_mode(regs))
279	goto no_context;
280
281	if (fault & VM_FAULT_SIGBUS) {
282	/*
283	* We had some memory, but were unable to
284	* successfully fix up this page fault.
285	*/
286	sig = SIGBUS;
287	code = BUS_ADRERR;
288	} else {
289	/*
290	* Something tried to access memory that
291	* isn't in our memory map..
292	*/
293	sig = SIGSEGV;
294	code = fault == VM_FAULT_BADACCESS ? SEGV_ACCERR : SEGV_MAPERR;
295	}
296
297	__do_user_fault(tsk, addr, fsr, sig, code, regs);
298	return 0;
299
300	no_context:
301	__do_kernel_fault(mm, addr, fsr, regs);
302	return 0;
303	}
304
305	/*
306	* First Level Translation Fault Handler
307	*
308	* We enter here because the first level page table doesn't contain
309	* a valid entry for the address.
310	*
311	* If the address is in kernel space (>= TASK_SIZE), then we are
312	* probably faulting in the vmalloc() area.
313	*
314	* If the init_task's first level page tables contains the relevant
315	* entry, we copy the it to this task. If not, we send the process
316	* a signal, fixup the exception, or oops the kernel.
317	*
318	* NOTE! We MUST NOT take any locks for this case. We may be in an
319	* interrupt or a critical region, and should only copy the information
320	* from the master page table, nothing more.
321	*/
322	static int do_ifault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
323	{
324	unsigned int index;
325	pgd_t pgd, pgd_k;
326	pmd_t pmd, pmd_k;
327
328	if (addr < TASK_SIZE)
329	return do_pf(addr, fsr, regs);
330
331	if (user_mode(regs))
332	goto bad_area;
333
334	index = pgd_index(addr);
335
336	pgd = cpu_get_pgd() + index;
337	pgd_k = init_mm.pgd + index;
338
339	if (pgd_none(*pgd_k))
340	goto bad_area;
341
342	pmd_k = pmd_offset((pud_t *) pgd_k, addr);
343	pmd = pmd_offset((pud_t *) pgd, addr);
344
345	if (pmd_none(*pmd_k))
346	goto bad_area;
347
348	set_pmd(pmd, *pmd_k);
349	flush_pmd_entry(pmd);
350	return 0;
351
352	bad_area:
353	do_bad_area(addr, fsr, regs);
354	return 0;
355	}
356
357	/*
358	* This abort handler always returns "fault".
359	*/
360	static int do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
361	{
362	return 1;
363	}
364
365	static int do_good(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
366	{
367	unsigned int res1, res2;
368
369	printk("dabt exception but no error!\n");
370
371	__asm__ __volatile__(
372	"mff %0,f0\n"
373	"mff %1,f1\n"
374	: "=r"(res1), "=r"(res2)
375	:
376	: "memory");
377
378	printk(KERN_EMERG "r0 :%08x r1 :%08x\n", res1, res2);
379	panic("shut up\n");
380	return 0;
381	}
382
383	static struct fsr_info {
384	int (fn) (unsigned long addr, unsigned int fsr, struct pt_regs regs);
385	int sig;
386	int code;
387	const char *name;
388	} fsr_info[] = {
389	/*
390	* The following are the standard Unicore-I and UniCore-II aborts.
391	*/
392	{ do_good, SIGBUS, 0, "no error" },
393	{ do_bad, SIGBUS, BUS_ADRALN, "alignment exception" },
394	{ do_bad, SIGBUS, BUS_OBJERR, "external exception" },
395	{ do_bad, SIGBUS, 0, "burst operation" },
396	{ do_bad, SIGBUS, 0, "unknown 00100" },
397	{ do_ifault, SIGSEGV, SEGV_MAPERR, "2nd level pt non-exist"},
398	{ do_bad, SIGBUS, 0, "2nd lvl large pt non-exist" },
399	{ do_bad, SIGBUS, 0, "invalid pte" },
400	{ do_pf, SIGSEGV, SEGV_MAPERR, "page miss" },
401	{ do_bad, SIGBUS, 0, "middle page miss" },
402	{ do_bad, SIGBUS, 0, "large page miss" },
403	{ do_pf, SIGSEGV, SEGV_MAPERR, "super page (section) miss" },
404	{ do_bad, SIGBUS, 0, "unknown 01100" },
405	{ do_bad, SIGBUS, 0, "unknown 01101" },
406	{ do_bad, SIGBUS, 0, "unknown 01110" },
407	{ do_bad, SIGBUS, 0, "unknown 01111" },
408	{ do_bad, SIGBUS, 0, "addr: up 3G or IO" },
409	{ do_pf, SIGSEGV, SEGV_ACCERR, "read unreadable addr" },
410	{ do_pf, SIGSEGV, SEGV_ACCERR, "write unwriteable addr"},
411	{ do_pf, SIGSEGV, SEGV_ACCERR, "exec unexecutable addr"},
412	{ do_bad, SIGBUS, 0, "unknown 10100" },
413	{ do_bad, SIGBUS, 0, "unknown 10101" },
414	{ do_bad, SIGBUS, 0, "unknown 10110" },
415	{ do_bad, SIGBUS, 0, "unknown 10111" },
416	{ do_bad, SIGBUS, 0, "unknown 11000" },
417	{ do_bad, SIGBUS, 0, "unknown 11001" },
418	{ do_bad, SIGBUS, 0, "unknown 11010" },
419	{ do_bad, SIGBUS, 0, "unknown 11011" },
420	{ do_bad, SIGBUS, 0, "unknown 11100" },
421	{ do_bad, SIGBUS, 0, "unknown 11101" },
422	{ do_bad, SIGBUS, 0, "unknown 11110" },
423	{ do_bad, SIGBUS, 0, "unknown 11111" }
424	};
425
426	void __init hook_fault_code(int nr,
427	int (fn) (unsigned long, unsigned int, struct pt_regs ),
428	int sig, int code, const char *name)
429	{
430	if (nr < 0 \|\| nr >= ARRAY_SIZE(fsr_info))
431	BUG();
432
433	fsr_info[nr].fn = fn;
434	fsr_info[nr].sig = sig;
435	fsr_info[nr].code = code;
436	fsr_info[nr].name = name;
437	}
438
439	/*
440	* Dispatch a data abort to the relevant handler.
441	*/
442	asmlinkage void do_DataAbort(unsigned long addr, unsigned int fsr,
443	struct pt_regs *regs)
444	{
445	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
446	struct siginfo info;
447
448	if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
449	return;
450
451	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
452	inf->name, fsr, addr);
453
454	info.si_signo = inf->sig;
455	info.si_errno = 0;
456	info.si_code = inf->code;
457	info.si_addr = (void __user *)addr;
458	uc32_notify_die("", regs, &info, fsr, 0);
459	}
460
461	asmlinkage void do_PrefetchAbort(unsigned long addr,
462	unsigned int ifsr, struct pt_regs *regs)
463	{
464	const struct fsr_info *inf = fsr_info + fsr_fs(ifsr);
465	struct siginfo info;
466
467	if (!inf->fn(addr, ifsr \| FSR_LNX_PF, regs))
468	return;
469
470	printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
471	inf->name, ifsr, addr);
472
473	info.si_signo = inf->sig;
474	info.si_errno = 0;
475	info.si_code = inf->code;
476	info.si_addr = (void __user *)addr;
477	uc32_notify_die("", regs, &info, ifsr, 0);
478	}