[linux-2.6-block.git] / arch / hexagon / mm / vm_fault.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Memory fault handling for Hexagon
 *
 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
 */

/*
 * Page fault handling for the Hexagon Virtual Machine.
 * Can also be called by a native port emulating the HVM
 * execptions.
 */

#include <asm/pgtable.h>
#include <asm/traps.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/signal.h>
#include <linux/extable.h>
#include <linux/hardirq.h>

/*
 * Decode of hardware exception sends us to one of several
 * entry points.  At each, we generate canonical arguments
 * for handling by the abstract memory management code.
 */
#define FLT_IFETCH     -1
#define FLT_LOAD        0
#define FLT_STORE       1


/*
 * Canonical page fault handler
 */
void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
{
	struct vm_area_struct *vma;
	struct mm_struct *mm = current->mm;
	int si_signo;
	int si_code = SEGV_MAPERR;
	vm_fault_t fault;
	const struct exception_table_entry *fixup;
	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;

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

	local_irq_enable();

	if (user_mode(regs))
		flags |= FAULT_FLAG_USER;
retry:
	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 (expand_stack(vma, address))
		goto bad_area;

good_area:
	/* Address space is OK.  Now check access rights. */
	si_code = SEGV_ACCERR;

	switch (cause) {
	case FLT_IFETCH:
		if (!(vma->vm_flags & VM_EXEC))
			goto bad_area;
		break;
	case FLT_LOAD:
		if (!(vma->vm_flags & VM_READ))
			goto bad_area;
		break;
	case FLT_STORE:
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
		flags |= FAULT_FLAG_WRITE;
		break;
	}

	fault = handle_mm_fault(vma, address, flags);

	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
		return;

	/* The most common case -- we are done. */
	if (likely(!(fault & VM_FAULT_ERROR))) {
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
			if (fault & VM_FAULT_MAJOR)
				current->maj_flt++;
			else
				current->min_flt++;
			if (fault & VM_FAULT_RETRY) {
				flags &= ~FAULT_FLAG_ALLOW_RETRY;
				flags |= FAULT_FLAG_TRIED;
				goto retry;
			}
		}

		up_read(&mm->mmap_sem);
		return;
	}

	up_read(&mm->mmap_sem);

	/* Handle copyin/out exception cases */
	if (!user_mode(regs))
		goto no_context;

	if (fault & VM_FAULT_OOM) {
		pagefault_out_of_memory();
		return;
	}

	/* User-mode address is in the memory map, but we are
	 * unable to fix up the page fault.
	 */
	if (fault & VM_FAULT_SIGBUS) {
		si_signo = SIGBUS;
		si_code = BUS_ADRERR;
	}
	/* Address is not in the memory map */
	else {
		si_signo = SIGSEGV;
		si_code  = SEGV_ACCERR;
	}
	force_sig_fault(si_signo, si_code, (void __user *)address);
	return;

bad_area:
	up_read(&mm->mmap_sem);

	if (user_mode(regs)) {
		force_sig_fault(SIGSEGV, si_code, (void __user *)address);
		return;
	}
	/* Kernel-mode fault falls through */

no_context:
	fixup = search_exception_tables(pt_elr(regs));
	if (fixup) {
		pt_set_elr(regs, fixup->fixup);
		return;
	}

	/* Things are looking very, very bad now */
	bust_spinlocks(1);
	printk(KERN_EMERG "Unable to handle kernel paging request at "
		"virtual address 0x%08lx, regs %p\n", address, regs);
	die("Bad Kernel VA", regs, SIGKILL);
}


void read_protection_fault(struct pt_regs *regs)
{
	unsigned long badvadr = pt_badva(regs);

	do_page_fault(badvadr, FLT_LOAD, regs);
}

void write_protection_fault(struct pt_regs *regs)
{
	unsigned long badvadr = pt_badva(regs);

	do_page_fault(badvadr, FLT_STORE, regs);
}

void execute_protection_fault(struct pt_regs *regs)
{
	unsigned long badvadr = pt_badva(regs);

	do_page_fault(badvadr, FLT_IFETCH, regs);
}
Commit	Line	Data
08dbd0f8	1	// SPDX-License-Identifier: GPL-2.0-only
499236d9 RK	2	/*
	3	* Memory fault handling for Hexagon
	4	*
e1858b2a	5	* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
499236d9 RK	6	*/
	7
	8	/*
	9	* Page fault handling for the Hexagon Virtual Machine.
	10	* Can also be called by a native port emulating the HVM
	11	* execptions.
	12	*/
	13
	14	#include <asm/pgtable.h>
	15	#include <asm/traps.h>
7c0f6ba6	16	#include <linux/uaccess.h>
499236d9	17	#include <linux/mm.h>
3f07c014	18	#include <linux/sched/signal.h>
499236d9	19	#include <linux/signal.h>
1e8fb9c3	20	#include <linux/extable.h>
499236d9 RK	21	#include <linux/hardirq.h>
	22
	23	/*
	24	* Decode of hardware exception sends us to one of several
	25	* entry points. At each, we generate canonical arguments
	26	* for handling by the abstract memory management code.
	27	*/
	28	#define FLT_IFETCH -1
	29	#define FLT_LOAD 0
	30	#define FLT_STORE 1
	31
	32
	33	/*
	34	* Canonical page fault handler
	35	*/
	36	void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
	37	{
	38	struct vm_area_struct *vma;
	39	struct mm_struct *mm = current->mm;
1a4bd979	40	int si_signo;
499236d9	41	int si_code = SEGV_MAPERR;
50a7ca3c	42	vm_fault_t fault;
499236d9	43	const struct exception_table_entry *fixup;
759496ba	44	unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
499236d9 RK	45
	46	/*
	47	* If we're in an interrupt or have no user context,
	48	* then must not take the fault.
	49	*/
	50	if (unlikely(in_interrupt() \|\| !mm))
	51	goto no_context;
	52
	53	local_irq_enable();
	54
759496ba JW	55	if (user_mode(regs))
759496ba JW	56	flags \|= FAULT_FLAG_USER;
393a86af	57	retry:
499236d9 RK	58	down_read(&mm->mmap_sem);
	59	vma = find_vma(mm, address);
	60	if (!vma)
	61	goto bad_area;
	62
	63	if (vma->vm_start <= address)
	64	goto good_area;
	65
	66	if (!(vma->vm_flags & VM_GROWSDOWN))
	67	goto bad_area;
	68
	69	if (expand_stack(vma, address))
	70	goto bad_area;
	71
	72	good_area:
	73	/* Address space is OK. Now check access rights. */
	74	si_code = SEGV_ACCERR;
	75
	76	switch (cause) {
	77	case FLT_IFETCH:
	78	if (!(vma->vm_flags & VM_EXEC))
	79	goto bad_area;
	80	break;
	81	case FLT_LOAD:
	82	if (!(vma->vm_flags & VM_READ))
	83	goto bad_area;
	84	break;
	85	case FLT_STORE:
	86	if (!(vma->vm_flags & VM_WRITE))
	87	goto bad_area;
759496ba	88	flags \|= FAULT_FLAG_WRITE;
499236d9 RK	89	break;
	90	}
	91
dcddffd4	92	fault = handle_mm_fault(vma, address, flags);
393a86af KC	93
	94	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	95	return;
499236d9 RK	96
	97	/* The most common case -- we are done. */
	98	if (likely(!(fault & VM_FAULT_ERROR))) {
393a86af KC	99	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	100	if (fault & VM_FAULT_MAJOR)
	101	current->maj_flt++;
	102	else
	103	current->min_flt++;
	104	if (fault & VM_FAULT_RETRY) {
	105	flags &= ~FAULT_FLAG_ALLOW_RETRY;
45cac65b	106	flags \|= FAULT_FLAG_TRIED;
393a86af KC	107	goto retry;
	108	}
	109	}
499236d9 RK	110
	111	up_read(&mm->mmap_sem);
	112	return;
	113	}
	114
	115	up_read(&mm->mmap_sem);
	116
	117	/* Handle copyin/out exception cases */
	118	if (!user_mode(regs))
	119	goto no_context;
	120
	121	if (fault & VM_FAULT_OOM) {
	122	pagefault_out_of_memory();
	123	return;
	124	}
	125
	126	/* User-mode address is in the memory map, but we are
	127	* unable to fix up the page fault.
	128	*/
	129	if (fault & VM_FAULT_SIGBUS) {
1a4bd979 EB	130	si_signo = SIGBUS;
1a4bd979 EB	131	si_code = BUS_ADRERR;
499236d9 RK	132	}
	133	/* Address is not in the memory map */
	134	else {
1a4bd979 EB	135	si_signo = SIGSEGV;
1a4bd979 EB	136	si_code = SEGV_ACCERR;
499236d9	137	}
2e1661d2	138	force_sig_fault(si_signo, si_code, (void __user *)address);
499236d9 RK	139	return;
	140
	141	bad_area:
	142	up_read(&mm->mmap_sem);
	143
	144	if (user_mode(regs)) {
2e1661d2	145	force_sig_fault(SIGSEGV, si_code, (void __user *)address);
499236d9 RK	146	return;
	147	}
	148	/* Kernel-mode fault falls through */
	149
	150	no_context:
	151	fixup = search_exception_tables(pt_elr(regs));
	152	if (fixup) {
	153	pt_set_elr(regs, fixup->fixup);
	154	return;
	155	}
	156
	157	/* Things are looking very, very bad now */
	158	bust_spinlocks(1);
	159	printk(KERN_EMERG "Unable to handle kernel paging request at "
	160	"virtual address 0x%08lx, regs %p\n", address, regs);
	161	die("Bad Kernel VA", regs, SIGKILL);
	162	}
	163
	164
	165	void read_protection_fault(struct pt_regs *regs)
	166	{
	167	unsigned long badvadr = pt_badva(regs);
	168
	169	do_page_fault(badvadr, FLT_LOAD, regs);
	170	}
	171
	172	void write_protection_fault(struct pt_regs *regs)
	173	{
	174	unsigned long badvadr = pt_badva(regs);
	175
	176	do_page_fault(badvadr, FLT_STORE, regs);
	177	}
	178
	179	void execute_protection_fault(struct pt_regs *regs)
	180	{
	181	unsigned long badvadr = pt_badva(regs);
	182
	183	do_page_fault(badvadr, FLT_IFETCH, regs);
	184	}