arch/parisc/mm/fault.c - kernel/msm-4.19 - Gitiles

 /* $Id: fault.c,v 1.5 2000/01/26 16:20:29 jsm Exp $
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  *
  * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
  * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
  * Copyright 1999 Hewlett Packard Co.
  *
  */

 #include <linux/mm.h>
 #include <linux/ptrace.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>

 #include <asm/uaccess.h>
 #include <asm/traps.h>

 #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
 			 /*  dumped to the console via printk)          */


 /* Defines for parisc_acctyp()	*/
 #define READ		0
 #define WRITE		1

 /* Various important other fields */
 #define bit22set(x)		(x & 0x00000200)
 #define bits23_25set(x)		(x & 0x000001c0)
 #define isGraphicsFlushRead(x)	((x & 0xfc003fdf) == 0x04001a80)
 				/* extended opcode is 0x6a */

 #define BITSSET		0x1c0	/* for identifying LDCW */


 DEFINE_PER_CPU(struct exception_data, exception_data);

 /*
  * parisc_acctyp(unsigned int inst) --
  *    Given a PA-RISC memory access instruction, determine if the
  *    the instruction would perform a memory read or memory write
  *    operation.
  *
  *    This function assumes that the given instruction is a memory access
  *    instruction (i.e. you should really only call it if you know that
  *    the instruction has generated some sort of a memory access fault).
  *
  * Returns:
  *   VM_READ  if read operation
  *   VM_WRITE if write operation
  *   VM_EXEC  if execute operation
  */
 static unsigned long
 parisc_acctyp(unsigned long code, unsigned int inst)
 {
 	if (code == 6 || code == 16)
 	    return VM_EXEC;

 	switch (inst & 0xf0000000) {
 	case 0x40000000: /* load */
 	case 0x50000000: /* new load */
 		return VM_READ;

 	case 0x60000000: /* store */
 	case 0x70000000: /* new store */
 		return VM_WRITE;

 	case 0x20000000: /* coproc */
 	case 0x30000000: /* coproc2 */
 		if (bit22set(inst))
 			return VM_WRITE;

 	case 0x0: /* indexed/memory management */
 		if (bit22set(inst)) {
 			/*
 			 * Check for the 'Graphics Flush Read' instruction.
 			 * It resembles an FDC instruction, except for bits
 			 * 20 and 21. Any combination other than zero will
 			 * utilize the block mover functionality on some
 			 * older PA-RISC platforms.  The case where a block
 			 * move is performed from VM to graphics IO space
 			 * should be treated as a READ.
 			 *
 			 * The significance of bits 20,21 in the FDC
 			 * instruction is:
 			 *
 			 *   00  Flush data cache (normal instruction behavior)
 			 *   01  Graphics flush write  (IO space -> VM)
 			 *   10  Graphics flush read   (VM -> IO space)
 			 *   11  Graphics flush read/write (VM <-> IO space)
 			 */
 			if (isGraphicsFlushRead(inst))
 				return VM_READ;
 			return VM_WRITE;
 		} else {
 			/*
 			 * Check for LDCWX and LDCWS (semaphore instructions).
 			 * If bits 23 through 25 are all 1's it is one of
 			 * the above two instructions and is a write.
 			 *
 			 * Note: With the limited bits we are looking at,
 			 * this will also catch PROBEW and PROBEWI. However,
 			 * these should never get in here because they don't
 			 * generate exceptions of the type:
 			 *   Data TLB miss fault/data page fault
 			 *   Data memory protection trap
 			 */
 			if (bits23_25set(inst) == BITSSET)
 				return VM_WRITE;
 		}
 		return VM_READ; /* Default */
 	}
 	return VM_READ; /* Default */
 }

 #undef bit22set
 #undef bits23_25set
 #undef isGraphicsFlushRead
 #undef BITSSET


 #if 0
 /* This is the treewalk to find a vma which is the highest that has
  * a start < addr.  We're using find_vma_prev instead right now, but
  * we might want to use this at some point in the future.  Probably
  * not, but I want it committed to CVS so I don't lose it :-)
  */
 			while (tree != vm_avl_empty) {
 				if (tree->vm_start > addr) {
 					tree = tree->vm_avl_left;
 				} else {
 					prev = tree;
 					if (prev->vm_next == NULL)
 						break;
 					if (prev->vm_next->vm_start > addr)
 						break;
 					tree = tree->vm_avl_right;
 				}
 			}
 #endif

 void do_page_fault(struct pt_regs *regs, unsigned long code,
 			      unsigned long address)
 {
 	struct vm_area_struct *vma, *prev_vma;
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
 	const struct exception_table_entry *fix;
 	unsigned long acc_type;

 	if (in_interrupt() || !mm)
 		goto no_context;

 	down_read(&mm->mmap_sem);
 	vma = find_vma_prev(mm, address, &prev_vma);
 	if (!vma || address < vma->vm_start)
 		goto check_expansion;
 /*
  * Ok, we have a good vm_area for this memory access. We still need to
  * check the access permissions.
  */

 good_area:

 	acc_type = parisc_acctyp(code,regs->iir);

 	if ((vma->vm_flags & acc_type) != acc_type)
 		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.
 	 */

 	switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) {
 	      case VM_FAULT_MINOR:
 		++current->min_flt;
 		break;
 	      case VM_FAULT_MAJOR:
 		++current->maj_flt;
 		break;
 	      case VM_FAULT_SIGBUS:
 		/*
 		 * We hit a shared mapping outside of the file, or some
 		 * other thing happened to us that made us unable to
 		 * handle the page fault gracefully.
 		 */
 		goto bad_area;
 	      default:
 		goto out_of_memory;
 	}
 	up_read(&mm->mmap_sem);
 	return;

 check_expansion:
 	vma = prev_vma;
 	if (vma && (expand_stack(vma, address) == 0))
 		goto good_area;

 /*
  * Something tried to access memory that isn't in our memory map..
  */
 bad_area:
 	up_read(&mm->mmap_sem);

 	if (user_mode(regs)) {
 		struct siginfo si;

 #ifdef PRINT_USER_FAULTS
 		printk(KERN_DEBUG "\n");
 		printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",
 		    tsk->pid, tsk->comm, code, address);
 		if (vma) {
 			printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",
 					vma->vm_start, vma->vm_end);
 		}
 		show_regs(regs);
 #endif
 		/* FIXME: actually we need to get the signo and code correct */
 		si.si_signo = SIGSEGV;
 		si.si_errno = 0;
 		si.si_code = SEGV_MAPERR;
 		si.si_addr = (void __user *) address;
 		force_sig_info(SIGSEGV, &si, current);
 		return;
 	}

 no_context:

 	if (!user_mode(regs)) {
 		fix = search_exception_tables(regs->iaoq[0]);

 		if (fix) {
 			struct exception_data *d;

 			d = &__get_cpu_var(exception_data);
 			d->fault_ip = regs->iaoq[0];
 			d->fault_space = regs->isr;
 			d->fault_addr = regs->ior;

 			regs->iaoq[0] = ((fix->fixup) & ~3);

 			/*
 			 * NOTE: In some cases the faulting instruction
 			 * may be in the delay slot of a branch. We
 			 * don't want to take the branch, so we don't
 			 * increment iaoq[1], instead we set it to be
 			 * iaoq[0]+4, and clear the B bit in the PSW
 			 */

 			regs->iaoq[1] = regs->iaoq[0] + 4;
 			regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */

 			return;
 		}
 	}

 	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);

   out_of_memory:
 	up_read(&mm->mmap_sem);
 	printk(KERN_CRIT "VM: killing process %s\n", current->comm);
 	if (user_mode(regs))
 		do_exit(SIGKILL);
 	goto no_context;
 }
	/* $Id: fault.c,v 1.5 2000/01/26 16:20:29 jsm Exp $
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	*
	* Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
	* Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
	* Copyright 1999 Hewlett Packard Co.
	*
	*/

	#include <linux/mm.h>
	#include <linux/ptrace.h>
	#include <linux/sched.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>

	#include <asm/uaccess.h>
	#include <asm/traps.h>

	#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
	/* dumped to the console via printk) */


	/* Defines for parisc_acctyp() */
	#define READ 0
	#define WRITE 1

	/* Various important other fields */
	#define bit22set(x) (x & 0x00000200)
	#define bits23_25set(x) (x & 0x000001c0)
	#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)
	/* extended opcode is 0x6a */

	#define BITSSET 0x1c0 /* for identifying LDCW */


	DEFINE_PER_CPU(struct exception_data, exception_data);

	/*
	* parisc_acctyp(unsigned int inst) --
	* Given a PA-RISC memory access instruction, determine if the
	* the instruction would perform a memory read or memory write
	* operation.
	*
	* This function assumes that the given instruction is a memory access
	* instruction (i.e. you should really only call it if you know that
	* the instruction has generated some sort of a memory access fault).
	*
	* Returns:
	* VM_READ if read operation
	* VM_WRITE if write operation
	* VM_EXEC if execute operation
	*/
	static unsigned long
	parisc_acctyp(unsigned long code, unsigned int inst)
	{
	if (code == 6 \|\| code == 16)
	return VM_EXEC;

	switch (inst & 0xf0000000) {
	case 0x40000000: /* load */
	case 0x50000000: /* new load */
	return VM_READ;

	case 0x60000000: /* store */
	case 0x70000000: /* new store */
	return VM_WRITE;

	case 0x20000000: /* coproc */
	case 0x30000000: /* coproc2 */
	if (bit22set(inst))
	return VM_WRITE;

	case 0x0: /* indexed/memory management */
	if (bit22set(inst)) {
	/*
	* Check for the 'Graphics Flush Read' instruction.
	* It resembles an FDC instruction, except for bits
	* 20 and 21. Any combination other than zero will
	* utilize the block mover functionality on some
	* older PA-RISC platforms. The case where a block
	* move is performed from VM to graphics IO space
	* should be treated as a READ.
	*
	* The significance of bits 20,21 in the FDC
	* instruction is:
	*
	* 00 Flush data cache (normal instruction behavior)
	* 01 Graphics flush write (IO space -> VM)
	* 10 Graphics flush read (VM -> IO space)
	* 11 Graphics flush read/write (VM <-> IO space)
	*/
	if (isGraphicsFlushRead(inst))
	return VM_READ;
	return VM_WRITE;
	} else {
	/*
	* Check for LDCWX and LDCWS (semaphore instructions).
	* If bits 23 through 25 are all 1's it is one of
	* the above two instructions and is a write.
	*
	* Note: With the limited bits we are looking at,
	* this will also catch PROBEW and PROBEWI. However,
	* these should never get in here because they don't
	* generate exceptions of the type:
	* Data TLB miss fault/data page fault
	* Data memory protection trap
	*/
	if (bits23_25set(inst) == BITSSET)
	return VM_WRITE;
	}
	return VM_READ; /* Default */
	}
	return VM_READ; /* Default */
	}

	#undef bit22set
	#undef bits23_25set
	#undef isGraphicsFlushRead
	#undef BITSSET


	#if 0
	/* This is the treewalk to find a vma which is the highest that has
	* a start < addr. We're using find_vma_prev instead right now, but
	* we might want to use this at some point in the future. Probably
	* not, but I want it committed to CVS so I don't lose it :-)
	*/
	while (tree != vm_avl_empty) {
	if (tree->vm_start > addr) {
	tree = tree->vm_avl_left;
	} else {
	prev = tree;
	if (prev->vm_next == NULL)
	break;
	if (prev->vm_next->vm_start > addr)
	break;
	tree = tree->vm_avl_right;
	}
	}
	#endif

	void do_page_fault(struct pt_regs *regs, unsigned long code,
	unsigned long address)
	{
	struct vm_area_struct vma, prev_vma;
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->mm;
	const struct exception_table_entry *fix;
	unsigned long acc_type;

	if (in_interrupt() \|\| !mm)
	goto no_context;

	down_read(&mm->mmap_sem);
	vma = find_vma_prev(mm, address, &prev_vma);
	if (!vma \|\| address < vma->vm_start)
	goto check_expansion;
	/*
	* Ok, we have a good vm_area for this memory access. We still need to
	* check the access permissions.
	*/

	good_area:

	acc_type = parisc_acctyp(code,regs->iir);

	if ((vma->vm_flags & acc_type) != acc_type)
	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.
	*/

	switch (handle_mm_fault(mm, vma, address, (acc_type & VM_WRITE) != 0)) {
	case VM_FAULT_MINOR:
	++current->min_flt;
	break;
	case VM_FAULT_MAJOR:
	++current->maj_flt;
	break;
	case VM_FAULT_SIGBUS:
	/*
	* We hit a shared mapping outside of the file, or some
	* other thing happened to us that made us unable to
	* handle the page fault gracefully.
	*/
	goto bad_area;
	default:
	goto out_of_memory;
	}
	up_read(&mm->mmap_sem);
	return;

	check_expansion:
	vma = prev_vma;
	if (vma && (expand_stack(vma, address) == 0))
	goto good_area;

	/*
	* Something tried to access memory that isn't in our memory map..
	*/
	bad_area:
	up_read(&mm->mmap_sem);

	if (user_mode(regs)) {
	struct siginfo si;

	#ifdef PRINT_USER_FAULTS
	printk(KERN_DEBUG "\n");
	printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",
	tsk->pid, tsk->comm, code, address);
	if (vma) {
	printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",
	vma->vm_start, vma->vm_end);
	}
	show_regs(regs);
	#endif
	/* FIXME: actually we need to get the signo and code correct */
	si.si_signo = SIGSEGV;
	si.si_errno = 0;
	si.si_code = SEGV_MAPERR;
	si.si_addr = (void __user *) address;
	force_sig_info(SIGSEGV, &si, current);
	return;
	}

	no_context:

	if (!user_mode(regs)) {
	fix = search_exception_tables(regs->iaoq[0]);

	if (fix) {
	struct exception_data *d;

	d = &__get_cpu_var(exception_data);
	d->fault_ip = regs->iaoq[0];
	d->fault_space = regs->isr;
	d->fault_addr = regs->ior;

	regs->iaoq[0] = ((fix->fixup) & ~3);

	/*
	* NOTE: In some cases the faulting instruction
	* may be in the delay slot of a branch. We
	* don't want to take the branch, so we don't
	* increment iaoq[1], instead we set it to be
	* iaoq[0]+4, and clear the B bit in the PSW
	*/

	regs->iaoq[1] = regs->iaoq[0] + 4;
	regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */

	return;
	}
	}

	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);

	out_of_memory:
	up_read(&mm->mmap_sem);
	printk(KERN_CRIT "VM: killing process %s\n", current->comm);
	if (user_mode(regs))
	do_exit(SIGKILL);
	goto no_context;
	}