mirror of https://gitee.com/openkylin/linux.git
213 lines
5.1 KiB
C
213 lines
5.1 KiB
C
/*
|
|
* 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/interrupt.h>
|
|
#include <linux/module.h>
|
|
|
|
#include <asm/setup.h>
|
|
#include <asm/traps.h>
|
|
#include <asm/system.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/pgalloc.h>
|
|
|
|
extern void die_if_kernel(char *, struct pt_regs *, long);
|
|
extern const int frame_extra_sizes[]; /* in m68k/kernel/signal.c */
|
|
|
|
int send_fault_sig(struct pt_regs *regs)
|
|
{
|
|
siginfo_t siginfo = { 0, 0, 0, };
|
|
|
|
siginfo.si_signo = current->thread.signo;
|
|
siginfo.si_code = current->thread.code;
|
|
siginfo.si_addr = (void *)current->thread.faddr;
|
|
#ifdef DEBUG
|
|
printk("send_fault_sig: %p,%d,%d\n", siginfo.si_addr, siginfo.si_signo, siginfo.si_code);
|
|
#endif
|
|
|
|
if (user_mode(regs)) {
|
|
force_sig_info(siginfo.si_signo,
|
|
&siginfo, current);
|
|
} else {
|
|
const struct exception_table_entry *fixup;
|
|
|
|
/* Are we prepared to handle this kernel fault? */
|
|
if ((fixup = search_exception_tables(regs->pc))) {
|
|
struct pt_regs *tregs;
|
|
/* Create a new four word stack frame, discarding the old
|
|
one. */
|
|
regs->stkadj = frame_extra_sizes[regs->format];
|
|
tregs = (struct pt_regs *)((ulong)regs + regs->stkadj);
|
|
tregs->vector = regs->vector;
|
|
tregs->format = 0;
|
|
tregs->pc = fixup->fixup;
|
|
tregs->sr = regs->sr;
|
|
return -1;
|
|
}
|
|
|
|
//if (siginfo.si_signo == SIGBUS)
|
|
// force_sig_info(siginfo.si_signo,
|
|
// &siginfo, current);
|
|
|
|
/*
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
|
* terminate things with extreme prejudice.
|
|
*/
|
|
if ((unsigned long)siginfo.si_addr < PAGE_SIZE)
|
|
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
|
|
else
|
|
printk(KERN_ALERT "Unable to handle kernel access");
|
|
printk(" at virtual address %p\n", siginfo.si_addr);
|
|
die_if_kernel("Oops", regs, 0 /*error_code*/);
|
|
do_exit(SIGKILL);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* This routine handles page faults. It determines the problem, and
|
|
* then passes it off to one of the appropriate routines.
|
|
*
|
|
* error_code:
|
|
* bit 0 == 0 means no page found, 1 means protection fault
|
|
* bit 1 == 0 means read, 1 means write
|
|
*
|
|
* If this routine detects a bad access, it returns 1, otherwise it
|
|
* returns 0.
|
|
*/
|
|
int do_page_fault(struct pt_regs *regs, unsigned long address,
|
|
unsigned long error_code)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct * vma;
|
|
int write, fault;
|
|
|
|
#ifdef DEBUG
|
|
printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",
|
|
regs->sr, regs->pc, address, error_code,
|
|
current->mm->pgd);
|
|
#endif
|
|
|
|
/*
|
|
* 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, address);
|
|
if (!vma)
|
|
goto map_err;
|
|
if (vma->vm_flags & VM_IO)
|
|
goto acc_err;
|
|
if (vma->vm_start <= address)
|
|
goto good_area;
|
|
if (!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto map_err;
|
|
if (user_mode(regs)) {
|
|
/* Accessing the stack below usp is always a bug. The
|
|
"+ 256" is there due to some instructions doing
|
|
pre-decrement on the stack and that doesn't show up
|
|
until later. */
|
|
if (address + 256 < rdusp())
|
|
goto map_err;
|
|
}
|
|
if (expand_stack(vma, address))
|
|
goto map_err;
|
|
|
|
/*
|
|
* Ok, we have a good vm_area for this memory access, so
|
|
* we can handle it..
|
|
*/
|
|
good_area:
|
|
#ifdef DEBUG
|
|
printk("do_page_fault: good_area\n");
|
|
#endif
|
|
write = 0;
|
|
switch (error_code & 3) {
|
|
default: /* 3: write, present */
|
|
/* fall through */
|
|
case 2: /* write, not present */
|
|
if (!(vma->vm_flags & VM_WRITE))
|
|
goto acc_err;
|
|
write++;
|
|
break;
|
|
case 1: /* read, present */
|
|
goto acc_err;
|
|
case 0: /* read, not present */
|
|
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
|
|
goto acc_err;
|
|
}
|
|
|
|
/*
|
|
* 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, address, write ? FAULT_FLAG_WRITE : 0);
|
|
#ifdef DEBUG
|
|
printk("handle_mm_fault returns %d\n",fault);
|
|
#endif
|
|
if (unlikely(fault & VM_FAULT_ERROR)) {
|
|
if (fault & VM_FAULT_OOM)
|
|
goto out_of_memory;
|
|
else if (fault & VM_FAULT_SIGBUS)
|
|
goto bus_err;
|
|
BUG();
|
|
}
|
|
if (fault & VM_FAULT_MAJOR)
|
|
current->maj_flt++;
|
|
else
|
|
current->min_flt++;
|
|
|
|
up_read(&mm->mmap_sem);
|
|
return 0;
|
|
|
|
/*
|
|
* 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(regs))
|
|
goto no_context;
|
|
pagefault_out_of_memory();
|
|
return 0;
|
|
|
|
no_context:
|
|
current->thread.signo = SIGBUS;
|
|
current->thread.faddr = address;
|
|
return send_fault_sig(regs);
|
|
|
|
bus_err:
|
|
current->thread.signo = SIGBUS;
|
|
current->thread.code = BUS_ADRERR;
|
|
current->thread.faddr = address;
|
|
goto send_sig;
|
|
|
|
map_err:
|
|
current->thread.signo = SIGSEGV;
|
|
current->thread.code = SEGV_MAPERR;
|
|
current->thread.faddr = address;
|
|
goto send_sig;
|
|
|
|
acc_err:
|
|
current->thread.signo = SIGSEGV;
|
|
current->thread.code = SEGV_ACCERR;
|
|
current->thread.faddr = address;
|
|
|
|
send_sig:
|
|
up_read(&mm->mmap_sem);
|
|
return send_fault_sig(regs);
|
|
}
|