/*
* 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 <linux/uaccess.h>
#include <asm/pgtable.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;
unsigned long flags = 0;
siginfo_t info;
pgd_t *pge;
pud_t *pue;
pte_t *pte;
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 (faulthandler_disabled() || !mm)
goto no_context;
if (user_mode(__frame))
flags |= FAULT_FLAG_USER;
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;
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;
flags |= FAULT_FLAG_WRITE;
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(vma, ear0, flags);
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
else if (fault & VM_FAULT_SIGSEGV)
goto bad_area;
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() */