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/* $Id: fault.c,v 1.49 2001/10/06 19:46:00 lethal Exp $
*
* linux/arch/sh/mm/fault.c
* Copyright (C) 1999 Niibe Yutaka
*
* Based on linux/arch/i386/mm/fault.c:
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/hardirq.h>
#include <asm/mmu_context.h>
extern void die(const char *,struct pt_regs *,long);
/*
* Ugly, ugly, but the goto's result in better assembly..
*/
int __verify_write(const void * addr, unsigned long size)
{
struct vm_area_struct * vma;
unsigned long start = (unsigned long) addr;
if (!size)
return 1;
vma = find_vma(current->mm, start);
if (!vma)
goto bad_area;
if (vma->vm_start > start)
goto check_stack;
good_area:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
size--;
size += start & ~PAGE_MASK;
size >>= PAGE_SHIFT;
start &= PAGE_MASK;
for (;;) {
if (handle_mm_fault(current->mm, vma, start, 1) <= 0)
goto bad_area;
if (!size)
break;
size--;
start += PAGE_SIZE;
if (start < vma->vm_end)
continue;
vma = vma->vm_next;
if (!vma || vma->vm_start != start)
goto bad_area;
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;;
}
return 1;
check_stack:
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, start) == 0)
goto good_area;
bad_area:
return 0;
}
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
unsigned long page;
unsigned long fixup;
tsk = current;
mm = tsk->mm;
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
if (in_interrupt() || !mm)
goto no_context;
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;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
if (writeaccess) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
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.
*/
survive:
switch (handle_mm_fault(mm, vma, address, writeaccess)) {
case 1:
tsk->min_flt++;
break;
case 2:
tsk->maj_flt++;
break;
case 0:
goto do_sigbus;
default:
goto out_of_memory;
}
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);
if (user_mode(regs)) {
tsk->thread.address = address;
tsk->thread.error_code = writeaccess;
force_sig(SIGSEGV, tsk);
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
fixup = search_exception_table(regs->pc);
if (fixup != 0) {
regs->pc = fixup;
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*
*/
if (address < 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 address %08lx\n", address);
printk(KERN_ALERT "pc = %08lx\n", regs->pc);
asm volatile("mov.l %1, %0"
: "=r" (page)
: "m" (__m(MMU_TTB)));
if (page) {
page = ((unsigned long *) page)[address >> 22];
printk(KERN_ALERT "*pde = %08lx\n", page);
if (page & _PAGE_PRESENT) {
page &= PAGE_MASK;
address &= 0x003ff000;
page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
printk(KERN_ALERT "*pte = %08lx\n", page);
}
}
die("Oops", regs, writeaccess);
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 (current->pid == 1) {
current->policy |= SCHED_YIELD;
schedule();
down_read(&mm->mmap_sem);
goto survive;
}
printk("VM: killing process %s\n", tsk->comm);
if (user_mode(regs))
do_exit(SIGKILL);
goto no_context;
do_sigbus:
up_read(&mm->mmap_sem);
/*
* Send a sigbus, regardless of whether we were in kernel
* or user mode.
*/
tsk->thread.address = address;
tsk->thread.error_code = writeaccess;
tsk->thread.trap_no = 14;
force_sig(SIGBUS, tsk);
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
goto no_context;
}
/*
* Called with interrupt disabled.
*/
asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
unsigned long address)
{
pgd_t *dir;
pmd_t *pmd;
pte_t *pte;
pte_t entry;
if (address >= P3SEG && address < P4SEG)
dir = pgd_offset_k(address);
else if (address >= TASK_SIZE)
return 1;
else
dir = pgd_offset(current->mm, address);
pmd = pmd_offset(dir, address);
if (pmd_none(*pmd))
return 1;
if (pmd_bad(*pmd)) {
pmd_ERROR(*pmd);
pmd_clear(pmd);
return 1;
}
pte = pte_offset(pmd, address);
entry = *pte;
if (pte_none(entry) || pte_not_present(entry)
|| (writeaccess && !pte_write(entry)))
return 1;
if (writeaccess)
entry = pte_mkdirty(entry);
entry = pte_mkyoung(entry);
#if defined(__SH4__)
/*
* ITLB is not affected by "ldtlb" instruction.
* So, we need to flush the entry by ourselves.
*/
__flush_tlb_page(get_asid(), address&PAGE_MASK);
#endif
set_pte(pte, entry);
update_mmu_cache(NULL, address, entry);
return 0;
}
void update_mmu_cache(struct vm_area_struct * vma,
unsigned long address, pte_t pte)
{
unsigned long flags;
unsigned long pteval;
unsigned long vpn;
#if defined(__SH4__)
struct page *page;
unsigned long ptea;
#endif
/* Ptrace may call this routine. */
if (vma && current->active_mm != vma->vm_mm)
return;
#if defined(__SH4__)
page = pte_page(pte);
if (VALID_PAGE(page) && !test_bit(PG_mapped, &page->flags)) {
unsigned long phys = pte_val(pte) & PTE_PHYS_MASK;
__flush_wback_region((void *)P1SEGADDR(phys), PAGE_SIZE);
__set_bit(PG_mapped, &page->flags);
}
#endif
save_and_cli(flags);
/* Set PTEH register */
vpn = (address & MMU_VPN_MASK) | get_asid();
ctrl_outl(vpn, MMU_PTEH);
pteval = pte_val(pte);
#if defined(__SH4__)
/* Set PTEA register */
/* TODO: make this look less hacky */
ptea = ((pteval >> 28) & 0xe) | (pteval & 0x1);
ctrl_outl(ptea, MMU_PTEA);
#endif
/* Set PTEL register */
pteval &= _PAGE_FLAGS_HARDWARE_MASK; /* drop software flags */
/* conveniently, we want all the software flags to be 0 anyway */
ctrl_outl(pteval, MMU_PTEL);
/* Load the TLB */
asm volatile("ldtlb": /* no output */ : /* no input */ : "memory");
restore_flags(flags);
}
void __flush_tlb_page(unsigned long asid, unsigned long page)
{
unsigned long addr, data;
/*
* NOTE: PTEH.ASID should be set to this MM
* _AND_ we need to write ASID to the array.
*
* It would be simple if we didn't need to set PTEH.ASID...
*/
#if defined(__sh3__)
addr = MMU_TLB_ADDRESS_ARRAY |(page & 0x1F000)| MMU_PAGE_ASSOC_BIT;
data = (page & 0xfffe0000) | asid; /* VALID bit is off */
ctrl_outl(data, addr);
#elif defined(__SH4__)
addr = MMU_UTLB_ADDRESS_ARRAY | MMU_PAGE_ASSOC_BIT;
data = page | asid; /* VALID bit is off */
jump_to_P2();
ctrl_outl(data, addr);
back_to_P1();
#endif
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
unsigned long flags;
unsigned long asid;
unsigned long saved_asid = MMU_NO_ASID;
asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
page &= PAGE_MASK;
save_and_cli(flags);
if (vma->vm_mm != current->mm) {
saved_asid = get_asid();
set_asid(asid);
}
__flush_tlb_page(asid, page);
if (saved_asid != MMU_NO_ASID)
set_asid(saved_asid);
restore_flags(flags);
}
}
void flush_tlb_range(struct mm_struct *mm, unsigned long start,
unsigned long end)
{
if (mm->context != NO_CONTEXT) {
unsigned long flags;
int size;
save_and_cli(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size > (MMU_NTLB_ENTRIES/4)) { /* Too many TLB to flush */
mm->context = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
} else {
unsigned long asid = mm->context&MMU_CONTEXT_ASID_MASK;
unsigned long saved_asid = MMU_NO_ASID;
start &= PAGE_MASK;
end += (PAGE_SIZE - 1);
end &= PAGE_MASK;
if (mm != current->mm) {
saved_asid = get_asid();
set_asid(asid);
}
while (start < end) {
__flush_tlb_page(asid, start);
start += PAGE_SIZE;
}
if (saved_asid != MMU_NO_ASID)
set_asid(saved_asid);
}
restore_flags(flags);
}
}
void flush_tlb_mm(struct mm_struct *mm)
{
/* Invalidate all TLB of this process. */
/* Instead of invalidating each TLB, we get new MMU context. */
if (mm->context != NO_CONTEXT) {
unsigned long flags;
save_and_cli(flags);
mm->context = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
restore_flags(flags);
}
}
void flush_tlb_all(void)
{
unsigned long flags, status;
/*
* Flush all the TLB.
*
* Write to the MMU control register's bit:
* TF-bit for SH-3, TI-bit for SH-4.
* It's same position, bit #2.
*/
save_and_cli(flags);
status = ctrl_inl(MMUCR);
status |= 0x04;
ctrl_outl(status, MMUCR);
restore_flags(flags);
}
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