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linux/arch/sh64/mm/fault.c

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/*
* 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.
*
* arch/sh64/mm/fault.c
*
* Copyright (C) 2000, 2001 Paolo Alberelli
* Copyright (C) 2003 Richard Curnow (/proc/tlb, bug fixes)
* Copyright (C) 2003 Paul Mundt
*
*/
#include <linux/signal.h>
#include <linux/rwsem.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/interrupt.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/tlb.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/registers.h> /* required by inline asm statements */
#if defined(CONFIG_SH64_PROC_TLB)
#include <linux/init.h>
#include <linux/proc_fs.h>
/* Count numbers of tlb refills in each region */
static unsigned long long calls_to_update_mmu_cache = 0ULL;
static unsigned long long calls_to_flush_tlb_page = 0ULL;
static unsigned long long calls_to_flush_tlb_range = 0ULL;
static unsigned long long calls_to_flush_tlb_mm = 0ULL;
static unsigned long long calls_to_flush_tlb_all = 0ULL;
unsigned long long calls_to_do_slow_page_fault = 0ULL;
unsigned long long calls_to_do_fast_page_fault = 0ULL;
/* Count size of ranges for flush_tlb_range */
static unsigned long long flush_tlb_range_1 = 0ULL;
static unsigned long long flush_tlb_range_2 = 0ULL;
static unsigned long long flush_tlb_range_3_4 = 0ULL;
static unsigned long long flush_tlb_range_5_7 = 0ULL;
static unsigned long long flush_tlb_range_8_11 = 0ULL;
static unsigned long long flush_tlb_range_12_15 = 0ULL;
static unsigned long long flush_tlb_range_16_up = 0ULL;
static unsigned long long page_not_present = 0ULL;
#endif
extern void die(const char *,struct pt_regs *,long);
#define PFLAG(val,flag) (( (val) & (flag) ) ? #flag : "" )
#define PPROT(flag) PFLAG(pgprot_val(prot),flag)
static inline void print_prots(pgprot_t prot)
{
printk("prot is 0x%08lx\n",pgprot_val(prot));
printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
}
static inline void print_vma(struct vm_area_struct *vma)
{
printk("vma start 0x%08lx\n", vma->vm_start);
printk("vma end 0x%08lx\n", vma->vm_end);
print_prots(vma->vm_page_prot);
printk("vm_flags 0x%08lx\n", vma->vm_flags);
}
static inline void print_task(struct task_struct *tsk)
{
printk("Task pid %d\n", tsk->pid);
}
static pte_t *lookup_pte(struct mm_struct *mm, unsigned long address)
{
pgd_t *dir;
pmd_t *pmd;
pte_t *pte;
pte_t entry;
dir = pgd_offset(mm, address);
if (pgd_none(*dir)) {
return NULL;
}
pmd = pmd_offset(dir, address);
if (pmd_none(*pmd)) {
return NULL;
}
pte = pte_offset_kernel(pmd, address);
entry = *pte;
if (pte_none(entry)) {
return NULL;
}
if (!pte_present(entry)) {
return NULL;
}
return pte;
}
/*
* 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 textaccess, unsigned long address)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
const struct exception_table_entry *fixup;
pte_t *pte;
int fault;
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_do_slow_page_fault;
#endif
/* SIM
* Note this is now called with interrupts still disabled
* This is to cope with being called for a missing IO port
* address with interrupts disabled. This should be fixed as
* soon as we have a better 'fast path' miss handler.
*
* Plus take care how you try and debug this stuff.
* For example, writing debug data to a port which you
* have just faulted on is not going to work.
*/
tsk = current;
mm = tsk->mm;
/* Not an IO address, so reenable interrupts */
local_irq_enable();
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
if (in_atomic() || !mm)
goto no_context;
/* TLB misses upon some cache flushes get done under cli() */
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma) {
#ifdef DEBUG_FAULT
print_task(tsk);
printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
__FUNCTION__,__LINE__,
address,regs->pc,textaccess,writeaccess);
show_regs(regs);
#endif
goto bad_area;
}
if (vma->vm_start <= address) {
goto good_area;
}
if (!(vma->vm_flags & VM_GROWSDOWN)) {
#ifdef DEBUG_FAULT
print_task(tsk);
printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
__FUNCTION__,__LINE__,
address,regs->pc,textaccess,writeaccess);
show_regs(regs);
print_vma(vma);
#endif
goto bad_area;
}
if (expand_stack(vma, address)) {
#ifdef DEBUG_FAULT
print_task(tsk);
printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
__FUNCTION__,__LINE__,
address,regs->pc,textaccess,writeaccess);
show_regs(regs);
#endif
goto bad_area;
}
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
if (textaccess) {
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
} else {
if (writeaccess) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
if (!(vma->vm_flags & VM_READ))
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:
fault = handle_mm_fault(mm, vma, address, writeaccess);
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
else if (fault & VM_FAULT_SIGBUS)
goto do_sigbus;
BUG();
}
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
/* If we get here, the page fault has been handled. Do the TLB refill
now from the newly-setup PTE, to avoid having to fault again right
away on the same instruction. */
pte = lookup_pte (mm, address);
if (!pte) {
/* From empirical evidence, we can get here, due to
!pte_present(pte). (e.g. if a swap-in occurs, and the page
is swapped back out again before the process that wanted it
gets rescheduled?) */
goto no_pte;
}
__do_tlb_refill(address, textaccess, pte);
no_pte:
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:
#ifdef DEBUG_FAULT
printk("fault:bad area\n");
#endif
up_read(&mm->mmap_sem);
if (user_mode(regs)) {
static int count=0;
siginfo_t info;
if (count < 4) {
/* This is really to help debug faults when starting
* usermode, so only need a few */
count++;
printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
address, current->pid, current->comm,
(unsigned long) regs->pc);
#if 0
show_regs(regs);
#endif
}
if (is_init(tsk)) {
panic("INIT had user mode bad_area\n");
}
tsk->thread.address = address;
tsk->thread.error_code = writeaccess;
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_addr = (void *) address;
force_sig_info(SIGSEGV, &info, tsk);
return;
}
no_context:
#ifdef DEBUG_FAULT
printk("fault:No context\n");
#endif
/* Are we prepared to handle this kernel fault? */
fixup = search_exception_tables(regs->pc);
if (fixup) {
regs->pc = fixup->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%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
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:
if (is_init(current)) {
panic("INIT out of memory\n");
yield();
goto survive;
}
printk("fault:Out of memory\n");
up_read(&mm->mmap_sem);
if (is_init(current)) {
yield();
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:
printk("fault:Do sigbus\n");
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;
}
void flush_tlb_all(void);
void update_mmu_cache(struct vm_area_struct * vma,
unsigned long address, pte_t pte)
{
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_update_mmu_cache;
#endif
/*
* This appears to get called once for every pte entry that gets
* established => I don't think it's efficient to try refilling the
* TLBs with the pages - some may not get accessed even. Also, for
* executable pages, it is impossible to determine reliably here which
* TLB they should be mapped into (or both even).
*
* So, just do nothing here and handle faults on demand. In the
* TLBMISS handling case, the refill is now done anyway after the pte
* has been fixed up, so that deals with most useful cases.
*/
}
static void __flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
unsigned long long match, pteh=0, lpage;
unsigned long tlb;
struct mm_struct *mm;
mm = vma->vm_mm;
if (mm->context == NO_CONTEXT)
return;
/*
* Sign-extend based on neff.
*/
lpage = (page & NEFF_SIGN) ? (page | NEFF_MASK) : page;
match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;
match |= lpage;
/* Do ITLB : don't bother for pages in non-exectutable VMAs */
if (vma->vm_flags & VM_EXEC) {
for_each_itlb_entry(tlb) {
asm volatile ("getcfg %1, 0, %0"
: "=r" (pteh)
: "r" (tlb) );
if (pteh == match) {
__flush_tlb_slot(tlb);
break;
}
}
}
/* Do DTLB : any page could potentially be in here. */
for_each_dtlb_entry(tlb) {
asm volatile ("getcfg %1, 0, %0"
: "=r" (pteh)
: "r" (tlb) );
if (pteh == match) {
__flush_tlb_slot(tlb);
break;
}
}
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
unsigned long flags;
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_flush_tlb_page;
#endif
if (vma->vm_mm) {
page &= PAGE_MASK;
local_irq_save(flags);
__flush_tlb_page(vma, page);
local_irq_restore(flags);
}
}
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
unsigned long flags;
unsigned long long match, pteh=0, pteh_epn, pteh_low;
unsigned long tlb;
struct mm_struct *mm;
mm = vma->vm_mm;
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_flush_tlb_range;
{
unsigned long size = (end - 1) - start;
size >>= 12; /* divide by PAGE_SIZE */
size++; /* end=start+4096 => 1 page */
switch (size) {
case 1 : flush_tlb_range_1++; break;
case 2 : flush_tlb_range_2++; break;
case 3 ... 4 : flush_tlb_range_3_4++; break;
case 5 ... 7 : flush_tlb_range_5_7++; break;
case 8 ... 11 : flush_tlb_range_8_11++; break;
case 12 ... 15 : flush_tlb_range_12_15++; break;
default : flush_tlb_range_16_up++; break;
}
}
#endif
if (mm->context == NO_CONTEXT)
return;
local_irq_save(flags);
start &= PAGE_MASK;
end &= PAGE_MASK;
match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;
/* Flush ITLB */
for_each_itlb_entry(tlb) {
asm volatile ("getcfg %1, 0, %0"
: "=r" (pteh)
: "r" (tlb) );
pteh_epn = pteh & PAGE_MASK;
pteh_low = pteh & ~PAGE_MASK;
if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
__flush_tlb_slot(tlb);
}
/* Flush DTLB */
for_each_dtlb_entry(tlb) {
asm volatile ("getcfg %1, 0, %0"
: "=r" (pteh)
: "r" (tlb) );
pteh_epn = pteh & PAGE_MASK;
pteh_low = pteh & ~PAGE_MASK;
if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
__flush_tlb_slot(tlb);
}
local_irq_restore(flags);
}
void flush_tlb_mm(struct mm_struct *mm)
{
unsigned long flags;
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_flush_tlb_mm;
#endif
if (mm->context == NO_CONTEXT)
return;
local_irq_save(flags);
mm->context=NO_CONTEXT;
if(mm==current->mm)
activate_context(mm);
local_irq_restore(flags);
}
void flush_tlb_all(void)
{
/* Invalidate all, including shared pages, excluding fixed TLBs */
unsigned long flags, tlb;
#if defined(CONFIG_SH64_PROC_TLB)
++calls_to_flush_tlb_all;
#endif
local_irq_save(flags);
/* Flush each ITLB entry */
for_each_itlb_entry(tlb) {
__flush_tlb_slot(tlb);
}
/* Flush each DTLB entry */
for_each_dtlb_entry(tlb) {
__flush_tlb_slot(tlb);
}
local_irq_restore(flags);
}
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
/* FIXME: Optimize this later.. */
flush_tlb_all();
}
#if defined(CONFIG_SH64_PROC_TLB)
/* Procfs interface to read the performance information */
static int
tlb_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
{
int len=0;
len += sprintf(buf+len, "do_fast_page_fault called %12lld times\n", calls_to_do_fast_page_fault);
len += sprintf(buf+len, "do_slow_page_fault called %12lld times\n", calls_to_do_slow_page_fault);
len += sprintf(buf+len, "update_mmu_cache called %12lld times\n", calls_to_update_mmu_cache);
len += sprintf(buf+len, "flush_tlb_page called %12lld times\n", calls_to_flush_tlb_page);
len += sprintf(buf+len, "flush_tlb_range called %12lld times\n", calls_to_flush_tlb_range);
len += sprintf(buf+len, "flush_tlb_mm called %12lld times\n", calls_to_flush_tlb_mm);
len += sprintf(buf+len, "flush_tlb_all called %12lld times\n", calls_to_flush_tlb_all);
len += sprintf(buf+len, "flush_tlb_range_sizes\n"
" 1 : %12lld\n"
" 2 : %12lld\n"
" 3 - 4 : %12lld\n"
" 5 - 7 : %12lld\n"
" 8 - 11 : %12lld\n"
"12 - 15 : %12lld\n"
"16+ : %12lld\n",
flush_tlb_range_1, flush_tlb_range_2, flush_tlb_range_3_4,
flush_tlb_range_5_7, flush_tlb_range_8_11, flush_tlb_range_12_15,
flush_tlb_range_16_up);
len += sprintf(buf+len, "page not present %12lld times\n", page_not_present);
*eof = 1;
return len;
}
static int __init register_proc_tlb(void)
{
create_proc_read_entry("tlb", 0, NULL, tlb_proc_info, NULL);
return 0;
}
__initcall(register_proc_tlb);
#endif
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