- 根目录:
- arch
- m32r
- mm
- fault.c
/*
* linux/arch/m32r/mm/fault.c
*
* Copyright (c) 2001, 2002 Hitoshi Yamamoto, and H. Kondo
* Copyright (c) 2004 Naoto Sugai, NIIBE Yutaka
*
* Some code taken from i386 version.
* 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/interrupt.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/m32r.h>
#include <asm/hardirq.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
extern void die(const char *, struct pt_regs *, long);
#ifndef CONFIG_SMP
asmlinkage unsigned int tlb_entry_i_dat;
asmlinkage unsigned int tlb_entry_d_dat;
#define tlb_entry_i tlb_entry_i_dat
#define tlb_entry_d tlb_entry_d_dat
#else
unsigned int tlb_entry_i_dat[NR_CPUS];
unsigned int tlb_entry_d_dat[NR_CPUS];
#define tlb_entry_i tlb_entry_i_dat[smp_processor_id()]
#define tlb_entry_d tlb_entry_d_dat[smp_processor_id()]
#endif
extern void init_tlb(void);
/*======================================================================*
* do_page_fault()
*======================================================================*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*
* ARGUMENT:
* regs : M32R SP reg.
* error_code : See below
* address : M32R MMU MDEVA reg. (Operand ACE)
* : M32R BPC reg. (Instruction ACE)
*
* error_code :
* bit 0 == 0 means no page found, 1 means protection fault
* bit 1 == 0 means read, 1 means write
* bit 2 == 0 means kernel, 1 means user-mode
* bit 3 == 0 means data, 1 means instruction
*======================================================================*/
#define ACE_PROTECTION 1
#define ACE_WRITE 2
#define ACE_USERMODE 4
#define ACE_INSTRUCTION 8
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code,
unsigned long address)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
unsigned long page, addr;
unsigned long flags = 0;
int fault;
siginfo_t info;
/*
* If BPSW IE bit enable --> set PSW IE bit
*/
if (regs->psw & M32R_PSW_BIE)
local_irq_enable();
tsk = current;
info.si_code = SEGV_MAPERR;
/*
* 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
* (error_code & ACE_USERMODE) == 0, and that the fault was not a
* protection error (error_code & ACE_PROTECTION) == 0.
*/
if (address >= TASK_SIZE && !(error_code & ACE_USERMODE))
goto vmalloc_fault;
mm = tsk->mm;
/*
* If we're in an interrupt or have no user context or have pagefaults
* disabled then we must not take the fault.
*/
if (faulthandler_disabled() || !mm)
goto bad_area_nosemaphore;
if (error_code & ACE_USERMODE)
flags |= FAULT_FLAG_USER;
/* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an
* erroneous fault occurring in a code path which already holds mmap_sem
* we will deadlock attempting to validate the fault against the
* address space. Luckily the kernel only validly references user
* space from well defined areas of code, which are listed in the
* exceptions table.
*
* As the vast majority of faults will be valid we will only perform
* the source reference check when there is a possibility of a deadlock.
* Attempt to lock the address space, if we cannot we then validate the
* source. If this is invalid we can skip the address space check,
* thus avoiding the deadlock.
*/
if (!down_read_trylock(&mm->mmap_sem)) {
if ((error_code & ACE_USERMODE) == 0 &&
!search_exception_tables(regs->psw))
goto bad_area_nosemaphore;
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 (error_code & ACE_USERMODE) {
/*
* accessing the stack below "spu" is always a bug.
* The "+ 4" is there due to the push instruction
* doing pre-decrement on the stack and that
* doesn't show up until later..
*/
if (address + 4 < regs->spu)
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:
info.si_code = SEGV_ACCERR;
switch (error_code & (ACE_WRITE|ACE_PROTECTION)) {
default: /* 3: write, present */
/* fall through */
case ACE_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
flags |= FAULT_FLAG_WRITE;
break;
case ACE_PROTECTION: /* read, present */
case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto bad_area;
}
/*
* For instruction access exception, check if the area is executable
*/
if ((error_code & ACE_INSTRUCTION) && !(vma->vm_flags & 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.
*/
addr = (address & PAGE_MASK);
set_thread_fault_code(error_code);
fault = handle_mm_fault(mm, vma, addr, 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)
tsk->maj_flt++;
else
tsk->min_flt++;
set_thread_fault_code(0);
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);
bad_area_nosemaphore:
/* User mode accesses just cause a SIGSEGV */
if (error_code & ACE_USERMODE) {
tsk->thread.address = address;
tsk->thread.error_code = error_code | (address >= TASK_SIZE);
tsk->thread.trap_no = 14;
info.si_signo = SIGSEGV;
info.si_errno = 0;
/* info.si_code has been set above */
info.si_addr = (void __user *)address;
force_sig_info(SIGSEGV, &info, tsk);
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks(1);
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 " printing bpc:\n");
printk("%08lx\n", regs->bpc);
page = *(unsigned long *)MPTB;
page = ((unsigned long *) page)[address >> PGDIR_SHIFT];
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, error_code);
bust_spinlocks(0);
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 (!(error_code & ACE_USERMODE))
goto no_context;
pagefault_out_of_memory();
return;
do_sigbus:
up_read(&mm->mmap_sem);
/* Kernel mode? Handle exception or die */
if (!(error_code & ACE_USERMODE))
goto no_context;
tsk->thread.address = address;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 14;
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void __user *)address;
force_sig_info(SIGBUS, &info, tsk);
return;
vmalloc_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 offset = pgd_index(address);
pgd_t *pgd, *pgd_k;
pmd_t *pmd, *pmd_k;
pte_t *pte_k;
pgd = (pgd_t *)*(unsigned long *)MPTB;
pgd = offset + (pgd_t *)pgd;
pgd_k = init_mm.pgd + offset;
if (!pgd_present(*pgd_k))
goto no_context;
/*
* set_pgd(pgd, *pgd_k); here would be useless on PAE
* and redundant with the set_pmd() on non-PAE.
*/
pmd = pmd_offset(pgd, address);
pmd_k = pmd_offset(pgd_k, address);
if (!pmd_present(*pmd_k))
goto no_context;
set_pmd(pmd, *pmd_k);
pte_k = pte_offset_kernel(pmd_k, address);
if (!pte_present(*pte_k))
goto no_context;
addr = (address & PAGE_MASK);
set_thread_fault_code(error_code);
update_mmu_cache(NULL, addr, pte_k);
set_thread_fault_code(0);
return;
}
}
/*======================================================================*
* update_mmu_cache()
*======================================================================*/
#define TLB_MASK (NR_TLB_ENTRIES - 1)
#define ITLB_END (unsigned long *)(ITLB_BASE + (NR_TLB_ENTRIES * 8))
#define DTLB_END (unsigned long *)(DTLB_BASE + (NR_TLB_ENTRIES * 8))
void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr,
pte_t *ptep)
{
volatile unsigned long *entry1, *entry2;
unsigned long pte_data, flags;
unsigned int *entry_dat;
int inst = get_thread_fault_code() & ACE_INSTRUCTION;
int i;
/* Ptrace may call this routine. */
if (vma && current->active_mm != vma->vm_mm)
return;
local_irq_save(flags);
vaddr = (vaddr & PAGE_MASK) | get_asid();
pte_data = pte_val(*ptep);
#ifdef CONFIG_CHIP_OPSP
entry1 = (unsigned long *)ITLB_BASE;
for (i = 0; i < NR_TLB_ENTRIES; i++) {
if (*entry1++ == vaddr) {
set_tlb_data(entry1, pte_data);
break;
}
entry1++;
}
entry2 = (unsigned long *)DTLB_BASE;
for (i = 0; i < NR_TLB_ENTRIES; i++) {
if (*entry2++ == vaddr) {
set_tlb_data(entry2, pte_data);
break;
}
entry2++;
}
#else
/*
* Update TLB entries
* entry1: ITLB entry address
* entry2: DTLB entry address
*/
__asm__ __volatile__ (
"seth %0, #high(%4) \n\t"
"st %2, @(%5, %0) \n\t"
"ldi %1, #1 \n\t"
"st %1, @(%6, %0) \n\t"
"add3 r4, %0, %7 \n\t"
".fillinsn \n"
"1: \n\t"
"ld %1, @(%6, %0) \n\t"
"bnez %1, 1b \n\t"
"ld %0, @r4+ \n\t"
"ld %1, @r4 \n\t"
"st %3, @+%0 \n\t"
"st %3, @+%1 \n\t"
: "=&r" (entry1), "=&r" (entry2)
: "r" (vaddr), "r" (pte_data), "i" (MMU_REG_BASE),
"i" (MSVA_offset), "i" (MTOP_offset), "i" (MIDXI_offset)
: "r4", "memory"
);
#endif
if ((!inst && entry2 >= DTLB_END) || (inst && entry1 >= ITLB_END))
goto notfound;
found:
local_irq_restore(flags);
return;
/* Valid entry not found */
notfound:
/*
* Update ITLB or DTLB entry
* entry1: TLB entry address
* entry2: TLB base address
*/
if (!inst) {
entry2 = (unsigned long *)DTLB_BASE;
entry_dat = &tlb_entry_d;
} else {
entry2 = (unsigned long *)ITLB_BASE;
entry_dat = &tlb_entry_i;
}
entry1 = entry2 + (((*entry_dat - 1) & TLB_MASK) << 1);
for (i = 0 ; i < NR_TLB_ENTRIES ; i++) {
if (!(entry1[1] & 2)) /* Valid bit check */
break;
if (entry1 != entry2)
entry1 -= 2;
else
entry1 += TLB_MASK << 1;
}
if (i >= NR_TLB_ENTRIES) { /* Empty entry not found */
entry1 = entry2 + (*entry_dat << 1);
*entry_dat = (*entry_dat + 1) & TLB_MASK;
}
*entry1++ = vaddr; /* Set TLB tag */
set_tlb_data(entry1, pte_data);
goto found;
}
/*======================================================================*
* flush_tlb_page() : flushes one page
*======================================================================*/
void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
if (vma->vm_mm && mm_context(vma->vm_mm) != NO_CONTEXT) {
unsigned long flags;
local_irq_save(flags);
page &= PAGE_MASK;
page |= (mm_context(vma->vm_mm) & MMU_CONTEXT_ASID_MASK);
__flush_tlb_page(page);
local_irq_restore(flags);
}
}
/*======================================================================*
* flush_tlb_range() : flushes a range of pages
*======================================================================*/
void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct mm_struct *mm;
mm = vma->vm_mm;
if (mm_context(mm) != NO_CONTEXT) {
unsigned long flags;
int size;
local_irq_save(flags);
size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (size > (NR_TLB_ENTRIES / 4)) { /* Too many TLB to flush */
mm_context(mm) = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
} else {
unsigned long asid;
asid = mm_context(mm) & MMU_CONTEXT_ASID_MASK;
start &= PAGE_MASK;
end += (PAGE_SIZE - 1);
end &= PAGE_MASK;
start |= asid;
end |= asid;
while (start < end) {
__flush_tlb_page(start);
start += PAGE_SIZE;
}
}
local_irq_restore(flags);
}
}
/*======================================================================*
* flush_tlb_mm() : flushes the specified mm context TLB's
*======================================================================*/
void local_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(mm) != NO_CONTEXT) {
unsigned long flags;
local_irq_save(flags);
mm_context(mm) = NO_CONTEXT;
if (mm == current->mm)
activate_context(mm);
local_irq_restore(flags);
}
}
/*======================================================================*
* flush_tlb_all() : flushes all processes TLBs
*======================================================================*/
void local_flush_tlb_all(void)
{
unsigned long flags;
local_irq_save(flags);
__flush_tlb_all();
local_irq_restore(flags);
}
/*======================================================================*
* init_mmu()
*======================================================================*/
void __init init_mmu(void)
{
tlb_entry_i = 0;
tlb_entry_d = 0;
mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
*(volatile unsigned long *)MPTB = (unsigned long)swapper_pg_dir;
}