diff options
Diffstat (limited to 'kernel/arch/m32r/mm/fault.c')
| -rw-r--r-- | kernel/arch/m32r/mm/fault.c | 549 |
1 files changed, 549 insertions, 0 deletions
diff --git a/kernel/arch/m32r/mm/fault.c b/kernel/arch/m32r/mm/fault.c new file mode 100644 index 000000000..8f9875b79 --- /dev/null +++ b/kernel/arch/m32r/mm/fault.c @@ -0,0 +1,549 @@ +/* + * 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; +} |