diff options
Diffstat (limited to 'kernel/arch/frv/mm/fault.c')
| -rw-r--r-- | kernel/arch/frv/mm/fault.c | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/kernel/arch/frv/mm/fault.c b/kernel/arch/frv/mm/fault.c new file mode 100644 index 000000000..61d99767f --- /dev/null +++ b/kernel/arch/frv/mm/fault.c @@ -0,0 +1,329 @@ +/* + * 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(mm, 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() */ |