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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/frv/mm/fault.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/frv/mm/fault.c')
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1 files changed, 325 insertions, 0 deletions
diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c
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+/*
+ * 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 <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/uaccess.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;
+ siginfo_t info;
+ pgd_t *pge;
+ pud_t *pue;
+ pte_t *pte;
+ int write;
+
+#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 (in_interrupt() || !mm)
+ goto no_context;
+
+ 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;
+ write = 0;
+ 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;
+ write = 1;
+ 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.
+ */
+ switch (handle_mm_fault(mm, vma, ear0, write)) {
+ case 1:
+ current->min_flt++;
+ break;
+ case 2:
+ current->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);
+
+ /* 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);
+ printk("VM: killing process %s\n", current->comm);
+ if (user_mode(__frame))
+ 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.
+ */
+ 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() */