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-rw-r--r--arch/sh/mm/fault.c514
1 files changed, 514 insertions, 0 deletions
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
new file mode 100644
index 000000000000..1fc25d85e515
--- /dev/null
+++ b/arch/sh/mm/fault.c
@@ -0,0 +1,514 @@
+/*
+ * Page fault handler for SH with an MMU.
+ *
+ * Copyright (C) 1999 Niibe Yutaka
+ * Copyright (C) 2003 - 2012 Paul Mundt
+ *
+ * Based on linux/arch/i386/mm/fault.c:
+ * Copyright (C) 1995 Linus Torvalds
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
+#include <linux/kdebug.h>
+#include <asm/io_trapped.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/traps.h>
+
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+ int ret = 0;
+
+ if (kprobes_built_in() && !user_mode(regs)) {
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, trap))
+ ret = 1;
+ preempt_enable();
+ }
+
+ return ret;
+}
+
+static void
+force_sig_info_fault(int si_signo, int si_code, unsigned long address,
+ struct task_struct *tsk)
+{
+ siginfo_t info;
+
+ info.si_signo = si_signo;
+ info.si_errno = 0;
+ info.si_code = si_code;
+ info.si_addr = (void __user *)address;
+
+ force_sig_info(si_signo, &info, tsk);
+}
+
+/*
+ * This is useful to dump out the page tables associated with
+ * 'addr' in mm 'mm'.
+ */
+static void show_pte(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+
+ if (mm)
+ pgd = mm->pgd;
+ else
+ pgd = get_TTB();
+
+ printk(KERN_ALERT "pgd = %p\n", pgd);
+ pgd += pgd_index(addr);
+ printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
+ (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd));
+
+ do {
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ if (pgd_none(*pgd))
+ break;
+
+ if (pgd_bad(*pgd)) {
+ printk("(bad)");
+ break;
+ }
+
+ pud = pud_offset(pgd, addr);
+ if (PTRS_PER_PUD != 1)
+ printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
+ (u64)pud_val(*pud));
+
+ if (pud_none(*pud))
+ break;
+
+ if (pud_bad(*pud)) {
+ printk("(bad)");
+ break;
+ }
+
+ pmd = pmd_offset(pud, addr);
+ if (PTRS_PER_PMD != 1)
+ printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2),
+ (u64)pmd_val(*pmd));
+
+ if (pmd_none(*pmd))
+ break;
+
+ if (pmd_bad(*pmd)) {
+ printk("(bad)");
+ break;
+ }
+
+ /* We must not map this if we have highmem enabled */
+ if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
+ break;
+
+ pte = pte_offset_kernel(pmd, addr);
+ printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2),
+ (u64)pte_val(*pte));
+ } while (0);
+
+ printk("\n");
+}
+
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
+{
+ unsigned index = pgd_index(address);
+ pgd_t *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd += index;
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k))
+ return NULL;
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ return NULL;
+
+ if (!pud_present(*pud))
+ set_pud(pud, *pud_k);
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ return NULL;
+
+ if (!pmd_present(*pmd))
+ set_pmd(pmd, *pmd_k);
+ else {
+ /*
+ * The page tables are fully synchronised so there must
+ * be another reason for the fault. Return NULL here to
+ * signal that we have not taken care of the fault.
+ */
+ BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
+ return NULL;
+ }
+
+ return pmd_k;
+}
+
+#ifdef CONFIG_SH_STORE_QUEUES
+#define __FAULT_ADDR_LIMIT P3_ADDR_MAX
+#else
+#define __FAULT_ADDR_LIMIT VMALLOC_END
+#endif
+
+/*
+ * Handle a fault on the vmalloc or module mapping area
+ */
+static noinline int vmalloc_fault(unsigned long address)
+{
+ pgd_t *pgd_k;
+ pmd_t *pmd_k;
+ pte_t *pte_k;
+
+ /* Make sure we are in vmalloc/module/P3 area: */
+ if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT))
+ return -1;
+
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Do _not_ use "current" here. We might be inside
+ * an interrupt in the middle of a task switch..
+ */
+ pgd_k = get_TTB();
+ pmd_k = vmalloc_sync_one(pgd_k, address);
+ if (!pmd_k)
+ return -1;
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ return -1;
+
+ return 0;
+}
+
+static void
+show_fault_oops(struct pt_regs *regs, unsigned long address)
+{
+ if (!oops_may_print())
+ return;
+
+ printk(KERN_ALERT "BUG: unable to handle kernel ");
+ if (address < PAGE_SIZE)
+ printk(KERN_CONT "NULL pointer dereference");
+ else
+ printk(KERN_CONT "paging request");
+
+ printk(KERN_CONT " at %08lx\n", address);
+ printk(KERN_ALERT "PC:");
+ printk_address(regs->pc, 1);
+
+ show_pte(NULL, address);
+}
+
+static noinline void
+no_context(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs))
+ return;
+
+ if (handle_trapped_io(regs, address))
+ return;
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ bust_spinlocks(1);
+
+ show_fault_oops(regs, address);
+
+ die("Oops", regs, error_code);
+ bust_spinlocks(0);
+ do_exit(SIGKILL);
+}
+
+static void
+__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, int si_code)
+{
+ struct task_struct *tsk = current;
+
+ /* User mode accesses just cause a SIGSEGV */
+ if (user_mode(regs)) {
+ /*
+ * It's possible to have interrupts off here:
+ */
+ local_irq_enable();
+
+ force_sig_info_fault(SIGSEGV, si_code, address, tsk);
+
+ return;
+ }
+
+ no_context(regs, error_code, address);
+}
+
+static noinline void
+bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
+}
+
+static void
+__bad_area(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, int si_code)
+{
+ struct mm_struct *mm = current->mm;
+
+ /*
+ * Something tried to access memory that isn't in our memory map..
+ * Fix it, but check if it's kernel or user first..
+ */
+ up_read(&mm->mmap_sem);
+
+ __bad_area_nosemaphore(regs, error_code, address, si_code);
+}
+
+static noinline void
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+ __bad_area(regs, error_code, address, SEGV_MAPERR);
+}
+
+static noinline void
+bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ __bad_area(regs, error_code, address, SEGV_ACCERR);
+}
+
+static void out_of_memory(void)
+{
+ /*
+ * We ran out of memory, call the OOM killer, and return the userspace
+ * (which will retry the fault, or kill us if we got oom-killed):
+ */
+ up_read(&current->mm->mmap_sem);
+
+ pagefault_out_of_memory();
+}
+
+static void
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ up_read(&mm->mmap_sem);
+
+ /* Kernel mode? Handle exceptions or die: */
+ if (!user_mode(regs))
+ no_context(regs, error_code, address);
+
+ force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
+}
+
+static noinline int
+mm_fault_error(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, unsigned int fault)
+{
+ /*
+ * Pagefault was interrupted by SIGKILL. We have no reason to
+ * continue pagefault.
+ */
+ if (fatal_signal_pending(current)) {
+ if (!(fault & VM_FAULT_RETRY))
+ up_read(&current->mm->mmap_sem);
+ if (!user_mode(regs))
+ no_context(regs, error_code, address);
+ return 1;
+ }
+
+ if (!(fault & VM_FAULT_ERROR))
+ return 0;
+
+ if (fault & VM_FAULT_OOM) {
+ /* Kernel mode? Handle exceptions or die: */
+ if (!user_mode(regs)) {
+ up_read(&current->mm->mmap_sem);
+ no_context(regs, error_code, address);
+ return 1;
+ }
+
+ out_of_memory();
+ } else {
+ if (fault & VM_FAULT_SIGBUS)
+ do_sigbus(regs, error_code, address);
+ else
+ BUG();
+ }
+
+ return 1;
+}
+
+static inline int access_error(int error_code, struct vm_area_struct *vma)
+{
+ if (error_code & FAULT_CODE_WRITE) {
+ /* write, present and write, not present: */
+ if (unlikely(!(vma->vm_flags & VM_WRITE)))
+ return 1;
+ return 0;
+ }
+
+ /* ITLB miss on NX page */
+ if (unlikely((error_code & FAULT_CODE_ITLB) &&
+ !(vma->vm_flags & VM_EXEC)))
+ return 1;
+
+ /* read, not present: */
+ if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
+ return 1;
+
+ return 0;
+}
+
+static int fault_in_kernel_space(unsigned long address)
+{
+ return address >= TASK_SIZE;
+}
+
+/*
+ * 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 __kprobes do_page_fault(struct pt_regs *regs,
+ unsigned long error_code,
+ unsigned long address)
+{
+ unsigned long vec;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct * vma;
+ int fault;
+ int write = error_code & FAULT_CODE_WRITE;
+ unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (write ? FAULT_FLAG_WRITE : 0));
+
+ tsk = current;
+ mm = tsk->mm;
+ vec = lookup_exception_vector();
+
+ /*
+ * 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.
+ */
+ if (unlikely(fault_in_kernel_space(address))) {
+ if (vmalloc_fault(address) >= 0)
+ return;
+ if (notify_page_fault(regs, vec))
+ return;
+
+ bad_area_nosemaphore(regs, error_code, address);
+ return;
+ }
+
+ if (unlikely(notify_page_fault(regs, vec)))
+ return;
+
+ /* Only enable interrupts if they were on before the fault */
+ if ((regs->sr & SR_IMASK) != SR_IMASK)
+ local_irq_enable();
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+ /*
+ * If we're in an interrupt, have no user context or are running
+ * in an atomic region then we must not take the fault:
+ */
+ if (unlikely(in_atomic() || !mm)) {
+ bad_area_nosemaphore(regs, error_code, address);
+ return;
+ }
+
+retry:
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, address);
+ if (unlikely(!vma)) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+ if (likely(vma->vm_start <= address))
+ goto good_area;
+ if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+ if (unlikely(expand_stack(vma, address))) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+ if (unlikely(access_error(error_code, vma))) {
+ bad_area_access_error(regs, error_code, address);
+ return;
+ }
+
+ set_thread_fault_code(error_code);
+
+ /*
+ * 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, address, flags);
+
+ if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
+ if (mm_fault_error(regs, error_code, address, fault))
+ return;
+
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR) {
+ tsk->maj_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
+ regs, address);
+ } else {
+ tsk->min_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
+ regs, address);
+ }
+ if (fault & VM_FAULT_RETRY) {
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+
+ /*
+ * No need to up_read(&mm->mmap_sem) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+ goto retry;
+ }
+ }
+
+ up_read(&mm->mmap_sem);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.