Linux-2.6.12-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!
diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c
new file mode 100644
index 0000000..03254b9
--- /dev/null
+++ b/arch/cris/mm/fault.c
@@ -0,0 +1,387 @@
+/*
+ * linux/arch/cris/mm/fault.c
+ *
+ * Copyright (C) 2000, 2001 Axis Communications AB
+ *
+ * Authors: Bjorn Wesen
+ *
+ * $Log: fault.c,v $
+ * Revision 1.11 2004/05/14 07:58:05 starvik
+ * Merge of changes from 2.4
+ *
+ * Revision 1.10 2003/10/27 14:51:24 starvik
+ * Removed debugcode
+ *
+ * Revision 1.9 2003/10/27 14:50:42 starvik
+ * Changed do_page_fault signature
+ *
+ * Revision 1.8 2003/07/04 13:02:48 tobiasa
+ * Moved code snippet from arch/cris/mm/fault.c that searches for fixup code
+ * to seperate function in arch-specific files.
+ *
+ * Revision 1.7 2003/01/22 06:48:38 starvik
+ * Fixed warnings issued by GCC 3.2.1
+ *
+ * Revision 1.6 2003/01/09 14:42:52 starvik
+ * Merge of Linux 2.5.55
+ *
+ * Revision 1.5 2002/12/11 14:44:48 starvik
+ * Extracted v10 (ETRAX 100LX) specific stuff to arch/cris/arch-v10/mm
+ *
+ * Revision 1.4 2002/11/13 15:10:28 starvik
+ * pte_offset has been renamed to pte_offset_kernel
+ *
+ * Revision 1.3 2002/11/05 06:45:13 starvik
+ * Merge of Linux 2.5.45
+ *
+ * Revision 1.2 2001/12/18 13:35:22 bjornw
+ * Applied the 2.4.13->2.4.16 CRIS patch to 2.5.1 (is a copy of 2.4.15).
+ *
+ * Revision 1.20 2001/11/22 13:34:06 bjornw
+ * * Bug workaround (LX TR89): force a rerun of the whole of an interrupted
+ * unaligned write, because the second half of the write will be corrupted
+ * otherwise. Affected unaligned writes spanning not-yet mapped pages.
+ * * Optimization: use the wr_rd bit in R_MMU_CAUSE to know whether a miss
+ * was due to a read or a write (before we didn't know this until the next
+ * restart of the interrupted instruction, thus wasting one fault-irq)
+ *
+ * Revision 1.19 2001/11/12 19:02:10 pkj
+ * Fixed compiler warnings.
+ *
+ * Revision 1.18 2001/07/18 22:14:32 bjornw
+ * Enable interrupts in the bulk of do_page_fault
+ *
+ * Revision 1.17 2001/07/18 13:07:23 bjornw
+ * * Detect non-existant PTE's in vmalloc pmd synchronization
+ * * Remove comment about fast-paths for VMALLOC_START etc, because all that
+ * was totally bogus anyway it turned out :)
+ * * Fix detection of vmalloc-area synchronization
+ * * Add some comments
+ *
+ * Revision 1.16 2001/06/13 00:06:08 bjornw
+ * current_pgd should be volatile
+ *
+ * Revision 1.15 2001/06/13 00:02:23 bjornw
+ * Use a separate variable to store the current pgd to avoid races in schedule
+ *
+ * Revision 1.14 2001/05/16 17:41:07 hp
+ * Last comment tweak further tweaked.
+ *
+ * Revision 1.13 2001/05/15 00:58:44 hp
+ * Expand a bit on the comment why we compare address >= TASK_SIZE rather
+ * than >= VMALLOC_START.
+ *
+ * Revision 1.12 2001/04/04 10:51:14 bjornw
+ * mmap_sem is grabbed for reading
+ *
+ * Revision 1.11 2001/03/23 07:36:07 starvik
+ * Corrected according to review remarks
+ *
+ * Revision 1.10 2001/03/21 16:10:11 bjornw
+ * CRIS_FRAME_FIXUP not needed anymore, use FRAME_NORMAL
+ *
+ * Revision 1.9 2001/03/05 13:22:20 bjornw
+ * Spell-fix and fix in vmalloc_fault handling
+ *
+ * Revision 1.8 2000/11/22 14:45:31 bjornw
+ * * 2.4.0-test10 removed the set_pgdir instantaneous kernel global mapping
+ * into all processes. Instead we fill in the missing PTE entries on demand.
+ *
+ * Revision 1.7 2000/11/21 16:39:09 bjornw
+ * fixup switches frametype
+ *
+ * Revision 1.6 2000/11/17 16:54:08 bjornw
+ * More detailed siginfo reporting
+ *
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+extern int find_fixup_code(struct pt_regs *);
+extern void die_if_kernel(const char *, struct pt_regs *, long);
+
+/* debug of low-level TLB reload */
+#undef DEBUG
+
+#ifdef DEBUG
+#define D(x) x
+#else
+#define D(x)
+#endif
+
+/* debug of higher-level faults */
+#define DPG(x)
+
+/* current active page directory */
+
+volatile pgd_t *current_pgd;
+
+/*
+ * This routine handles page faults. It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ *
+ * Notice that the address we're given is aligned to the page the fault
+ * occurred in, since we only get the PFN in R_MMU_CAUSE not the complete
+ * address.
+ *
+ * error_code:
+ * bit 0 == 0 means no page found, 1 means protection fault
+ * bit 1 == 0 means read, 1 means write
+ *
+ * If this routine detects a bad access, it returns 1, otherwise it
+ * returns 0.
+ */
+
+asmlinkage void
+do_page_fault(unsigned long address, struct pt_regs *regs,
+ int protection, int writeaccess)
+{
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct * vma;
+ siginfo_t info;
+
+ D(printk("Page fault for %X at %X, prot %d write %d\n",
+ address, regs->erp, protection, writeaccess));
+
+ tsk = current;
+
+ /*
+ * 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.
+ *
+ * NOTE2: This is done so that, when updating the vmalloc
+ * mappings we don't have to walk all processes pgdirs and
+ * add the high mappings all at once. Instead we do it as they
+ * are used. However vmalloc'ed page entries have the PAGE_GLOBAL
+ * bit set so sometimes the TLB can use a lingering entry.
+ *
+ * This verifies that the fault happens in kernel space
+ * and that the fault was not a protection error (error_code & 1).
+ */
+
+ if (address >= VMALLOC_START &&
+ !protection &&
+ !user_mode(regs))
+ goto vmalloc_fault;
+
+ /* we can and should enable interrupts at this point */
+ sti();
+
+ mm = tsk->mm;
+ 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, address);
+ if (!vma)
+ goto bad_area;
+ if (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto bad_area;
+ if (user_mode(regs)) {
+ /*
+ * accessing the stack below usp is always a bug.
+ * we get page-aligned addresses so we can only check
+ * if we're within a page from usp, but that might be
+ * enough to catch brutal errors at least.
+ */
+ if (address + PAGE_SIZE < rdusp())
+ 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;
+
+ /* first do some preliminary protection checks */
+
+ if (writeaccess) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ } else {
+ if (!(vma->vm_flags & (VM_READ | 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.
+ */
+
+ switch (handle_mm_fault(mm, vma, address, writeaccess)) {
+ case 1:
+ tsk->min_flt++;
+ break;
+ case 2:
+ tsk->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);
+
+ bad_area_nosemaphore:
+ DPG(show_registers(regs));
+
+ /* User mode accesses just cause a SIGSEGV */
+
+ if (user_mode(regs)) {
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void *)address;
+ force_sig_info(SIGSEGV, &info, tsk);
+ return;
+ }
+
+ no_context:
+
+ /* Are we prepared to handle this kernel fault?
+ *
+ * (The kernel has valid exception-points in the source
+ * when it acesses user-memory. When it fails in one
+ * of those points, we find it in a table and do a jump
+ * to some fixup code that loads an appropriate error
+ * code)
+ */
+
+ if (find_fixup_code(regs))
+ return;
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+
+ if ((unsigned long) (address) < PAGE_SIZE)
+ printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
+ else
+ printk(KERN_ALERT "Unable to handle kernel access");
+ printk(" at virtual address %08lx\n",address);
+
+ die_if_kernel("Oops", regs, (writeaccess << 1) | protection);
+
+ 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", tsk->comm);
+ if (user_mode(regs))
+ 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 *)address;
+ force_sig_info(SIGBUS, &info, tsk);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (!user_mode(regs))
+ goto no_context;
+ return;
+
+vmalloc_fault:
+ {
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Use current_pgd instead of tsk->active_mm->pgd
+ * since the latter might be unavailable if this
+ * code is executed in a misfortunately run irq
+ * (like inside schedule() between switch_mm and
+ * switch_to...).
+ */
+
+ int offset = pgd_index(address);
+ pgd_t *pgd, *pgd_k;
+ pmd_t *pmd, *pmd_k;
+ pte_t *pte_k;
+
+ pgd = (pgd_t *)current_pgd + offset;
+ pgd_k = init_mm.pgd + offset;
+
+ /* Since we're two-level, we don't need to do both
+ * set_pgd and set_pmd (they do the same thing). If
+ * we go three-level at some point, do the right thing
+ * with pgd_present and set_pgd here.
+ *
+ * Also, since the vmalloc area is global, we don't
+ * need to copy individual PTE's, it is enough to
+ * copy the pgd pointer into the pte page of the
+ * root task. If that is there, we'll find our pte if
+ * it exists.
+ */
+
+ pmd = pmd_offset(pgd, address);
+ pmd_k = pmd_offset(pgd_k, address);
+
+ if (!pmd_present(*pmd_k))
+ goto bad_area_nosemaphore;
+
+ set_pmd(pmd, *pmd_k);
+
+ /* Make sure the actual PTE exists as well to
+ * catch kernel vmalloc-area accesses to non-mapped
+ * addresses. If we don't do this, this will just
+ * silently loop forever.
+ */
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ goto no_context;
+
+ return;
+ }
+}