1 files changed, 527 insertions, 0 deletions

diff --git a/arch/sparc64/mm/fault.c b/arch/sparc64/mm/fault.c
new file mode 100644
index 000000000000..3ffee7b51aed
--- /dev/null
+++ b/arch/sparc64/mm/fault.c
@@ -0,0 +1,527 @@
+/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
+ * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
+ */
+
+#include <asm/head.h>
+
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/uaccess.h>
+#include <asm/asi.h>
+#include <asm/lsu.h>
+#include <asm/sections.h>
+#include <asm/kdebug.h>
+
+#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0]))
+
+extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS];
+
+/*
+ * To debug kernel during syscall entry.
+ */
+void syscall_trace_entry(struct pt_regs *regs)
+{
+        printk("scall entry: %s[%d]/cpu%d: %d\n", current->comm, current->pid, smp_processor_id(), (int) regs->u_regs[UREG_G1]);
+}
+
+/*
+ * To debug kernel during syscall exit.
+ */
+void syscall_trace_exit(struct pt_regs *regs)
+{
+        printk("scall exit: %s[%d]/cpu%d: %d\n", current->comm, current->pid, smp_processor_id(), (int) regs->u_regs[UREG_G1]);
+}
+
+/*
+ * To debug kernel to catch accesses to certain virtual/physical addresses.
+ * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
+ * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
+ * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
+ * watched. This is only useful on a single cpu machine for now. After the watchpoint
+ * is detected, the process causing it will be killed, thus preventing an infinite loop.
+ */
+void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
+{
+        unsigned long lsubits;
+
+        __asm__ __volatile__("ldxa [%%g0] %1, %0"
+                             : "=r" (lsubits)
+                             : "i" (ASI_LSU_CONTROL));
+        lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM |
+                     LSU_CONTROL_PR | LSU_CONTROL_VR |
+                     LSU_CONTROL_PW | LSU_CONTROL_VW);
+
+        __asm__ __volatile__("stxa      %0, [%1] %2\n\t"
+                             "membar    #Sync"
+                             : /* no outputs */
+                             : "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
+                               "i" (ASI_DMMU));
+
+        lsubits |= ((unsigned long)mask << (mode ? 25 : 33));
+        if (flags & VM_READ)
+                lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
+        if (flags & VM_WRITE)
+                lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
+        __asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
+                             "membar #Sync"
+                             : /* no outputs */
+                             : "r" (lsubits), "i" (ASI_LSU_CONTROL)
+                             : "memory");
+}
+
+/* Nice, simple, prom library does all the sweating for us. ;) */
+unsigned long __init prom_probe_memory (void)
+{
+        register struct linux_mlist_p1275 *mlist;
+        register unsigned long bytes, base_paddr, tally;
+        register int i;
+
+        i = 0;
+        mlist = *prom_meminfo()->p1275_available;
+        bytes = tally = mlist->num_bytes;
+        base_paddr = mlist->start_adr;
+  
+        sp_banks[0].base_addr = base_paddr;
+        sp_banks[0].num_bytes = bytes;
+
+        while (mlist->theres_more != (void *) 0) {
+                i++;
+                mlist = mlist->theres_more;
+                bytes = mlist->num_bytes;
+                tally += bytes;
+                if (i >= SPARC_PHYS_BANKS-1) {
+                        printk ("The machine has more banks than "
+                                "this kernel can support\n"
+                                "Increase the SPARC_PHYS_BANKS "
+                                "setting (currently %d)\n",
+                                SPARC_PHYS_BANKS);
+                        i = SPARC_PHYS_BANKS-1;
+                        break;
+                }
+    
+                sp_banks[i].base_addr = mlist->start_adr;
+                sp_banks[i].num_bytes = mlist->num_bytes;
+        }
+
+        i++;
+        sp_banks[i].base_addr = 0xdeadbeefbeefdeadUL;
+        sp_banks[i].num_bytes = 0;
+
+        /* Now mask all bank sizes on a page boundary, it is all we can
+         * use anyways.
+         */
+        for (i = 0; sp_banks[i].num_bytes != 0; i++)
+                sp_banks[i].num_bytes &= PAGE_MASK;
+
+        return tally;
+}
+
+static void unhandled_fault(unsigned long address, struct task_struct *tsk,
+                            struct pt_regs *regs)
+{
+        if ((unsigned long) address < PAGE_SIZE) {
+                printk(KERN_ALERT "Unable to handle kernel NULL "
+                       "pointer dereference\n");
+        } else {
+                printk(KERN_ALERT "Unable to handle kernel paging request "
+                       "at virtual address %016lx\n", (unsigned long)address);
+        }
+        printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
+               (tsk->mm ?
+                CTX_HWBITS(tsk->mm->context) :
+                CTX_HWBITS(tsk->active_mm->context)));
+        printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
+               (tsk->mm ? (unsigned long) tsk->mm->pgd :
+                          (unsigned long) tsk->active_mm->pgd));
+        if (notify_die(DIE_GPF, "general protection fault", regs,
+                       0, 0, SIGSEGV) == NOTIFY_STOP)
+                return;
+        die_if_kernel("Oops", regs);
+}
+
+static void bad_kernel_pc(struct pt_regs *regs)
+{
+        unsigned long *ksp;
+
+        printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
+               regs->tpc);
+        __asm__("mov %%sp, %0" : "=r" (ksp));
+        show_stack(current, ksp);
+        unhandled_fault(regs->tpc, current, regs);
+}
+
+/*
+ * We now make sure that mmap_sem is held in all paths that call 
+ * this. Additionally, to prevent kswapd from ripping ptes from
+ * under us, raise interrupts around the time that we look at the
+ * pte, kswapd will have to wait to get his smp ipi response from
+ * us. This saves us having to get page_table_lock.
+ */
+static unsigned int get_user_insn(unsigned long tpc)
+{
+        pgd_t *pgdp = pgd_offset(current->mm, tpc);
+        pud_t *pudp;
+        pmd_t *pmdp;
+        pte_t *ptep, pte;
+        unsigned long pa;
+        u32 insn = 0;
+        unsigned long pstate;
+
+        if (pgd_none(*pgdp))
+                goto outret;
+        pudp = pud_offset(pgdp, tpc);
+        if (pud_none(*pudp))
+                goto outret;
+        pmdp = pmd_offset(pudp, tpc);
+        if (pmd_none(*pmdp))
+                goto outret;
+
+        /* This disables preemption for us as well. */
+        __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
+        __asm__ __volatile__("wrpr %0, %1, %%pstate"
+                                : : "r" (pstate), "i" (PSTATE_IE));
+        ptep = pte_offset_map(pmdp, tpc);
+        pte = *ptep;
+        if (!pte_present(pte))
+                goto out;
+
+        pa  = (pte_val(pte) & _PAGE_PADDR);
+        pa += (tpc & ~PAGE_MASK);
+
+        /* Use phys bypass so we don't pollute dtlb/dcache. */
+        __asm__ __volatile__("lduwa [%1] %2, %0"
+                             : "=r" (insn)
+                             : "r" (pa), "i" (ASI_PHYS_USE_EC));
+
+out:
+        pte_unmap(ptep);
+        __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
+outret:
+        return insn;
+}
+
+extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
+
+static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
+                             unsigned int insn, int fault_code)
+{
+        siginfo_t info;
+
+        info.si_code = code;
+        info.si_signo = sig;
+        info.si_errno = 0;
+        if (fault_code & FAULT_CODE_ITLB)
+                info.si_addr = (void __user *) regs->tpc;
+        else
+                info.si_addr = (void __user *)
+                        compute_effective_address(regs, insn, 0);
+        info.si_trapno = 0;
+        force_sig_info(sig, &info, current);
+}
+
+extern int handle_ldf_stq(u32, struct pt_regs *);
+extern int handle_ld_nf(u32, struct pt_regs *);
+
+static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
+{
+        if (!insn) {
+                if (!regs->tpc || (regs->tpc & 0x3))
+                        return 0;
+                if (regs->tstate & TSTATE_PRIV) {
+                        insn = *(unsigned int *) regs->tpc;
+                } else {
+                        insn = get_user_insn(regs->tpc);
+                }
+        }
+        return insn;
+}
+
+static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
+                            unsigned int insn, unsigned long address)
+{
+        unsigned long g2;
+        unsigned char asi = ASI_P;
+ 
+        if ((!insn) && (regs->tstate & TSTATE_PRIV))
+                goto cannot_handle;
+
+        /* If user insn could be read (thus insn is zero), that
+         * is fine.  We will just gun down the process with a signal
+         * in that case.
+         */
+
+        if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
+            (insn & 0xc0800000) == 0xc0800000) {
+                if (insn & 0x2000)
+                        asi = (regs->tstate >> 24);
+                else
+                        asi = (insn >> 5);
+                if ((asi & 0xf2) == 0x82) {
+                        if (insn & 0x1000000) {
+                                handle_ldf_stq(insn, regs);
+                        } else {
+                                /* This was a non-faulting load. Just clear the
+                                 * destination register(s) and continue with the next
+                                 * instruction. -jj
+                                 */
+                                handle_ld_nf(insn, regs);
+                        }
+                        return;
+                }
+        }
+                
+        g2 = regs->u_regs[UREG_G2];
+
+        /* Is this in ex_table? */
+        if (regs->tstate & TSTATE_PRIV) {
+                unsigned long fixup;
+
+                if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
+                        if (insn & 0x2000)
+                                asi = (regs->tstate >> 24);
+                        else
+                                asi = (insn >> 5);
+                }
+        
+                /* Look in asi.h: All _S asis have LS bit set */
+                if ((asi & 0x1) &&
+                    (fixup = search_extables_range(regs->tpc, &g2))) {
+                        regs->tpc = fixup;
+                        regs->tnpc = regs->tpc + 4;
+                        regs->u_regs[UREG_G2] = g2;
+                        return;
+                }
+        } else {
+                /* The si_code was set to make clear whether
+                 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
+                 */
+                do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
+                return;
+        }
+
+cannot_handle:
+        unhandled_fault (address, current, regs);
+}
+
+asmlinkage void do_sparc64_fault(struct pt_regs *regs)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        unsigned int insn = 0;
+        int si_code, fault_code;
+        unsigned long address;
+
+        fault_code = get_thread_fault_code();
+
+        if (notify_die(DIE_PAGE_FAULT, "page_fault", regs,
+                       fault_code, 0, SIGSEGV) == NOTIFY_STOP)
+                return;
+
+        si_code = SEGV_MAPERR;
+        address = current_thread_info()->fault_address;
+
+        if ((fault_code & FAULT_CODE_ITLB) &&
+            (fault_code & FAULT_CODE_DTLB))
+                BUG();
+
+        if (regs->tstate & TSTATE_PRIV) {
+                unsigned long tpc = regs->tpc;
+
+                /* Sanity check the PC. */
+                if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) ||
+                    (tpc >= MODULES_VADDR && tpc < MODULES_END)) {
+                        /* Valid, no problems... */
+                } else {
+                        bad_kernel_pc(regs);
+                        return;
+                }
+        }
+
+        /*
+         * If we're in an interrupt or have no user
+         * context, we must not take the fault..
+         */
+        if (in_atomic() || !mm)
+                goto intr_or_no_mm;
+
+        if (test_thread_flag(TIF_32BIT)) {
+                if (!(regs->tstate & TSTATE_PRIV))
+                        regs->tpc &= 0xffffffff;
+                address &= 0xffffffff;
+        }
+
+        if (!down_read_trylock(&mm->mmap_sem)) {
+                if ((regs->tstate & TSTATE_PRIV) &&
+                    !search_exception_tables(regs->tpc)) {
+                        insn = get_fault_insn(regs, insn);
+                        goto handle_kernel_fault;
+                }
+                down_read(&mm->mmap_sem);
+        }
+
+        vma = find_vma(mm, address);
+        if (!vma)
+                goto bad_area;
+
+        /* Pure DTLB misses do not tell us whether the fault causing
+         * load/store/atomic was a write or not, it only says that there
+         * was no match.  So in such a case we (carefully) read the
+         * instruction to try and figure this out.  It's an optimization
+         * so it's ok if we can't do this.
+         *
+         * Special hack, window spill/fill knows the exact fault type.
+         */
+        if (((fault_code &
+              (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
+            (vma->vm_flags & VM_WRITE) != 0) {
+                insn = get_fault_insn(regs, 0);
+                if (!insn)
+                        goto continue_fault;
+                if ((insn & 0xc0200000) == 0xc0200000 &&
+                    (insn & 0x1780000) != 0x1680000) {
+                        /* Don't bother updating thread struct value,
+                         * because update_mmu_cache only cares which tlb
+                         * the access came from.
+                         */
+                        fault_code |= FAULT_CODE_WRITE;
+                }
+        }
+continue_fault:
+
+        if (vma->vm_start <= address)
+                goto good_area;
+        if (!(vma->vm_flags & VM_GROWSDOWN))
+                goto bad_area;
+        if (!(fault_code & FAULT_CODE_WRITE)) {
+                /* Non-faulting loads shouldn't expand stack. */
+                insn = get_fault_insn(regs, insn);
+                if ((insn & 0xc0800000) == 0xc0800000) {
+                        unsigned char asi;
+
+                        if (insn & 0x2000)
+                                asi = (regs->tstate >> 24);
+                        else
+                                asi = (insn >> 5);
+                        if ((asi & 0xf2) == 0x82)
+                                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:
+        si_code = SEGV_ACCERR;
+
+        /* If we took a ITLB miss on a non-executable page, catch
+         * that here.
+         */
+        if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
+                BUG_ON(address != regs->tpc);
+                BUG_ON(regs->tstate & TSTATE_PRIV);
+                goto bad_area;
+        }
+
+        if (fault_code & FAULT_CODE_WRITE) {
+                if (!(vma->vm_flags & VM_WRITE))
+                        goto bad_area;
+
+                /* Spitfire has an icache which does not snoop
+                 * processor stores.  Later processors do...
+                 */
+                if (tlb_type == spitfire &&
+                    (vma->vm_flags & VM_EXEC) != 0 &&
+                    vma->vm_file != NULL)
+                        set_thread_fault_code(fault_code |
+                                              FAULT_CODE_BLKCOMMIT);
+        } else {
+                /* Allow reads even for write-only mappings */
+                if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+                        goto bad_area;
+        }
+
+        switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) {
+        case VM_FAULT_MINOR:
+                current->min_flt++;
+                break;
+        case VM_FAULT_MAJOR:
+                current->maj_flt++;
+                break;
+        case VM_FAULT_SIGBUS:
+                goto do_sigbus;
+        case VM_FAULT_OOM:
+                goto out_of_memory;
+        default:
+                BUG();
+        }
+
+        up_read(&mm->mmap_sem);
+        goto fault_done;
+
+        /*
+         * 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:
+        insn = get_fault_insn(regs, insn);
+        up_read(&mm->mmap_sem);
+
+handle_kernel_fault:
+        do_kernel_fault(regs, si_code, fault_code, insn, address);
+
+        goto fault_done;
+
+/*
+ * 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:
+        insn = get_fault_insn(regs, insn);
+        up_read(&mm->mmap_sem);
+        printk("VM: killing process %s\n", current->comm);
+        if (!(regs->tstate & TSTATE_PRIV))
+                do_exit(SIGKILL);
+        goto handle_kernel_fault;
+
+intr_or_no_mm:
+        insn = get_fault_insn(regs, 0);
+        goto handle_kernel_fault;
+
+do_sigbus:
+        insn = get_fault_insn(regs, insn);
+        up_read(&mm->mmap_sem);
+
+        /*
+         * Send a sigbus, regardless of whether we were in kernel
+         * or user mode.
+         */
+        do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
+
+        /* Kernel mode? Handle exceptions or die */
+        if (regs->tstate & TSTATE_PRIV)
+                goto handle_kernel_fault;
+
+fault_done:
+        /* These values are no longer needed, clear them. */
+        set_thread_fault_code(0);
+        current_thread_info()->fault_address = 0;
+}