1 files changed, 543 insertions, 0 deletions

diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
new file mode 100644
index 000000000000..a507e1174662
--- /dev/null
+++ b/arch/sparc/mm/fault_32.c
@@ -0,0 +1,543 @@
+/*
+ * fault.c:  Page fault handlers for the Sparc.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
+ * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.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/threads.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/kdebug.h>
+
+#include <asm/system.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/memreg.h>
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/smp.h>
+#include <asm/traps.h>
+#include <asm/uaccess.h>
+
+extern int prom_node_root;
+
+/* At boot time we determine these two values necessary for setting
+ * up the segment maps and page table entries (pte's).
+ */
+
+int num_segmaps, num_contexts;
+int invalid_segment;
+
+/* various Virtual Address Cache parameters we find at boot time... */
+
+int vac_size, vac_linesize, vac_do_hw_vac_flushes;
+int vac_entries_per_context, vac_entries_per_segment;
+int vac_entries_per_page;
+
+/* Return how much physical memory we have.  */
+unsigned long probe_memory(void)
+{
+        unsigned long total = 0;
+        int i;
+
+        for (i = 0; sp_banks[i].num_bytes; i++)
+                total += sp_banks[i].num_bytes;
+
+        return total;
+}
+
+extern void sun4c_complete_all_stores(void);
+
+/* Whee, a level 15 NMI interrupt memory error.  Let's have fun... */
+asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
+                                unsigned long svaddr, unsigned long aerr,
+                                unsigned long avaddr)
+{
+        sun4c_complete_all_stores();
+        printk("FAULT: NMI received\n");
+        printk("SREGS: Synchronous Error %08lx\n", serr);
+        printk("       Synchronous Vaddr %08lx\n", svaddr);
+        printk("      Asynchronous Error %08lx\n", aerr);
+        printk("      Asynchronous Vaddr %08lx\n", avaddr);
+        if (sun4c_memerr_reg)
+                printk("     Memory Parity Error %08lx\n", *sun4c_memerr_reg);
+        printk("REGISTER DUMP:\n");
+        show_regs(regs);
+        prom_halt();
+}
+
+static void unhandled_fault(unsigned long, struct task_struct *,
+                struct pt_regs *) __attribute__ ((noreturn));
+
+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 %08lx\n", address);
+        }
+        printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
+                (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
+        printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
+                (tsk->mm ? (unsigned long) tsk->mm->pgd :
+                        (unsigned long) tsk->active_mm->pgd));
+        die_if_kernel("Oops", regs);
+}
+
+asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc, 
+                            unsigned long address)
+{
+        struct pt_regs regs;
+        unsigned long g2;
+        unsigned int insn;
+        int i;
+        
+        i = search_extables_range(ret_pc, &g2);
+        switch (i) {
+        case 3:
+                /* load & store will be handled by fixup */
+                return 3;
+
+        case 1:
+                /* store will be handled by fixup, load will bump out */
+                /* for _to_ macros */
+                insn = *((unsigned int *) pc);
+                if ((insn >> 21) & 1)
+                        return 1;
+                break;
+
+        case 2:
+                /* load will be handled by fixup, store will bump out */
+                /* for _from_ macros */
+                insn = *((unsigned int *) pc);
+                if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
+                        return 2; 
+                break; 
+
+        default:
+                break;
+        };
+
+        memset(&regs, 0, sizeof (regs));
+        regs.pc = pc;
+        regs.npc = pc + 4;
+        __asm__ __volatile__(
+                "rd %%psr, %0\n\t"
+                "nop\n\t"
+                "nop\n\t"
+                "nop\n" : "=r" (regs.psr));
+        unhandled_fault(address, current, &regs);
+
+        /* Not reached */
+        return 0;
+}
+
+extern unsigned long safe_compute_effective_address(struct pt_regs *,
+                                                    unsigned int);
+
+static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
+{
+        unsigned int insn;
+
+        if (text_fault)
+                return regs->pc;
+
+        if (regs->psr & PSR_PS) {
+                insn = *(unsigned int *) regs->pc;
+        } else {
+                __get_user(insn, (unsigned int *) regs->pc);
+        }
+
+        return safe_compute_effective_address(regs, insn);
+}
+
+asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
+                               unsigned long address)
+{
+        struct vm_area_struct *vma;
+        struct task_struct *tsk = current;
+        struct mm_struct *mm = tsk->mm;
+        unsigned int fixup;
+        unsigned long g2;
+        siginfo_t info;
+        int from_user = !(regs->psr & PSR_PS);
+        int fault;
+
+        if(text_fault)
+                address = regs->pc;
+
+        /*
+         * 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 (!ARCH_SUN4C && address >= TASK_SIZE)
+                goto vmalloc_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_atomic() || !mm)
+                goto no_context;
+
+        down_read(&mm->mmap_sem);
+
+        /*
+         * The kernel referencing a bad kernel pointer can lock up
+         * a sun4c machine completely, so we must attempt recovery.
+         */
+        if(!from_user && address >= PAGE_OFFSET)
+                goto bad_area;
+
+        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(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;
+        if(write) {
+                if(!(vma->vm_flags & VM_WRITE))
+                        goto bad_area;
+        } else {
+                /* Allow reads even for write-only mappings */
+                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.
+         */
+        fault = handle_mm_fault(mm, vma, address, write);
+        if (unlikely(fault & VM_FAULT_ERROR)) {
+                if (fault & VM_FAULT_OOM)
+                        goto out_of_memory;
+                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);
+
+bad_area_nosemaphore:
+        /* User mode accesses just cause a SIGSEGV */
+        if(from_user) {
+#if 0
+                printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n",
+                       tsk->comm, tsk->pid, address, regs->pc);
+#endif
+                info.si_signo = SIGSEGV;
+                info.si_errno = 0;
+                /* info.si_code set above to make clear whether
+                   this was a SEGV_MAPERR or SEGV_ACCERR fault.  */
+                info.si_addr = (void __user *)compute_si_addr(regs, text_fault);
+                info.si_trapno = 0;
+                force_sig_info (SIGSEGV, &info, tsk);
+                return;
+        }
+
+        /* Is this in ex_table? */
+no_context:
+        g2 = regs->u_regs[UREG_G2];
+        if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) {
+                if (fixup > 10) { /* Values below are reserved for other things */
+                        extern const unsigned __memset_start[];
+                        extern const unsigned __memset_end[];
+                        extern const unsigned __csum_partial_copy_start[];
+                        extern const unsigned __csum_partial_copy_end[];
+
+#ifdef DEBUG_EXCEPTIONS
+                        printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
+                        printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
+                                regs->pc, fixup, g2);
+#endif
+                        if ((regs->pc >= (unsigned long)__memset_start &&
+                             regs->pc < (unsigned long)__memset_end) ||
+                            (regs->pc >= (unsigned long)__csum_partial_copy_start &&
+                             regs->pc < (unsigned long)__csum_partial_copy_end)) {
+                                regs->u_regs[UREG_I4] = address;
+                                regs->u_regs[UREG_I5] = regs->pc;
+                        }
+                        regs->u_regs[UREG_G2] = g2;
+                        regs->pc = fixup;
+                        regs->npc = regs->pc + 4;
+                        return;
+                }
+        }
+        
+        unhandled_fault (address, tsk, regs);
+        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 (from_user)
+                do_group_exit(SIGKILL);
+        goto no_context;
+
+do_sigbus:
+        up_read(&mm->mmap_sem);
+        info.si_signo = SIGBUS;
+        info.si_errno = 0;
+        info.si_code = BUS_ADRERR;
+        info.si_addr = (void __user *) compute_si_addr(regs, text_fault);
+        info.si_trapno = 0;
+        force_sig_info (SIGBUS, &info, tsk);
+        if (!from_user)
+                goto no_context;
+
+vmalloc_fault:
+        {
+                /*
+                 * Synchronize this task's top level page-table
+                 * with the 'reference' page table.
+                 */
+                int offset = pgd_index(address);
+                pgd_t *pgd, *pgd_k;
+                pmd_t *pmd, *pmd_k;
+
+                pgd = tsk->active_mm->pgd + offset;
+                pgd_k = init_mm.pgd + offset;
+
+                if (!pgd_present(*pgd)) {
+                        if (!pgd_present(*pgd_k))
+                                goto bad_area_nosemaphore;
+                        pgd_val(*pgd) = pgd_val(*pgd_k);
+                        return;
+                }
+
+                pmd = pmd_offset(pgd, address);
+                pmd_k = pmd_offset(pgd_k, address);
+
+                if (pmd_present(*pmd) || !pmd_present(*pmd_k))
+                        goto bad_area_nosemaphore;
+                *pmd = *pmd_k;
+                return;
+        }
+}
+
+asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
+                               unsigned long address)
+{
+        extern void sun4c_update_mmu_cache(struct vm_area_struct *,
+                                           unsigned long,pte_t);
+        extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
+        struct task_struct *tsk = current;
+        struct mm_struct *mm = tsk->mm;
+        pgd_t *pgdp;
+        pte_t *ptep;
+
+        if (text_fault) {
+                address = regs->pc;
+        } else if (!write &&
+                   !(regs->psr & PSR_PS)) {
+                unsigned int insn, __user *ip;
+
+                ip = (unsigned int __user *)regs->pc;
+                if (!get_user(insn, ip)) {
+                        if ((insn & 0xc1680000) == 0xc0680000)
+                                write = 1;
+                }
+        }
+
+        if (!mm) {
+                /* We are oopsing. */
+                do_sparc_fault(regs, text_fault, write, address);
+                BUG();  /* P3 Oops already, you bitch */
+        }
+
+        pgdp = pgd_offset(mm, address);
+        ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
+
+        if (pgd_val(*pgdp)) {
+            if (write) {
+                if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
+                                   == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
+                        unsigned long flags;
+
+                        *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
+                                      _SUN4C_PAGE_MODIFIED |
+                                      _SUN4C_PAGE_VALID |
+                                      _SUN4C_PAGE_DIRTY);
+
+                        local_irq_save(flags);
+                        if (sun4c_get_segmap(address) != invalid_segment) {
+                                sun4c_put_pte(address, pte_val(*ptep));
+                                local_irq_restore(flags);
+                                return;
+                        }
+                        local_irq_restore(flags);
+                }
+            } else {
+                if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
+                                   == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
+                        unsigned long flags;
+
+                        *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
+                                      _SUN4C_PAGE_VALID);
+
+                        local_irq_save(flags);
+                        if (sun4c_get_segmap(address) != invalid_segment) {
+                                sun4c_put_pte(address, pte_val(*ptep));
+                                local_irq_restore(flags);
+                                return;
+                        }
+                        local_irq_restore(flags);
+                }
+            }
+        }
+
+        /* This conditional is 'interesting'. */
+        if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
+            && (pte_val(*ptep) & _SUN4C_PAGE_VALID))
+                /* Note: It is safe to not grab the MMAP semaphore here because
+                 *       we know that update_mmu_cache() will not sleep for
+                 *       any reason (at least not in the current implementation)
+                 *       and therefore there is no danger of another thread getting
+                 *       on the CPU and doing a shrink_mmap() on this vma.
+                 */
+                sun4c_update_mmu_cache (find_vma(current->mm, address), address,
+                                        *ptep);
+        else
+                do_sparc_fault(regs, text_fault, write, address);
+}
+
+/* This always deals with user addresses. */
+static void force_user_fault(unsigned long address, int write)
+{
+        struct vm_area_struct *vma;
+        struct task_struct *tsk = current;
+        struct mm_struct *mm = tsk->mm;
+        siginfo_t info;
+
+        info.si_code = SEGV_MAPERR;
+
+#if 0
+        printk("wf<pid=%d,wr=%d,addr=%08lx>\n",
+               tsk->pid, write, address);
+#endif
+        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(expand_stack(vma, address))
+                goto bad_area;
+good_area:
+        info.si_code = SEGV_ACCERR;
+        if(write) {
+                if(!(vma->vm_flags & VM_WRITE))
+                        goto bad_area;
+        } else {
+                if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
+                        goto bad_area;
+        }
+        switch (handle_mm_fault(mm, vma, address, write)) {
+        case VM_FAULT_SIGBUS:
+        case VM_FAULT_OOM:
+                goto do_sigbus;
+        }
+        up_read(&mm->mmap_sem);
+        return;
+bad_area:
+        up_read(&mm->mmap_sem);
+#if 0
+        printk("Window whee %s [%d]: segfaults at %08lx\n",
+               tsk->comm, tsk->pid, address);
+#endif
+        info.si_signo = SIGSEGV;
+        info.si_errno = 0;
+        /* info.si_code set above to make clear whether
+           this was a SEGV_MAPERR or SEGV_ACCERR fault.  */
+        info.si_addr = (void __user *) address;
+        info.si_trapno = 0;
+        force_sig_info (SIGSEGV, &info, tsk);
+        return;
+
+do_sigbus:
+        up_read(&mm->mmap_sem);
+        info.si_signo = SIGBUS;
+        info.si_errno = 0;
+        info.si_code = BUS_ADRERR;
+        info.si_addr = (void __user *) address;
+        info.si_trapno = 0;
+        force_sig_info (SIGBUS, &info, tsk);
+}
+
+void window_overflow_fault(void)
+{
+        unsigned long sp;
+
+        sp = current_thread_info()->rwbuf_stkptrs[0];
+        if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+                force_user_fault(sp + 0x38, 1);
+        force_user_fault(sp, 1);
+}
+
+void window_underflow_fault(unsigned long sp)
+{
+        if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+                force_user_fault(sp + 0x38, 0);
+        force_user_fault(sp, 0);
+}
+
+void window_ret_fault(struct pt_regs *regs)
+{
+        unsigned long sp;
+
+        sp = regs->u_regs[UREG_FP];
+        if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
+                force_user_fault(sp + 0x38, 0);
+        force_user_fault(sp, 0);
+}