patch-2.1.19 linux/arch/sparc64/mm/fault.c

• Lines: 197
• Date: Mon Dec 30 11:59:59 1996
• Orig file: v2.1.18/linux/arch/sparc64/mm/fault.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.18/linux/arch/sparc64/mm/fault.c linux/arch/sparc64/mm/fault.c
@@ -0,0 +1,196 @@
+/* $Id: fault.c,v 1.2 1996/12/26 18:03:04 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)
+ */
+
+#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0]))
+
+extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS];
+extern int prom_node_root;
+
+/* Nice, simple, prom library does all the sweating for us. ;) */
+unsigned int prom_probe_memory (void)
+{
+	register struct linux_mlist_v0 *mlist;
+	register unsigned int bytes, base_paddr, tally;
+	register int i;
+
+	i = 0;
+	mlist= *prom_meminfo()->v0_available;
+	bytes = tally = mlist->num_bytes;
+	base_paddr = (unsigned int) 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 = (unsigned int) mlist->start_adr;
+		sp_banks[i].num_bytes = mlist->num_bytes;
+	}
+
+	i++;
+	sp_banks[i].base_addr = 0xdeadbeef;
+	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;
+}
+
+/* Traverse the memory lists in the prom to see how much physical we
+ * have.
+ */
+unsigned int
+probe_memory(void)
+{
+	unsigned int total;
+
+	total = prom_probe_memory();
+
+	/* Oh man, much nicer, keep the dirt in promlib. */
+	return total;
+}
+
+asmlinkage void do_sparc64_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;
+	int from_user = !(regs->tstate & TSTATE_PRIV);
+
+	down(&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;
+	/*
+	 * Ok, we have a good vm_area for this memory access, so
+	 * we can handle it..
+	 */
+good_area:
+	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;
+	}
+	handle_mm_fault(vma, address, write);
+	up(&mm->mmap_sem);
+	return;
+
+	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:
+	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;
+	}
+	handle_mm_fault(vma, address, write);
+	up(&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(&mm->mmap_sem);
+	/* Is this in ex_table? */
+	
+	g2 = regs->u_regs[UREG_G2];
+	if (!from_user && (fixup = search_exception_table (regs->pc, &g2))) {
+		printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
+		printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
+			regs->pc, fixup, g2);
+		regs->pc = fixup;
+		regs->npc = regs->pc + 4;
+		regs->u_regs[UREG_G2] = g2;
+		return;
+	}
+	/* Did we have an exception handler installed? */
+	if(current->tss.ex.count == 1) {
+		if(from_user) {
+			printk("Yieee, exception signalled from user mode.\n");
+		} else {
+			/* Set pc to %g1, set %g1 to -EFAULT and %g2 to
+			 * the faulting address so we can cleanup.
+			 */
+			printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
+			printk("EX: count<%d> pc<%08lx> expc<%08lx> address<%08lx>\n",
+			       (int) current->tss.ex.count, current->tss.ex.pc,
+			       current->tss.ex.expc, current->tss.ex.address);
+			current->tss.ex.count = 0;
+			regs->pc = current->tss.ex.expc;
+			regs->npc = regs->pc + 4;
+			regs->u_regs[UREG_G1] = -EFAULT;
+			regs->u_regs[UREG_G2] = address - current->tss.ex.address;
+			regs->u_regs[UREG_G3] = current->tss.ex.pc;
+			return;
+		}
+	}
+	if(from_user) {
+#if 0
+		printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n",
+		       tsk->comm, tsk->pid, address, regs->pc);
+#endif
+		tsk->tss.sig_address = address;
+		tsk->tss.sig_desc = SUBSIG_NOMAPPING;
+		send_sig(SIGSEGV, tsk, 1);
+		return;
+	}
+	if((unsigned long) address < PAGE_SIZE) {
+		printk(KERN_ALERT "Unable to handle kernel NULL "
+		       "pointer dereference");
+	} else {
+		printk(KERN_ALERT "Unable to handle kernel paging request "
+		       "at virtual address %08lx\n", address);
+	}
+	printk(KERN_ALERT "tsk->mm->context = %08lx\n",
+	       (unsigned long) tsk->mm->context);
+	printk(KERN_ALERT "tsk->mm->pgd = %08lx\n",
+	       (unsigned long) tsk->mm->pgd);
+	die_if_kernel("Oops", regs);
+}