patch-2.4.9 linux/arch/sparc64/mm/fault.c

• Lines: 141
• Date: Sun Aug 12 11:23:32 2001
• Orig file: v2.4.8/linux/arch/sparc64/mm/fault.c
• Orig date: Sun Mar 25 18:14:21 2001

diff -u --recursive --new-file v2.4.8/linux/arch/sparc64/mm/fault.c linux/arch/sparc64/mm/fault.c
@@ -1,4 +1,4 @@
-/* $Id: fault.c,v 1.54 2001/03/24 09:36:11 davem Exp $
+/* $Id: fault.c,v 1.55 2001/08/09 20:18:43 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)
@@ -92,6 +92,13 @@
 	die_if_kernel("Oops", 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);
@@ -99,13 +106,17 @@
 	pte_t *ptep, pte;
 	unsigned long pa;
 	u32 insn = 0;
+	unsigned long pstate;
 
 	if (pgd_none(*pgdp))
-		goto out;
+		goto outret;
 	pmdp = pmd_offset(pgdp, tpc);
 	if (pmd_none(*pmdp))
-		goto out;
+		goto outret;
 	ptep = pte_offset(pmdp, tpc);
+	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
+	__asm__ __volatile__("wrpr %0, %1, %%pstate"
+				: : "r" (pstate), "i" (PSTATE_IE));
 	pte = *ptep;
 	if (!pte_present(pte))
 		goto out;
@@ -119,6 +130,8 @@
 			     : "r" (pa), "i" (ASI_PHYS_USE_EC));
 
 out:
+	__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
+outret:
 	return insn;
 }
 
@@ -137,21 +150,28 @@
 extern int handle_ldf_stq(u32, struct pt_regs *);
 extern int handle_ld_nf(u32, struct pt_regs *);
 
-static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
-			    unsigned int insn, unsigned long address)
+static inline unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
 {
-	unsigned long g2;
-	unsigned char asi = ASI_P;
-
 	if (!insn) {
+		if (!regs->tpc || (regs->tpc & 0x3))
+			return 0;
 		if (regs->tstate & TSTATE_PRIV) {
-			if (!regs->tpc || (regs->tpc & 0x3))
-				goto cannot_handle;
 			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)
+		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
@@ -232,7 +252,7 @@
 	 * context, we must not take the fault..
 	 */
 	if (in_interrupt() || !mm)
-		goto handle_kernel_fault;
+		goto intr_or_no_mm;
 
 	if ((current->thread.flags & SPARC_FLAG_32BIT) != 0) {
 		regs->tpc &= 0xffffffff;
@@ -255,16 +275,9 @@
 	if (((fault_code &
 	      (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
 	    (vma->vm_flags & VM_WRITE) != 0) {
-		unsigned long tpc = regs->tpc;
-
-		if (tpc & 0x3)
+		insn = get_fault_insn(regs, 0);
+		if (!insn)
 			goto continue_fault;
-
-		if (regs->tstate & TSTATE_PRIV)
-			insn = *(unsigned int *)tpc;
-		else
-			insn = get_user_insn(tpc);
-
 		if ((insn & 0xc0200000) == 0xc0200000 &&
 		    (insn & 0x1780000) != 0x1680000) {
 			/* Don't bother updating thread struct value,
@@ -326,6 +339,7 @@
 	 * 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:
@@ -338,13 +352,19 @@
  * 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);
 
 	/*