[xtensa-cvscommit] linux/arch/xtensa/mm mmu.c,1.2,1.3

[<joe...@us...>]

Update of /cvsroot/xtensa/linux/arch/xtensa/mm
In directory usw-pr-cvs1:/tmp/cvs-serv11036/arch/xtensa/mm

Modified Files:
	mmu.c 
Log Message:


The 2nd-level miss handlers overlooked a rare case where current->mm might be NULL and they should use current->active_mm instead.  See the inline comments for details.

This fixes the board crash manifested by 'apachectl stop'.


Index: mmu.c
===================================================================
RCS file: /cvsroot/xtensa/linux/arch/xtensa/mm/mmu.c,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** mmu.c	18 Oct 2002 21:57:27 -0000	1.2
--- mmu.c	22 Oct 2002 17:59:46 -0000	1.3
***************
*** 160,163 ****
--- 160,164 ----
  {
  	struct task_struct *tsk = current;
+ 	struct mm_struct *mm = tsk->mm;
  	unsigned long vpnval;
  	pgd_t *pgd;
***************
*** 166,173 ****
  	pte_t pteval;
  
! 	/*  We need to map the page of PTEs for the user task.  Find
!          *  the pointer to that page.  */
  
! 	pgd = pgd_offset (tsk->mm, regs->excvaddr);
  	pmd = pmd_offset (pgd, regs->excvaddr);
  
--- 167,183 ----
  	pte_t pteval;
  
! 	/*  We need to map the page of PTEs for the user task.  Find *
! 	 * the pointer to that page.  Also, it's possible for tsk->mm
! 	 * to be NULL while tsk->active_mm is nonzero if we faulted on
! 	 * a vmalloc address.  In that rare case, we must use
! 	 * active_mm instead to avoid a fault in this handler.  See
! 	 *
! 	 * http://mail.nl.linux.org/linux-mm/2002-08/msg00258.html
! 	 *   (or search Internet on "mm vs. active_mm")
! 	 */
  
! 	if (!mm)
! 		mm = tsk->active_mm;
! 	pgd = pgd_offset (mm, regs->excvaddr);
  	pmd = pmd_offset (pgd, regs->excvaddr);
  
***************
*** 185,197 ****
  		pmdval = __pmd((unsigned long)exception_pte_table);
  
- #if 0   /* XTFIXME: Remove this old code after a while.. [JET, 25 Mar 2002] */
- 	/* convert regs->excvaddr to relative offset into page-table pages */
- 	vpnval = (regs->excvaddr / PAGE_SIZE) * sizeof(pte_t);
- 	vpnval += PGTABLE_START; /* convert to absolute, virtual address */
- 	vpnval &= PAGE_MASK;     /* convert to top of page-table page */
- #else
  	/* read ptevaddr and convert to top of page-table page */
  	vpnval = read_ptevaddr_register() & PAGE_MASK; 
- #endif
  	vpnval += WIRED_WAY_FOR_PAGE_TABLE; /* add way number for 'wdtlb' insn */
  	pteval = mk_pte (virt_to_page(pmd_val(pmdval)), PAGE_KERNEL);
--- 195,200 ----