[PATCH] CRIS update: mm

Memory management patches.

* SMP support.
* Non-executable stack (on v32).
* 4-level page tables.
* Added simple Thread Local Storage support.

Signed-off-by: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 83 insertions, 12 deletions

diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c
index 03254b9eded1..fe1cc36b5aca 100644
--- a/arch/cris/mm/fault.c
+++ b/arch/cris/mm/fault.c
@@ -6,6 +6,38 @@
  *  Authors:  Bjorn Wesen 
  * 
  *  $Log: fault.c,v $
+ *  Revision 1.20  2005/03/04 08:16:18  starvik
+ *  Merge of Linux 2.6.11.
+ *
+ *  Revision 1.19  2005/01/14 10:07:59  starvik
+ *  Fixed warning.
+ *
+ *  Revision 1.18  2005/01/12 08:10:14  starvik
+ *  Readded the change of frametype when handling kernel page fault fixup
+ *  for v10. This is necessary to avoid that the CPU remakes the faulting
+ *  access.
+ *
+ *  Revision 1.17  2005/01/11 13:53:05  starvik
+ *  Use raw_printk.
+ *
+ *  Revision 1.16  2004/12/17 11:39:41  starvik
+ *  SMP support.
+ *
+ *  Revision 1.15  2004/11/23 18:36:18  starvik
+ *  Stack is now non-executable.
+ *  Signal handler trampolines are placed in a reserved page mapped into all
+ *  processes.
+ *
+ *  Revision 1.14  2004/11/23 07:10:21  starvik
+ *  Moved find_fixup_code to generic code.
+ *
+ *  Revision 1.13  2004/11/23 07:00:54  starvik
+ *  Actually use the execute permission bit in the MMU. This makes it possible
+ *  to prevent e.g. attacks where executable code is put on the stack.
+ *
+ *  Revision 1.12  2004/09/29 06:16:04  starvik
+ *  Use instruction_pointer
+ *
  *  Revision 1.11  2004/05/14 07:58:05  starvik
  *  Merge of changes from 2.4
  *
@@ -103,6 +135,7 @@
 
 extern int find_fixup_code(struct pt_regs *);
 extern void die_if_kernel(const char *, struct pt_regs *, long);
+extern int raw_printk(const char *fmt, ...);
 
 /* debug of low-level TLB reload */
 #undef DEBUG
@@ -118,7 +151,8 @@ extern void die_if_kernel(const char *, struct pt_regs *, long);
 
 /* current active page directory */
 
-volatile pgd_t *current_pgd;
+volatile DEFINE_PER_CPU(pgd_t *,current_pgd);
+unsigned long cris_signal_return_page;
 
 /*
  * This routine handles page faults.  It determines the address,
@@ -146,8 +180,9 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
         struct vm_area_struct * vma;
         siginfo_t info;
 
-        D(printk("Page fault for %X at %X, prot %d write %d\n",
-                 address, regs->erp, protection, writeaccess));
+        D(printk("Page fault for %lX on %X at %lX, prot %d write %d\n",
+                 address, smp_processor_id(), instruction_pointer(regs),
+                 protection, writeaccess));
 
         tsk = current;
 
@@ -175,8 +210,19 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
             !user_mode(regs))
                 goto vmalloc_fault;
 
+        /* When stack execution is not allowed we store the signal
+         * trampolines in the reserved cris_signal_return_page.
+         * Handle this in the exact same way as vmalloc (we know
+         * that the mapping is there and is valid so no need to
+         * call handle_mm_fault).
+         */
+        if (cris_signal_return_page &&
+            address == cris_signal_return_page &&
+            !protection && user_mode(regs))
+                goto vmalloc_fault;
+
         /* we can and should enable interrupts at this point */
-        sti();
+        local_irq_enable();
 
         mm = tsk->mm;
         info.si_code = SEGV_MAPERR;
@@ -220,7 +266,10 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
 
         /* first do some preliminary protection checks */
 
-        if (writeaccess) {
+        if (writeaccess == 2){
+                if (!(vma->vm_flags & VM_EXEC))
+                        goto bad_area;
+        } else if (writeaccess == 1) {
                 if (!(vma->vm_flags & VM_WRITE))
                         goto bad_area;
         } else {
@@ -234,7 +283,7 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
          * the fault.
          */
 
-        switch (handle_mm_fault(mm, vma, address, writeaccess)) {
+        switch (handle_mm_fault(mm, vma, address, writeaccess & 1)) {
         case 1:
                 tsk->min_flt++;
                 break;
@@ -292,10 +341,10 @@ do_page_fault(unsigned long address, struct pt_regs *regs,
          */
 
         if ((unsigned long) (address) < PAGE_SIZE)
-                printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
+                raw_printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
         else
-                printk(KERN_ALERT "Unable to handle kernel access");
-        printk(" at virtual address %08lx\n",address);
+                raw_printk(KERN_ALERT "Unable to handle kernel access");
+        raw_printk(" at virtual address %08lx\n",address);
 
         die_if_kernel("Oops", regs, (writeaccess << 1) | protection);
 
@@ -346,10 +395,11 @@ vmalloc_fault:
 
                 int offset = pgd_index(address);
                 pgd_t *pgd, *pgd_k;
+                pud_t *pud, *pud_k;
                 pmd_t *pmd, *pmd_k;
                 pte_t *pte_k;
 
-                pgd = (pgd_t *)current_pgd + offset;
+                pgd = (pgd_t *)per_cpu(current_pgd, smp_processor_id()) + offset;
                 pgd_k = init_mm.pgd + offset;
 
                 /* Since we're two-level, we don't need to do both
@@ -364,8 +414,13 @@ vmalloc_fault:
                  * it exists.
                  */
 
-                pmd = pmd_offset(pgd, address);
-                pmd_k = pmd_offset(pgd_k, address);
+                pud = pud_offset(pgd, address);
+                pud_k = pud_offset(pgd_k, address);
+                if (!pud_present(*pud_k))
+                        goto no_context;
+
+                pmd = pmd_offset(pud, address);
+                pmd_k = pmd_offset(pud_k, address);
 
                 if (!pmd_present(*pmd_k))
                         goto bad_area_nosemaphore;
@@ -385,3 +440,19 @@ vmalloc_fault:
                 return;
         }
 }
+
+/* Find fixup code. */
+int
+find_fixup_code(struct pt_regs *regs)
+{
+        const struct exception_table_entry *fixup;
+
+        if ((fixup = search_exception_tables(instruction_pointer(regs))) != 0) {
+                /* Adjust the instruction pointer in the stackframe. */
+                instruction_pointer(regs) = fixup->fixup;
+                arch_fixup(regs);
+                return 1;
+        }
+
+        return 0;
+}