Changeset 0fd9b35 in mainline

Timestamp:

2011-12-30T18:30:47Z (13 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

41deb2a

Parents:

aaa6af2

Message:

Limit kernel identity on ia64 to low memory and make sure to use
the kernel address space for kernel non-identity page table
lookups.

Location:

kernel/arch/ia64

Files:

• include/mm/frame.h (modified) (1 diff)
• src/mm/frame.c (modified) (2 diffs)
• src/mm/tlb.c (modified) (9 diffs)

kernel/arch/ia64/include/mm/frame.h

@@ -43 +43 @@
 #include <typedefs.h>
 
+extern uintptr_t end_of_identity;
+
 extern void frame_low_arch_init(void);
 extern void frame_high_arch_init(void);

kernel/arch/ia64/src/mm/frame.c

@@ -51 +51 @@
 #define MINCONF 1
 
+uintptr_t end_of_identity = -1ULL;
+
 static void frame_common_arch_init(bool low)
 {
@@ -102 +104 @@
         frame_mark_unavailable(ADDR2PFN(KERNEL_RESERVED_AREA_BASE),
             SIZE2FRAMES(KERNEL_RESERVED_AREA_SIZE));
+
+        /* PA2KA will work only on low-memory. */
+        end_of_identity = PA2KA(config.physmem_end - FRAME_SIZE) + PAGE_SIZE;
 }
 

kernel/arch/ia64/src/mm/tlb.c

@@ -467 +467 @@
 }
 
+static bool is_kernel_fault(uintptr_t va)
+{
+        region_register_t rr;
+
+        rr.word = rr_read(VA2VRN(va));
+        rid_t rid = rr.map.rid;
+        return (RID2ASID(rid) == ASID_KERNEL) && (VA2VRN(va) == VRN_KERNEL);
+}
+
 /** Instruction TLB fault handler for faults with VHPT turned off.
  *
@@ -480 +489 @@
         va = istate->cr_ifa; /* faulting address */
         
+        ASSERT(!is_kernel_fault(va));
+
         t = page_mapping_find(AS, va, true);
         if (t) {
@@ -567 +578 @@
 {
         if (istate->cr_isr.sp) {
-                /* Speculative load. Deffer the exception
-                   until a more clever approach can be used.
-                   
-                   Currently if we try to find the mapping
-                   for the speculative load while in the kernel,
-                   we might introduce a livelock because of
-                   the possibly invalid values of the address. */
+                /*
+                 * Speculative load. Deffer the exception until a more clever
+                 * approach can be used. Currently if we try to find the
+                 * mapping for the speculative load while in the kernel, we
+                 * might introduce a livelock because of the possibly invalid
+                 * values of the address.
+                 */
                 istate->cr_ipsr.ed = true;
                 return;
@@ -579 +590 @@
         
         uintptr_t va = istate->cr_ifa;  /* faulting address */
-        
-        region_register_t rr;
-        rr.word = rr_read(VA2VRN(va));
-        rid_t rid = rr.map.rid;
-        if (RID2ASID(rid) == ASID_KERNEL) {
-                if (VA2VRN(va) == VRN_KERNEL) {
+        as_t *as = AS;
+        
+        if (is_kernel_fault(va)) {
+                if (va < end_of_identity) {
                         /*
-                         * Provide KA2PA(identity) mapping for faulting piece of
-                         * kernel address space.
+                         * Create kernel identity mapping for low memory. 
                          */
                         dtlb_kernel_mapping_insert(va, KA2PA(va), false, 0);
                         return;
+                } else {
+                        as = AS_KERNEL;
                 }
         }
         
         
-        pte_t *entry = page_mapping_find(AS, va, true);
+        pte_t *entry = page_mapping_find(as, va, true);
         if (entry) {
                 /*
@@ -641 +651 @@
         uintptr_t va;
         pte_t *t;
+        as_t *as = AS;
         
         va = istate->cr_ifa;  /* faulting address */
         
-        t = page_mapping_find(AS, va, true);
+        if (is_kernel_fault(va))
+                as = AS_KERNEL;
+
+        t = page_mapping_find(as, va, true);
         ASSERT((t) && (t->p));
         if ((t) && (t->p) && (t->w)) {
@@ -674 +688 @@
         
         va = istate->cr_ifa;  /* faulting address */
+
+        ASSERT(!is_kernel_fault(va));
         
         t = page_mapping_find(AS, va, true);
@@ -703 +719 @@
         uintptr_t va;
         pte_t *t;
+        as_t *as = AS;
         
         va = istate->cr_ifa;  /* faulting address */
         
-        t = page_mapping_find(AS, va, true);
+        if (is_kernel_fault(va))
+                as = AS_KERNEL;
+
+        t = page_mapping_find(as, va, true);
         ASSERT((t) && (t->p));
         if ((t) && (t->p)) {
@@ -736 +756 @@
         
         va = istate->cr_ifa;  /* faulting address */
+
+        ASSERT(!is_kernel_fault(va));
         
         /*
@@ -763 +785 @@
         va = istate->cr_ifa;  /* faulting address */
         
+        ASSERT(!is_kernel_fault(va));
+
         t = page_mapping_find(AS, va, true);
         ASSERT(t);