[Xen-devel] [PATCH v2 11/18] mini-os: add checks for out of memory

[Juergen Gross <jgross@xxxxxxxx>]

There are several core functions in Mini-OS not checking for failed
memory allocations. Add such checks.

Add do_map_frames() dummy function to arm architecture as it will be
needed in future for compilations to succeed.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 arch/arm/mm.c |  8 ++++++++
 arch/x86/mm.c | 26 +++++++++++++++++++-------
 include/mm.h  |  2 +-
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mm.c b/arch/arm/mm.c
index f75888d..fc8d4bc 100644
--- a/arch/arm/mm.c
+++ b/arch/arm/mm.c
@@ -1,6 +1,7 @@
 #include <mini-os/console.h>
 #include <xen/memory.h>
 #include <arch_mm.h>
+#include <mini-os/errno.h>
 #include <mini-os/hypervisor.h>
 #include <libfdt.h>
 #include <lib.h>
@@ -79,6 +80,13 @@ void arch_init_demand_mapping_area(void)
 {
 }
 
+int do_map_frames(unsigned long addr,
+        const unsigned long *f, unsigned long n, unsigned long stride,
+        unsigned long increment, domid_t id, int *err, unsigned long prot)
+{
+    return -ENOSYS;
+}
+
 /* Get Xen's suggested physical page assignments for the grant table. */
 static paddr_t get_gnttab_base(void)
 {
diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index e2f026b..12f7fe4 100644
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -34,6 +34,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <mini-os/errno.h>
 #include <mini-os/os.h>
 #include <mini-os/hypervisor.h>
 #include <mini-os/mm.h>
@@ -354,6 +355,8 @@ pgentry_t *need_pgt(unsigned long va)
     if ( !(tab[offset] & _PAGE_PRESENT) )
     {
         pt_pfn = virt_to_pfn(alloc_page());
+        if ( !pt_pfn )
+            return NULL;
         new_pt_frame(&pt_pfn, pt_mfn, offset, L3_FRAME);
     }
     ASSERT(tab[offset] & _PAGE_PRESENT);
@@ -364,6 +367,8 @@ pgentry_t *need_pgt(unsigned long va)
     if ( !(tab[offset] & _PAGE_PRESENT) ) 
     {
         pt_pfn = virt_to_pfn(alloc_page());
+        if ( !pt_pfn )
+            return NULL;
         new_pt_frame(&pt_pfn, pt_mfn, offset, L2_FRAME);
     }
     ASSERT(tab[offset] & _PAGE_PRESENT);
@@ -373,6 +378,8 @@ pgentry_t *need_pgt(unsigned long va)
     if ( !(tab[offset] & _PAGE_PRESENT) )
     {
         pt_pfn = virt_to_pfn(alloc_page());
+        if ( !pt_pfn )
+            return NULL;
         new_pt_frame(&pt_pfn, pt_mfn, offset, L1_FRAME);
     }
     ASSERT(tab[offset] & _PAGE_PRESENT);
@@ -445,10 +452,10 @@ unsigned long allocate_ondemand(unsigned long n, unsigned 
long alignment)
  * va. map f[i*stride]+i*increment for i in 0..n-1.
  */
 #define MAP_BATCH ((STACK_SIZE / 2) / sizeof(mmu_update_t))
-void do_map_frames(unsigned long va,
-                   const unsigned long *mfns, unsigned long n, 
-                   unsigned long stride, unsigned long incr, 
-                   domid_t id, int *err, unsigned long prot)
+int do_map_frames(unsigned long va,
+                  const unsigned long *mfns, unsigned long n,
+                  unsigned long stride, unsigned long incr,
+                  domid_t id, int *err, unsigned long prot)
 {
     pgentry_t *pgt = NULL;
     unsigned long done = 0;
@@ -458,7 +465,7 @@ void do_map_frames(unsigned long va,
     if ( !mfns ) 
     {
         printk("do_map_frames: no mfns supplied\n");
-        return;
+        return -EINVAL;
     }
     DEBUG("va=%p n=0x%lx, mfns[0]=0x%lx stride=0x%lx incr=0x%lx prot=0x%lx\n",
           va, n, mfns[0], stride, incr, prot);
@@ -484,7 +491,9 @@ void do_map_frames(unsigned long va,
             {
                 if ( !pgt || !(va & L1_MASK) )
                     pgt = need_pgt(va);
-                
+                if ( !pgt )
+                    return -ENOMEM;
+
                 mmu_updates[i].ptr = virt_to_mach(pgt) | MMU_NORMAL_PT_UPDATE;
                 mmu_updates[i].val = ((pgentry_t)(mfns[(done + i) * stride] +
                                                   (done + i) * incr)
@@ -505,6 +514,8 @@ void do_map_frames(unsigned long va,
         }
         done += todo;
     }
+
+    return 0;
 }
 
 /*
@@ -521,7 +532,8 @@ void *map_frames_ex(const unsigned long *mfns, unsigned 
long n,
     if ( !va )
         return NULL;
 
-    do_map_frames(va, mfns, n, stride, incr, id, err, prot);
+    if ( do_map_frames(va, mfns, n, stride, incr, id, err, prot) )
+        return NULL;
 
     return (void *)va;
 }
diff --git a/include/mm.h b/include/mm.h
index a22dcd1..9244e26 100644
--- a/include/mm.h
+++ b/include/mm.h
@@ -68,7 +68,7 @@ unsigned long allocate_ondemand(unsigned long n, unsigned 
long alignment);
 void *map_frames_ex(const unsigned long *f, unsigned long n, unsigned long 
stride,
        unsigned long increment, unsigned long alignment, domid_t id,
        int *err, unsigned long prot);
-void do_map_frames(unsigned long addr,
+int do_map_frames(unsigned long addr,
         const unsigned long *f, unsigned long n, unsigned long stride,
        unsigned long increment, domid_t id, int *err, unsigned long prot);
 int unmap_frames(unsigned long va, unsigned long num_frames);
-- 
2.6.6


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