From: Peter Dinda <pdinda@northwestern.edu>
Date: Sat, 7 Jul 2012 23:33:46 +0000 (-0500)
Subject: Expose kmalloc flags within linux_module + add further debugging features for heap... 
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=06ad2088c1bf59d4d6d11986d4de2195e64baaac

Expose kmalloc flags within linux_module + add further debugging features for heap alloc
---

diff --git a/linux_module/palacios-stubs.c b/linux_module/palacios-stubs.c
index 60b481f..5ced6d2 100644
--- a/linux_module/palacios-stubs.c
+++ b/linux_module/palacios-stubs.c
@@ -24,6 +24,12 @@
 
 #include "mm.h"
 
+// The following can be used to track heap bugs
+// zero memory after allocation
+#define ALLOC_ZERO_MEM 0
+// pad allocations by this many bytes on both ends of block
+#define ALLOC_PAD      0
+
 
 u32 pg_allocs = 0;
 u32 pg_frees = 0;
@@ -168,32 +174,44 @@ void palacios_free_pages(void * page_paddr, int num_pages) {
 }
 
 
+void *
+palacios_alloc_extended(unsigned int size, unsigned int flags) {
+    void * addr = NULL;
+
+    addr = kmalloc(size+2*ALLOC_PAD, flags);
+
+    if (!addr) { 
+       ERROR("ALERT ALERT  kmalloc has FAILED FAILED FAILED\n");
+       return NULL;
+    }	
+
+    mallocs++;
+
+#if ALLOC_ZERO_MEM
+    memset(addr,0,size+2*ALLOC_PAD);
+#endif
+
+    return addr+ALLOC_PAD;
+}
+
+
 /**
  * Allocates 'size' bytes of kernel memory.
  * Returns the kernel virtual address of the memory allocated.
  */
 void *
 palacios_alloc(unsigned int size) {
-    void * addr = NULL;
 
     // It is very important that this test remains since 
     // this function is used extensively throughout palacios and the linux
     // module, both in places where interrupts are off and where they are on
     // a GFP_KERNEL call, when done with interrupts off can lead to DEADLOCK
     if (irqs_disabled()) {
-    	addr = kmalloc(size, GFP_ATOMIC);
+	return palacios_alloc_extended(size,GFP_ATOMIC);
     } else {
-    	addr = kmalloc(size, GFP_KERNEL);
+	return palacios_alloc_extended(size,GFP_KERNEL);
     }
 
-    if (!addr) { 
-       ERROR("ALERT ALERT  kmalloc has FAILED FAILED FAILED\n");
-       return NULL;
-    }	
-
-    mallocs++;
-
-    return addr;
 }
 
 /**
@@ -205,7 +223,7 @@ palacios_free(
 )
 {
     frees++;
-    kfree(addr);
+    kfree(addr-ALLOC_PAD);
     return;
 }
 
diff --git a/linux_module/palacios.h b/linux_module/palacios.h
index 9bee6c9..43ffa57 100644
--- a/linux_module/palacios.h
+++ b/linux_module/palacios.h
@@ -107,6 +107,7 @@ void  palacios_print(const char *fmt, ...);
 void *palacios_allocate_pages(int num_pages, unsigned int alignment);
 void  palacios_free_pages(void *page_addr, int num_pages);
 void *palacios_alloc(unsigned int size);
+void *palacios_alloc_extended(unsigned int size, unsigned int flags);
 void  palacios_free(void *);
 void *palacios_vaddr_to_paddr(void *vaddr);
 void *palacios_paddr_to_vaddr(void *paddr);