Changeset 32 for trunk/modules/vci_mem_cache_v1

Timestamp:

Apr 23, 2010, 4:41:46 PM (15 years ago)

Author:

guthmull

Message:

Add SC randomization to V1

Location:

trunk/modules/vci_mem_cache_v1/caba/source

Files:

• include/vci_mem_cache_v1.h (modified) (1 diff)
• src/vci_mem_cache_v1.cpp (modified) (3 diffs)

trunk/modules/vci_mem_cache_v1/caba/source/include/vci_mem_cache_v1.h

@@ -489 +489 @@
       sc_signal<int>       r_llsc_fsm;          // FSM state
       sc_signal<data_t>    r_llsc_data;             // read data word
+      sc_signal<uint32_t>  r_llsc_lfsr;         // lfsr for random introducing
       sc_signal<copy_t>    r_llsc_i_copies;         // bit_vector of copies
       sc_signal<copy_t>    r_llsc_d_copies;         // bit_vector of copies

trunk/modules/vci_mem_cache_v1/caba/source/src/vci_mem_cache_v1.cpp

@@ -33 +33 @@
 //#define IDEBUG
 //#define DEBUG_VCI_MEM_CACHE 2
+#define RANDOMIZE_SC
 
 namespace soclib { namespace caba {
@@ -469 +470 @@
       r_init_rsp_to_tgt_rsp_req = false;
 
+      r_llsc_lfsr                       = -1;
       r_llsc_to_tgt_rsp_req         = false;
       r_llsc_to_ixr_cmd_req         = false;
@@ -2364 +2366 @@
                 r_llsc_i_copies = entry.i_copies;
                 r_llsc_count    = entry.count;
-                if ( entry.valid )  r_llsc_fsm = SC_DIR_LOCK;
-                else                r_llsc_fsm = LLSC_TRT_LOCK;
+              /* to avoid livelock, force the atomic access to fail (pseudo-)randomly */
+                bool fail = (r_llsc_lfsr % (64) == 0);
+                r_llsc_lfsr = (r_llsc_lfsr >> 1) ^ ((-(r_llsc_lfsr & 1)) & 0xd0000001);
+#ifdef RANDOMIZE_SC
+                if(fail){
+#else
+                if(0){
+#endif
+                  r_llsc_fsm = SC_RSP_FALSE;
+                } else {
+                  if ( entry.valid )  r_llsc_fsm = SC_DIR_LOCK;
+                  else                r_llsc_fsm = LLSC_TRT_LOCK;
+                }
               } else {
                 r_llsc_fsm = SC_RSP_FALSE;