Merge pull request #177 from riscv/debug_auth

Add debug module authentication.

1 files changed, 13 insertions, 2 deletions

diff --git a/riscv/debug_module.h b/riscv/debug_module.h
index 82c449e..813c647 100644
--- a/riscv/debug_module.h
+++ b/riscv/debug_module.h
@@ -74,7 +74,14 @@ typedef struct {
 class debug_module_t : public abstract_device_t
 {
   public:
-    debug_module_t(sim_t *sim, unsigned progbufsize, unsigned max_bus_master_bits);
+    /*
+     * If require_authentication is true, then a debugger must authenticate as
+     * follows:
+     * 1. Read a 32-bit value from authdata:
+     * 2. Write the value that was read back, plus one, to authdata.
+     */
+    debug_module_t(sim_t *sim, unsigned progbufsize, unsigned max_bus_master_bits,
+        bool require_authentication);
     ~debug_module_t();
 
     void add_device(bus_t *bus);
@@ -96,7 +103,8 @@ class debug_module_t : public abstract_device_t
     // Actual size of the program buffer, which is 1 word bigger than we let on
     // to implement the implicit ebreak at the end.
     unsigned program_buffer_bytes;
-    unsigned max_bus_master_bits ;
+    unsigned max_bus_master_bits;
+    bool require_authentication;
     static const unsigned debug_data_start = 0x380;
     unsigned debug_progbuf_start;
 
@@ -134,6 +142,9 @@ class debug_module_t : public abstract_device_t
     uint32_t sbaddress[4];
     uint32_t sbdata[4];
 
+    uint32_t challenge;
+    const uint32_t secret = 1;
+
     processor_t *current_proc() const;
     void reset();
     bool perform_abstract_command();