runtime: process essential kernel CPU messages at all time

soc/runtime/kloader.c

@@ -4,6 +4,7 @@
 #include "log.h"
 #include "flash_storage.h"
 #include "mailbox.h"
+#include "messages.h"
 #include "elf_loader.h"
 #include "services.h"
 #include "kloader.h"
@@ -122,3 +123,65 @@ void kloader_stop(void)
     kernel_cpu_reset_write(1);
     mailbox_acknowledge();
 }
+
+int kloader_validate_kpointer(void *p)
+{
+    unsigned int v = (unsigned int)p;
+    if((v < 0x40400000) || (v > (0x4fffffff - 1024*1024))) {
+        log("Received invalid pointer from kernel CPU: 0x%08x", v);
+        return 0;
+    }
+    return 1;
+}
+
+int kloader_is_essential_kmsg(int msgtype)
+{
+    switch(msgtype) {
+        case MESSAGE_TYPE_NOW_INIT_REQUEST:
+        case MESSAGE_TYPE_NOW_SAVE:
+        case MESSAGE_TYPE_LOG:
+            return 1;
+        default:
+            return 0;
+    }
+}
+
+long long int now;
+
+void kloader_service_essential_kmsg(void)
+{
+    struct msg_base *umsg;
+
+    umsg = mailbox_receive();
+    if(umsg) {
+        if(!kloader_validate_kpointer(umsg))
+            return;
+        switch(umsg->type) {
+            case MESSAGE_TYPE_NOW_INIT_REQUEST: {
+                struct msg_now_init_reply reply;
+
+                reply.type = MESSAGE_TYPE_NOW_INIT_REPLY;
+                reply.now = now;
+                mailbox_send_and_wait(&reply);
+                break;
+            }
+            case MESSAGE_TYPE_NOW_SAVE: {
+                struct msg_now_save *msg = (struct msg_now_save *)umsg;
+
+                now = msg->now;
+                mailbox_acknowledge();
+                break;
+            }
+            case MESSAGE_TYPE_LOG: {
+                struct msg_log *msg = (struct msg_log *)umsg;
+
+                log_va(msg->fmt, msg->args);
+                mailbox_acknowledge();
+                break;
+            }
+            default:
+                /* handled elsewhere */
+                break;
+        }
+    }
+}

soc/runtime/kloader.h

@@ -4,6 +4,8 @@
 #define KERNELCPU_EXEC_ADDRESS 0x40400000
 #define KERNELCPU_PAYLOAD_ADDRESS 0x40404000
 
+extern long long int now;
+
 typedef void (*kernel_function)(void);
 
 int kloader_load(void *buffer, int length);
@@ -14,4 +16,8 @@ void kloader_start_idle_kernel(void);
 void kloader_start_user_kernel(kernel_function k);
 void kloader_stop(void);
 
+int kloader_validate_kpointer(void *p);
+int kloader_is_essential_kmsg(int msgtype);
+void kloader_service_essential_kmsg(void);
+
 #endif /* __KLOADER_H */

soc/runtime/main.c

@@ -143,6 +143,7 @@ static void regular_main(void)
     session_end();
     while(1) {
         lwip_service();
+        kloader_service_essential_kmsg();
         kserver_service();
     }
 }
@@ -201,8 +202,10 @@ static void regular_main(void)
 
     /* Open the session for the serial control. */
     session_start();
-    while(1)
+    while(1) {
+        kloader_service_essential_kmsg();
         serial_service();
+    }
 }
 
 #endif

soc/runtime/session.c

@@ -11,8 +11,8 @@
 #include "log.h"
 #include "kloader.h"
 #include "exceptions.h"
-#include "session.h"
 #include "flash_storage.h"
+#include "session.h"
 
 #define BUFFER_IN_SIZE (1024*1024)
 #define BUFFER_OUT_SIZE (1024*1024)
@@ -55,7 +55,6 @@ static void submit_output(int len)
 }
 
 static int user_kernel_state;
-static long long int now;
 
 enum {
     USER_KERNEL_NONE = 0,
@@ -153,7 +152,7 @@ static int process_input(void)
                 log("Attempted to switch RTIO clock while kernel running");
                 buffer_out[8] = REMOTEMSG_TYPE_CLOCK_SWITCH_FAILED;
                 submit_output(9);
-                break;    
+                break;
             }
             rtio_crg_clock_sel_write(buffer_in[9]);
             buffer_out[8] = REMOTEMSG_TYPE_CLOCK_SWITCH_COMPLETED;
@@ -421,16 +420,6 @@ static int add_rpc_value(int bi, int type_tag, void *value)
     return bi - obi;
 }
 
-static int validate_kpointer(void *p)
-{
-    unsigned int v = (unsigned int)p;
-    if((v < 0x40400000) || (v > (0x4fffffff - 1024*1024))) {
-        log("Received invalid pointer from kernel CPU: 0x%08x", v);
-        return 0;
-    }
-    return 1;
-}
-
 static int send_rpc_request(int rpc_num, va_list args)
 {
     int r;
@@ -448,7 +437,7 @@ static int send_rpc_request(int rpc_num, va_list args)
             v = NULL;
         else {
             v = va_arg(args, void *);
-            if(!validate_kpointer(v))
+            if(!kloader_validate_kpointer(v))
                 return 0;
         }
         r = add_rpc_value(bi, type_tag, v);
@@ -467,31 +456,16 @@ static int send_rpc_request(int rpc_num, va_list args)
 /* assumes output buffer is empty when called */
 static int process_kmsg(struct msg_base *umsg)
 {
-    if(!validate_kpointer(umsg))
+    if(!kloader_validate_kpointer(umsg))
         return 0;
-    if((user_kernel_state != USER_KERNEL_RUNNING)
+    if(kloader_is_essential_kmsg(umsg->type))
-      && (umsg->type != MESSAGE_TYPE_NOW_INIT_REQUEST)
+        return 1; /* handled elsewhere */
-      && (umsg->type != MESSAGE_TYPE_NOW_SAVE)) {
+    if(user_kernel_state != USER_KERNEL_RUNNING) {
         log("Received unexpected message from kernel CPU while not in running state");
         return 0;
     }
 
     switch(umsg->type) {
-        case MESSAGE_TYPE_NOW_INIT_REQUEST: {
-            struct msg_now_init_reply reply;
-
-            reply.type = MESSAGE_TYPE_NOW_INIT_REPLY;
-            reply.now = now;
-            mailbox_send_and_wait(&reply);
-            break;
-        }
-        case MESSAGE_TYPE_NOW_SAVE: {
-            struct msg_now_save *msg = (struct msg_now_save *)umsg;
-
-            now = msg->now;
-            mailbox_acknowledge();
-            break;
-        }
         case MESSAGE_TYPE_FINISHED:
             buffer_out[8] = REMOTEMSG_TYPE_KERNEL_FINISHED;
             submit_output(9);
@@ -538,13 +512,6 @@ static int process_kmsg(struct msg_base *umsg)
             mailbox_acknowledge();
             break;
         }
-        case MESSAGE_TYPE_LOG: {
-            struct msg_log *msg = (struct msg_log *)umsg;
-
-            log_va(msg->fmt, msg->args);
-            mailbox_acknowledge();
-            break;
-        }
         default: {
             log("Received invalid message type from kernel CPU");
             return 0;