util: implements "writefile" gem5 op to export file from guest to host filesystem

Usage: m5 writefile <filename>

File will be created in the gem5 output folder with the identical filename.
Implementation is largely based on the existing "readfile" functionality.
Currently does not support exporting of folders.

4 files changed, 45 insertions, 2 deletions

diff --git a/util/m5/m5.c b/util/m5/m5.c
index 40328bc38..a0ce9b3ec 100644
--- a/util/m5/m5.c
+++ b/util/m5/m5.c
@@ -88,6 +88,33 @@ read_file(int dest_fid)
     }
 }
 
+int
+write_file(const char *filename)
+{
+    fprintf(stderr, "opening %s\n", filename);
+    int src_fid = open(filename, O_RDONLY);
+
+    if (src_fid < 0) {
+        fprintf(stderr, "error opening %s\n", filename);
+        return;
+    }
+
+    char buf[256*1024];
+    int offset = 0;
+    int len;
+    int bytes = 0;
+
+    memset(buf, 0, sizeof(buf));
+
+    while ((len = read(src_fid, buf, sizeof(buf))) > 0) {
+        bytes += m5_writefile(buf, len, offset, filename);
+        offset += len;
+    }
+    fprintf(stderr, "written %d bytes\n", bytes);
+
+    close(src_fid);
+}
+
 void
 do_exit(int argc, char *argv[])
 {
@@ -131,6 +158,17 @@ do_read_file(int argc, char *argv[])
 }
 
 void
+do_write_file(int argc, char *argv[])
+{
+    if (argc != 1)
+        usage();
+
+    const char *filename = argv[0];
+
+    write_file(filename);
+}
+
+void
 do_exec_file(int argc, char *argv[])
 {
     if (argc > 0)
@@ -227,8 +265,9 @@ struct MainFunc mainfuncs[] = {
     { "resetstats",     do_reset_stats,      "[delay [period]]" },
     { "dumpstats",      do_dump_stats,       "[delay [period]]" },
     { "dumpresetstats", do_dump_reset_stats, "[delay [period]]" },
-    { "readfile",       do_read_file,        "[filename]" },
-    { "execfile",       do_exec_file,        "<filename>" },
+    { "readfile",       do_read_file,        "" },
+    { "writefile",      do_write_file,       "<filename>" },
+    { "execfile",       do_exec_file,        "" },
     { "checkpoint",     do_checkpoint,       "[delay [period]]" },
     { "loadsymbol",     do_load_symbol,      "<address> <symbol>" },
     { "initparam",      do_initparam,        "" },
diff --git a/util/m5/m5op.h b/util/m5/m5op.h
index 38815e3c3..4e1d0b638 100644
--- a/util/m5/m5op.h
+++ b/util/m5/m5op.h
@@ -49,6 +49,7 @@ void m5_reset_stats(uint64_t ns_delay, uint64_t ns_period);
 void m5_dump_stats(uint64_t ns_delay, uint64_t ns_period);
 void m5_dumpreset_stats(uint64_t ns_delay, uint64_t ns_period);
 uint64_t m5_readfile(void *buffer, uint64_t len, uint64_t offset);
+uint64_t m5_writefile(void *buffer, uint64_t len, uint64_t offset, const char *filename);
 void m5_debugbreak(void);
 void m5_switchcpu(void);
 void m5_addsymbol(uint64_t addr, char *symbol);
diff --git a/util/m5/m5op_arm.S b/util/m5/m5op_arm.S
index b9557ee9d..8cdf5c62d 100644
--- a/util/m5/m5op_arm.S
+++ b/util/m5/m5op_arm.S
@@ -80,6 +80,7 @@ func:
 #define DUMPRST_STATS INST(m5_op, 0, 0, dumprststats_func)
 #define CHECKPOINT INST(m5_op, 0, 0, ckpt_func)
 #define READFILE INST(m5_op, 0, 0, readfile_func)
+#define WRITEFILE INST(m5_op, 0, 0, writefile_func)
 #define DEBUGBREAK INST(m5_op, 0, 0, debugbreak_func)
 #define SWITCHCPU INST(m5_op, 0, 0, switchcpu_func)
 #define ADDSYMBOL INST(m5_op, 0, 0, addsymbol_func)
@@ -121,6 +122,7 @@ SIMPLE_OP(m5_dump_stats, DUMP_STATS)
 SIMPLE_OP(m5_dumpreset_stats, DUMPRST_STATS)
 SIMPLE_OP(m5_checkpoint, CHECKPOINT)
 SIMPLE_OP(m5_readfile, READFILE)
+SIMPLE_OP(m5_writefile, WRITEFILE)
 SIMPLE_OP(m5_debugbreak, DEBUGBREAK)
 SIMPLE_OP(m5_switchcpu, SWITCHCPU)
 SIMPLE_OP(m5_addsymbol, ADDSYMBOL)
diff --git a/util/m5/m5ops.h b/util/m5/m5ops.h
index bc2ae06be..f08524014 100644
--- a/util/m5/m5ops.h
+++ b/util/m5/m5ops.h
@@ -46,6 +46,7 @@
 #define dumpstats_func          0x41
 #define dumprststats_func       0x42
 #define ckpt_func               0x43
+#define writefile_func          0x4F
 #define readfile_func           0x50
 #define debugbreak_func         0x51
 #define switchcpu_func          0x52