commit 23c6e60409a580e53834f90c1de1438a8ac94e88
author Andreas Sandberg <andreas.sandberg@arm.com> Wed Feb 21 12:07:01 2018 +0000
committer Andreas Sandberg <andreas.sandberg@arm.com> Wed May 16 17:20:27 2018 +0000
tree de59605e447fa05621c6a41897cccb032e6c1b0e
parent abb21ba99f3ae910101fc9f17341a52039c0547b

arch-arm: Add support for semihosting STDIO redirection

The Arm Semihosting layer currently assumes that the guest application
shares STDIO with gem5. This makes it hard to distinguish application
output from gem5's output and makes it impossible to redirect STDIN
when running in interactive mode. Add support for custom STDIO
redirection when instantiating the Semihosting model.

Change-Id: I3411a6b9bfb008ffc3087d8837f59be72bd1e8ae
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Anouk Van Laer <anouk.vanlaer@arm.com>
Reviewed-by: Jack Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10021
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

src/arch/arm/ArmSemihosting.py

diff --git a/src/arch/arm/ArmSemihosting.py b/src/arch/arm/ArmSemihosting.py
index 1da4c49..7846499 100644
--- a/src/arch/arm/ArmSemihosting.py
+++ b/src/arch/arm/ArmSemihosting.py
@@ -46,6 +46,12 @@
     cxx_header = "arch/arm/semihosting.hh"
 
     cmd_line = Param.String("", "Command line to report to guest");
+    stdin = Param.String("stdin",
+                         "Standard input (stdin for gem5's terminal)")
+    stdout = Param.String("stdout",
+                          "Standard output (stdout for gem5's terminal)")
+    stderr = Param.String("stderr",
+                          "Standard error (stderr for gem5's terminal)")
 
     mem_reserve = Param.MemorySize("32MB",
         "Amount of memory to reserve at the start of the address map. This "

src/arch/arm/semihosting.cc

diff --git a/src/arch/arm/semihosting.cc b/src/arch/arm/semihosting.cc
index 89e1b2e..46d964d 100644
--- a/src/arch/arm/semihosting.cc
+++ b/src/arch/arm/semihosting.cc
@@ -121,6 +121,15 @@
     0x3,                    // EXT_EXIT_EXTENDED, EXT_STDOUT_STDERR
 };
 
+const std::map<const std::string, FILE *> ArmSemihosting::stdioMap{
+    {"cin",    ::stdin},
+    {"stdin",  ::stdin},
+    {"cout",   ::stdout},
+    {"stdout", ::stdout},
+    {"cerr",   ::stderr},
+    {"stderr", ::stderr},
+};
+
 ArmSemihosting::ArmSemihosting(const ArmSemihostingParams *p)
     : SimObject(p),
       cmdLine(p->cmd_line),
@@ -128,7 +137,11 @@
       stackSize(p->stack_size),
       timeBase([p]{ struct tm t = p->time; return mkutctime(&t); }()),
       tickShift(calcTickShift()),
-      semiErrno(0)
+      semiErrno(0),
+      stdin(getSTDIO("stdin", p->stdin, "r")),
+      stdout(getSTDIO("stdout", p->stdout, "w")),
+      stderr(p->stderr == p->stdout ?
+             stdout : getSTDIO("stderr", p->stderr, "w"))
 {
     // Create an empty place-holder file for position 0 as semi-hosting
     // calls typically expect non-zero file handles.
@@ -681,6 +694,23 @@
     }
 }
 
+FILE *
+ArmSemihosting::getSTDIO(const char *stream_name,
+                         const std::string &name, const char *mode)
+{
+    auto it = stdioMap.find(name);
+    if (it == stdioMap.end()) {
+        FILE *f = fopen(name.c_str(), mode);
+        if (!f) {
+            fatal("Failed to open %s (%s): %s\n",
+                  stream_name, name, strerror(errno));
+        }
+        return f;
+    } else {
+        return it->second;
+    }
+}
+
 std::unique_ptr<ArmSemihosting::FileBase>
 ArmSemihosting::FileBase::create(
     ArmSemihosting &parent, const std::string &fname, const char *mode)
@@ -819,11 +849,11 @@
 
     if (_name == ":tt") {
         if (mode[0] == 'r') {
-            file = stdin;
+            file = parent.stdin;
         } else if (mode[0] == 'w') {
-            file = stdout;
+            file = parent.stdout;
         } else if (mode[0] == 'a') {
-            file = stderr;
+            file = parent.stderr;
         } else {
             warn("Unknown file mode for the ':tt' special file");
             return -EINVAL;
@@ -857,7 +887,9 @@
 bool
 ArmSemihosting::File::isTTY() const
 {
-    return file == stdout || file == stderr || file == stdin;
+    return file == parent.stdout ||
+        file == parent.stderr ||
+        file == parent.stdin;
 }
 
 int64_t

src/arch/arm/semihosting.hh

diff --git a/src/arch/arm/semihosting.hh b/src/arch/arm/semihosting.hh
index 14c5f9d..5816460 100644
--- a/src/arch/arm/semihosting.hh
+++ b/src/arch/arm/semihosting.hh
@@ -244,6 +244,9 @@
     };
 
     std::vector<std::unique_ptr<FileBase>> files;
+    FILE *stdin;
+    FILE *stdout;
+    FILE *stderr;
 
   protected: // Helper functions
     unsigned calcTickShift() const {
@@ -342,11 +345,14 @@
 #undef SEMI_CALL
 
     static const SemiCall *getCall(uint32_t op, bool aarch64);
+    static FILE *getSTDIO(const char *stream_name,
+                          const std::string &name, const char *mode);
 
     static const std::map<uint32_t, SemiCall> calls;
     static const std::vector<const char *> fmodes;
     static const std::map<uint64_t, const char *> exitCodes;
     static const std::vector<uint8_t> features;
+    static const std::map<const std::string, FILE *> stdioMap;
 };
 
 #endif // __ARCH_ARM_SEMIHOSTING_HH__