From 9b4249410ec18cac9df2c7e9c0a4a6ce5459233d Mon Sep 17 00:00:00 2001
From: Brandon Potter <brandon.potter@amd.com>
Date: Thu, 17 Mar 2016 10:31:03 -0700
Subject: base: support dynamic loading of Linux ELF objects in SE mode

---
 src/sim/process.cc | 47 ++++++++++++++++++++++++++++++++++++++++++-----
 src/sim/process.hh |  8 ++++++++
 2 files changed, 50 insertions(+), 5 deletions(-)

(limited to 'src/sim')

diff --git a/src/sim/process.cc b/src/sim/process.cc
index 81a7ec89e..7fa160995 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -518,6 +518,48 @@ LiveProcess::findDriver(std::string filename)
     return NULL;
 }
 
+void
+LiveProcess::updateBias()
+{
+    ObjectFile *interp = objFile->getInterpreter();
+
+    if (!interp || !interp->relocatable())
+        return;
+
+    // Determine how large the interpreters footprint will be in the process
+    // address space.
+    Addr interp_mapsize = roundUp(interp->mapSize(), TheISA::PageBytes);
+
+    // We are allocating the memory area; set the bias to the lowest address
+    // in the allocated memory region.
+    Addr ld_bias = mmapGrowsDown() ? mmap_end - interp_mapsize : mmap_end;
+
+    // Adjust the process mmap area to give the interpreter room; the real
+    // execve system call would just invoke the kernel's internal mmap
+    // functions to make these adjustments.
+    mmap_end = mmapGrowsDown() ? ld_bias : mmap_end + interp_mapsize;
+
+    interp->updateBias(ld_bias);
+}
+
+
+Addr
+LiveProcess::getBias()
+{
+    ObjectFile *interp = objFile->getInterpreter();
+
+    return interp ? interp->bias() : objFile->bias();
+}
+
+
+Addr
+LiveProcess::getStartPC()
+{
+    ObjectFile *interp = objFile->getInterpreter();
+
+    return interp ? interp->entryPoint() : objFile->entryPoint();
+}
+
 
 LiveProcess *
 LiveProcess::create(LiveProcessParams * params)
@@ -535,11 +577,6 @@ LiveProcess::create(LiveProcessParams * params)
         fatal("Can't load object file %s", params->executable);
     }
 
-    if (objFile->isDynamic())
-       fatal("Object file is a dynamic executable however only static "
-             "executables are supported!\n       Please recompile your "
-             "executable as a static binary and try again.\n");
-
 #if THE_ISA == ALPHA_ISA
     if (objFile->getArch() != ObjectFile::Alpha)
         fatal("Object file architecture does not match compiled ISA (Alpha).");
diff --git a/src/sim/process.hh b/src/sim/process.hh
index 72f789ec7..aa4c7a008 100644
--- a/src/sim/process.hh
+++ b/src/sim/process.hh
@@ -336,6 +336,14 @@ class LiveProcess : public Process
      */
     EmulatedDriver *findDriver(std::string filename);
 
+    // This function acts as a callback to update the bias value in
+    // the object file because the parameters needed to calculate the
+    // bias are not available when the object file is created.
+    void updateBias();
+
+    Addr getBias();
+    Addr getStartPC();
+
     // this function is used to create the LiveProcess object, since
     // we can't tell which subclass of LiveProcess to use until we
     // open and look at the object file.
-- 
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