From 52adf37ea428ccbca91d8c1daa2632a25b3f1f35 Mon Sep 17 00:00:00 2001
From: Sandipan Das <sandipan@linux.ibm.com>
Date: Sat, 6 Feb 2021 17:27:40 +0530
Subject: [PATCH] arch-power: Refactor process initialization

This generalizes parts of the process initialization
routines in preparation for multi-mode support and
adds flexibility in terms of data types and byte order
used for setting up the environment corresponding to
the mode in use.

Change-Id: Ia9efb93d044682af8b0f0809bca64a17570bf197
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40941
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Maintainer: Boris Shingarov <shingarov@labware.com>
Tested-by: kokoro <noreply+kokoro@google.com>
---
 src/arch/power/process.cc | 41 +++++++++++++++++++++------------------
 src/arch/power/process.hh |  3 ++-
 2 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/src/arch/power/process.cc b/src/arch/power/process.cc
index a9a28b3548..bc631468a9 100644
--- a/src/arch/power/process.cc
+++ b/src/arch/power/process.cc
@@ -81,13 +81,16 @@ PowerProcess::initState()
 {
     Process::initState();
 
-    argsInit(sizeof(uint32_t), PageBytes);
+    argsInit<uint32_t>(PageBytes);
 }
 
+template <typename IntType>
 void
-PowerProcess::argsInit(int intSize, int pageSize)
+PowerProcess::argsInit(int pageSize)
 {
-    std::vector<gem5::auxv::AuxVector<uint32_t>> auxv;
+    int intSize = sizeof(IntType);
+    ByteOrder byteOrder = objFile->getByteOrder();
+    std::vector<gem5::auxv::AuxVector<IntType>> auxv;
 
     std::string filename;
     if (argv.size() < 1)
@@ -106,7 +109,7 @@ PowerProcess::argsInit(int intSize, int pageSize)
     //Auxilliary vectors are loaded only for elf formatted executables.
     auto *elfObject = dynamic_cast<loader::ElfObject *>(objFile);
     if (elfObject) {
-        uint32_t features = 0;
+        IntType features = 0;
 
         //Bits which describe the system hardware capabilities
         //XXX Figure out what these should be
@@ -209,15 +212,15 @@ PowerProcess::argsInit(int intSize, int pageSize)
                         roundUp(memState->getStackSize(), pageSize), "stack");
 
     // map out initial stack contents
-    uint32_t sentry_base = memState->getStackBase() - sentry_size;
-    uint32_t aux_data_base = sentry_base - aux_data_size;
-    uint32_t env_data_base = aux_data_base - env_data_size;
-    uint32_t arg_data_base = env_data_base - arg_data_size;
-    uint32_t platform_base = arg_data_base - platform_size;
-    uint32_t auxv_array_base = platform_base - aux_array_size - aux_padding;
-    uint32_t envp_array_base = auxv_array_base - envp_array_size;
-    uint32_t argv_array_base = envp_array_base - argv_array_size;
-    uint32_t argc_base = argv_array_base - argc_size;
+    IntType sentry_base = memState->getStackBase() - sentry_size;
+    IntType aux_data_base = sentry_base - aux_data_size;
+    IntType env_data_base = aux_data_base - env_data_size;
+    IntType arg_data_base = env_data_base - arg_data_size;
+    IntType platform_base = arg_data_base - platform_size;
+    IntType auxv_array_base = platform_base - aux_array_size - aux_padding;
+    IntType envp_array_base = auxv_array_base - envp_array_size;
+    IntType argv_array_base = envp_array_base - argv_array_size;
+    IntType argc_base = argv_array_base - argc_size;
 
     DPRINTF(Stack, "The addresses of items on the initial stack:\n");
     DPRINTF(Stack, "0x%x - aux data\n", aux_data_base);
@@ -233,11 +236,11 @@ PowerProcess::argsInit(int intSize, int pageSize)
     // write contents to stack
 
     // figure out argc
-    uint32_t argc = argv.size();
-    uint32_t guestArgc = htobe(argc);
+    IntType argc = argv.size();
+    IntType guestArgc = htog(argc, byteOrder);
 
     //Write out the sentry void *
-    uint32_t sentry_NULL = 0;
+    IntType sentry_NULL = 0;
     initVirtMem->writeBlob(sentry_base, &sentry_NULL, sentry_size);
 
     //Fix up the aux vectors which point to other data
@@ -256,7 +259,7 @@ PowerProcess::argsInit(int intSize, int pageSize)
     //Copy the aux stuff
     Addr auxv_array_end = auxv_array_base;
     for (const auto &aux: auxv) {
-        initVirtMem->write(auxv_array_end, aux, ByteOrder::big);
+        initVirtMem->write(auxv_array_end, aux, byteOrder);
         auxv_array_end += sizeof(aux);
     }
     //Write out the terminating zeroed auxilliary vector
@@ -265,9 +268,9 @@ PowerProcess::argsInit(int intSize, int pageSize)
     auxv_array_end += sizeof(zero);
 
     copyStringArray(envp, envp_array_base, env_data_base,
-                    ByteOrder::big, *initVirtMem);
+                    byteOrder, *initVirtMem);
     copyStringArray(argv, argv_array_base, arg_data_base,
-                    ByteOrder::big, *initVirtMem);
+                    byteOrder, *initVirtMem);
 
     initVirtMem->writeBlob(argc_base, &guestArgc, intSize);
 
diff --git a/src/arch/power/process.hh b/src/arch/power/process.hh
index 210bce2614..9f2ce4b77e 100644
--- a/src/arch/power/process.hh
+++ b/src/arch/power/process.hh
@@ -49,7 +49,8 @@ class PowerProcess : public Process
   public:
     PowerProcess(const ProcessParams &params, loader::ObjectFile *objFile);
 
-    void argsInit(int intSize, int pageSize);
+    template <typename IntType>
+    void argsInit(int pageSize);
 };
 
 } // namespace gem5