From: Gabe Black <gabeblack@google.com>
Date: Wed, 18 Mar 2020 04:13:04 +0000 (-0700)
Subject: sparc: Add the AT_RANDOM aux vector to the initial stack.
X-Git-Tag: v20.0.0.0~295
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9877dc66ab7a5956effcecfb53ef81781b478580;p=gem5.git

sparc: Add the AT_RANDOM aux vector to the initial stack.

This is blindly used by at least modern glibc-s

Change-Id: I175ce5f1495e367badf0fab32f5837e3cdfa955a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/26824
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Gabe Black <gabeblack@google.com>
---

diff --git a/src/arch/sparc/process.cc b/src/arch/sparc/process.cc
index 816df4f47..c55e9cbbc 100644
--- a/src/arch/sparc/process.cc
+++ b/src/arch/sparc/process.cc
@@ -251,6 +251,8 @@ SparcProcess::argsInit(int pageSize)
         auxv.emplace_back(M5_AT_EGID, egid());
         // Whether to enable "secure mode" in the executable
         auxv.emplace_back(M5_AT_SECURE, 0);
+        // The address of 16 "random" bytes.
+        auxv.emplace_back(M5_AT_RANDOM, 0);
     }
 
     // Figure out how big the initial stack needs to be
@@ -262,6 +264,9 @@ SparcProcess::argsInit(int pageSize)
     // It's purpose is to let the user space linker examine the original file.
     int file_name_size = filename.size() + 1;
 
+    const int numRandomBytes = 16;
+    int aux_data_size = numRandomBytes;
+
     int env_data_size = 0;
     for (int i = 0; i < envp.size(); ++i) {
         env_data_size += envp[i].size() + 1;
@@ -303,6 +308,7 @@ SparcProcess::argsInit(int pageSize)
 
     int space_needed =
         info_block_size +
+        aux_data_size +
         aux_padding +
         frame_size;
 
@@ -319,8 +325,8 @@ SparcProcess::argsInit(int pageSize)
     IntType file_name_base = sentry_base - file_name_size;
     IntType env_data_base = file_name_base - env_data_size;
     IntType arg_data_base = env_data_base - arg_data_size;
-    IntType auxv_array_base = arg_data_base -
-        info_block_padding - aux_array_size - aux_padding;
+    IntType aux_data_base = arg_data_base - info_block_padding - aux_data_size;
+    IntType auxv_array_base = aux_data_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;
@@ -356,6 +362,12 @@ SparcProcess::argsInit(int pageSize)
     // Write the file name
     initVirtMem->writeString(file_name_base, filename.c_str());
 
+    // Fix up the aux vectors which point to data.
+    for (auto &aux: auxv) {
+        if (aux.type == M5_AT_RANDOM)
+            aux.val = aux_data_base;
+    }
+
     // Copy the aux stuff
     Addr auxv_array_end = auxv_array_base;
     for (const auto &aux: auxv) {