From: Gabe Black <gblack@eecs.umich.edu>
Date: Mon, 28 May 2012 02:01:08 +0000 (-0700)
Subject: X86: Move the GDT down to where it can be accessed in 32 bit mode.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=40084e0c3eb466e41bd5f39285db2b651fb368b5;p=gem5.git

X86: Move the GDT down to where it can be accessed in 32 bit mode.

The GDT can be accessed by user level software running in compatibility mode
by moving segment selectors into segment registers. The GDT needs to be set up
at an address accessible in this mode.
---

diff --git a/src/arch/x86/process.cc b/src/arch/x86/process.cc
index 088a0661c..cce8e3a3d 100644
--- a/src/arch/x86/process.cc
+++ b/src/arch/x86/process.cc
@@ -132,7 +132,7 @@ I386LiveProcess::I386LiveProcess(LiveProcessParams *params,
         int _numSyscallDescs) :
     X86LiveProcess(params, objFile, _syscallDescs, _numSyscallDescs)
 {
-    _gdtStart = ULL(0x100000000);
+    _gdtStart = ULL(0xffffd000);
     _gdtSize = VMPageSize;
 
     vsyscallPage.base = 0xffffe000ULL;
@@ -140,7 +140,7 @@ I386LiveProcess::I386LiveProcess(LiveProcessParams *params,
     vsyscallPage.vsyscallOffset = 0x400;
     vsyscallPage.vsysexitOffset = 0x410;
 
-    stack_base = vsyscallPage.base;
+    stack_base = _gdtStart;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
     next_thread_stack_base = stack_base - (8 * 1024 * 1024);