From 40084e0c3eb466e41bd5f39285db2b651fb368b5 Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Sun, 27 May 2012 19:01:08 -0700 Subject: [PATCH] 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. --- src/arch/x86/process.cc | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) 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); -- 2.30.2