syscall-emul: Move memState into its own file

The Process class is full of implementation details and
structures related to SE Mode. This changeset factors out an
internal class from Process and moves it into a separate file.
The purpose behind doing this is to clean up the code and make
it a bit more modular.

Change-Id: Ic6941a1657751e8d51d5b6b1dcc04f1195884280
Reviewed-on: https://gem5-review.googlesource.com/2263
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/arch/alpha/process.cc

@@ -50,21 +50,24 @@ using namespace std;
 AlphaProcess::AlphaProcess(ProcessParams *params, ObjectFile *objFile)
     : Process(params, objFile)
 {
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
+    Addr brk_point = objFile->dataBase() + objFile->dataSize() +
-                         objFile->bssSize();
+                     objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
+    brk_point = roundUp(brk_point, PageBytes);
 
     // Set up stack.  On Alpha, stack goes below text section.  This
     // code should get moved to some architecture-specific spot.
-    memState->stackBase = objFile->textBase() - (409600+4096);
+    Addr stack_base = objFile->textBase() - (409600+4096);
 
-    // Set up region for mmaps.  Tru64 seems to start just above 0 and
+    // Set up region for mmaps.
-    // grow up from there.
+    Addr mmap_end = 0x10000;
-    memState->mmapEnd = 0x10000;
+
+    Addr max_stack_size = 8 * 1024 * 1024;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+    Addr next_thread_stack_base = stack_base - max_stack_size;
 
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
+                                     next_thread_stack_base, mmap_end);
 }
 
 void
@@ -131,15 +134,16 @@ AlphaProcess::argsInit(int intSize, int pageSize)
         space_needed = 32*1024;
 
     // set bottom of stack
-    memState->stackMin = memState->stackBase - space_needed;
+    memState->setStackMin(memState->getStackBase() - space_needed);
     // align it
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(memState->getStackMin(), pageSize));
-    memState->stackSize = memState->stackBase - memState->stackMin;
+    memState->setStackSize(memState->getStackBase() - memState->getStackMin());
     // map memory
-    allocateMem(memState->stackMin, roundUp(memState->stackSize, pageSize));
+    allocateMem(memState->getStackMin(), roundUp(memState->getStackSize(),
+                pageSize));
 
     // map out initial stack contents
-    Addr argv_array_base = memState->stackMin + intSize; // room for argc
+    Addr argv_array_base = memState->getStackMin() + intSize; // room for argc
     Addr envp_array_base = argv_array_base + argv_array_size;
     Addr auxv_array_base = envp_array_base + envp_array_size;
     Addr arg_data_base = auxv_array_base + auxv_array_size;
@@ -154,7 +158,7 @@ AlphaProcess::argsInit(int intSize, int pageSize)
     else
         panic("Unknown int size");
 
-    initVirtMem.writeBlob(memState->stackMin, (uint8_t*)&argc, intSize);
+    initVirtMem.writeBlob(memState->getStackMin(), (uint8_t*)&argc, intSize);
 
     copyStringArray(argv, argv_array_base, arg_data_base, initVirtMem);
     copyStringArray(envp, envp_array_base, env_data_base, initVirtMem);
@@ -171,7 +175,7 @@ AlphaProcess::argsInit(int intSize, int pageSize)
 
     setSyscallArg(tc, 0, argc);
     setSyscallArg(tc, 1, argv_array_base);
-    tc->setIntReg(StackPointerReg, memState->stackMin);
+    tc->setIntReg(StackPointerReg, memState->getStackMin());
 
     tc->pcState(getStartPC());
 }

src/arch/arm/process.cc

@@ -70,36 +70,30 @@ ArmProcess32::ArmProcess32(ProcessParams *params, ObjectFile *objFile,
                            ObjectFile::Arch _arch)
     : ArmProcess(params, objFile, _arch)
 {
-    memState->stackBase = 0xbf000000L;
+    Addr brk_point = roundUp(objFile->dataBase() + objFile->dataSize() +
+                             objFile->bssSize(), PageBytes);
+    Addr stack_base = 0xbf000000L;
+    Addr max_stack_size = 8 * 1024 * 1024;
+    Addr next_thread_stack_base = stack_base - max_stack_size;
+    Addr mmap_end = 0x40000000L;
 
-    // Set pointer for next thread stack.  Reserve 8M for main stack.
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+                                     next_thread_stack_base, mmap_end);
-
-    // Set up break point (Top of Heap)
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
-                         objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
-
-    // Set up region for mmaps. For now, start at bottom of kuseg space.
-    memState->mmapEnd = 0x40000000L;
 }
 
 ArmProcess64::ArmProcess64(ProcessParams *params, ObjectFile *objFile,
                            ObjectFile::Arch _arch)
     : ArmProcess(params, objFile, _arch)
 {
-    memState->stackBase = 0x7fffff0000L;
+    Addr brk_point = roundUp(objFile->dataBase() + objFile->dataSize() +
+                             objFile->bssSize(), PageBytes);
+    Addr stack_base = 0x7fffff0000L;
+    Addr max_stack_size = 8 * 1024 * 1024;
+    Addr next_thread_stack_base = stack_base - max_stack_size;
+    Addr mmap_end = 0x4000000000L;
 
-    // Set pointer for next thread stack.  Reserve 8M for main stack.
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+                                     next_thread_stack_base, mmap_end);
-
-    // Set up break point (Top of Heap)
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
-                         objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
-
-    // Set up region for mmaps. For now, start at bottom of kuseg space.
-    memState->mmapEnd = 0x4000000000L;
 }
 
 void
@@ -302,16 +296,16 @@ ArmProcess::argsInit(int pageSize, IntRegIndex spIndex)
 
     int space_needed = frame_size + aux_padding;
 
-    memState->stackMin = memState->stackBase - space_needed;
+    memState->setStackMin(memState->getStackBase() - space_needed);
-    memState->stackMin = roundDown(memState->stackMin, align);
+    memState->setStackMin(roundDown(memState->getStackMin(), align));
-    memState->stackSize = memState->stackBase - memState->stackMin;
+    memState->setStackSize(memState->getStackBase() - memState->getStackMin());
 
     // map memory
-    allocateMem(roundDown(memState->stackMin, pageSize),
+    allocateMem(roundDown(memState->getStackMin(), pageSize),
-                          roundUp(memState->stackSize, pageSize));
+                          roundUp(memState->getStackSize(), pageSize));
 
     // map out initial stack contents
-    IntType sentry_base = memState->stackBase - sentry_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;
@@ -332,7 +326,7 @@ ArmProcess::argsInit(int pageSize, IntRegIndex spIndex)
     DPRINTF(Stack, "0x%x - envp array\n", envp_array_base);
     DPRINTF(Stack, "0x%x - argv array\n", argv_array_base);
     DPRINTF(Stack, "0x%x - argc \n", argc_base);
-    DPRINTF(Stack, "0x%x - stack min\n", memState->stackMin);
+    DPRINTF(Stack, "0x%x - stack min\n", memState->getStackMin());
 
     // write contents to stack
 
@@ -378,7 +372,7 @@ ArmProcess::argsInit(int pageSize, IntRegIndex spIndex)
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     //Set the stack pointer register
-    tc->setIntReg(spIndex, memState->stackMin);
+    tc->setIntReg(spIndex, memState->getStackMin());
     //A pointer to a function to run when the program exits. We'll set this
     //to zero explicitly to make sure this isn't used.
     tc->setIntReg(ArgumentReg0, 0);
@@ -405,7 +399,7 @@ ArmProcess::argsInit(int pageSize, IntRegIndex spIndex)
     tc->pcState(pc);
 
     //Align the "stackMin" to a page boundary.
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(memState->getStackMin(), pageSize));
 }
 
 ArmISA::IntReg

src/arch/mips/process.cc

@@ -53,18 +53,23 @@ MipsProcess::MipsProcess(ProcessParams * params, ObjectFile *objFile)
 {
     // Set up stack. On MIPS, stack starts at the top of kuseg
     // user address space. MIPS stack grows down from here
-    memState->stackBase = 0x7FFFFFFF;
+    Addr stack_base = 0x7FFFFFFF;
+
+    Addr max_stack_size = 8 * 1024 * 1024;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+    Addr next_thread_stack_base = stack_base - max_stack_size;
 
     // Set up break point (Top of Heap)
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
+    Addr brk_point = objFile->dataBase() + objFile->dataSize() +
-                         objFile->bssSize();
+                     objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
+    brk_point = roundUp(brk_point, PageBytes);
 
     // Set up region for mmaps.  Start it 1GB above the top of the heap.
-    memState->mmapEnd = memState->brkPoint + 0x40000000L;
+    Addr mmap_end = brk_point + 0x40000000L;
+
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
+                                     next_thread_stack_base, mmap_end);
 }
 
 void
@@ -141,15 +146,16 @@ MipsProcess::argsInit(int pageSize)
         env_data_size;
 
     // set bottom of stack
-    memState->stackMin = memState->stackBase - space_needed;
+    memState->setStackMin(memState->getStackBase() - space_needed);
     // align it
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(memState->getStackMin(), pageSize));
-    memState->stackSize = memState->stackBase - memState->stackMin;
+    memState->setStackSize(memState->getStackBase() - memState->getStackMin());
     // map memory
-    allocateMem(memState->stackMin, roundUp(memState->stackSize, pageSize));
+    allocateMem(memState->getStackMin(), roundUp(memState->getStackSize(),
+                pageSize));
 
-    // map out initial stack contents
+    // map out initial stack contents; leave room for argc
-    IntType argv_array_base = memState->stackMin + intSize; // room for argc
+    IntType argv_array_base = memState->getStackMin() + intSize;
     IntType envp_array_base = argv_array_base + argv_array_size;
     IntType auxv_array_base = envp_array_base + envp_array_size;
     IntType arg_data_base = auxv_array_base + auxv_array_size;
@@ -160,7 +166,7 @@ MipsProcess::argsInit(int pageSize)
 
     argc = htog((IntType)argc);
 
-    initVirtMem.writeBlob(memState->stackMin, (uint8_t*)&argc, intSize);
+    initVirtMem.writeBlob(memState->getStackMin(), (uint8_t*)&argc, intSize);
 
     copyStringArray(argv, argv_array_base, arg_data_base, initVirtMem);
 
@@ -185,7 +191,7 @@ MipsProcess::argsInit(int pageSize)
 
     setSyscallArg(tc, 0, argc);
     setSyscallArg(tc, 1, argv_array_base);
-    tc->setIntReg(StackPointerReg, memState->stackMin);
+    tc->setIntReg(StackPointerReg, memState->getStackMin());
 
     tc->pcState(getStartPC());
 }

src/arch/power/process.cc

@@ -51,18 +51,23 @@ using namespace PowerISA;
 PowerProcess::PowerProcess(ProcessParams *params, ObjectFile *objFile)
     : Process(params, objFile)
 {
-    memState->stackBase = 0xbf000000L;
+    // Set up break point (Top of Heap)
+    Addr brk_point = objFile->dataBase() + objFile->dataSize() +
+                     objFile->bssSize();
+    brk_point = roundUp(brk_point, PageBytes);
+
+    Addr stack_base = 0xbf000000L;
+
+    Addr max_stack_size = 8 * 1024 * 1024;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+    Addr next_thread_stack_base = stack_base - max_stack_size;
-
-    // Set up break point (Top of Heap)
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
-                         objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
 
     // Set up region for mmaps. For now, start at bottom of kuseg space.
-    memState->mmapEnd = 0x70000000L;
+    Addr mmap_end = 0x70000000L;
+
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
+                                     next_thread_stack_base, mmap_end);
 }
 
 void
@@ -186,16 +191,17 @@ PowerProcess::argsInit(int intSize, int pageSize)
 
     int space_needed = frame_size + aux_padding;
 
-    memState->stackMin = memState->stackBase - space_needed;
+    Addr stack_min = memState->getStackBase() - space_needed;
-    memState->stackMin = roundDown(memState->stackMin, align);
+    stack_min = roundDown(stack_min, align);
-    memState->stackSize = memState->stackBase - memState->stackMin;
+
+    memState->setStackSize(memState->getStackBase() - stack_min);
 
     // map memory
-    allocateMem(roundDown(memState->stackMin, pageSize),
+    allocateMem(roundDown(stack_min, pageSize),
-                roundUp(memState->stackSize, pageSize));
+                roundUp(memState->getStackSize(), pageSize));
 
     // map out initial stack contents
-    uint32_t sentry_base = memState->stackBase - sentry_size;
+    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;
@@ -214,7 +220,7 @@ PowerProcess::argsInit(int intSize, int pageSize)
     DPRINTF(Stack, "0x%x - envp array\n", envp_array_base);
     DPRINTF(Stack, "0x%x - argv array\n", argv_array_base);
     DPRINTF(Stack, "0x%x - argc \n", argc_base);
-    DPRINTF(Stack, "0x%x - stack min\n", memState->stackMin);
+    DPRINTF(Stack, "0x%x - stack min\n", stack_min);
 
     // write contents to stack
 
@@ -259,12 +265,12 @@ PowerProcess::argsInit(int intSize, int pageSize)
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
 
     //Set the stack pointer register
-    tc->setIntReg(StackPointerReg, memState->stackMin);
+    tc->setIntReg(StackPointerReg, stack_min);
 
     tc->pcState(getStartPC());
 
     //Align the "stack_min" to a page boundary.
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(stack_min, pageSize));
 }
 
 PowerISA::IntReg

src/arch/riscv/process.cc

@@ -56,16 +56,21 @@ RiscvProcess::RiscvProcess(ProcessParams * params,
 {
     // Set up stack. On RISC-V, stack starts at the top of kuseg
     // user address space. RISC-V stack grows down from here
-    memState->stackBase = (Addr)0x7FFFFFFF;
+    Addr stack_base = 0x7FFFFFFF;
+
+    Addr max_stack_size = 8 * 1024 * 1024;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+    Addr next_thread_stack_base = stack_base - max_stack_size;
 
     // Set up break point (Top of Heap)
-    memState->brkPoint = objFile->bssBase() + objFile->bssSize();
+    Addr brk_point = objFile->bssBase() + objFile->bssSize();
 
     // Set up region for mmaps.  Start it 1GB above the top of the heap.
-    memState->mmapEnd = memState->brkPoint + 0x40000000L;
+    Addr mmap_end = brk_point + 0x40000000L;
+
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
+                                     next_thread_stack_base, mmap_end);
 }
 
 void
@@ -124,19 +129,24 @@ RiscvProcess::argsInit(int pageSize)
         env_data_size += env.size() + 1;
     int auxv_array_size = 2 * sizeof(IntType)*auxv.size();
 
-    memState->stackSize = sizeof(IntType) + argv_array_size + 2 *
+    Addr stack_size = sizeof(IntType) + argv_array_size + 2 * sizeof(Addr) +
         sizeof(Addr) + arg_data_size + 2 * sizeof(Addr);
     if (!envp.empty()) {
-        memState->stackSize += 2 * sizeof(Addr) + envp_array_size + 2 *
+        stack_size += 2 * sizeof(Addr) + envp_array_size + 2 *
             sizeof(Addr) + env_data_size;
     }
     if (!auxv.empty())
-        memState->stackSize += 2 * sizeof(Addr) + auxv_array_size;
+        stack_size += 2 * sizeof(Addr) + auxv_array_size;
-    memState->stackMin = roundDown(memState->stackBase - memState->stackSize,
-                                   pageSize);
-    allocateMem(memState->stackMin, roundUp(memState->stackSize, pageSize));
 
-    Addr argv_array_base = memState->stackMin + sizeof(IntType);
+    memState->setStackSize(stack_size);
+
+    Addr stack_min = roundDown(memState->getStackBase() -
+                               stack_size, pageSize);
+    allocateMem(stack_min, roundUp(memState->getStackSize(), pageSize));
+
+    memState->setStackMin(stack_min);
+
+    Addr argv_array_base = memState->getStackMin() + sizeof(IntType);
     Addr arg_data_base = argv_array_base + argv_array_size + 2 * sizeof(Addr);
     Addr envp_array_base = arg_data_base + arg_data_size;
     if (!envp.empty())
@@ -161,7 +171,7 @@ RiscvProcess::argsInit(int pageSize)
         }
     }
 
-    Addr sp = memState->stackMin;
+    Addr sp = memState->getStackMin();
     initVirtMem.writeBlob(sp, (uint8_t *)&argc, sizeof(IntType));
     sp += sizeof(IntType);
     for (Addr arg_pointer: arg_pointers) {
@@ -212,7 +222,7 @@ RiscvProcess::argsInit(int pageSize)
     }
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
-    tc->setIntReg(StackPointerReg, memState->stackMin);
+    tc->setIntReg(StackPointerReg, memState->getStackMin());
     tc->pcState(getStartPC());
 }
 

src/arch/sparc/process.cc

@@ -57,15 +57,6 @@ SparcProcess::SparcProcess(ProcessParams * params, ObjectFile *objFile,
                            Addr _StackBias)
     : Process(params, objFile), StackBias(_StackBias)
 {
-
-    // XXX all the below need to be updated for SPARC - Ali
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
-                          objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
-
-    // Set pointer for next thread stack.  Reserve 8M for main stack.
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
-
     // Initialize these to 0s
     fillStart = 0;
     spillStart = 0;
@@ -325,16 +316,16 @@ SparcProcess::argsInit(int pageSize)
         aux_padding +
         frame_size;
 
-    memState->stackMin = memState->stackBase - space_needed;
+    memState->setStackMin(memState->getStackBase() - space_needed);
-    memState->stackMin = roundDown(memState->stackMin, align);
+    memState->setStackMin(roundDown(memState->getStackMin(), align));
-    memState->stackSize = memState->stackBase - memState->stackMin;
+    memState->setStackSize(memState->getStackBase() - memState->getStackMin());
 
     // Allocate space for the stack
-    allocateMem(roundDown(memState->stackMin, pageSize),
+    allocateMem(roundDown(memState->getStackMin(), pageSize),
-                roundUp(memState->stackSize, pageSize));
+                roundUp(memState->getStackSize(), pageSize));
 
     // map out initial stack contents
-    IntType sentry_base = memState->stackBase - sentry_size;
+    IntType sentry_base = memState->getStackBase() - sentry_size;
     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;
@@ -358,9 +349,9 @@ SparcProcess::argsInit(int pageSize)
     DPRINTF(Stack, "%#x - argv array\n", argv_array_base);
     DPRINTF(Stack, "%#x - argc \n", argc_base);
     DPRINTF(Stack, "%#x - window save\n", window_save_base);
-    DPRINTF(Stack, "%#x - stack min\n", memState->stackMin);
+    DPRINTF(Stack, "%#x - stack min\n", memState->getStackMin());
 
-    assert(window_save_base == memState->stackMin);
+    assert(window_save_base == memState->getStackMin());
 
     // write contents to stack
 
@@ -399,7 +390,7 @@ SparcProcess::argsInit(int pageSize)
     // Set up space for the trap handlers into the processes address space.
     // Since the stack grows down and there is reserved address space abov
     // it, we can put stuff above it and stay out of the way.
-    fillStart = memState->stackBase;
+    fillStart = memState->getStackBase();
     spillStart = fillStart + sizeof(MachInst) * numFillInsts;
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
@@ -407,7 +398,7 @@ SparcProcess::argsInit(int pageSize)
     // assert(NumArgumentRegs >= 2);
     // tc->setIntReg(ArgumentReg[0], argc);
     // tc->setIntReg(ArgumentReg[1], argv_array_base);
-    tc->setIntReg(StackPointerReg, memState->stackMin - StackBias);
+    tc->setIntReg(StackPointerReg, memState->getStackMin() - StackBias);
 
     // %g1 is a pointer to a function that should be run at exit. Since we
     // don't have anything like that, it should be set to 0.
@@ -416,7 +407,7 @@ SparcProcess::argsInit(int pageSize)
     tc->pcState(getStartPC());
 
     // Align the "stack_min" to a page boundary.
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(memState->getStackMin(), pageSize));
 }
 
 void

src/arch/sparc/process.hh

@@ -32,15 +32,16 @@
 #ifndef __SPARC_PROCESS_HH__
 #define __SPARC_PROCESS_HH__
 
+#include <memory>
 #include <string>
 #include <vector>
 
+#include "arch/sparc/isa_traits.hh"
+#include "base/loader/object_file.hh"
 #include "mem/page_table.hh"
 #include "sim/byteswap.hh"
 #include "sim/process.hh"
 
-class ObjectFile;
-
 class SparcProcess : public Process
 {
   protected:
@@ -77,12 +78,27 @@ class Sparc32Process : public SparcProcess
     Sparc32Process(ProcessParams * params, ObjectFile *objFile)
         : SparcProcess(params, objFile, 0)
     {
+        Addr brk_point = objFile->dataBase() + objFile->dataSize() +
+                         objFile->bssSize();
+        brk_point = roundUp(brk_point, SparcISA::PageBytes);
+
+        // Reserve 8M for main stack.
+        Addr max_stack_size = 8 * 1024 * 1024;
+
         // Set up stack. On SPARC Linux, stack goes from the top of memory
         // downward, less the hole for the kernel address space.
-        memState->stackBase = (Addr)0xf0000000ULL;
+        Addr stack_base = 0xf0000000ULL;
+
+        // Set pointer for next thread stack.
+        Addr next_thread_stack_base = stack_base - max_stack_size;
 
         // Set up region for mmaps.
-        memState->mmapEnd = 0x70000000;
+        Addr mmap_end = 0x70000000;
+
+        memState = std::make_shared<MemState>(brk_point, stack_base,
+                                              max_stack_size,
+                                              next_thread_stack_base,
+                                              mmap_end);
     }
 
     void initState();
@@ -107,12 +123,26 @@ class Sparc64Process : public SparcProcess
     Sparc64Process(ProcessParams * params, ObjectFile *objFile)
         : SparcProcess(params, objFile, 2047)
     {
+        Addr brk_point = objFile->dataBase() + objFile->dataSize() +
+                         objFile->bssSize();
+        brk_point = roundUp(brk_point, SparcISA::PageBytes);
+
+        Addr max_stack_size = 8 * 1024 * 1024;
+
         // Set up stack. On SPARC Linux, stack goes from the top of memory
         // downward, less the hole for the kernel address space.
-        memState->stackBase = (Addr)0x80000000000ULL;
+        Addr stack_base = 0x80000000000ULL;
+
+        // Set pointer for next thread stack.  Reserve 8M for main stack.
+        Addr next_thread_stack_base = stack_base - max_stack_size;
 
         // Set up region for mmaps.
-        memState->mmapEnd = 0xfffff80000000000ULL;
+        Addr mmap_end = 0xfffff80000000000ULL;
+
+        memState = std::make_shared<MemState>(brk_point, stack_base,
+                                              max_stack_size,
+                                              next_thread_stack_base,
+                                              mmap_end);
     }
 
     void initState();

src/arch/x86/process.cc

@@ -100,9 +100,6 @@ X86Process::X86Process(ProcessParams * params, ObjectFile *objFile,
     : Process(params, objFile), syscallDescs(_syscallDescs),
       numSyscallDescs(_numSyscallDescs)
 {
-    memState->brkPoint = objFile->dataBase() + objFile->dataSize()
-                       + objFile->bssSize();
-    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
 }
 
 void X86Process::clone(ThreadContext *old_tc, ThreadContext *new_tc,
@@ -123,23 +120,15 @@ X86_64Process::X86_64Process(ProcessParams *params, ObjectFile *objFile,
     vsyscallPage.vtimeOffset = 0x400;
     vsyscallPage.vgettimeofdayOffset = 0x0;
 
-    // Set up stack. On X86_64 Linux, stack goes from the top of memory
+    Addr brk_point = roundUp(objFile->dataBase() + objFile->dataSize() +
-    // downward, less the hole for the kernel address space plus one page
+                             objFile->bssSize(), PageBytes);
-    // for undertermined purposes.
+    Addr stack_base = 0x7FFFFFFFF000ULL;
-    memState->stackBase = (Addr)0x7FFFFFFFF000ULL;
+    Addr max_stack_size = 8 * 1024 * 1024;
+    Addr next_thread_stack_base = stack_base - max_stack_size;
+    Addr mmap_end = 0x7FFFF7FFF000ULL;
 
-    // Set pointer for next thread stack.  Reserve 8M for main stack.
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+                                     next_thread_stack_base, mmap_end);
-
-    // "mmap_base" is a function which defines where mmap region starts in
-    // the process address space.
-    // mmap_base: PAGE_ALIGN(TASK_SIZE-MIN_GAP-mmap_rnd())
-    // TASK_SIZE: (1<<47)-PAGE_SIZE
-    // MIN_GAP: 128*1024*1024+stack_maxrandom_size()
-    // We do not use any address space layout randomization in gem5
-    // therefore the random fields become zero; the smallest gap space was
-    // chosen but gap could potentially be much larger.
-    memState->mmapEnd = (Addr)0x7FFFF7FFF000ULL;
 }
 
 void
@@ -168,20 +157,15 @@ I386Process::I386Process(ProcessParams *params, ObjectFile *objFile,
     vsyscallPage.vsyscallOffset = 0x400;
     vsyscallPage.vsysexitOffset = 0x410;
 
-    memState->stackBase = _gdtStart;
+    Addr brk_point = roundUp(objFile->dataBase() + objFile->dataSize() +
+                             objFile->bssSize(), PageBytes);
+    Addr stack_base = _gdtStart;
+    Addr max_stack_size = 8 * 1024 * 1024;
+    Addr next_thread_stack_base = stack_base - max_stack_size;
+    Addr mmap_end = 0xB7FFF000ULL;
 
-    // Set pointer for next thread stack.  Reserve 8M for main stack.
+    memState = make_shared<MemState>(brk_point, stack_base, max_stack_size,
-    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
+                                     next_thread_stack_base, mmap_end);
-
-    // "mmap_base" is a function which defines where mmap region starts in
-    // the process address space.
-    // mmap_base: PAGE_ALIGN(TASK_SIZE-MIN_GAP-mmap_rnd())
-    // TASK_SIZE: 0xC0000000
-    // MIN_GAP: 128*1024*1024+stack_maxrandom_size()
-    // We do not use any address space layout randomization in gem5
-    // therefore the random fields become zero; the smallest gap space was
-    // chosen but gap could potentially be much larger.
-    memState->mmapEnd = (Addr)0xB7FFF000ULL;
 }
 
 SyscallDesc*
@@ -955,21 +939,23 @@ X86Process::argsInit(int pageSize,
         aux_padding +
         frame_size;
 
-    memState->stackMin = memState->stackBase - space_needed;
+    Addr stack_base = memState->getStackBase();
-    memState->stackMin = roundDown(memState->stackMin, align);
+
-    memState->stackSize = roundUp(memState->stackBase - memState->stackMin,
+    Addr stack_min = stack_base - space_needed;
-                                  pageSize);
+    stack_min = roundDown(stack_min, align);
+
+    unsigned stack_size = stack_base - stack_min;
+    stack_size = roundUp(stack_size, pageSize);
+    memState->setStackSize(stack_size);
 
     // map memory
-    Addr stack_end = roundDown(memState->stackBase - memState->stackSize,
+    Addr stack_end = roundDown(stack_base - stack_size, pageSize);
-                               pageSize);
 
-    DPRINTF(Stack, "Mapping the stack: 0x%x %dB\n",
+    DPRINTF(Stack, "Mapping the stack: 0x%x %dB\n", stack_end, stack_size);
-            stack_end, memState->stackSize);
+    allocateMem(stack_end, stack_size);
-    allocateMem(stack_end, memState->stackSize);
 
     // map out initial stack contents
-    IntType sentry_base = memState->stackBase - sentry_size;
+    IntType sentry_base = stack_base - sentry_size;
     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;
@@ -988,7 +974,7 @@ X86Process::argsInit(int pageSize,
     DPRINTF(Stack, "0x%x - envp array\n", envp_array_base);
     DPRINTF(Stack, "0x%x - argv array\n", argv_array_base);
     DPRINTF(Stack, "0x%x - argc \n", argc_base);
-    DPRINTF(Stack, "0x%x - stack min\n", memState->stackMin);
+    DPRINTF(Stack, "0x%x - stack min\n", stack_min);
 
     // write contents to stack
 
@@ -1035,14 +1021,14 @@ X86Process::argsInit(int pageSize,
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     //Set the stack pointer register
-    tc->setIntReg(StackPointerReg, memState->stackMin);
+    tc->setIntReg(StackPointerReg, stack_min);
 
     // There doesn't need to be any segment base added in since we're dealing
     // with the flat segmentation model.
     tc->pcState(getStartPC());
 
     //Align the "stack_min" to a page boundary.
-    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->setStackMin(roundDown(stack_min, pageSize));
 }
 
 void

src/gpu-compute/shader.cc

@@ -83,15 +83,16 @@ Shader::mmap(int length)
 
     if (proc->mmapGrowsDown()) {
         DPRINTF(HSAIL, "GROWS DOWN");
-        start = mem_state->mmapEnd - length;
+        start = mem_state->getMmapEnd() - length;
-        mem_state->mmapEnd = start;
+        mem_state->setMmapEnd(start);
     } else {
         DPRINTF(HSAIL, "GROWS UP");
-        start = mem_state->mmapEnd;
+        start = mem_state->getMmapEnd();
-        mem_state->mmapEnd += length;
+        mem_state->setMmapEnd(start + length);
 
         // assertion to make sure we don't overwrite the stack (it grows down)
-        assert(mem_state->stackBase - proc->maxStackSize > mem_state->mmapEnd);
+        assert(mem_state->getStackBase() - mem_state->getMaxStackSize() >
+               mem_state->getMmapEnd());
     }
 
     DPRINTF(HSAIL,"Shader::mmap start= %#x, %#x\n", start, length);

src/sim/mem_state.hh

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2017 Advanced Micro Devices, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Author: Brandon Potter
+ */
+
+#ifndef SRC_SIM_MEM_STATE_HH
+#define SRC_SIM_MEM_STATE_HH
+
+/**
+ * This class holds the memory state for the Process class and all of its
+ * derived, architecture-specific children.
+ *
+ * The fields held in this class dynamically change as the process object
+ * is run in the simulator. They are updated by system calls and faults;
+ * each change represents a modification to the process address space.
+ * The stack, heap, and mmap boundaries are held with this class along with
+ * the base of the next thread stack.
+ *
+ * The class is meant to be allocated dynamically and shared through a
+ * pointer interface because two process can potentially share their virtual
+ * address space if certain options are passed into the clone(2).
+ */
+class MemState
+{
+  public:
+    MemState(Addr brk_point, Addr stack_base, Addr max_stack_size,
+             Addr next_thread_stack_base, Addr mmap_end)
+        : _brkPoint(brk_point), _stackBase(stack_base), _stackSize(0),
+          _maxStackSize(max_stack_size), _stackMin(0),
+          _nextThreadStackBase(next_thread_stack_base), _mmapEnd(mmap_end)
+    { }
+
+    MemState&
+    operator=(const MemState &in)
+    {
+        if (this == &in)
+            return *this;
+
+        _brkPoint = in._brkPoint;
+        _stackBase = in._stackBase;
+        _stackSize = in._stackSize;
+        _maxStackSize = in._maxStackSize;
+        _stackMin = in._stackMin;
+        _nextThreadStackBase = in._nextThreadStackBase;
+        _mmapEnd = in._mmapEnd;
+        return *this;
+    }
+
+    Addr getBrkPoint() const { return _brkPoint; }
+    Addr getStackBase() const { return _stackBase; }
+    Addr getStackSize() const { return _stackSize; }
+    Addr getMaxStackSize() const { return _maxStackSize; }
+    Addr getStackMin() const { return _stackMin; }
+    Addr getNextThreadStackBase() const { return _nextThreadStackBase; }
+    Addr getMmapEnd() const { return _mmapEnd; }
+
+    void setBrkPoint(Addr brk_point) { _brkPoint = brk_point; }
+    void setStackBase(Addr stack_base) { _stackBase = stack_base; }
+    void setStackSize(Addr stack_size) { _stackSize = stack_size; }
+    void setMaxStackSize(Addr max_stack) { _maxStackSize = max_stack; }
+    void setStackMin(Addr stack_min) { _stackMin = stack_min; }
+    void setNextThreadStackBase(Addr ntsb) { _nextThreadStackBase = ntsb; }
+    void setMmapEnd(Addr mmap_end) { _mmapEnd = mmap_end; }
+
+  private:
+    Addr _brkPoint;
+    Addr _stackBase;
+    Addr _stackSize;
+    Addr _maxStackSize;
+    Addr _stackMin;
+    Addr _nextThreadStackBase;
+    Addr _mmapEnd;
+};
+
+#endif

src/sim/process.cc

@@ -111,7 +111,6 @@ Process::Process(ProcessParams * params, ObjectFile * obj_file)
       _pid(params->pid), _ppid(params->ppid),
       _pgid(params->pgid), drivers(params->drivers),
       fds(make_shared<FDArray>(params->input, params->output, params->errout)),
-      maxStackSize(params->maxStackSize),
       childClearTID(0)
 {
     if (_pid >= System::maxPID)
@@ -136,7 +135,6 @@ Process::Process(ProcessParams * params, ObjectFile * obj_file)
     _tgid = params->pid;
 
     exitGroup = new bool();
-    memState = new MemState();
     sigchld = new bool();
 
     if (!debugSymbolTable) {
@@ -164,7 +162,6 @@ Process::clone(ThreadContext *otc, ThreadContext *ntc,
         np->pTable = pTable;
         ntc->getMemProxy().setPageTable(np->pTable);
 
-        delete np->memState;
         np->memState = memState;
     } else {
         /**
@@ -323,24 +320,28 @@ Process::replicatePage(Addr vaddr, Addr new_paddr, ThreadContext *old_tc,
 bool
 Process::fixupStackFault(Addr vaddr)
 {
+    Addr stack_min = memState->getStackMin();
+    Addr stack_base = memState->getStackBase();
+    Addr max_stack_size = memState->getMaxStackSize();
+
     // Check if this is already on the stack and there's just no page there
     // yet.
-    if (vaddr >= memState->stackMin && vaddr < memState->stackBase) {
+    if (vaddr >= stack_min && vaddr < stack_base) {
         allocateMem(roundDown(vaddr, PageBytes), PageBytes);
         return true;
     }
 
     // We've accessed the next page of the stack, so extend it to include
     // this address.
-    if (vaddr < memState->stackMin
+    if (vaddr < stack_min && vaddr >= stack_base - max_stack_size) {
-        && vaddr >= memState->stackBase - maxStackSize) {
+        while (vaddr < stack_min) {
-        while (vaddr < memState->stackMin) {
+            stack_min -= TheISA::PageBytes;
-            memState->stackMin -= TheISA::PageBytes;
+            if (stack_base - stack_min > max_stack_size)
-            if (memState->stackBase - memState->stackMin > maxStackSize)
                 fatal("Maximum stack size exceeded\n");
-            allocateMem(memState->stackMin, TheISA::PageBytes);
+            allocateMem(stack_min, TheISA::PageBytes);
             inform("Increasing stack size by one page.");
         };
+        memState->setStackMin(stack_min);
         return true;
     }
     return false;
@@ -349,12 +350,6 @@ Process::fixupStackFault(Addr vaddr)
 void
 Process::serialize(CheckpointOut &cp) const
 {
-    SERIALIZE_SCALAR(memState->brkPoint);
-    SERIALIZE_SCALAR(memState->stackBase);
-    SERIALIZE_SCALAR(memState->stackSize);
-    SERIALIZE_SCALAR(memState->stackMin);
-    SERIALIZE_SCALAR(memState->nextThreadStackBase);
-    SERIALIZE_SCALAR(memState->mmapEnd);
     pTable->serialize(cp);
     /**
      * Checkpoints for file descriptors currently do not work. Need to
@@ -372,12 +367,6 @@ Process::serialize(CheckpointOut &cp) const
 void
 Process::unserialize(CheckpointIn &cp)
 {
-    UNSERIALIZE_SCALAR(memState->brkPoint);
-    UNSERIALIZE_SCALAR(memState->stackBase);
-    UNSERIALIZE_SCALAR(memState->stackSize);
-    UNSERIALIZE_SCALAR(memState->stackMin);
-    UNSERIALIZE_SCALAR(memState->nextThreadStackBase);
-    UNSERIALIZE_SCALAR(memState->mmapEnd);
     pTable->unserialize(cp);
     /**
      * Checkpoints for file descriptors currently do not work. Need to
@@ -446,13 +435,14 @@ Process::updateBias()
 
     // We are allocating the memory area; set the bias to the lowest address
     // in the allocated memory region.
-    Addr *end = &memState->mmapEnd;
+    Addr mmap_end = memState->getMmapEnd();
-    Addr ld_bias = mmapGrowsDown() ? *end - interp_mapsize : *end;
+    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.
-    *end = mmapGrowsDown() ? ld_bias : *end + interp_mapsize;
+    mmap_end = mmapGrowsDown() ? ld_bias : mmap_end + interp_mapsize;
+    memState->setMmapEnd(mmap_end);
 
     interp->updateBias(ld_bias);
 }

src/sim/process.hh

@@ -47,6 +47,7 @@
 #include "mem/se_translating_port_proxy.hh"
 #include "sim/fd_array.hh"
 #include "sim/fd_entry.hh"
+#include "sim/mem_state.hh"
 #include "sim/sim_object.hh"
 
 struct ProcessParams;
@@ -62,40 +63,6 @@ class ThreadContext;
 class Process : public SimObject
 {
   public:
-
-    struct MemState
-    {
-        Addr brkPoint;
-        Addr stackBase;
-        unsigned stackSize;
-        Addr stackMin;
-        Addr nextThreadStackBase;
-        Addr mmapEnd;
-
-        MemState()
-            : brkPoint(0), stackBase(0), stackSize(0), stackMin(0),
-              nextThreadStackBase(0), mmapEnd(0)
-        { }
-
-        MemState&
-        operator=(const MemState &in)
-        {
-            if (this == &in)
-                return *this;
-
-            brkPoint = in.brkPoint;
-            stackBase = in.stackBase;
-            stackSize = in.stackSize;
-            stackMin = in.stackMin;
-            nextThreadStackBase = in.nextThreadStackBase;
-            mmapEnd = in.mmapEnd;
-            return *this;
-        }
-
-        void serialize(CheckpointOut &cp) const;
-        void unserialize(CheckpointIn &cp);
-    };
-
     Process(ProcessParams *params, ObjectFile *obj_file);
 
     void serialize(CheckpointOut &cp) const override;
@@ -236,9 +203,7 @@ class Process : public SimObject
     std::shared_ptr<FDArray> fds;
 
     bool *exitGroup;
-
+    std::shared_ptr<MemState> memState;
-    Addr maxStackSize;
-    MemState *memState;
 
     /**
      * Calls a futex wakeup at the address specified by this pointer when

src/sim/syscall_emul.cc

@@ -150,22 +150,25 @@ brkFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
     int index = 0;
     Addr new_brk = p->getSyscallArg(tc, index);
 
+    std::shared_ptr<MemState> mem_state = p->memState;
+    Addr brk_point = mem_state->getBrkPoint();
+
     // in Linux at least, brk(0) returns the current break value
     // (note that the syscall and the glibc function have different behavior)
     if (new_brk == 0)
-        return p->memState->brkPoint;
+        return brk_point;
 
-    if (new_brk > p->memState->brkPoint) {
+    if (new_brk > brk_point) {
         // might need to allocate some new pages
-        for (ChunkGenerator gen(p->memState->brkPoint,
+        for (ChunkGenerator gen(brk_point,
-                                new_brk - p->memState->brkPoint,
+                                new_brk - brk_point,
                                 PageBytes); !gen.done(); gen.next()) {
             if (!p->pTable->translate(gen.addr()))
                 p->allocateMem(roundDown(gen.addr(), PageBytes), PageBytes);
 
             // if the address is already there, zero it out
             else {
-                uint8_t zero  = 0;
+                uint8_t zero = 0;
                 SETranslatingPortProxy &tp = tc->getMemProxy();
 
                 // split non-page aligned accesses
@@ -183,10 +186,10 @@ brkFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
         }
     }
 
-    p->memState->brkPoint = new_brk;
+    mem_state->setBrkPoint(new_brk);
     DPRINTF_SYSCALL(Verbose, "brk: break point changed to: %#X\n",
-                    p->memState->brkPoint);
+                    mem_state->getBrkPoint());
-    return p->memState->brkPoint;
+    return mem_state->getBrkPoint();
 }
 
 SyscallReturn

src/sim/syscall_emul.hh

@@ -885,11 +885,14 @@ mremapFunc(SyscallDesc *desc, int callnum, Process *process, ThreadContext *tc)
     new_length = roundUp(new_length, TheISA::PageBytes);
 
     if (new_length > old_length) {
-        if ((start + old_length) == process->memState->mmapEnd &&
+        std::shared_ptr<MemState> mem_state = process->memState;
+        Addr mmap_end = mem_state->getMmapEnd();
+
+        if ((start + old_length) == mmap_end &&
             (!use_provided_address || provided_address == start)) {
             uint64_t diff = new_length - old_length;
-            process->allocateMem(process->memState->mmapEnd, diff);
+            process->allocateMem(mmap_end, diff);
-            process->memState->mmapEnd += diff;
+            mem_state->setMmapEnd(mmap_end + diff);
             return start;
         } else {
             if (!use_provided_address && !(flags & OS::TGT_MREMAP_MAYMOVE)) {
@@ -897,7 +900,7 @@ mremapFunc(SyscallDesc *desc, int callnum, Process *process, ThreadContext *tc)
                 return -ENOMEM;
             } else {
                 uint64_t new_start = use_provided_address ?
-                    provided_address : process->memState->mmapEnd;
+                    provided_address : mmap_end;
                 process->pTable->remap(start, old_length, new_start);
                 warn("mremapping to new vaddr %08p-%08p, adding %d\n",
                      new_start, new_start + new_length,
@@ -907,9 +910,9 @@ mremapFunc(SyscallDesc *desc, int callnum, Process *process, ThreadContext *tc)
                                      new_length - old_length,
                                      use_provided_address /* clobber */);
                 if (!use_provided_address)
-                    process->memState->mmapEnd += new_length;
+                    mem_state->setMmapEnd(mmap_end + new_length);
                 if (use_provided_address &&
-                    new_start + new_length > process->memState->mmapEnd) {
+                    new_start + new_length > mem_state->getMmapEnd()) {
                     // something fishy going on here, at least notify the user
                     // @todo: increase mmap_end?
                     warn("mmap region limit exceeded with MREMAP_FIXED\n");
@@ -1214,7 +1217,6 @@ cloneFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
     pp->executable.assign(*(new std::string(p->progName())));
     pp->cmd.push_back(*(new std::string(p->progName())));
     pp->system = p->system;
-    pp->maxStackSize = p->maxStackSize;
     pp->cwd.assign(p->getcwd());
     pp->input.assign("stdin");
     pp->output.assign("stdout");
@@ -1457,9 +1459,13 @@ mmapImpl(SyscallDesc *desc, int num, Process *p, ThreadContext *tc,
     // Extend global mmap region if necessary. Note that we ignore the
     // start address unless MAP_FIXED is specified.
     if (!(tgt_flags & OS::TGT_MAP_FIXED)) {
-        Addr *end = &p->memState->mmapEnd;
+        std::shared_ptr<MemState> mem_state = p->memState;
-        start = p->mmapGrowsDown() ? *end - length : *end;
+        Addr mmap_end = mem_state->getMmapEnd();
-        *end = p->mmapGrowsDown() ? start : *end + length;
+
+        start = p->mmapGrowsDown() ? mmap_end - length : mmap_end;
+        mmap_end = p->mmapGrowsDown() ? start : mmap_end + length;
+
+        mem_state->setMmapEnd(mmap_end);
     }
 
     DPRINTF_SYSCALL(Verbose, " mmap range is 0x%x - 0x%x\n",
@@ -1768,7 +1774,6 @@ execveFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
     pp->errout.assign("cerr");
     pp->cwd.assign(p->getcwd());
     pp->system = p->system;
-    pp->maxStackSize = p->maxStackSize;
     /**
      * Prevent process object creation with identical PIDs (which will trip
      * a fatal check in Process constructor). The execve call is supposed to