syscall_emul: [PATCH 15/22] add clone/execve for threading and multiprocess simulations

Modifies the clone system call and adds execve system call. Requires allowing
processes to steal thread contexts from other processes in the same system
object and the ability to detach pieces of process state (such as MemState)
to allow dynamic sharing.

1 files changed, 13 insertions, 12 deletions

diff --git a/src/arch/mips/process.cc b/src/arch/mips/process.cc
index c1943bf39..4993b3c68 100644
--- a/src/arch/mips/process.cc
+++ b/src/arch/mips/process.cc
@@ -53,17 +53,18 @@ 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
-    stack_base = 0x7FFFFFFF;
+    memState->stackBase = 0x7FFFFFFF;
 
     // Set pointer for next thread stack.  Reserve 8M for main stack.
-    next_thread_stack_base = stack_base - (8 * 1024 * 1024);
+    memState->nextThreadStackBase = memState->stackBase - (8 * 1024 * 1024);
 
     // Set up break point (Top of Heap)
-    brk_point = objFile->dataBase() + objFile->dataSize() + objFile->bssSize();
-    brk_point = roundUp(brk_point, PageBytes);
+    memState->brkPoint = objFile->dataBase() + objFile->dataSize() +
+                         objFile->bssSize();
+    memState->brkPoint = roundUp(memState->brkPoint, PageBytes);
 
     // Set up region for mmaps.  Start it 1GB above the top of the heap.
-    mmap_end = brk_point + 0x40000000L;
+    memState->mmapEnd = memState->brkPoint + 0x40000000L;
 }
 
 void
@@ -140,15 +141,15 @@ MipsProcess::argsInit(int pageSize)
         env_data_size;
 
     // set bottom of stack
-    stack_min = stack_base - space_needed;
+    memState->stackMin = memState->stackBase - space_needed;
     // align it
-    stack_min = roundDown(stack_min, pageSize);
-    stack_size = stack_base - stack_min;
+    memState->stackMin = roundDown(memState->stackMin, pageSize);
+    memState->stackSize = memState->stackBase - memState->stackMin;
     // map memory
-    allocateMem(stack_min, roundUp(stack_size, pageSize));
+    allocateMem(memState->stackMin, roundUp(memState->stackSize, pageSize));
 
     // map out initial stack contents
-    IntType argv_array_base = stack_min + intSize; // room for argc
+    IntType argv_array_base = memState->stackMin + intSize; // room for argc
     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;
@@ -159,7 +160,7 @@ MipsProcess::argsInit(int pageSize)
 
     argc = htog((IntType)argc);
 
-    initVirtMem.writeBlob(stack_min, (uint8_t*)&argc, intSize);
+    initVirtMem.writeBlob(memState->stackMin, (uint8_t*)&argc, intSize);
 
     copyStringArray(argv, argv_array_base, arg_data_base, initVirtMem);
 
@@ -184,7 +185,7 @@ MipsProcess::argsInit(int pageSize)
 
     setSyscallArg(tc, 0, argc);
     setSyscallArg(tc, 1, argv_array_base);
-    tc->setIntReg(StackPointerReg, stack_min);
+    tc->setIntReg(StackPointerReg, memState->stackMin);
 
     tc->pcState(getStartPC());
 }