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authorAli Saidi <Ali.Saidi@ARM.com>2013-01-07 13:05:33 -0500
committerAli Saidi <Ali.Saidi@ARM.com>2013-01-07 13:05:33 -0500
commit5146a69835bc9ba37fba7d3b0ff72ecaf9b98b74 (patch)
tree694786d4ffd6384a3736d48e1fd20e29408bf56d /src/cpu/inorder/thread_state.hh
parent90bd20aae2bc940397628a4598b5b25f2c8549b5 (diff)
downloadgem5-5146a69835bc9ba37fba7d3b0ff72ecaf9b98b74.tar.xz
cpu: rename the misleading inSyscall to noSquashFromTC
isSyscall was originally created because during handling of a syscall in SE mode the threadcontext had to be updated. However, in many places this is used in FS mode (e.g. fault handlers) and the name doesn't make much sense. The boolean actually stops gem5 from squashing speculative and non-committed state when a write to a threadcontext happens, so re-name the variable to something more appropriate
Diffstat (limited to 'src/cpu/inorder/thread_state.hh')
-rw-r--r--src/cpu/inorder/thread_state.hh14
1 files changed, 10 insertions, 4 deletions
diff --git a/src/cpu/inorder/thread_state.hh b/src/cpu/inorder/thread_state.hh
index 34c146b42..4472bf1dd 100644
--- a/src/cpu/inorder/thread_state.hh
+++ b/src/cpu/inorder/thread_state.hh
@@ -61,10 +61,15 @@ class InOrderThreadState : public ThreadState {
InOrderCPU *cpu;
public:
- /** Whether or not the thread is currently in syscall mode, and
- * thus able to be externally updated without squashing.
+ /* This variable controls if writes to a thread context should cause a all
+ * dynamic/speculative state to be thrown away. Nominally this is the
+ * desired behavior because the external thread context write has updated
+ * some state that could be used by an inflight instruction, however there
+ * are some cases like in a fault/trap handler where this behavior would
+ * lead to successive restarts and forward progress couldn't be made. This
+ * variable controls if the squashing will occur.
*/
- bool inSyscall;
+ bool noSquashFromTC;
/** Whether or not the thread is currently waiting on a trap, and
* thus able to be externally updated without squashing.
@@ -75,7 +80,8 @@ class InOrderThreadState : public ThreadState {
Process *_process)
: ThreadState(reinterpret_cast<BaseCPU*>(_cpu), _thread_num,
_process),
- cpu(_cpu), inSyscall(0), trapPending(0), lastGradIsBranch(false)
+ cpu(_cpu), noSquashFromTC(false), trapPending(false),
+ lastGradIsBranch(false)
{ }
/** Handles the syscall. */