Reduce stack usage for overflow checks
This reduces the stack space reserved for overflow checks to 12K, split
into an 8K gap and a 4K protected region. GC needs over 8K when running
in a stack overflow situation.
Also prevents signal runaway by detecting a signal inside code that
resulted from a signal handler invokation. And adds a max signal count to
the SignalTest to prevent it running forever.
Also reduces the number of iterations for the InterfaceTest as this was
taking (almost) forever with the --trace option on run-test.
Bug: 15435566
Change-Id: Id4fd46f22d52d42a9eb431ca07948673e8fda694
diff --git a/runtime/arch/arm/fault_handler_arm.cc b/runtime/arch/arm/fault_handler_arm.cc
index be28544..28b69ec 100644
--- a/runtime/arch/arm/fault_handler_arm.cc
+++ b/runtime/arch/arm/fault_handler_arm.cc
@@ -35,7 +35,7 @@
namespace art {
extern "C" void art_quick_throw_null_pointer_exception();
-extern "C" void art_quick_throw_stack_overflow_from_signal();
+extern "C" void art_quick_throw_stack_overflow();
extern "C" void art_quick_implicit_suspend();
// Get the size of a thumb2 instruction in bytes.
@@ -194,40 +194,19 @@
uintptr_t overflow_addr = sp - GetStackOverflowReservedBytes(kArm);
- Thread* self = reinterpret_cast<Thread*>(sc->arm_r9);
- CHECK_EQ(self, Thread::Current());
- uintptr_t pregion = reinterpret_cast<uintptr_t>(self->GetStackEnd()) -
- Thread::kStackOverflowProtectedSize;
-
// Check that the fault address is the value expected for a stack overflow.
if (fault_addr != overflow_addr) {
VLOG(signals) << "Not a stack overflow";
return false;
}
- // We know this is a stack overflow. We need to move the sp to the overflow region
- // that exists below the protected region. Determine the address of the next
- // available valid address below the protected region.
- uintptr_t prevsp = sp;
- sp = pregion;
- VLOG(signals) << "setting sp to overflow region at " << std::hex << sp;
+ VLOG(signals) << "Stack overflow found";
- // Since the compiler puts the implicit overflow
- // check before the callee save instructions, the SP is already pointing to
- // the previous frame.
- VLOG(signals) << "previous frame: " << std::hex << prevsp;
-
- // Now establish the stack pointer for the signal return.
- sc->arm_sp = prevsp;
-
- // Tell the stack overflow code where the new stack pointer should be.
- sc->arm_ip = sp; // aka r12
-
- // Now arrange for the signal handler to return to art_quick_throw_stack_overflow_from_signal.
+ // Now arrange for the signal handler to return to art_quick_throw_stack_overflow_from.
// The value of LR must be the same as it was when we entered the code that
// caused this fault. This will be inserted into a callee save frame by
- // the function to which this handler returns (art_quick_throw_stack_overflow_from_signal).
- sc->arm_pc = reinterpret_cast<uintptr_t>(art_quick_throw_stack_overflow_from_signal);
+ // the function to which this handler returns (art_quick_throw_stack_overflow).
+ sc->arm_pc = reinterpret_cast<uintptr_t>(art_quick_throw_stack_overflow);
// The kernel will now return to the address in sc->arm_pc.
return true;