From 9bcbd965dc7ef0f4d79f3d0302444b72b4b42a1f Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi.kivity@gmail.com>
Date: Wed, 2 Jan 2013 17:48:08 +0200
Subject: [PATCH] sched: switch main thread stack from original stack
This way everyone's running on a similar sized stack. Theoretically the
main thread can be destroyed as well.
---
arch/x64/arch-switch.hh | 15 +++++++++++++++
arch/x64/entry.S | 13 +++++++++++++
loader.cc | 2 +-
sched.cc | 4 ++--
sched.hh | 2 ++
5 files changed, 33 insertions(+), 3 deletions(-)
diff --git a/arch/x64/arch-switch.hh b/arch/x64/arch-switch.hh
index 09ddce5b0..3ed343969 100644
--- a/arch/x64/arch-switch.hh
+++ b/arch/x64/arch-switch.hh
@@ -7,6 +7,8 @@
extern "C" {
void thread_main(void);
void thread_main_c(sched::thread* t);
+void stack_trampoline(sched::thread* t, void (*func)(sched::thread*),
+ void** stacktop);
}
namespace sched {
@@ -37,6 +39,19 @@ void thread::init_stack()
_state.rsp = stacktop;
}
+void thread::switch_to_thread_stack()
+{
+ void** stacktop = reinterpret_cast<void**>(_stack + sizeof(_stack));
+ stack_trampoline(this, &thread::on_thread_stack, stacktop);
+}
+
+void thread::on_thread_stack(thread* t)
+{
+ t->_func();
+ t->_waiting = true;
+ schedule();
+}
+
void thread::setup_tcb()
{
// FIXME: respect alignment
diff --git a/arch/x64/entry.S b/arch/x64/entry.S
index a99cd3820..849cd9511 100644
--- a/arch/x64/entry.S
+++ b/arch/x64/entry.S
@@ -100,3 +100,16 @@ thread_main:
pop %rdi
call thread_main_c
.cfi_endproc
+
+.global stack_trampoline
+stack_trampoline: # %rsi=arg, %rdi=func, %rdx=stack
+ .cfi_startproc simple
+ .cfi_def_cfa %rsp, 0
+ mov %rsp, -8(%rdx)
+ lea -8(%rdx), %rsp
+ .cfi_rel_offset %rsp, 0
+ call *%rsi
+ pop %rsp
+ .cfi_restore %rsp
+ ret
+ .cfi_endproc
diff --git a/loader.cc b/loader.cc
index a10f74bbb..fd9c571d9 100644
--- a/loader.cc
+++ b/loader.cc
@@ -157,7 +157,7 @@ int main(int ac, char **av)
void main_thread(elf::program& prog)
{
- new thread([] { test_threads(); });
+ test_threads();
prog.add("libjvm.so");
auto JNI_GetDefaultJavaVMInitArgs
= prog.lookup_function<void (void*)>("JNI_GetDefaultJavaVMInitArgs");
diff --git a/sched.cc b/sched.cc
index f39bd0156..0131a7c61 100644
--- a/sched.cc
+++ b/sched.cc
@@ -34,7 +34,7 @@ void schedule()
thread::thread(std::function<void ()> func, bool main)
: _func(func)
- , _on_runqueue(true)
+ , _on_runqueue(!main)
, _waiting(false)
{
if (!main) {
@@ -44,7 +44,7 @@ thread::thread(std::function<void ()> func, bool main)
} else {
setup_tcb_main();
s_current = this;
- func();
+ switch_to_thread_stack();
abort();
}
}
diff --git a/sched.hh b/sched.hh
index 323137a56..19958a14b 100644
--- a/sched.hh
+++ b/sched.hh
@@ -32,6 +32,8 @@ private:
void init_stack();
void setup_tcb();
void setup_tcb_main();
+ static void on_thread_stack(thread* t);
+ void switch_to_thread_stack();
private:
std::function<void ()> _func;
thread_state _state;
--
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