2009-03-15 18:02:36 +00:00
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/* Copyright (c) 2008-2009, Avian Contributors
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2008-02-19 18:06:52 +00:00
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Permission to use, copy, modify, and/or distribute this software
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for any purpose with or without fee is hereby granted, provided
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that the above copyright notice and this permission notice appear
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in all copies.
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There is NO WARRANTY for this software. See license.txt for
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details. */
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2007-09-26 23:23:03 +00:00
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#include "types.h"
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2008-06-15 18:49:37 +00:00
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#define LOCAL(x) .L##x
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2009-05-29 01:13:15 +00:00
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#if defined __APPLE__ || defined __MINGW32__ || defined __CYGWIN32__
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# define GLOBAL(x) _##x
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#else
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# define GLOBAL(x) x
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#endif
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2007-09-26 23:23:03 +00:00
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.text
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#ifdef __x86_64__
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2010-09-14 16:49:41 +00:00
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#define THREAD_STACK 2216
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fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
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2009-12-03 02:37:22 +00:00
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#if defined __MINGW32__ || defined __CYGWIN32__
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2009-07-26 02:48:36 +00:00
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#define CALLEE_SAVED_REGISTER_FOOTPRINT 64
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.globl GLOBAL(vmInvoke)
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GLOBAL(vmInvoke):
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2009-06-11 15:48:27 +00:00
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pushq %rbp
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movq %rsp,%rbp
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// %rcx: thread
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// %rdx: function
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// %r8 : arguments
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// %r9 : argumentsFootprint
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// 48(%rbp) : frameSize
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// 56(%rbp) : returnType (ignored)
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// allocate stack space, adding room for callee-saved registers
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movl 48(%rbp),%eax
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subq %rax,%rsp
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2009-07-26 02:48:36 +00:00
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subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%rsp
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2009-06-11 15:48:27 +00:00
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// save callee-saved registers
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movq %rsp,%r11
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addq %rax,%r11
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movq %rbx,0(%r11)
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movq %r12,8(%r11)
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movq %r13,16(%r11)
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movq %r14,24(%r11)
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movq %r15,32(%r11)
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movq %rsi,40(%r11)
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movq %rdi,48(%r11)
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// we use rbx to hold the thread pointer, by convention
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mov %rcx,%rbx
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// copy arguments into place
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movq $0,%r11
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2009-07-26 02:48:36 +00:00
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jmp LOCAL(vmInvoke_argumentTest)
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2009-06-11 15:48:27 +00:00
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2009-07-26 02:48:36 +00:00
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LOCAL(vmInvoke_argumentLoop):
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2009-06-11 15:48:27 +00:00
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movq (%r8,%r11,1),%rsi
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movq %rsi,(%rsp,%r11,1)
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addq $8,%r11
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2009-07-26 02:48:36 +00:00
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LOCAL(vmInvoke_argumentTest):
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2009-06-11 15:48:27 +00:00
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cmpq %r9,%r11
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2009-07-26 02:48:36 +00:00
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jb LOCAL(vmInvoke_argumentLoop)
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2009-06-11 15:48:27 +00:00
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// call function
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call *%rdx
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2009-07-26 02:48:36 +00:00
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.globl GLOBAL(vmInvoke_returnAddress)
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GLOBAL(vmInvoke_returnAddress):
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2009-06-11 15:48:27 +00:00
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// restore stack pointer
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movq %rbp,%rsp
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2009-07-26 02:48:36 +00:00
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fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
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// clear MyThread::stack to avoid confusing another thread calling
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// java.lang.Thread.getStackTrace on this one. See
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// MyProcess::getStackTrace in compile.cpp for details on how we get
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// a reliable stack trace from a thread that might be interrupted at
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// any point in its execution.
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movq $0,THREAD_STACK(%rbx)
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.globl GLOBAL(vmInvoke_safeStack)
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GLOBAL(vmInvoke_safeStack):
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2009-07-26 02:48:36 +00:00
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#ifdef AVIAN_CONTINUATIONS
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# include "continuations-x86.S"
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#endif // AVIAN_CONTINUATIONS
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// restore callee-saved registers (below the stack pointer, but in
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// the red zone)
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2009-06-11 15:48:27 +00:00
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movq %rsp,%r11
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2009-07-26 02:48:36 +00:00
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subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%r11
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2009-06-11 15:48:27 +00:00
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movq 0(%r11),%rbx
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movq 8(%r11),%r12
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movq 16(%r11),%r13
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movq 24(%r11),%r14
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movq 32(%r11),%r15
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movq 40(%r11),%rsi
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movq 48(%r11),%rdi
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// return
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popq %rbp
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ret
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2009-07-26 02:48:36 +00:00
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.globl GLOBAL(vmJumpAndInvoke)
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GLOBAL(vmJumpAndInvoke):
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#ifdef AVIAN_CONTINUATIONS
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// %rcx: thread
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// %rdx: address
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// %r8 : base
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// %r9 : (unused)
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2009-12-03 19:46:29 +00:00
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// 40(%rsp): argumentFootprint
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// 48(%rsp): arguments
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// 56(%rsp): frameSize
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2009-07-26 02:48:36 +00:00
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movq %r8,%rbp
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// restore (pseudo)-stack pointer (we don't want to touch the real
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// stack pointer, since we haven't copied the arguments yet)
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movq %rbp,%r9
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// allocate new frame, adding room for callee-saved registers
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2009-12-03 19:46:29 +00:00
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movl 56(%rsp),%eax
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2009-07-26 02:48:36 +00:00
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subq %rax,%r9
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subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%r9
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2009-05-05 01:04:17 +00:00
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2009-07-26 02:48:36 +00:00
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movq %rcx,%rbx
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// set return address
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2009-12-03 19:46:29 +00:00
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leaq GLOBAL(vmInvoke_returnAddress)(%rip),%r10
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2009-07-26 02:48:36 +00:00
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movq %r10,(%r9)
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2009-06-11 15:48:27 +00:00
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2009-07-26 02:48:36 +00:00
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// copy arguments into place
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movq $0,%r11
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2009-12-03 19:46:29 +00:00
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movl 48(%rsp),%r8d
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movl 40(%rsp),%eax
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2009-07-26 02:48:36 +00:00
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jmp LOCAL(vmJumpAndInvoke_argumentTest)
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LOCAL(vmJumpAndInvoke_argumentLoop):
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movq (%r8,%r11,1),%r10
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movq %r10,8(%r9,%r11,1)
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addq $8,%r11
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LOCAL(vmJumpAndInvoke_argumentTest):
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cmpq %rax,%r11
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jb LOCAL(vmJumpAndInvoke_argumentLoop)
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// the arguments have been copied, so we can set the real stack
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// pointer now
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movq %r9,%rsp
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jmp *%rdx
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#else // not AVIAN_CONTINUATIONS
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// vmJumpAndInvoke should only be called when continuations are
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// enabled
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int3
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#endif // not AVIAN_CONTINUATIONS
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2009-05-05 01:04:17 +00:00
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2009-12-03 06:15:27 +00:00
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#else // not __MINGW32__ || __CYGWIN32__
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2007-09-26 23:23:03 +00:00
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2009-05-29 01:54:32 +00:00
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#define CALLEE_SAVED_REGISTER_FOOTPRINT 48
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2009-05-29 01:13:15 +00:00
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.globl GLOBAL(vmInvoke)
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GLOBAL(vmInvoke):
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2007-09-26 23:23:03 +00:00
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pushq %rbp
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movq %rsp,%rbp
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2007-12-11 21:26:59 +00:00
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// %rdi: thread
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// %rsi: function
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2009-02-17 02:49:28 +00:00
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// %rdx: arguments
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// %rcx: argumentFootprint
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// %r8 : frameSize
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// %r9 : returnType (ignored)
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// allocate stack space, adding room for callee-saved registers
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2009-05-29 01:54:32 +00:00
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subq %r8,%rsp
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subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%rsp
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2009-02-17 02:49:28 +00:00
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// save callee-saved registers
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movq %rsp,%r9
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addq %r8,%r9
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movq %rbx,0(%r9)
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movq %r12,8(%r9)
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movq %r13,16(%r9)
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movq %r14,24(%r9)
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movq %r15,32(%r9)
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2007-12-11 21:26:59 +00:00
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2009-02-16 15:21:12 +00:00
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// we use rbx to hold the thread pointer, by convention
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2007-12-11 21:26:59 +00:00
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mov %rdi,%rbx
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2007-12-20 01:42:12 +00:00
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2007-12-26 23:59:55 +00:00
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// copy arguments into place
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2007-12-11 21:26:59 +00:00
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movq $0,%r9
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2009-05-03 20:57:11 +00:00
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jmp LOCAL(vmInvoke_argumentTest)
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2007-09-26 23:23:03 +00:00
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2009-05-03 20:57:11 +00:00
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LOCAL(vmInvoke_argumentLoop):
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2009-02-17 02:49:28 +00:00
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movq (%rdx,%r9,1),%r8
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movq %r8,(%rsp,%r9,1)
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addq $8,%r9
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2007-09-26 23:23:03 +00:00
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2009-05-03 20:57:11 +00:00
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LOCAL(vmInvoke_argumentTest):
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2007-12-11 21:26:59 +00:00
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cmpq %rcx,%r9
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2009-05-03 20:57:11 +00:00
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jb LOCAL(vmInvoke_argumentLoop)
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2007-09-26 23:23:03 +00:00
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// call function
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2007-12-11 21:26:59 +00:00
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call *%rsi
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2007-09-26 23:23:03 +00:00
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2009-05-29 01:13:15 +00:00
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.globl GLOBAL(vmInvoke_returnAddress)
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GLOBAL(vmInvoke_returnAddress):
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2009-02-17 02:49:28 +00:00
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// restore stack pointer
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movq %rbp,%rsp
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fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
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// clear MyThread::stack to avoid confusing another thread calling
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// java.lang.Thread.getStackTrace on this one. See
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// MyProcess::getStackTrace in compile.cpp for details on how we get
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// a reliable stack trace from a thread that might be interrupted at
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// any point in its execution.
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movq $0,THREAD_STACK(%rbx)
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.globl GLOBAL(vmInvoke_safeStack)
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GLOBAL(vmInvoke_safeStack):
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2009-05-03 20:57:11 +00:00
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2009-05-29 01:13:15 +00:00
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#ifdef AVIAN_CONTINUATIONS
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2009-07-26 02:48:36 +00:00
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# include "continuations-x86.S"
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2009-05-29 01:13:15 +00:00
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#endif // AVIAN_CONTINUATIONS
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2009-05-29 01:54:32 +00:00
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// restore callee-saved registers (below the stack pointer, but in
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// the red zone)
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2009-02-17 02:49:28 +00:00
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movq %rsp,%r9
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2009-05-29 01:54:32 +00:00
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subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%r9
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2009-02-17 02:49:28 +00:00
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movq 0(%r9),%rbx
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movq 8(%r9),%r12
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movq 16(%r9),%r13
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movq 24(%r9),%r14
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movq 32(%r9),%r15
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// return
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2007-09-26 23:23:03 +00:00
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popq %rbp
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ret
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2009-05-03 20:57:11 +00:00
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2009-05-29 01:13:15 +00:00
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.globl GLOBAL(vmJumpAndInvoke)
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GLOBAL(vmJumpAndInvoke):
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#ifdef AVIAN_CONTINUATIONS
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2009-05-27 01:02:39 +00:00
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// %rdi: thread
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// %rsi: address
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// %rdx: base
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2009-05-29 01:54:32 +00:00
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// %rcx: (unused)
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2009-05-27 01:02:39 +00:00
|
|
|
// %r8 : argumentFootprint
|
|
|
|
// %r9 : arguments
|
|
|
|
// 8(%rsp): frameSize
|
2009-05-24 06:32:49 +00:00
|
|
|
|
2009-05-27 01:02:39 +00:00
|
|
|
movq %rdx,%rbp
|
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
// restore (pseudo)-stack pointer (we don't want to touch the real
|
|
|
|
// stack pointer, since we haven't copied the arguments yet)
|
|
|
|
movq %rbp,%rcx
|
|
|
|
|
|
|
|
// allocate new frame, adding room for callee-saved registers
|
|
|
|
movl 8(%rsp),%eax
|
|
|
|
subq %rax,%rcx
|
|
|
|
subq $CALLEE_SAVED_REGISTER_FOOTPRINT,%rcx
|
2009-05-03 20:57:11 +00:00
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
movq %rdi,%rbx
|
2009-05-27 01:02:39 +00:00
|
|
|
|
2009-05-23 22:15:06 +00:00
|
|
|
// set return address
|
2009-12-03 06:15:27 +00:00
|
|
|
movq GLOBAL(vmInvoke_returnAddress)@GOTPCREL(%rip),%r10
|
2009-05-24 17:18:17 +00:00
|
|
|
movq %r10,(%rcx)
|
2009-05-23 22:15:06 +00:00
|
|
|
|
|
|
|
// copy arguments into place
|
|
|
|
movq $0,%r11
|
|
|
|
jmp LOCAL(vmJumpAndInvoke_argumentTest)
|
|
|
|
|
|
|
|
LOCAL(vmJumpAndInvoke_argumentLoop):
|
2009-05-24 06:32:49 +00:00
|
|
|
movq (%r9,%r11,1),%r10
|
2009-05-24 17:18:17 +00:00
|
|
|
movq %r10,8(%rcx,%r11,1)
|
2009-05-23 22:15:06 +00:00
|
|
|
addq $8,%r11
|
|
|
|
|
|
|
|
LOCAL(vmJumpAndInvoke_argumentTest):
|
|
|
|
cmpq %r8,%r11
|
|
|
|
jb LOCAL(vmJumpAndInvoke_argumentLoop)
|
2009-05-24 17:18:17 +00:00
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
// the arguments have been copied, so we can set the real stack
|
|
|
|
// pointer now
|
2009-05-24 17:18:17 +00:00
|
|
|
movq %rcx,%rsp
|
2009-05-23 22:15:06 +00:00
|
|
|
|
2009-05-03 20:57:11 +00:00
|
|
|
jmp *%rsi
|
2009-05-29 01:13:15 +00:00
|
|
|
#else // not AVIAN_CONTINUATIONS
|
|
|
|
// vmJumpAndInvoke should only be called when continuations are
|
|
|
|
// enabled
|
|
|
|
int3
|
|
|
|
#endif // not AVIAN_CONTINUATIONS
|
2009-07-26 02:48:36 +00:00
|
|
|
|
2009-12-03 02:37:22 +00:00
|
|
|
#endif // not __MINGW32__ || __CYGWIN32__
|
2009-05-03 20:57:11 +00:00
|
|
|
|
2007-09-26 23:23:03 +00:00
|
|
|
#elif defined __i386__
|
2009-05-24 06:32:49 +00:00
|
|
|
|
2010-06-25 01:12:15 +00:00
|
|
|
#define THREAD_STACK 2144
|
fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
#define CALLEE_SAVED_REGISTER_FOOTPRINT 16
|
|
|
|
|
2009-05-29 01:13:15 +00:00
|
|
|
.globl GLOBAL(vmInvoke)
|
|
|
|
GLOBAL(vmInvoke):
|
2007-09-26 23:23:03 +00:00
|
|
|
pushl %ebp
|
|
|
|
movl %esp,%ebp
|
|
|
|
|
2007-12-11 21:26:59 +00:00
|
|
|
// 8(%ebp): thread
|
|
|
|
// 12(%ebp): function
|
2009-02-17 02:49:28 +00:00
|
|
|
// 16(%ebp): arguments
|
|
|
|
// 20(%ebp): argumentFootprint
|
|
|
|
// 24(%ebp): frameSize
|
|
|
|
// 28(%ebp): returnType
|
|
|
|
|
|
|
|
// allocate stack space, adding room for callee-saved registers
|
|
|
|
subl 24(%ebp),%esp
|
2009-05-29 01:54:32 +00:00
|
|
|
subl $CALLEE_SAVED_REGISTER_FOOTPRINT,%esp
|
2009-02-17 02:49:28 +00:00
|
|
|
|
|
|
|
// save callee-saved registers
|
|
|
|
movl %esp,%ecx
|
|
|
|
addl 24(%ebp),%ecx
|
|
|
|
|
|
|
|
movl %ebx,0(%ecx)
|
|
|
|
movl %esi,4(%ecx)
|
|
|
|
movl %edi,8(%ecx)
|
2007-12-11 21:26:59 +00:00
|
|
|
|
2009-02-16 15:21:12 +00:00
|
|
|
// we use ebx to hold the thread pointer, by convention
|
2007-12-12 18:59:45 +00:00
|
|
|
mov 8(%ebp),%ebx
|
2007-09-26 23:23:03 +00:00
|
|
|
|
|
|
|
// copy arguments into place
|
|
|
|
movl $0,%ecx
|
2009-02-17 02:49:28 +00:00
|
|
|
movl 16(%ebp),%edx
|
2009-05-24 06:32:49 +00:00
|
|
|
jmp LOCAL(vmInvoke_argumentTest)
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_argumentLoop):
|
2009-02-17 02:49:28 +00:00
|
|
|
movl (%edx,%ecx,1),%eax
|
|
|
|
movl %eax,(%esp,%ecx,1)
|
|
|
|
addl $4,%ecx
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_argumentTest):
|
2007-12-11 21:26:59 +00:00
|
|
|
cmpl 20(%ebp),%ecx
|
2009-05-24 06:32:49 +00:00
|
|
|
jb LOCAL(vmInvoke_argumentLoop)
|
2007-09-26 23:23:03 +00:00
|
|
|
|
|
|
|
// call function
|
2007-12-11 21:26:59 +00:00
|
|
|
call *12(%ebp)
|
2009-05-24 06:32:49 +00:00
|
|
|
|
2010-06-17 00:37:22 +00:00
|
|
|
.globl GLOBAL(vmInvoke_returnAddress)
|
|
|
|
GLOBAL(vmInvoke_returnAddress):
|
2009-05-29 01:54:32 +00:00
|
|
|
// restore stack pointer, preserving the area containing saved
|
|
|
|
// registers
|
2009-04-25 23:31:24 +00:00
|
|
|
movl %ebp,%ecx
|
2009-05-29 01:54:32 +00:00
|
|
|
subl $CALLEE_SAVED_REGISTER_FOOTPRINT,%ecx
|
2009-04-25 23:31:24 +00:00
|
|
|
movl %ecx,%esp
|
fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
|
|
|
|
|
|
|
// clear MyThread::stack to avoid confusing another thread calling
|
|
|
|
// java.lang.Thread.getStackTrace on this one. See
|
|
|
|
// MyProcess::getStackTrace in compile.cpp for details on how we get
|
|
|
|
// a reliable stack trace from a thread that might be interrupted at
|
|
|
|
// any point in its execution.
|
2010-06-16 01:47:06 +00:00
|
|
|
movl $0,THREAD_STACK(%ebx)
|
fix Thread.getStackTrace race conditions
Implementing Thread.getStackTrace is tricky. A thread may interrupt
another thread at any time to grab a stack trace, including while the
latter is executing Java code, JNI code, helper thunks, VM code, or
while transitioning between any of these.
To create a stack trace we use several context fields associated with
the target thread, including snapshots of the instruction pointer,
stack pointer, and frame pointer. These fields must be current,
accurate, and consistent with each other in order to get a reliable
trace. Otherwise, we risk crashing the VM by trying to walk garbage
stack frames or by misinterpreting the size and/or content of
legitimate frames.
This commit addresses sensitive transition points such as entering the
helper thunks which bridge the transitions from Java to native code
(where we must save the stack and frame registers for use from native
code) and stack unwinding (where we must atomically update the thread
context fields to indicate which frame we are unwinding to). When
grabbing a trace for another thread, we determine what kind of code we
caught the thread executing in and use that information to choose the
thread context values with which to begin the trace. See
MyProcessor::getStackTrace::Visitor::visit for details.
In order to atomically update the thread context fields, we do the
following:
1. Create a temporary "transition" object to serve as a staging area
and populate it with the new field values.
2. Update a transition pointer in the thread object to point to the
object created above. As long as this pointer is non-null,
interrupting threads will use the context values in the staging
object instead of those in the thread object.
3. Update the fields in the thread object.
4. Clear the transition pointer in the thread object.
We use a memory barrier between each of these steps to ensure they are
made visible to other threads in program order. See
MyThread::doTransition for details.
2010-06-16 01:10:48 +00:00
|
|
|
|
|
|
|
.globl GLOBAL(vmInvoke_safeStack)
|
|
|
|
GLOBAL(vmInvoke_safeStack):
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-29 01:13:15 +00:00
|
|
|
#ifdef AVIAN_CONTINUATIONS
|
2009-07-26 02:48:36 +00:00
|
|
|
# include "continuations-x86.S"
|
2009-05-29 01:13:15 +00:00
|
|
|
#endif // AVIAN_CONTINUATIONS
|
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
// restore callee-saved registers
|
2009-03-19 14:44:08 +00:00
|
|
|
movl 0(%esp),%ebx
|
|
|
|
movl 4(%esp),%esi
|
|
|
|
movl 8(%esp),%edi
|
2007-10-12 02:52:16 +00:00
|
|
|
|
2007-09-26 23:23:03 +00:00
|
|
|
// handle return value based on expected type
|
2009-02-17 02:49:28 +00:00
|
|
|
movl 28(%ebp),%ecx
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
addl $CALLEE_SAVED_REGISTER_FOOTPRINT,%esp
|
2009-03-19 14:44:08 +00:00
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_void):
|
2007-09-26 23:23:03 +00:00
|
|
|
cmpl $VOID_TYPE,%ecx
|
2009-05-24 06:32:49 +00:00
|
|
|
jne LOCAL(vmInvoke_int64)
|
|
|
|
jmp LOCAL(vmInvoke_return)
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_int64):
|
2007-09-26 23:23:03 +00:00
|
|
|
cmpl $INT64_TYPE,%ecx
|
2009-05-24 06:32:49 +00:00
|
|
|
jne LOCAL(vmInvoke_int32)
|
|
|
|
jmp LOCAL(vmInvoke_return)
|
2007-09-26 23:23:03 +00:00
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_int32):
|
2007-09-26 23:23:03 +00:00
|
|
|
movl $0,%edx
|
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
LOCAL(vmInvoke_return):
|
2007-09-26 23:23:03 +00:00
|
|
|
popl %ebp
|
|
|
|
ret
|
2009-05-24 06:32:49 +00:00
|
|
|
|
|
|
|
LOCAL(getPC):
|
|
|
|
movl (%esp),%esi
|
|
|
|
ret
|
|
|
|
|
2009-05-29 01:13:15 +00:00
|
|
|
.globl GLOBAL(vmJumpAndInvoke)
|
|
|
|
GLOBAL(vmJumpAndInvoke):
|
|
|
|
#ifdef AVIAN_CONTINUATIONS
|
2009-05-24 17:18:17 +00:00
|
|
|
// 4(%esp): thread
|
|
|
|
// 8(%esp): address
|
|
|
|
// 12(%esp): base
|
2009-05-29 01:54:32 +00:00
|
|
|
// 16(%esp): (unused)
|
2009-05-24 17:18:17 +00:00
|
|
|
// 20(%esp): argumentFootprint
|
|
|
|
// 24(%esp): arguments
|
2009-05-27 01:02:39 +00:00
|
|
|
// 28(%esp): frameSize
|
2009-05-24 06:32:49 +00:00
|
|
|
|
2009-05-27 01:02:39 +00:00
|
|
|
movl 12(%esp),%ebp
|
|
|
|
|
2009-05-29 01:54:32 +00:00
|
|
|
// restore (pseudo)-stack pointer (we don't want to touch the real
|
|
|
|
// stack pointer, since we haven't copied the arguments yet)
|
|
|
|
movl %ebp,%ecx
|
|
|
|
|
|
|
|
// allocate new frame, adding room for callee-saved registers
|
2009-05-27 01:02:39 +00:00
|
|
|
subl 28(%esp),%ecx
|
2009-05-29 01:54:32 +00:00
|
|
|
subl $CALLEE_SAVED_REGISTER_FOOTPRINT,%ecx
|
|
|
|
|
|
|
|
movl 4(%esp),%ebx
|
2009-05-24 06:32:49 +00:00
|
|
|
|
|
|
|
// set return address
|
2009-12-03 02:37:22 +00:00
|
|
|
#if defined __MINGW32__ || defined __CYGWIN32__
|
2010-06-25 01:12:15 +00:00
|
|
|
movl $GLOBAL(vmInvoke_returnAddress),%esi
|
2009-12-03 02:29:57 +00:00
|
|
|
#else
|
2009-05-24 06:32:49 +00:00
|
|
|
call LOCAL(getPC)
|
2009-12-03 06:15:27 +00:00
|
|
|
# if defined __APPLE__
|
|
|
|
LOCAL(vmJumpAndInvoke_offset):
|
2010-06-25 01:12:15 +00:00
|
|
|
leal GLOBAL(vmInvoke_returnAddress)-LOCAL(vmJumpAndInvoke_offset)(%esi),%esi
|
2009-12-03 06:15:27 +00:00
|
|
|
# else
|
2009-05-24 06:32:49 +00:00
|
|
|
addl $_GLOBAL_OFFSET_TABLE_,%esi
|
2010-06-25 01:12:15 +00:00
|
|
|
movl GLOBAL(vmInvoke_returnAddress)@GOT(%esi),%esi
|
2009-12-03 06:15:27 +00:00
|
|
|
# endif
|
2009-12-03 02:29:57 +00:00
|
|
|
#endif
|
2009-05-24 17:18:17 +00:00
|
|
|
movl %esi,(%ecx)
|
2009-05-24 06:32:49 +00:00
|
|
|
|
|
|
|
// copy arguments into place
|
2009-05-24 17:18:17 +00:00
|
|
|
movl $0,%esi
|
|
|
|
movl 20(%esp),%edx
|
|
|
|
movl 24(%esp),%eax
|
2009-05-24 06:32:49 +00:00
|
|
|
jmp LOCAL(vmJumpAndInvoke_argumentTest)
|
|
|
|
|
|
|
|
LOCAL(vmJumpAndInvoke_argumentLoop):
|
2009-05-24 17:18:17 +00:00
|
|
|
movl (%eax,%esi,1),%edi
|
|
|
|
movl %edi,4(%ecx,%esi,1)
|
|
|
|
addl $4,%esi
|
2009-05-24 06:32:49 +00:00
|
|
|
|
|
|
|
LOCAL(vmJumpAndInvoke_argumentTest):
|
2009-05-24 17:18:17 +00:00
|
|
|
cmpl %edx,%esi
|
2009-05-24 06:32:49 +00:00
|
|
|
jb LOCAL(vmJumpAndInvoke_argumentLoop)
|
|
|
|
|
2009-05-24 17:18:17 +00:00
|
|
|
movl 8(%esp),%esi
|
2009-05-29 01:54:32 +00:00
|
|
|
|
|
|
|
// the arguments have been copied, so we can set the real stack
|
|
|
|
// pointer now
|
2009-05-24 17:18:17 +00:00
|
|
|
movl %ecx,%esp
|
|
|
|
|
2009-05-24 06:32:49 +00:00
|
|
|
jmp *%esi
|
2009-05-29 01:13:15 +00:00
|
|
|
#else // not AVIAN_CONTINUATIONS
|
|
|
|
// vmJumpAndInvoke should only be called when continuations are
|
|
|
|
// enabled
|
|
|
|
int3
|
|
|
|
#endif // AVIAN_CONTINUATIONS
|
2007-10-04 00:41:54 +00:00
|
|
|
|
2007-09-26 23:23:03 +00:00
|
|
|
#else
|
2009-06-11 15:48:27 +00:00
|
|
|
#error unsupported architecture
|
|
|
|
#endif //def __x86_64__
|