This CL redesign how we get the TLS pointer on windows/amd64.
We were previously reading it from the [TEB] arbitrary data slot,
located at 0x28(GS), which can only hold 1 TLS pointer.
With this CL, we will read the TLS pointer from the TEB TLS slot array,
located at 0x1480(GS). The TLS slot array can hold multiple
TLS pointers, up to 64, so multiple Go runtimes running on the
same thread can coexists with different TLS.
Each new TLS slot has to be allocated via [TlsAlloc],
which returns the slot index. This index can then be used to get the
slot offset from GS with the following formula: 0x1480 + index*8
The slot index is fixed per Go runtime, so we can store it
in runtime.tls_g and use it latter on to read/update the TLS pointer.
Loading the TLS pointer requires the following asm instructions:
MOVQ runtime.tls_g, AX
MOVQ AX(GS), AX
Notice that this approach is also implemented on windows/arm64.
[TEB]: https://en.wikipedia.org/wiki/Win32_Thread_Information_Block
[TlsAlloc]: https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-tlsalloc
Updates #22192
Change-Id: Idea7119fd76a3cd083979a4d57ed64b552fa101b
Reviewed-on: https://go-review.googlesource.com/c/go/+/431775
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
The stack pointer must lie within system stack limits
when Control Flow Guard (CFG) is enabled on Windows.
This CL updates runtime.sigtramp to honor this restriction by
porting some code from the windows/arm64 version, which
already supports CFG.
Fixes#53560
Change-Id: I7f88f9ae788b2bac38aac898b2567f1bea62f8f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/437559
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
On 64-bit, this is more efficient, and on ARM64, this prevents the time
from moving backwards due to the weaker memory model. On ARM32 due to
the weaker memory model, we issue a memory barrier.
Updates #48072.
Change-Id: If4695716c3039d8af14e14808af217f5c99fc93a
Reviewed-on: https://go-review.googlesource.com/c/go/+/361057
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This CL adds a new syscall.SyscallN API.
The proposal discussion also suggests the API should not only for
Windows but other platforms. However, the existing API set already
contain differences between platforms, hence the CL only implements
the Windows platform.
Moreover, although the API offers variadic parameters, the permitted
parameters remains up to a limit, which is selected as 42, and arguably
large enough.
Fixes#46552
Change-Id: I66b49988a304d9fc178c7cd5de46d0b75e167a4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/336550
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
There are a few assembly functions in the runtime that are marked
as ABIInternal, solely because funcPC can get the right address.
The functions themselves do not actually follow ABIInternal (or
irrelevant). Now we have internal/abi.FuncPCABI0, use that, and
un-mark the functions.
Also un-mark assembly functions that are only called in assembly.
For them, it only matters if the caller and callee are consistent.
Change-Id: I240e126ac13cb362f61ff8482057ee9f53c24097
Reviewed-on: https://go-review.googlesource.com/c/go/+/321950
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Currently if a signal lands on a non-Go thread that's handled by the Go
handler, Go will emit a message. However, unlike everywhere else in the
runtime, Go will not abort the process after, and the signal handler
will try to continue executing.
This leads to cascading failures and possibly even memory corruption.
For #45638.
Change-Id: I546f4e82f339d555bed295528d819ac883b92bc6
Reviewed-on: https://go-review.googlesource.com/c/go/+/316809
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This is a step toward separating whether time.now is implemented in
assembly from whether we are using faketime.
Change-Id: I8bf059b44a103b034835e3d3b799319cc05e9552
Reviewed-on: https://go-review.googlesource.com/c/go/+/314273
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Change-Id: I1a583d3da9cca4ac51f3fec9b508b7638b452d60
Reviewed-on: https://go-review.googlesource.com/c/go/+/314270
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Currently we call runtimeQPC as ABIInternal because it shaves off 24
bytes by not having an extra wrapper, and at the time we were exceeding
the nosplit stack limit in some cases.
However, this code was written before we had the regabiargs GOEXPERIMENT
flag, and wasn't properly flagged. Naturally, with regabiargs enabled,
it leads to garbage being returned, because it needs to store
runtimeQPC's result to the stack.
We didn't notice this because today runtimeQPC is only used in Wine, not
on any native Windows platform.
Back when I wrote this code, it appeared to be necessary on even native
Windows, but it turns out that's not true anymore. Turn it back into a
native call through a wrapper.
For #40724.
Change-Id: Ia2e5901965ef46c5f299daccef49952026854fe6
Reviewed-on: https://go-review.googlesource.com/c/go/+/312429
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
There are several assembly functions that transition from the Windows
ABI to the Go ABI. These all need to save all registers that are
callee-save in the Windows ABI and caller-save in the Go ABI and
prepare the register state for Go. However, they all do this slightly
differently and most of them don't save the necessary XMM registers
for this transition (which could corrupt them in the C caller).
Furthermore, now that we have a carefully specified Go ABI, it's clear
that none of these actually get all of the details 100% right.
So, unify this code into two macros in a shared header in
runtime/cgo/abi_amd64.h that handle all necessary registers and setup
and use these macros everywhere on Windows that handles transitions
from C to Go.
Change-Id: I62f41345a507aad1ca383814ac8b7e2a9ffb821e
Reviewed-on: https://go-review.googlesource.com/c/go/+/309769
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This function is no longer used.
Eliminating this actually fixes several problems:
- It made assumptions about what registers memclrNoHeapPointers would
preserve. Besides being an abstraction violation and lurking
maintenance issue, this actively became a problem for regabi because
the call to memclrNoHeapPointers now happens through an ABI wrapper,
which is generated by the compiler and hence we can't easily control
what registers it clobbers.
- The amd64 implementation (at least), does not interact with the host
ABI correctly. Notably, it doesn't save many of the registers that
are callee-save in the host ABI but caller-save in the Go ABI.
- It interacts strangely with the NOSPLIT checker because it allocates
an entire M and G on its stack. It worked around this on arm64, and
happened to do things the NOSPLIT checker couldn't track on 386 and
amd64, and happened to be *4 bytes* below the limit on arm (so any
addition to the m or g structs would cause a NOSPLIT failure). See
CL 309031 for a more complete explanation.
Fixes#45530.
Updates #40724.
Change-Id: Ic70d4d7e1c17f1d796575b3377b8529449e93576
Reviewed-on: https://go-review.googlesource.com/c/go/+/309634
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This replaces the externalthreadhandler-based implementation of
profileloop with one that uses newm to start a new thread. This is a
step toward eliminating externalthreadhandler.
For #45530.
Change-Id: Id8e5540423fe2d2004024b649afec6998f77b092
Reviewed-on: https://go-review.googlesource.com/c/go/+/309633
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This replaces the externalthreadhandler-based implementation of
ctrlhandler with one based on compileCallback. This is a step toward
eliminating externalthreadhandler.
For #45530.
Change-Id: I2de2f2f37777af292db67ccf8057b7566aab81f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/309632
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Fixes#45498
Change-Id: I89365f3517bc84376f0f580c64a57f38aaba0cbb
Reviewed-on: https://go-review.googlesource.com/c/go/+/308997
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Alex Brainman <alex.brainman@gmail.com>
The covers three kinds of uses:
1. Calls of closures from assembly. These are always ABIInternal calls
without wrappers. I went through every indirect call in the runtime
and I think mcall is the only case of assembly calling a Go closure in
a way that's affected by ABIInternal. systemstack also calls a
closure, but it takes no arguments.
2. Calls of Go functions that expect raw ABIInternal pointers. I also
only found one of these: callbackasm1 -> cgocallback on Windows. These
are trickier to find, though.
3. Finally, I found one case on NetBSD where new OS threads were
directly calling the Go runtime entry-point from assembly via a PC,
rather than going through a wrapper. This meant new threads may not
have special registers set up. In this case, a change on all other
OSes had already forced new thread entry to go through an ABI wrapper,
so I just caught NetBSD up with that change.
With this change, I'm able to run a "hello world" with
GOEXPERIMENT=regabi,regabiargs.
For #40724.
Change-Id: I2a6d0e530c4fd4edf13484d923891c6160d683aa
Reviewed-on: https://go-review.googlesource.com/c/go/+/305669
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
On Windows, when calling into needm in cgocallback on a new thread that
is unknown to the Go runtime, we currently call through an ABI wrapper.
The ABI wrapper tries to restore the G register from TLS.
On other platforms, TLS is set up just enough that the wrapper will
simply load a nil g from TLS, but on Windows TLS isn't set up at all, so
there's nowhere for the wrapper to load from.
So, bypass the wrapper in the call to needm. needm takes no arguments
and returns no results so there are no special ABI considerations,
except that we must clear X15 which is used as a zero register in Go
code (a function normally performed by the ABI wrapper). needm is also
otherwise already special and carefully crafted to avoid doing anything
that would require a valid G or M, at least until it is able to create
one.
While we're here, this change simplifies setg so that it doesn't set up
TLS on Windows and instead provides an OS-specific osSetupTLS to do
that.
The result of this is that setg(nil) no longer clears the TLS space
pointer on Windows. There's exactly one place this is used (dropm) where
it doesn't matter anymore, and an empty TLS means that setg's wrapper
will crash on the return path. Another result is that the G slot in the
TLS will be properly cleared, however, which isn't true today.
For #40724.
Change-Id: I65c3d924a3b16abe667b06fd91d467d6d5da31d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/303070
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
In the runtime there are Windows-specific assembly routines that are
address-taken via funcPC and are not intended to be called through a
wrapper. Mark them as ABIInternal so that we don't grab the wrapper,
because that will break in all sorts of contexts.
For #40724.
For #44065.
Change-Id: I12a728786786f423e5b229f8622e4a80ec27a31c
Reviewed-on: https://go-review.googlesource.com/c/go/+/302109
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This changes makes it so that nanotimeQPC calls nanotime1 without an ABI
wrapper by specifying the ABIInternal version directly. The reason why
this is necessary is because ABI wrappers typically require additional
stack space, and nanotimeQPC is used deep within nosplit contexts,
and with the ABI wrappers now enabled, this exhausts the stack guard
space held for nosplit functions. Rather than increase the stack guard,
we choose to do this.
For #40724.
Change-Id: Ia9173ca903335a9d6f380f57f4a45e49b58da6bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/303069
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
No change to actual runtime, but helps reduce the laundry list
of functions.
mcall, morestack, and asmcgocall are not actually top-of-frame,
so those need more attention in follow-up CLs.
mstart moved to assembly so that it can be marked TOPFRAME.
Since TOPFRAME also tells DWARF consumers not to unwind
this way, this change should also improve debuggers a
marginal amount.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: If1e0d46ca973de5e46b62948d076f675f285b5d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288802
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Both asmcgocall and systemstack need to save the calling Go code's
context for use by traceback, but they do it differently.
Systemstack's appraoch is better, because it doesn't require a
special case in traceback.
So make them both use that.
While we are here, the fake mstart caller in systemstack is
no longer needed and can be removed.
(traceback knows to stop in systemstack because of the writes to SP.)
Also remove the fake mstarts in sys_windows_*.s.
And while we are there, fix the control flow guard code in sys_windows_arm.s.
The current code is using pointers to a stack frame that technically is gone
once we hit the RET instruction. Clearly it's working OK, but better not to depend
on data below SP being preserved, even for just a few instructions.
Store the value we need in other registers instead.
(This code is only used for pushing a sigpanic call, which does not
actually return to the site of the fault and therefore doesn't need to
preserve any of the registers.)
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: Id1e3ef5e54f7ad786e4b87043f2626eba7c3bbd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288799
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This is dead code and need not be ported to each architecture.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I2d0072b377f73e49d7158ea304670c26f5486c59
Reviewed-on: https://go-review.googlesource.com/c/go/+/288794
Trust: Russ Cox <rsc@golang.org>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
During a cgocallback, the runtime calls needm to get an m.
The calls made during needm cannot themselves assume that
there is an m or a g (which is attached to the m).
In the old days of making direct system calls, the only thing
you had to do for such functions was mark them //go:nosplit,
to avoid the use of g in the stack split prologue.
But now, on operating systems that make system calls through
shared libraries and use code that saves state in the g or m
before doing so, it's not safe to assume g exists. In fact, it is
not even safe to call getg(), because it might fault deferencing
the TLS storage to find the g pointer (that storage may not be
initialized yet, at least on Windows, and perhaps on other systems
in the future).
The specific routines that are problematic are usleep and osyield,
which are called during lock contention in lockextra, called
from needm.
All this is rather subtle and hidden, so in addition to fixing the
problem on Windows, this CL makes the fact of not running on
a g much clearer by introducing variants usleep_no_g and
osyield_no_g whose names should make clear that there is no g.
And then we can remove the various sketchy getg() == nil checks
in the existing routines.
As part of this cleanup, this CL also deletes onosstack on Windows.
onosstack is from back when the runtime was implemented in C.
It predates systemstack but does essentially the same thing.
Instead of having two different copies of this code, we can use
systemstack consistently. This way we need not port onosstack
to each architecture.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I3352de1fd0a3c26267c6e209063e6e86abd26187
Reviewed-on: https://go-review.googlesource.com/c/go/+/288793
Trust: Russ Cox <rsc@golang.org>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
This change adjusts usleep2HighRes so it does not crash when TLS is
not configured. When g is not available, usleep2HighRes just calls
usleep2 instead.
Updates #8687
Change-Id: Idbb80f7b71d1da350a6a7df7c49154eb1ffe29a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/271907
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Simon Rozman <simon@rozman.si>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
This redesigns the way calls work from C to exported Go functions. It
removes several steps from the call path, makes cmd/cgo no longer
sensitive to the Go calling convention, and eliminates the use of
reflectcall from cgo.
In order to avoid generating a large amount of FFI glue between the C
and Go ABIs, the cgo tool has long depended on generating a C function
that marshals the arguments into a struct, and then the actual ABI
switch happens in functions with fixed signatures that simply take a
pointer to this struct. In a way, this CL simply pushes this idea
further.
Currently, the cgo tool generates this argument struct in the exact
layout of the Go stack frame and depends on reflectcall to unpack it
into the appropriate Go call (even though it's actually
reflectcall'ing a function generated by cgo).
In this CL, we decouple this struct from the Go stack layout. Instead,
cgo generates a Go function that takes the struct, unpacks it, and
calls the exported function. Since this generated function has a
generic signature (like the rest of the call path), we don't need
reflectcall and can instead depend on the Go compiler itself to
implement the call to the exported Go function.
One complication is that syscall.NewCallback on Windows, which
converts a Go function into a C function pointer, depends on
cgocallback's current dynamic calling approach since the signatures of
the callbacks aren't known statically. For this specific case, we
continue to depend on reflectcall. Really, the current approach makes
some overly simplistic assumptions about translating the C ABI to the
Go ABI. Now we're at least in a much better position to do a proper
ABI translation.
For comparison, the current cgo call path looks like:
GoF (generated C function) ->
crosscall2 (in cgo/asm_*.s) ->
_cgoexp_GoF (generated Go function) ->
cgocallback (in asm_*.s) ->
cgocallback_gofunc (in asm_*.s) ->
cgocallbackg (in cgocall.go) ->
cgocallbackg1 (in cgocall.go) ->
reflectcall (in asm_*.s) ->
_cgoexpwrap_GoF (generated Go function) ->
p.GoF
Now the call path looks like:
GoF (generated C function) ->
crosscall2 (in cgo/asm_*.s) ->
cgocallback (in asm_*.s) ->
cgocallbackg (in cgocall.go) ->
cgocallbackg1 (in cgocall.go) ->
_cgoexp_GoF (generated Go function) ->
p.GoF
Notably:
1. We combine _cgoexp_GoF and _cgoexpwrap_GoF and move the combined
operation to the end of the sequence. This combined function also
handles reflectcall's previous role.
2. We combined cgocallback and cgocallback_gofunc since the only
purpose of having both was to convert a raw PC into a Go function
value. We instead construct the Go function value in cgocallbackg1.
3. cgocallbackg1 no longer reaches backwards through the stack to get
the arguments to cgocallback_gofunc. Instead, we just pass the
arguments down.
4. Currently, we need an explicit msanwrite to mark the results struct
as written because reflectcall doesn't do this. Now, the results are
written by regular Go assignments, so the Go compiler generates the
necessary MSAN annotations. This also means we no longer need to track
the size of the arguments frame.
Updates #40724, since now we don't need to teach cgo about the
register ABI or change how it uses reflectcall.
Change-Id: I7840489a2597962aeb670e0c1798a16a7359c94f
Reviewed-on: https://go-review.googlesource.com/c/go/+/258938
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
@jstarks suggested that recent versions of Windows provide access to high resolution timers. See
https://github.com/golang/go/issues/8687#issuecomment-656259353
for details.
I tried to run this C program on my Windows 10 computer
```
#include <stdio.h>
#include <Windows.h>
#pragma comment(lib, "Winmm.lib")
// Apparently this is already defined when I use msvc cl.
//#define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION = 0x00000002;
int usleep(HANDLE timer, LONGLONG d) {
LARGE_INTEGER liDueTime;
DWORD ret;
LARGE_INTEGER StartingTime, EndingTime, ElapsedMicroseconds;
LARGE_INTEGER Frequency;
QueryPerformanceFrequency(&Frequency);
QueryPerformanceCounter(&StartingTime);
liDueTime.QuadPart = d;
liDueTime.QuadPart = liDueTime.QuadPart * 10; // us into 100 of ns units
liDueTime.QuadPart = -liDueTime.QuadPart; // negative for relative dure time
if (!SetWaitableTimer(timer, &liDueTime, 0, NULL, NULL, 0)) {
printf("SetWaitableTimer failed: errno=%d\n", GetLastError());
return 1;
}
ret = WaitForSingleObject(timer, INFINITE);
if (ret != WAIT_OBJECT_0) {
printf("WaitForSingleObject failed: ret=%d errno=%d\n", ret, GetLastError());
return 1;
}
QueryPerformanceCounter(&EndingTime);
ElapsedMicroseconds.QuadPart = EndingTime.QuadPart - StartingTime.QuadPart;
ElapsedMicroseconds.QuadPart *= 1000000;
ElapsedMicroseconds.QuadPart /= Frequency.QuadPart;
printf("delay is %lld us - slept for %lld us\n", d, ElapsedMicroseconds.QuadPart);
return 0;
}
int testTimer(DWORD createFlag)
{
HANDLE timer;
timer = CreateWaitableTimerEx(NULL, NULL, createFlag, TIMER_ALL_ACCESS);
if (timer == NULL) {
printf("CreateWaitableTimerEx failed: errno=%d\n", GetLastError());
return 1;
}
usleep(timer, 1000LL);
usleep(timer, 100LL);
usleep(timer, 10LL);
usleep(timer, 1LL);
CloseHandle(timer);
return 0;
}
int main()
{
printf("\n1. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is off\n");
testTimer(0);
printf("\n2. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is off\n");
testTimer(CREATE_WAITABLE_TIMER_HIGH_RESOLUTION);
timeBeginPeriod(1);
printf("\n3. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is on\n");
testTimer(0);
printf("\n4. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is on\n");
testTimer(CREATE_WAITABLE_TIMER_HIGH_RESOLUTION);
}
```
and I see this output
```
1. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is off
delay is 1000 us - slept for 4045 us
delay is 100 us - slept for 3915 us
delay is 10 us - slept for 3291 us
delay is 1 us - slept for 2234 us
2. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is off
delay is 1000 us - slept for 1076 us
delay is 100 us - slept for 569 us
delay is 10 us - slept for 585 us
delay is 1 us - slept for 17 us
3. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is on
delay is 1000 us - slept for 742 us
delay is 100 us - slept for 893 us
delay is 10 us - slept for 414 us
delay is 1 us - slept for 920 us
4. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is on
delay is 1000 us - slept for 1466 us
delay is 100 us - slept for 559 us
delay is 10 us - slept for 535 us
delay is 1 us - slept for 5 us
```
That shows, that indeed using CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
will provide sleeps as low as about 500 microseconds, while our
current approach provides about 1 millisecond sleep.
New approach also does not require for timeBeginPeriod to be on,
so this change solves long standing problem with go programs draining
laptop battery, because it calls timeBeginPeriod.
This change will only run on systems where
CREATE_WAITABLE_TIMER_HIGH_RESOLUTION flag is available. If not
available, the runtime will fallback to original code that uses
timeBeginPeriod.
This is how this change affects benchmark reported in issue #14790
name old time/op new time/op delta
ChanToSyscallPing 1.05ms ± 2% 0.68ms ±11% -35.43% (p=0.000 n=10+10)
The benchmark was run with GOMAXPROCS set to 1.
Fixes#8687
Updates #14790
Change-Id: I5b97ba58289c088c17c05292e12e45285c467eae
Reviewed-on: https://go-review.googlesource.com/c/go/+/248699
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
In preparation for general faketime support, this renames the existing
nanotime, walltime, and write functions to nanotime1, walltime1, and
write1 and wraps them with trivial Go functions. This will let us
inject different implementations on all platforms when faketime is
enabled.
Updates #30439.
Change-Id: Ice5ccc513a32a6d89ea051638676d3ee05b00418
Reviewed-on: https://go-review.googlesource.com/c/go/+/192738
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This reverts CL 191759.
Reason for revert: broke most Go programs using the time package on Wine,
including on 4.15, the latest stable version. Only wine-staging (with
experimental patches) contains an upstream fix we could rely on.
Change-Id: Ic8ba126022e54f412174042fbb9abed82d5eb318
Reviewed-on: https://go-review.googlesource.com/c/go/+/192622
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
A few years ago, Wine-specific detection was added as an ugly hack to
work around shortcomings in the emulation layer. Probably it's best to
not special case this emulator versus that emulator versus the real
deal, but there were two arguments presented in the hack's favor:
1. Wine is useful and developers will appreciate being able to debug
stuff with it.
2. The existing KUSER_SHARED_DATA technique for gathering time is
undocumented, and we shouldn't be relying on it anyway, since
Microsoft might remove it without notice.
As it turns out, neither one of these are, at the time of writing, true.
(1) has been handled for some time by Wine with the introduction of the
commit entitled "ntdll: Create thread to update user_shared_data time
values when necessary". And (2) is in fact documented:
https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/content/ntddk/ns-ntddk-kuser_shared_datahttps://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/-kuser
It's in use so widely by both third-party software (such as games, a
massive market segment) and by Microsoft binaries that removing it from
the operating system will basically never happen.
So with both issues taken care of, this commit simply gets rid of the
old hack.
Change-Id: I80093f50e0d10d53648128d0f9dd76b1b92a119e
Reviewed-on: https://go-review.googlesource.com/c/go/+/191759
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
I forgot that in Go assembly, x+16(SP) is not the same as 16(SP).
The former is the virtual stack pointer (one word below FP on x86)
while the latter is the actual stack pointer.
Change-Id: Ibb7012bb97261949f5e1a0dc70869d9a6f50aa99
Reviewed-on: https://go-review.googlesource.com/c/go/+/176557
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Working toward making the tree vet-safe instead of having
so many exceptions in cmd/vet/all/whitelist.
This CL makes "go vet -unsafeptr=false runtime" happy for windows/*,
while keeping "GO_BUILDER_NAME=misc-vetall go tool dist test" happy too.
For #31916.
Change-Id: If37ab2b3f6fca4696b8a6afb2ef11ba6c4fb42e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/176106
Reviewed-by: Austin Clements <austin@google.com>
syscall.NewCallback mistakenly used MOVL even for windows/amd64,
which only returned the lower 32 bits regardless of the architecture.
This was due to a copy and paste after porting from windows/386.
The code now uses MOVQ, which will return all the available bits.
Also adjust TestReturnAfterStackGrowInCallback to ensure we never
regress.
Fixes#29331
Change-Id: I4f5c8021c33f234c2bb7baa9ef7a6b4870172509
Reviewed-on: https://go-review.googlesource.com/c/159579
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Move startNano from runtime to time package.
In preparation for a subsequent change that speeds up Since and Until.
This also makes code simpler as we have less assembly as the result,
monotonic time handling is better localized in time package.
This changes values returned from nanotime on windows
(it does not account for startNano anymore), current comments state
that it's important, but it's unclear how it can be important
since no other OS does this.
Update #25729
Change-Id: I2275d57b7b5ed8fd0d53eb0f19d55a86136cc555
Reviewed-on: https://go-review.googlesource.com/c/146340
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Don't worry, this patch just remove trailing whitespace from
assembly files, and does not touch any logical changes.
Change-Id: Ia724ac0b1abf8bc1e41454bdc79289ef317c165d
Reviewed-on: https://go-review.googlesource.com/c/113595
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, on Windows, the thread stack size is set or assumed in many
different places. In non-cgo binaries, both the Go linker and the
runtime have a copy of the stack size, the Go linker sets the size of
the main thread stack, and the runtime sets the size of other thread
stacks. In cgo binaries, the external linker sets the main thread
stack size, the runtime assumes the size of the main thread stack will
be the same as used by the Go linker, and the cgo entry code assumes
the same.
Furthermore, users can change the main thread stack size using
editbin, so the runtime doesn't even really know what size it is, and
user C code can create threads with unknown thread stack sizes, which
we also assume have the same default stack size.
This is all a mess.
Fix the corner cases of this and the duplication of knowledge between
the linker and the runtime by querying the OS for the stack bounds
during thread setup. Furthermore, we unify all of this into just
runtime.minit for both cgo and non-cgo binaries and for the main
thread, other runtime-created threads, and C-created threads.
Updates #20975.
Change-Id: I45dbee2b5ea2ae721a85a27680737ff046f9d464
Reviewed-on: https://go-review.googlesource.com/120336
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, we allocate 1MB or 2MB thread stacks on Windows, but in
non-cgo binaries still set the g0 stack bounds assuming only 64k is
available. While this is fine in pure Go binaries, a non-cgo Go binary
on Windows can use the syscall package to call arbitrary DLLs, which
may call back into Go. If a DLL function uses more than 64k of stack
and then calls back into Go, the Go runtime will believe that it's out
of stack space and crash.
Fix this by plumbing the correct stack size into the g0 stacks of
non-cgo binaries. Cgo binaries already use the correct size because
their g0 stack sizes are set by a different code path.
Fixes#20975.
Change-Id: Id6fb559cfe1e1ea0dfac56d4654865c20dccf68d
Reviewed-on: https://go-review.googlesource.com/120195
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Each URL was manually verified to ensure it did not serve up incorrect
content.
Change-Id: I4dc846227af95a73ee9a3074d0c379ff0fa955df
Reviewed-on: https://go-review.googlesource.com/115798
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Implemented low-level time system for windows on hardware (software),
which does not support memory mapped _KSYSTEM_TIME page update.
In particular this problem exists on Wine where _KSYSTEM_TIME
only contains time at the start, and is never modified.
On start we try to detect Wine and if it's so we fallback to
GetSystemTimeAsFileTime() for current time and a monotonic
timer based on QueryPerformanceCounter family of syscalls:
https://msdn.microsoft.com/en-us/library/windows/desktop/dn553408(v=vs.85).aspxFixes#18537
Change-Id: I269d22467ed9b0afb62056974d23e731b80c83ed
Reviewed-on: https://go-review.googlesource.com/35710
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fetch both monotonic and wall time together when possible.
Avoids skew and is cheaper.
Also shave a few ns off in conversion in package time.
Compared to current implementation (after monotonic changes):
name old time/op new time/op delta
Now 19.6ns ± 1% 9.7ns ± 1% -50.63% (p=0.000 n=41+49) darwin/amd64
Now 23.5ns ± 4% 10.6ns ± 5% -54.61% (p=0.000 n=30+28) windows/amd64
Now 54.5ns ± 5% 29.8ns ± 9% -45.40% (p=0.000 n=27+29) windows/386
More importantly, compared to Go 1.8:
name old time/op new time/op delta
Now 9.5ns ± 1% 9.7ns ± 1% +1.94% (p=0.000 n=41+49) darwin/amd64
Now 12.9ns ± 5% 10.6ns ± 5% -17.73% (p=0.000 n=30+28) windows/amd64
Now 15.3ns ± 5% 29.8ns ± 9% +94.36% (p=0.000 n=30+29) windows/386
This brings time.Now back in line with Go 1.8 on darwin/amd64 and windows/amd64.
It's not obvious why windows/386 is still noticeably worse than Go 1.8,
but it's better than before this CL. The windows/386 speed is not too
important; the changes just keep the two architectures similar.
Change-Id: If69b94970c8a1a57910a371ee91e0d4e82e46c5d
Reviewed-on: https://go-review.googlesource.com/36428
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Since barrier-less memclr is only safe in very narrow circumstances,
this commit renames memclr to avoid accidentally calling memclr on
typed memory. This can cause subtle, non-deterministic bugs, so it's
worth some effort to prevent. In the near term, this will also prevent
bugs creeping in from any concurrent CLs that add calls to memclr; if
this happens, whichever patch hits master second will fail to compile.
This also adds the other new memclr variants to the compiler's
builtin.go to minimize the churn on that binary blob. We'll use these
in future commits.
Updates #17503.
Change-Id: I00eead049f5bd35ca107ea525966831f3d1ed9ca
Reviewed-on: https://go-review.googlesource.com/31369
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
A few other architectures have already defined a NOFRAME flag.
Use it to disable frame pointer code on a few very low-level functions
that must behave like Windows code.
Makes the failing os/signal test pass on a Windows gomote.
Change-Id: I982365f2c59a0aa302b4428c970846c61027cf3e
Reviewed-on: https://go-review.googlesource.com/23456
Reviewed-by: Austin Clements <austin@google.com>
It appears that windows osyield is just 15ms sleep on my computer
(see benchmarks below). Replace NtWaitForSingleObject in osyield
with SwitchToThread (as suggested by Dmitry).
Also add issue #14790 related benchmarks, so we can track perfomance
changes in CL 20834 and CL 20835 and beyond.
Update #14790
benchmark old ns/op new ns/op delta
BenchmarkChanToSyscallPing1ms 1953200 1953000 -0.01%
BenchmarkChanToSyscallPing15ms 31562904 31248400 -1.00%
BenchmarkSyscallToSyscallPing1ms 5247 4202 -19.92%
BenchmarkSyscallToSyscallPing15ms 5260 4374 -16.84%
BenchmarkChanToChanPing1ms 474 494 +4.22%
BenchmarkChanToChanPing15ms 468 489 +4.49%
BenchmarkOsYield1ms 980018 75.5 -99.99%
BenchmarkOsYield15ms 15625200 75.8 -100.00%
Change-Id: I1b4cc7caca784e2548ee3c846ca07ef152ebedce
Reviewed-on: https://go-review.googlesource.com/21294
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On Windows, externalthreadhandler currently sets the assumed stack
size for the profiler thread and the ctrlhandler threads to 8KB. The
actual stack size is determined by the SizeOfStackReserve field in the
binary set by the linker, which is currently at least 64KB (and
typically 128KB).
It turns out the profiler thread is running within a few words of the
8KB-(stack guard) bound set by externalthreadhandler. If it overflows
this bound, morestack crashes unceremoniously with an access
violation, which we then fail to handle, causing the whole process to
exit without explanation.
To avoid this problem and give us some breathing room, increase the
assumed stack size in externalthreadhandler to 32KB (there's some
unknown amount of stack already in use, so it's not safe to increase
this all the way to the reserve size).
We also document the relationships between externalthreadhandler and
SizeOfStackReserve to make this more obvious in the future.
Change-Id: I2f9f9c0892076d78e09827022ff0f2bedd9680a9
Reviewed-on: https://go-review.googlesource.com/18304
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
Windows amd64 requires all syscall callers to provide room for first
4 parameters on stack. We do that for all our syscalls, except inside
of usleep2. In https://codereview.appspot.com/7563043#msg3 rsc says:
"We don't need the stack alignment and first 4 parameters on amd64
because it's just a system call, not an ordinary function call."
He seems to be wrong on both counts. But alignment is already fixed.
Fix parameter space now too.
Fixes#12444
Change-Id: I66a2a18d2f2c3846e3aa556cc3acc8ec6240bea0
Reviewed-on: https://go-review.googlesource.com/14282
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
When Windows calls externalthreadhandler it expects to receive
return value in AX. We don't set AX anywhere. Change that.
Store ctrlhandler1 and profileloop1 return values into AX before
returning from externalthreadhandler.
Fixes#10215.
Change-Id: Ied04542cc3ebe7d4a26660e970f9f78098143591
Reviewed-on: https://go-review.googlesource.com/8901
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
qmuntal
Jason A. Donenfeld
Changkun Ou
Cherry Mui
Michael Anthony Knyszek
Ian Lance Taylor
Austin Clements
El Mostafa Idrassi
Paschalis Tsilias
Russ Cox
Alex Brainman
Richard Wilkes
Daniel Martí
Dmitry Vyukov
Zhou Peng
Kazuhiro Sera
Tim Cooper
Evgeniy Polyakov
David Crawshaw