This CL is the darwin/arm and darwin/arm64 equivalent to CL 108679,
110215, 110437, 110438, 111258, 110655.
Updates #17490
Change-Id: Ia95b27b38f9c3535012c566f17a44b4ed26b9db6
Reviewed-on: https://go-review.googlesource.com/111015
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
A few libc_ calls were missing stack switches.
Unfortunately, adding the stack switches revealed a deeper problem.
systemstack() is fundamentally flawed because when you do
systemstack(func() { ... })
There's no way to mark the anonymous function as nosplit. At first I
thought it didn't matter, as that function runs on the g0 stack. But
nosplit is still required, because some syscalls are done when stack
bounds are not set up correctly (e.g. in a signal handler, which runs
on the g0 stack, but g is still pointing at the g stack). Instead use
asmcgocall and funcPC, so we can be nosplit all the way down.
Mid-stack inlining now pushes darwin over the nosplit limit also.
Leaving that as a TODO.
Update #23168
This might fix the cause of occasional darwin hangs.
Update #25181
Update #17490
Change-Id: If9c3ef052822c7679f5a1dd192443f714483327e
Reviewed-on: https://go-review.googlesource.com/111258
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use AT_TIMEKEEP ELF aux entry to access a kernel mapped ring of timehands structs.
The timehands are updated by the kernel periodically, but for accurate measure the
timecounter still needs to be queried.
Currently the fast path is used only when kern.timecounter.hardware==TSC-low
or kern.timecounter.hardware=='ARM MPCore Timecounter',
other timecounters revert back to regular system call.
TODO: add support for HPET timecounter on 386/amd64.
Change-Id: I321ca4e92be63ba21a2574b758ef5c1e729086ad
Reviewed-on: https://go-review.googlesource.com/93156
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, threads created by the runtime exist until the whole
program exits. For #14592 and #20395, we want to be able to exit and
clean up threads created by the runtime. This commit implements that
mechanism.
The main difficulty is how to clean up the g0 stack. In cgo mode and
on Solaris and Windows where the OS manages thread stacks, we simply
arrange to return from mstart and let the system clean up the thread.
If the runtime allocated the g0 stack, then we use a new exitThread
syscall wrapper that arranges to clear a flag in the M once the stack
can safely be reaped and call the thread termination syscall.
exitThread is based on the existing exit1 wrapper, which was always
meant to terminate the calling thread. However, exit1 has never been
used since it was introduced 9 years ago, so it was broken on several
platforms. exitThread also has the additional complication of having
to flag that the stack is unused, which requires some tricks on
platforms that use the stack for syscalls.
This still leaves the problem of how to reap the unused g0 stacks. For
this, we move the M from allm to a new freem list as part of the M
exiting. Later, allocm scans the freem list, finds Ms that are marked
as done with their stack, removes these from the list and frees their
g0 stacks. This also allows these Ms to be garbage collected.
This CL does not yet use any of this functionality. Follow-up CLs
will. Likewise, there are no new tests in this CL because we'll need
follow-up functionality to test it.
Change-Id: Ic851ee74227b6d39c6fc1219fc71b45d3004bc63
Reviewed-on: https://go-review.googlesource.com/46037
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
For cgo programs on linux-amd64 we call the C function mmap.
This supports programs such as the C memory sanitizer that need to
intercept all calls to mmap. It turns out that there are programs that
intercept both mmap and munmap, or that at least expect that if they
intercept mmap, they also intercept munmap. So, if we permit mmap
to be intercepted, also permit munmap to be intercepted.
No test, as it requires two odd things: a C program that intercepts
mmap and munmap, and a Go program that calls munmap.
Change-Id: Iec33f47d59f70dbb7463fd12d30728c24cd4face
Reviewed-on: https://go-review.googlesource.com/45016
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The memory sanitizer (msan) is a nice compiler feature that can
dynamically check for memory errors in C code. It's not useful for Go
code, since Go is memory safe. But it is useful to be able to use the
memory sanitizer on C code that is linked into a Go program via cgo.
Without this change it does not work, as msan considers memory passed
from Go to C as uninitialized.
To make this work, change the runtime to call the C mmap function when
using cgo. When using msan the mmap call will be intercepted and marked
as returning initialized memory.
Work around what appears to be an msan bug by calling malloc before we
call mmap.
Change-Id: I8ab7286d7595ae84782f68a98bef6d3688b946f9
Reviewed-on: https://go-review.googlesource.com/15170
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Avoids shadowing the builtin channel close function.
Change-Id: I7a729b0937c8248fe27222be61318a88db995eee
Reviewed-on: https://go-review.googlesource.com/8898
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Thanks to Aram Hăvărneanu, Nick Owens
and Russ Cox for the early reviews.
LGTM=aram, rsc
R=rsc, lucio.dere, aram, ality
CC=golang-codereviews, mischief
https://golang.org/cl/175370043
Memory management was consolitated with the BSD ports, since
it was almost identical.
Assembly thunks are gone, being replaced by the new //go:linkname
feature.
This change supersedes CL 138390043 (runtime: convert solaris
netpoll to Go), which was previously reviewed and tested.
This change is only the first step, the port now builds,
but doesn't run. Binaries fail to exec:
ld.so.1: 6.out: fatal: 6.out: TLS requirement failure : TLS support is unavailable
Killed
This seems to happen because binaries don't link with libc.so
anymore. We will have to solve that in a different CL.
Also this change is just a rough translation of the original
C code, cleanup will come in a different CL.
[This CL is part of the removal of C code from package runtime.
See golang.org/s/dev.cc for an overview.]
LGTM=rsc
R=rsc, dave
CC=golang-codereviews, iant, khr, minux, r, rlh
https://golang.org/cl/174960043
