Currently throw() in the signal handler results in "fatal error: unknown
return pc from runtime.sigreturn ...".
Marking sigtramp as TOPFRAME allows gentraceback to stop tracebacks at
the end of a signal handler, since there is not much beyond sigtramp.
This is just done on Linux for now, but may apply to other Unix systems
as well.
Change-Id: I96edcb945283f417a5bfe00ce2fb2b1a0d578692
Reviewed-on: https://go-review.googlesource.com/c/go/+/402190
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
sigtramp on openbsd-arm64 is teetering on the edge of the nosplit stack
limit. Add more headroom by calling sigtrampgo using ABIInternal, which
eliminates a 48-byte ABI wrapper frame.
openbsd-amd64 has slightly more space, but is also close to the limit,
so convert it as well.
Other operating systems don't have it as bad, but many have nearly
identical implementations of sigtramp, so I have converted them as well.
I've omitted darwin-arm64 and solaris, as those are quite different and
would benefit from not needing ifdef for both cases.
For #51485.
Change-Id: I70512645d4208b346a59d5e5d03836a45833b1d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/390814
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
On Linux, the minimum required kernel version for Go 1.18 was be changed
to 2.6.32, see #45964. The pipe2 syscall was added in 2.6.27.
All other platforms already provide the pipe2 syscall in the minimum
supported version:
- DragonFly BSD added it in version 4.2, see
https://www.dragonflybsd.org/release42/
- FreeBSD added it in version 10.0, see
https://www.freebsd.org/cgi/man.cgi?pipe(2)#end
- NetBSD added it in version 6.0, see
https://man.netbsd.org/pipe2.2#HISTORY
- OpenBSD added it in version 5.7, see
https://man.openbsd.org/pipe.2#HISTORY
- Illumos supports it since 2013, see
https://www.illumos.org/issues/3714
- Solaris supports it since 11.4
This also allows to remove setNonblock which was only used in the pipe
fallback path on these platforms.
Change-Id: I1f40d32fd3065d74e22af77b9ff2292b9cf66706
Reviewed-on: https://go-review.googlesource.com/c/go/+/389354
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
Always enable regabig on AMD64, which enables the G register and
the X15 zero register. Remove the fallback path.
Also remove the regabig GOEXPERIMENT. On AMD64 it is always
enabled (this CL). Other architectures already have a G register,
except for 386, where there are too few registers and it is
unlikely that we will reserve one. (If we really do, we can just
add a new experiment).
Change-Id: I229cac0060f48fe58c9fdaabd38d6fa16b8a0855
Reviewed-on: https://go-review.googlesource.com/c/go/+/327272
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
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>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
It's never called.
Change-Id: I8956743b21301816b5f37a9b34e3f50ef7b2e70a
Reviewed-on: https://go-review.googlesource.com/c/go/+/314771
Trust: Ian Lance Taylor <iant@golang.org>
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Change-Id: Iec9de5ca56eb68d524bbaa0668515dbd09ad38a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/314770
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
The previous CL introduced macros for transitions from the Windows ABI
to the Go ABI. This CL does the same for SysV and uses them in almost
all places where we transition from the C ABI to the Go ABI.
Compared to Windows, this transition is much simpler and I didn't find
any places that were getting it wrong. But this does let us unify a
lot of code nicely and introduces some degree of abstraction around
these ABI transitions.
Change-Id: Ib6bdecafce587ce18fca4c8300fcf401284a2bcd
Reviewed-on: https://go-review.googlesource.com/c/go/+/309930
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
Currently, the objabi.Experiment fields use Go-standard CamelCase, the
GOEXPERIMENT environment variable flags and build tags use all
lowercase, and the asm macros use upper-case with underscores.
This CL makes asm use the lowercase names for macros so there is one
less spelling, e.g., GOEXPERIMENT_regabiargs. This also makes them
consistent with the GOOS_* and GOARCH_* macros, which also use lower
case.
Change-Id: I305cd89af5e8cd1a89cc148746c034bcfd76db3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/307816
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.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>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This separates GOEXPERIMENT=regabi into five sub-experiments:
regabiwrappers, regabig, regabireflect, regabidefer, and regabiargs.
Setting GOEXPERIMENT=regabi now implies the working subset of these
(currently, regabiwrappers, regabig, and regabireflect).
This simplifies testing, helps derisk the register ABI project,
and will also help with performance comparisons.
This replaces the -abiwrap flag to the compiler and linker with
the regabiwrappers experiment.
As part of this, regabiargs now enables registers for all calls
in the compiler. Previously, this was statically disabled in
regabiEnabledForAllCompilation, but now that we can control it
independently, this isn't necessary.
For #40724.
Change-Id: I5171e60cda6789031f2ef034cc2e7c5d62459122
Reviewed-on: https://go-review.googlesource.com/c/go/+/302070
Trust: Austin Clements <austin@google.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Now that we have a g register, just use it.
Note: functions that can be called from ABI0 context (e.g.
morestack) is unchanged. Functions that switch g is also
unchanged, because we need to set the new g in both the register
and TLS.
TODO: other OSes.
Change-Id: I692a82a7caa8417ff620a59676a6275f56747b94
Reviewed-on: https://go-review.googlesource.com/c/go/+/289718
Trust: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
This is a proof-of-concept change for using the g register on
AMD64. getg is now lowered to R14 in the new ABI. The g register
is not yet used in all places where it can be used (e.g. stack
bounds check, runtime assembly code).
Change-Id: I10123ddf38e31782cf58bafcdff170aee0ff0d1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/289196
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
[This is a roll-forward of CL 262319, with a fix for some Darwin test
failures].
Change the definitions of selected runtime assembly routines
from ABI0 (the default) to ABIInternal. The ABIInternal def is
intended to indicate that these functions don't follow the existing Go
runtime ABI. In addition, convert the assembly reference to
runtime.main (from runtime.mainPC) to ABIInternal. Finally, for
functions such as "runtime.duffzero" that are called directly from
generated code, make sure that the compiler looks up the correct
ABI version.
This is intended to support the register abi work, however these
changes should not have any issues even when GOEXPERIMENT=regabi is
not in effect.
Updates #27539, #40724.
Change-Id: Idf507f1c06176073563845239e1a54dad51a9ea9
Reviewed-on: https://go-review.googlesource.com/c/go/+/266638
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TryBot-Result: Go Bot <gobot@golang.org>
This reverts commit 50af50d136.
Reason for revert: Causes failures in the runtime package test on Darwin, apparently.
Change-Id: I006bc1b3443fa7207e92fb4a93e3fb438d4d3de3
Reviewed-on: https://go-review.googlesource.com/c/go/+/266257
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Change the definitions of selected runtime assembly routines
from ABI0 (the default) to ABIInternal. The ABIInternal def is
intended to indicate that these functions don't follow the existing Go
runtime ABI. In addition, convert the assembly reference to
runtime.main (from runtime.mainPC) to ABIInternal. Finally, for
functions such as "runtime.duffzero" that are called directly from
generated code, make sure that the compiler looks up the correct
ABI version.
This is intended to support the register abi work, however these
changes should not have any issues even when GOEXPERIMENT=regabi is
not in effect.
Updates #27539, #40724.
Change-Id: I9846f8dcaccc95718cf2e61a18b7e924a0677e4c
Reviewed-on: https://go-review.googlesource.com/c/go/+/262319
Run-TryBot: Than McIntosh <thanm@google.com>
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If vdso is disabled, the goruntime calls gettimeofday from vsyscall,
but if vsyscall is disabled too, all golang binaries crash:
SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0xffffffffff600000} ---
killed by SIGSEGV (core dumped) ++
vsyscall doesn't work as it was designed for a long time due to security
reasons and now vsyscall is a little more expensive than real syscalls:
https://github.com/torvalds/linux/commit/5cec93c216db
This patch reworks the code to call syscalls if the vdso library isn't
available.
Change-Id: I16cbf3f49871bea91e26af1f49aa0ae2fbd3a01d
GitHub-Last-Rev: 1d133cd30a
GitHub-Pull-Request: golang/go#41681
Reviewed-on: https://go-review.googlesource.com/c/go/+/257982
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
Trust: Michael Pratt <mpratt@google.com>
BP should be callee-save. It will be saved automatically if
there is a nonzero frame size. Otherwise, we need to avoid this register.
Change-Id: If3f551efa42d830c8793d9f0183cb8daad7a2ab5
Reviewed-on: https://go-review.googlesource.com/c/go/+/248260
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Go 1.14 included a (rather awful) workaround for a Linux kernel bug
that corrupted vector registers on x86 CPUs during signal delivery
(https://bugzilla.kernel.org/show_bug.cgi?id=205663). This bug was
introduced in Linux 5.2 and fixed in 5.3.15, 5.4.2 and all 5.5 and
later kernels. The fix was also back-ported by major distros. This
workaround was necessary, but had unfortunate downsides, including
causing Go programs to exceed the mlock ulimit in many configurations
(#37436).
We're reasonably confident that by the Go 1.16 release, the number of
systems running affected kernels will be vanishingly small. Hence,
this CL removes this workaround.
This effectively reverts CLs 209597 (version parser), 209899 (mlock
top of signal stack), 210299 (better failure message), 223121 (soft
mlock failure handling), and 244059 (special-case patched Ubuntu
kernels). The one thing we keep is the osArchInit function. It's empty
everywhere now, but is a reasonable hook to have.
Updates #35326, #35777 (the original register corruption bugs).
Updates #40184 (request to revert in 1.15).
Fixes#35979.
Change-Id: Ie213270837095576f1f3ef46bf3de187dc486c50
Reviewed-on: https://go-review.googlesource.com/c/go/+/246200
Run-TryBot: Austin Clements <austin@google.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, nanotime1 (and walltime1) is not reentrant, in that it
sets m.vdsoSP at entry and clears it at exit. If a signal lands
in between, and nanotime1 is called from the signal handler, it
will clear m.vdsoSP while we are still in nanotime1. If (in the
unlikely event) it is signaled again, m.vdsoSP will be wrong,
which may cause the stack unwinding code to crash.
This CL makes it reentrant, by saving/restoring the previous
vdsoPC and vdsoSP, instead of setting it to 0 at exit.
TODO: have some way to test?
Change-Id: I9ee53b251f1d8a5a489c71d4b4c0df1dee70c3e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/246763
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
In walltime1/nanotime1, we save the caller's PC and SP for stack
unwinding. The code does that assumed zero frame size. Now that
the frame size is not zero, correct the offset. Rewrite it in a
way that doesn't depend on hard-coded frame size.
May fix#37127.
Change-Id: I47d6d54fc3499d7d5946c3f6a2dbd24fbd679de1
Reviewed-on: https://go-review.googlesource.com/c/go/+/219118
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
nanotime1 and walltime1 do not preserve BP on linux amd64. Previously, this
did not cause a problem, because nanotime/walltime do preserve the BP. But now
with mid-stack inlining, nanotime/walltime are usually inlined, so BP is not
preserved. So, the BP is now wrong in any function after a call to
nanotime()/walltime() on amd64. That means the frame pointer on the stack can
be wrong for any further function call made after the nanotime() call (notably
runtime.main and various GC functions). [386 doesn't use framepointer.]
Fix is to set a frame size of 8 for nanotime1 and walltime1, which means the
standard prolog/epilog that saves/restore BP in the stack frame is added.
I noticed this while investigating issue 16638 (use frame pointers for
runtime.Callers). This change would needed for progress on that issue (which
doesn't have a high priority). Verified that this fix works/is useful for issue
16638.
Change-Id: I19e19ef2c1a517d737a34928baae034f2eb0b2c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/212079
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
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Linux 5.2 introduced a bug that can corrupt vector registers on return
from a signal if the signal stack isn't faulted in:
https://bugzilla.kernel.org/show_bug.cgi?id=205663
This CL works around this by mlocking the top page of all Go signal
stacks on the affected kernels.
Fixes#35326, #35777
Change-Id: I77c80a2baa4780827633f92f464486caa222295d
Reviewed-on: https://go-review.googlesource.com/c/go/+/209899
Run-TryBot: Austin Clements <austin@google.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Chase <drchase@google.com>
We'll add a test once all of the POSIX platforms are done.
For #10958, #24543.
Change-Id: If7e3f14e8391791364877629bf415d9f8e788b0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/201401
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The internal read and write functions used to return -1 on error;
change them to return a negative errno value instead.
This will be used by later CLs in this series.
For most targets this is a simplification, although for ones that call
into libc it is a complication.
Updates #27707
Change-Id: Id02bf9487f03e7e88e4f2b85e899e986738697ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/171823
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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This requires defining pipe, pipe2, and setNonblock for various platforms.
The new function is currently only used on AIX. It will be used by
later CLs in this series.
Updates #27707
Change-Id: Id2f987b66b4c66a3ef40c22484ff1d14f58e9b31
Reviewed-on: https://go-review.googlesource.com/c/go/+/171822
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We're going to need a different TLS offset for Android Q, so the static
offsets used for 386 and amd64 are no longer viable on Android.
Introduce runtime·tls_g and use that for indexing into TLS storage. As
an added benefit, we can then merge the TLS setup code for all android
GOARCHs.
While we're at it, remove a bunch of android special cases no longer
needed.
Updates #29674
Updates #29249 (perhaps fixes it)
Change-Id: I77c7385aec7de8f1f6a4da7c9c79999157e39572
Reviewed-on: https://go-review.googlesource.com/c/go/+/169817
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
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>
On Linux, sysUnused currently uses madvise(MADV_DONTNEED) to signal the
kernel that a range of allocated memory contains unneeded data. After a
successful call, the range (but not the data it contained before the
call to madvise) is still available but the first access to that range
will unconditionally incur a page fault (needed to 0-fill the range).
A faster alternative is MADV_FREE, available since Linux 4.5. The
mechanism is very similar, but the page fault will only be incurred if
the kernel, between the call to madvise and the first access, decides to
reuse that memory for something else.
In sysUnused, test whether MADV_FREE is supported and fall back to
MADV_DONTNEED in case it isn't. This requires making the return value of
the madvise syscall available to the caller, so change runtime.madvise
to return it.
Fixes#23687
Change-Id: I962c3429000dd9f4a00846461ad128b71201bb04
Reviewed-on: https://go-review.googlesource.com/135395
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
raise uses tkill to send a signal to the current thread. For this use,
tgkill is functionally equivalent to tkill expect that it also takes the
pid as the first argument.
Using tgkill makes it simpler to run a Go program in a strict sandbox.
With kill and tgkill, the sandbox policy (e.g., seccomp) can prevent the
program from sending signals to other processes by checking that the
first argument == getpid().
With tkill, the policy must whitelist all tids in the process, which is
effectively impossible given Go's dynamic thread creation.
Fixes#27548
Change-Id: I8ed282ef1f7215b02ef46de144493e36454029ea
Reviewed-on: https://go-review.googlesource.com/133975
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
Ever since we added sleep to the runtime back in 2008, we've
implemented it on GNU/Linux with the select (or pselect or pselect6)
system call. But the Linux kernel has a nanosleep system call,
which should be a tiny bit more efficient since it doesn't have to
check to see whether there are any file descriptors. So use it.
Change-Id: Icc3430baca46b082a4d33f97c6c47e25fa91cb9a
Reviewed-on: https://go-review.googlesource.com/108538
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently if a profiling signal arrives while executing within a VDSO
the profiler will report _ExternalCode, which is needlessly confusing
for a pure Go program. Change the VDSO calling code to record the
caller's PC/SP, so that we can do a traceback from that point. If that
fails for some reason, report _VDSO rather than _ExternalCode, which
should at least point in the right direction.
This adds some instructions to the code that calls the VDSO, but the
slowdown is reasonably negligible:
name old time/op new time/op delta
ClockVDSOAndFallbackPaths/vDSO-8 40.5ns ± 2% 41.3ns ± 1% +1.85% (p=0.002 n=10+10)
ClockVDSOAndFallbackPaths/Fallback-8 41.9ns ± 1% 43.5ns ± 1% +3.84% (p=0.000 n=9+9)
TimeNow-8 41.5ns ± 3% 41.5ns ± 2% ~ (p=0.723 n=10+10)
Fixes#24142
Change-Id: Iacd935db3c4c782150b3809aaa675a71799b1c9c
Reviewed-on: https://go-review.googlesource.com/97315
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This normalizes the Linux code to act like other targets. The size
argument to the rt_sigaction system call is pushed to a single
function, sysSigaction.
This is intended as a simplification step for CL 93875 for #14327.
Change-Id: I594788e235f0da20e16e8a028e27ac8c883907c4
Reviewed-on: https://go-review.googlesource.com/99077
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This was originally C code using names with underscores, which were
retained when the code was rewritten into Go. Change the code to use
Go-like camel case names.
The names that come from the ELF ABI are left unchanged.
Change-Id: I181bc5dd81284c07bc67b7df4635f4734b41d646
Reviewed-on: https://go-review.googlesource.com/98520
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Follow CL 93655 which removed the (commented-out) usage of this
function.
Also remove unused constant _RLIMIT_AS and type rlimit.
Change-Id: Ifb6e6b2104f4c2555269f8ced72bfcae24f5d5e9
Reviewed-on: https://go-review.googlesource.com/94775
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Also order the syscall number list by numerically for mips64x.
Follow-up for CL 92895.
Change-Id: I5f01f8c626132a06160997fce8a2aef0c486bb1c
Reviewed-on: https://go-review.googlesource.com/93616
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently mmap returns an unsafe.Pointer that encodes OS errors as
values less than 4096. In practice this is okay, but it borders on
being really unsafe: for example, the value has to be checked
immediately after return and if stack copying were ever to observe
such a value, it would panic. It's also not remotely idiomatic.
Fix this by making mmap return a separate pointer value and error,
like a normal Go function.
Updates #22218.
Change-Id: Iefd965095ffc82cc91118872753a5d39d785c3a6
Reviewed-on: https://go-review.googlesource.com/71270
Run-TryBot: Austin Clements <austin@google.com>
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>
Matches other architectures by using names for syscalls instead of
numbers directly.
Fixes#20499.
Change-Id: I63d606b0b1fe6fb517fd994a7542a3f38d80dd54
Reviewed-on: https://go-review.googlesource.com/44213
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@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>
Android O black-lists the select system call because its libc, Bionic,
does not use this system call. Replace our use of select with pselect6
(which is allowed) on the platforms that support targeting Android.
linux/arm64 already uses pselect6 because there is no select on arm64,
so only linux/amd64 and linux/arm need changing. pselect6 has been
available since Linux 2.6.16, which is before Go's minimum
requirement.
Fixes#20409.
Change-Id: Ic526b5b259a9e01d2f145a1f4d2e76e8c49ce809
Reviewed-on: https://go-review.googlesource.com/43641
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
On 32-bit architectures (or if we fail to map a 64-bit-style arena),
we try to map the heap arena just above the end of the process image.
While we can accept any address, using lower addresses is preferable
because lower addresses cause us to map less of the heap bitmap.
However, if a program is linked against C code that has global
constructors, those constructors may call brk/sbrk to allocate memory
(e.g., many C malloc implementations do this for small allocations).
The brk also starts just above the process image, so this may adjust
the brk past the beginning of where we want to put the heap arena. In
this case, the kernel will pick a different address for the arena and
it will usually be very high (at least, as these things go in a 32-bit
address space).
Fix this by consulting the current value of the brk and using this in
addition to the end of the process image to compute the initial arena
placement.
This is implemented only on Linux currently, since we have no evidence
that it's an issue on any other OSes.
Fixes#19831.
Change-Id: Id64b45d08d8c91e4f50d92d0339146250b04f2f8
Reviewed-on: https://go-review.googlesource.com/39810
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Michael Pratt
Tobias Klauser
Rhys Hiltner
Cherry Mui
Ian Lance Taylor
Austin Clements
Than McIntosh
Andrei Vagin
cui
Keith Randall
Dan Scales
Elias Naur
Zhou Peng
Jason A. Donenfeld
Chris Ball