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>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Some, but not all, architectures mix in OS-provided random seeds when
initializing the fastrand state. The others have TODOs saying we need
to do the same. Lift that logic up in the architecture-independent
part, and use memhash to mix the seed instead of a simple addition.
Previously, dumping the fastrand state at initialization would yield
something like the following on linux-amd64, where the values in the
first column do not change between runs (as thread IDs are sequential
and always start at 0), and the values in the second column, while
changing every run, are pretty correlated:
first run:
0x0 0x44d82f1c
0x5f356495 0x44f339de
0xbe6ac92a 0x44f91cd8
0x1da02dbf 0x44fd91bc
0x7cd59254 0x44fee8a4
0xdc0af6e9 0x4547a1e0
0x3b405b7e 0x474c76fc
0x9a75c013 0x475309dc
0xf9ab24a8 0x4bffd075
second run:
0x0 0xa63fc3eb
0x5f356495 0xa6648dc2
0xbe6ac92a 0xa66c1c59
0x1da02dbf 0xa671bce8
0x7cd59254 0xa70e8287
0xdc0af6e9 0xa7129d2e
0x3b405b7e 0xa7379e2d
0x9a75c013 0xa7e4c64c
0xf9ab24a8 0xa7ecce07
With this change, we get initial states that appear to be much more
unpredictable, both within the same run as well as between runs:
0x11bddad7 0x97241c63
0x553dacc6 0x2bcd8523
0x62c01085 0x16413d92
0x6f40e9e6 0x7a138de6
0xa4898053 0x70d816f0
0x5ca5b433 0x188a395b
0x62778ca9 0xd462c3b5
0xd6e160e4 0xac9b4bd
0xb9571d65 0x597a981d
Change-Id: Ib22c530157d74200df0083f830e0408fd4aaea58
Reviewed-on: https://go-review.googlesource.com/c/go/+/203439
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The kernel on some Samsung S9+ models reports support for arm64 8.1
atomics, but in reality only some of the cores support them. Go
programs scheduled to cores without support will crash with SIGILL.
This change unconditionally disables the optimization on Android.
A better fix is to precisely detect the offending chipset.
Fixes#28431
Change-Id: I35a1273e5660603824d30ebef2ce7e429241bf1f
Reviewed-on: https://go-review.googlesource.com/c/147377
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The runtime package already imports the internal/cpu package, so there
is no reason for it to use go:linkname comments to refer to
internal/cpu functions and variables. Since internal/cpu is internal,
we can just export those names. Removing the obscurity of go:linkname
outweighs the minor additional complexity added to the internal/cpu API.
Change-Id: Id89951b7f3fc67cd9bce67ac6d01d44a647a10ad
Reviewed-on: https://go-review.googlesource.com/128755
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Go runtime currently only populates hwcap for ppc64 and arm64.
While the interpretation of hwcap is platform specific the hwcap
information is generally available on linux.
Changing the runtime variable name to cpu_hwcap for cpu.hwcap makes it
consistent with the general naming of runtime variables that are linked
to other packages.
Change-Id: I1e1f932a73ed624a219b9298faafbb6355e47ada
Reviewed-on: https://go-review.googlesource.com/94757
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
After CL 104636 the feature flags in internal/cpu are initialized before
alginit and can now be used for aeshash feature detection. Also remove
now unused runtime variables:
x86:
support_ssse3
support_sse42
support_aes
arm64:
support_aes
Change-Id: I2f64198d91750eaf3c6cf2aac6e9e17615811ec8
Reviewed-on: https://go-review.googlesource.com/106015
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
change hash/crc32 package to use cpu package instead of using
runtime internal variables to check crc32 instruction
Change-Id: I8f88d2351bde8ed4e256f9adf822a08b9a00f532
Reviewed-on: https://go-review.googlesource.com/76490
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
The Linux kernel provides 16 bytes of random data via the auxv vector
at startup. Currently we consume this separately on 386, amd64, arm,
and arm64. Now that we have a common auxv parser, handle _AT_RANDOM in
the common path.
Change-Id: Ib69549a1d37e2d07a351cf0f44007bcd24f0d20d
Reviewed-on: https://go-review.googlesource.com/22062
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently several different Linux architectures have separate copies
of the auxv parser. Bring these all together into a single copy of the
parser that calls out to a per-arch handler for each tag/value pair.
This is in preparation for handling common auxv tags in one place.
For #9993.
Change-Id: Iceebc3afad6b4133b70fca7003561ae370445c10
Reviewed-on: https://go-review.googlesource.com/22061
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Fixes#10450
runtime.cputicks is called from runtime.exitsyscall and must not
split the stack. cputicks is implemented in several ways and the
NOSPLIT annotation was missing from a few of these.
Change-Id: I5cbbb4e5888c5d298fe2fef240782d0e49f59af8
Reviewed-on: https://go-review.googlesource.com/8939
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Austin Clements
Carlo Alberto Ferraris
Elias Naur
Ian Lance Taylor
Martin Möhrmann
Meng Zhuo
Fangming.Fang
Mikio Hara
Wei Xiao
Josh Bleecher Snyder
Shenghou Ma
Dave Cheney
Aram Hăvărneanu