delta/go-git.git/src/runtime/sys_linux_amd64.s, branch dev.go2go

[dev.regabi] runtime: use g register in some assembly functions on AMD64

2021-02-08T18:48:12+00:00

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 
Run-TryBot: Cherry Zhang 
TryBot-Result: Go Bot 
Reviewed-by: Michael Knyszek

[dev.regabi] cmd/compile, runtime: reserve R14 as g registers on AMD64

2021-02-08T16:30:07+00:00

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 
Run-TryBot: Cherry Zhang 
TryBot-Result: Go Bot 
Reviewed-by: Than McIntosh 
Reviewed-by: David Chase

reflect,runtime: use internal ABI for selected ASM routines, attempt 2

2020-10-30T17:41:35+00:00

[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
Trust: Than McIntosh 
Run-TryBot: Than McIntosh 
Reviewed-by: Cherry Zhang 
TryBot-Result: Go Bot

Revert "reflect,runtime: use internal ABI for selected ASM routines"

2020-10-29T15:58:40+00:00

This reverts commit 50af50d136551e2009b2b52e829570536271cdaa.

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 
Run-TryBot: Than McIntosh 
TryBot-Result: Go Bot 
Reviewed-by: Cherry Zhang

reflect,runtime: use internal ABI for selected ASM routines

2020-10-29T15:13:09+00:00

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 
TryBot-Result: Go Bot 
Trust: Than McIntosh 
Reviewed-by: Cherry Zhang

runtime: don't crash if vsyscall and vdso are disabled on x86_64

2020-09-30T05:39:59+00:00

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: 1d133cd30a5dee1fea9aee0fb4ea0b07e0e87f2a
GitHub-Pull-Request: golang/go#41681
Reviewed-on: https://go-review.googlesource.com/c/go/+/257982
Run-TryBot: Tobias Klauser 
TryBot-Result: Go Bot 
Reviewed-by: Ian Lance Taylor 
Reviewed-by: Michael Pratt 
Trust: Michael Pratt

runtime: reduce syscall when call runtime.clone

2020-08-19T00:02:38+00:00

Change-Id: I3ea398fd86aae4c86557dd6fff65d90a6f756890
GitHub-Last-Rev: 4c295388f7b5e6768ffd2530337f78b4c75a9310
GitHub-Pull-Request: golang/go#40392
Reviewed-on: https://go-review.googlesource.com/c/go/+/244626
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Ian Lance Taylor

crypto,internal/bytealg: fix assembly that clobbers BP

2020-08-16T17:05:18+00:00

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 
Reviewed-by: Michael Knyszek 
Reviewed-by: Martin Möhrmann 
TryBot-Result: Gobot Gobot

runtime: revert signal stack mlocking

2020-08-13T02:17:17+00:00

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 
TryBot-Result: Gobot Gobot 
Reviewed-by: Ian Lance Taylor

runtime: make nanotime1 reentrant

2020-08-10T18:06:04+00:00

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 
TryBot-Result: Gobot Gobot 
Reviewed-by: Ian Lance Taylor