delta/go-git.git/src/runtime/os_linux.go, branch dev.inline

runtime: fall back to /proc/self/auxv in Android libs

2016-11-29T15:27:53+00:00

Android's libc doesn't provide access to auxv, so currently the Go
runtime synthesizes a fake, minimal auxv when loaded as a library on
Android. This used to be sufficient, but now we depend on auxv to
retrieve the system physical page size and panic if we can't retrieve
it.

Fix this by falling back to reading auxv from /proc/self/auxv if the
loader-provided auxv is empty and removing the synthetic auxv vectors.

Fixes #18041.

Change-Id: Ia2ec2c764a6609331494a5d359032c56cbb83482
Reviewed-on: https://go-review.googlesource.com/33652
Run-TryBot: Austin Clements 
TryBot-Result: Gobot Gobot 
Reviewed-by: David Crawshaw

runtime: extract Linux auxv handling

2016-11-29T15:27:49+00:00

This refactoring is in preparation for handling auxv differently in
Android shared libraries.

Updates #18041.

Change-Id: If0458a309f9c804e7abd0a58b5a224d89f8da257
Reviewed-on: https://go-review.googlesource.com/33651
Run-TryBot: Austin Clements 
TryBot-Result: Gobot Gobot 
Reviewed-by: David Crawshaw

runtime/cgo: use libc for sigaction syscalls when possible

2016-11-16T05:38:38+00:00

This ensures that runtime's signal handlers pass through the TSAN and
MSAN libc interceptors and subsequent calls to the intercepted
sigaction function from C will correctly see them.

Fixes #17753.

Change-Id: I9798bb50291a4b8fa20caa39c02a4465ec40bb8d
Reviewed-on: https://go-review.googlesource.com/33142
Reviewed-by: Ian Lance Taylor 
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot

runtime: get ppc64x ISA level and hardware capabilities from HWCAP/HWCAP2

2016-11-01T13:41:04+00:00

This implements a check that can be done at runtime for the ISA level and
hardware capability. It follows the same implementation as in s390x.

These checks will be important as we enable new instructions and write go
asm implementations using those.

Updates #15403
Fixes #16643

Change-Id: Idfee374a3ffd7cf13a7d8cf0a6c83d247d3bee16
Reviewed-on: https://go-review.googlesource.com/32330
Reviewed-by: Lynn Boger 
Reviewed-by: Brad Fitzpatrick 
Run-TryBot: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot

runtime: get s390x vector facility availability from AT_HWCAP

2016-10-19T21:50:13+00:00

This is a more robust method for obtaining the availability of vx.
Since this variable may be checked frequently I've also now
padded it so that it will be in its own cache line.

I've kept the other check (in hash/crc32) the same for now until
I can figure out the best way to update it.

Updates #15403.

Change-Id: I74eed651afc6f6a9c5fa3b88fa6a2b0c9ecf5875
Reviewed-on: https://go-review.googlesource.com/31149
Reviewed-by: Austin Clements

runtime: don't call cgocallback from signal handler

2016-10-05T13:21:49+00:00

Calling cgocallback from a signal handler can fail when using the race
detector. Calling cgocallback will lead to a call to newextram which
will call oneNewExtraM which will call racegostart. The racegostart
function will set up some race detector data structures, and doing that
will sometimes call the C memory allocator. If we are running the signal
handler from a signal that interrupted the C memory allocator, we will
crash or hang.

Instead, change the signal handler code to call needm and dropm. The
needm function will grab allocated m and g structures and initialize the
g to use the current stack--the signal stack. That is all we need to
safely call code that allocates memory and checks whether it needs to
split the stack. This may temporarily leave us with no m available to
run a cgo callback, but that is OK in this case since the code we call
will quickly either crash or call dropm to return the m.

Implementing this required changing some of the setSignalstackSP
functions to avoid a write barrier. These functions never need a write
barrier but in some cases generated one anyhow because on some systems
the ss_sp field is a pointer.

Change-Id: I3893f47c3a66278f85eab7f94c1ab11d4f3be133
Reviewed-on: https://go-review.googlesource.com/30218
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Dmitry Vyukov

runtime: minor simplifications to signal code

2016-09-28T13:12:47+00:00

Change setsig, setsigstack, getsig, raise, raiseproc to take uint32 for
signal number parameter, as that is the type mostly used for signal
numbers.  Same for dieFromSignal, sigInstallGoHandler, raisebadsignal.

Remove setsig restart parameter, as it is always either true or
irrelevant.

Don't check the handler in setsigstack, as the only caller does that
anyhow.

Don't bother to convert the handler from sigtramp to sighandler in
getsig, as it will never be called when the handler is sigtramp or
sighandler.

Don't check the return value from rt_sigaction in the GNU/Linux version
of setsigstack; no other setsigstack checks it, and it never fails.

Change-Id: I6bbd677e048a77eddf974dd3d017bc3c560fbd48
Reviewed-on: https://go-review.googlesource.com/29953
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick

runtime: unify Unix implementations of unminit

2016-09-26T19:33:26+00:00

Change-Id: I2cbb13eb85876ad05a52cbd498a9b86e7a28899c
Reviewed-on: https://go-review.googlesource.com/29772
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick

runtime: merge setting new signal mask in minit

2016-09-26T18:29:32+00:00

All the variants that sets the new signal mask in minit do the same
thing, so merge them. This requires an OS-specific sigdelset function;
the function already exists for linux, and is now added for other OS's.

Change-Id: Ie96f6f02e2cf09c43005085985a078bd9581f670
Reviewed-on: https://go-review.googlesource.com/29771
Run-TryBot: Ian Lance Taylor 
Reviewed-by: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot

runtime: unify sigtrampgo

2016-09-26T17:22:42+00:00

Combine the various versions of sigtrampgo into a single function in
signal_unix.go. This requires defining a fixsigcode method on sigctxt
for all operating systems; it only does something on Darwin. This also
requires changing the darwin/amd64 signal handler to call sigreturn
itself, rather than relying on sigtrampgo to call sigreturn for it. We
can then drop the Darwin sigreturn function, as it is no longer used.

Change-Id: I5a0b9d2d2c141957e151b41e694efeb20e4b4b9a
Reviewed-on: https://go-review.googlesource.com/29761
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick