The PowerPC ISA does not have a PC-relative load instruction, which poses
obvious challenges when generating position-independent code. The way the ELFv2
ABI addresses this is to specify that r2 points to a per "module" (shared
library or executable) TOC pointer. Maintaining this pointer requires
cooperation between codegen and the system linker:
* Non-leaf functions leave space on the stack at r1+24 to save the TOC pointer.
* A call to a function that *might* have to go via a PLT stub must be followed
by a nop instruction that the system linker can replace with "ld r1, 24(r1)"
to restore the TOC pointer (only when dynamically linking Go code).
* When calling a function via a function pointer, the address of the function
must be in r12, and the first couple of instructions (the "global entry
point") of the called function use this to derive the address of the TOC
for the module it is in.
* When calling a function that is implemented in the same module, the system
linker adjusts the call to skip over the instructions mentioned above (the
"local entry point"), assuming that r2 is already correctly set.
So this changeset adds the global entry point instructions, sets the metadata so
the system linker knows where the local entry point is, inserts code to save the
TOC pointer at 24(r1), adds a nop after any call not known to be local and copes
with the odd non-local code transfer in the runtime (e.g. the stuff around
jmpdefer). It does not actually compile PIC yet.
Change-Id: I7522e22bdfd2f891745a900c60254fe9e372c854
Reviewed-on: https://go-review.googlesource.com/15967
Reviewed-by: Russ Cox <rsc@golang.org>
PIC code on ppc64le uses R2 as a TOC pointer and when calling a function
through a function pointer must ensure the function pointer is in R12. These
rules are easy enough to follow unconditionally in our assembly, so do that.
Change-Id: Icfc4e47ae5dfbe15f581cbdd785cdeed6e40bc32
Reviewed-on: https://go-review.googlesource.com/15526
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Shared libraries on ppc64le will require a larger minimum stack frame (because
the ABI mandates that the TOC pointer is available at 24(R1)). Part 3 of that
is using a #define in the ppc64 assembly to refer to the size of the fixed
part of the stack (finding all these took me about a week!).
Change-Id: I50f22fe1c47af1ec59da1bd7ea8f84a4750df9b7
Reviewed-on: https://go-review.googlesource.com/15525
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Replace the confusing game where a frame size of $-8 would suppress the
implicit setting up of a stack frame with a nice explicit flag.
The code to set up the function prologue is still a little confusing but better
than it was.
Change-Id: I1d49278ff42c6bc734ebfb079998b32bc53f8d9a
Reviewed-on: https://go-review.googlesource.com/15670
Reviewed-by: Minux Ma <minux@golang.org>
For debuggers and other program inspectors.
Fixes#9914.
Change-Id: I670728cea28c045e6eaba1808c550ee2f34d16ff
Reviewed-on: https://go-review.googlesource.com/11341
Reviewed-by: Austin Clements <austin@google.com>
All of the architectures except ppc64 have only "RET" for the return
mnemonic. ppc64 used to have only "RETURN", but commit cf06ea6
introduced RET as a synonym for RETURN to make ppc64 consistent with
the other architectures. However, that commit was never followed up to
make the code itself consistent by eliminating uses of RETURN.
This commit replaces all uses of RETURN in the ppc64 assembly with
RET.
This was done with
sed -i 's/\<RETURN\>/RET/' **/*_ppc64x.s
plus one manual change to syscall/asm.s.
Change-Id: I3f6c8d2be157df8841d48de988ee43f3e3087995
Reviewed-on: https://go-review.googlesource.com/10672
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Forward signals to signal handlers installed before Go installs its own,
under certain circumstances. In particular, as iant@ suggests, signals are
forwarded iff:
(1) a non-SIG_DFL signal handler existed before Go, and
(2) signal is synchronous (i.e., one of SIGSEGV, SIGBUS, SIGFPE), and
(3a) signal occured on a non-Go thread, or
(3b) signal occurred on a Go thread but in CGo code.
Supported only on Linux, for now.
Change-Id: I403219ee47b26cf65da819fb86cf1ec04d3e25f5
Reviewed-on: https://go-review.googlesource.com/8712
Reviewed-by: Ian Lance Taylor <iant@golang.org>
There is an assumption that the function executed in child thread
created by runtime.close should not return. And different systems
enforce that differently: some exit that thread, some exit the
whole process.
The test TestNewOSProc0 introduced in CL 9161 breaks that assumption,
so we need to adjust the code to only exit the thread should the
called function return.
Change-Id: Id631cb2f02ec6fbd765508377a79f3f96c6a2ed6
Reviewed-on: https://go-review.googlesource.com/9246
Reviewed-by: Dave Cheney <dave@cheney.net>
We initially added clone0 to handle the case when G or M don't exist, but
it turns out that we could have just modified clone. (It also helps that
the function we're invoking in clone0 no longer needs arguments.)
As a side-effect, newosproc0 is now supported on all linux archs.
Change-Id: Ie603af75d8f164310fc16446052d83743961f3ca
Reviewed-on: https://go-review.googlesource.com/9164
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>
I guess we need more builders.
Change-Id: I309e3df7608b9eef9339196fdc50dedf5f9422e4
Reviewed-on: https://go-review.googlesource.com/8434
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
This is Part 2 of the change, see Part 1 here: in https://go-review.googlesource.com/#/c/7692/
Suggested by iant@, we use the library initialization entry point to:
- create a new OS thread and run the "regular" runtime init stack on
that thread
- return immediately from the main (i.e., loader) thread
- at the first CGO invocation, we wait for the runtime initialization
to complete.
The above mechanism is implemented only on linux_amd64. Next step is to
support it on linux_arm. Other platforms don't yet support shared library
compiling/linking, but we intend to use the same strategy there as well.
Change-Id: Ib2c81b1b83bee837134084b75a3beecfb8de6bf4
Reviewed-on: https://go-review.googlesource.com/8094
Run-TryBot: Srdjan Petrovic <spetrovic@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Error detection code copied from syscall, where presumably
we actually do it right.
Note that we throw the errno away. The runtime doesn't use it.
Fixes#10052
Change-Id: I8de77dda6bf287276b137646c26b84fa61554ec8
Reviewed-on: https://go-review.googlesource.com/6571
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Normally, a panic/throw only shows the thread stack for the current thread
and all paused goroutines. Goroutines running on other threads, or other threads
running on their system stacks, are opaque. Change that when GODEBUG=crash,
by passing a SIGQUIT around to all the threads when GODEBUG=crash.
If this works out reasonably well, we might make the SIGQUIT relay part of
the standard panic/throw death, perhaps eliding idle m's.
Change-Id: If7dd354f7f3a6e326d17c254afcf4f7681af2f8b
Reviewed-on: https://go-review.googlesource.com/2811
Reviewed-by: Rick Hudson <rlh@golang.org>
This implements support for calls to and from C in the ppc64 C ABI, as
well as supporting functionality such as an entry point from the
dynamic linker.
Change-Id: I68da6df50d5638cb1a3d3fef773fb412d7bf631a
Reviewed-on: https://go-review.googlesource.com/2009
Reviewed-by: Russ Cox <rsc@golang.org>
