code review 13824044: runtime, syscall: update freebsd/arm calling convention...

runtime, syscall: update freebsd/arm calling convention to match EABI

Fixes issue 6451.

There is still some breakages unrelated to the syscall change.

[root@beaglebone ~/go/src]# /root/go/pkg/tool/freebsd_arm/go_bootstrap version
go version devel freebsd/arm
a std@beaglebone ~/go/src]# /root/go/pkg/tool/freebsd_arm/go_bootstrap install - 
fatal error: mark - finalizer inconsistency

runtime stack:
runtime.throw(0x3e80ac)
        /root/go/src/pkg/runtime/panic.c:464 +0x5c
addfinroots(0x2)
        /root/go/src/pkg/runtime/mgc0.c:1501 +0x74
runtime.walkfintab(0x6c200)
        /root/go/src/pkg/runtime/mfinal.c:216 +0xa0
addroots()
        /root/go/src/pkg/runtime/mgc0.c:1561 +0x188
gc(0x50632f78)
        /root/go/src/pkg/runtime/mgc0.c:2098 +0x19c
mgc(0x306170a0)
        /root/go/src/pkg/runtime/mgc0.c:2049 +0x30
runtime.mcall(0x3e97b0)
        /root/go/src/pkg/runtime/asm_arm.s:165 +0x3c

goroutine 1 [garbage collection]:
runtime.gc(0x0)
        /root/go/src/pkg/runtime/mgc0.c:2020 +0x1a0 fp=0x50632f80
runtime.mallocgc(0x680, 0x1b1971, 0x1)
        /root/go/src/pkg/runtime/malloc.goc:143 +0x210 fp=0x50632fbc
----- stack segment boundary -----
cnew(0x1b1970, 0x640, 0x1)
        /root/go/src/pkg/runtime/malloc.goc:718 +0xc4 fp=0x50626110
runtime.cnewarray(0x1b1970, 0x640)
        /root/go/src/pkg/runtime/malloc.goc:731 +0x3c fp=0x50626120
makeslice1(0x1ac6d0, 0x500, 0x640, 0x50626190)
        /root/go/src/pkg/runtime/slice.c:57 +0x50 fp=0x5062612c
growslice1(0x1ac6d0, 0x30714a00, 0x500, 0x500, 0x501, ...)
        /root/go/src/pkg/runtime/slice.c:113 +0x8c fp=0x50626144
runtime.growslice(0x1ac6d0, 0x30714a00, 0x500, 0x500, 0x1, ...)
        /root/go/src/pkg/runtime/slice.c:80 +0x19c fp=0x50626174
go/build.(*importReader).readByte(0x3070d1b0, 0xb384e)
        /root/go/src/pkg/go/build/read.go:43 +0xbc fp=0x506261b4
go/build.(*importReader).peekByte(0x3070d1b0, 0x3070d101, 0x3070d180)
        /root/go/src/pkg/go/build/read.go:89 +0x210 fp=0x506261d0
go/build.readComments(0x203e2560, 0x306f79a8, 0x306f79a8, 0x203e2560, 0x306f79a8, ...)
        /root/go/src/pkg/go/build/read.go:194 +0x84 fp=0x506261f4
go/build.(*Context).matchFile(0x3e9730, 0x306209c0, 0x13, 0x306c42b4, 0x5, ...)
        /root/go/src/pkg/go/build/build.go:812 +0x74c fp=0x5062629c
go/build.(*Context).Import(0x3e9730, 0x1f95c8, 0x1, 0x30620960, 0x13, ...)
        /root/go/src/pkg/go/build/build.go:580 +0xd64 fp=0x506268dc
go/build.(*Context).ImportDir(0x3e9730, 0x30620960, 0x13, 0x0, 0x24d901, ...)
        /root/go/src/pkg/go/build/build.go:397 +0x5c fp=0x50626904
main.func·021(0x30620960, 0x13, 0x203e2200, 0x30680330, 0x0, ...)
        /root/go/src/cmd/go/main.go:521 +0x2cc fp=0x5062696c
path/filepath.walk(0x30620960, 0x13, 0x203e2200, 0x30680330, 0x50626ae8, ...)
        /root/go/src/pkg/path/filepath/path.go:341 +0x5c fp=0x506269d8
path/filepath.walk(0x3067e720, 0x11, 0x203e2200, 0x30680210, 0x50626ae8, ...)
        /root/go/src/pkg/path/filepath/path.go:359 +0x308 fp=0x50626a44
path/filepath.Walk(0x3067e720, 0x11, 0x50626ae8, 0x1f9728, 0x1)
        /root/go/src/pkg/path/filepath/path.go:380 +0xb4 fp=0x50626a68
main.matchPackages(0xbfffedea, 0x3, 0x1b1190, 0x3067e600, 0x10)
        /root/go/src/cmd/go/main.go:530 +0x2c0 fp=0x50626b1c
main.allPackages(0xbfffedea, 0x3, 0x1fadc8, 0x3, 0x1)
        /root/go/src/cmd/go/main.go:474 +0x34 fp=0x50626b70
main.importPathsNoDotExpansion(0x30620018, 0x1, 0x1, 0x0, 0xffffffff, ...)
        /root/go/src/cmd/go/main.go:305 +0x2f8 fp=0x50626c04
main.importPaths(0x30620018, 0x1, 0x1, 0x3, 0x0, ...)
        /root/go/src/cmd/go/main.go:315 +0x44 fp=0x50626c88
main.packagesAndErrors(0x30620018, 0x1, 0x1, 0x50626d60, 0x90f44, ...)
        /root/go/src/cmd/go/pkg.go:798 +0x1bc fp=0x50626d1c
main.packagesForBuild(0x30620018, 0x1, 0x1, 0x53490, 0x0, ...)
        /root/go/src/cmd/go/pkg.go:818 +0x44 fp=0x50626dac
main.runInstall(0x3e46e0, 0x30620018, 0x1, 0x1)
        /root/go/src/cmd/go/build.go:311 +0x48 fp=0x50626e60
main.main()
        /root/go/src/cmd/go/main.go:161 +0x518 fp=0x50626f8c
runtime.main()
        /root/go/src/pkg/runtime/proc.c:222 +0x100 fp=0x50626fc0
runtime.goexit()
        /root/go/src/pkg/runtime/proc.c:1396 fp=0x50626fc0

goroutine 3 [syscall]:
os/signal.loop()
        /root/go/src/pkg/os/signal/signal_unix.go:21 +0x24
created by os/signal.init·1
        /root/go/src/pkg/os/signal/signal_unix.go:27 +0x48

[minux1, 2013-09-23 06:05:46]

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
File src/pkg/runtime/sys_freebsd_arm.s (right):

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:134: MOVW 8(FP), R2	// TODO(dfc) what is this
one ?
i think we can remove this line.

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:166: // TODO(dfc) this looks differnt to
sys_linux_arm, why ?
the linux version just blindly assumes the high 32-bit is zero.
we might need to fix it after year 2038 ;-).

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:252: MOVW $SYS_mmap, R7
did you try still passing the arg 5 and 6 on stack?

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:312: SWI $0
same. after reading freebsd libc source, i suspect the 5th argument and beyond
are still passed on stack.

[dave_cheney.net, 2013-09-23 06:16:55]

Thanks for your feedback

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
File src/pkg/runtime/sys_freebsd_arm.s (right):

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:134: MOVW 8(FP), R2	// TODO(dfc) what is this
one ?
On 2013/09/23 06:05:46, minux wrote:
> i think we can remove this line.

Done.

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:166: // TODO(dfc) this looks differnt to
sys_linux_arm, why ?
On 2013/09/23 06:05:46, minux wrote:
> the linux version just blindly assumes the high 32-bit is zero.
> we might need to fix it after year 2038 ;-).

ok, not touching that for the moment

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:252: MOVW $SYS_mmap, R7
On 2013/09/23 06:05:46, minux wrote:
> did you try still passing the arg 5 and 6 on stack?

I think arg 5 is valid in R4 as it is a 32bit quantity, but offset is a 64bit
quantity so has to be passed in the first even register pair, which would be
R6/R7, but R7 is the trap number.

What makes me more concerned is what is here now is exactly how linux/arm's
mmap2 call works, or maybe it doesn't work ...

https://codereview.appspot.com/13824044/diff/3001/src/pkg/runtime/sys_freebsd...
src/pkg/runtime/sys_freebsd_arm.s:312: SWI $0
On 2013/09/23 06:05:46, minux wrote:
> same. after reading freebsd libc source, i suspect the 5th argument and beyond
> are still passed on stack.

I'll try reverting this, docs on the EABI syscall convention are scarce.

[rsc, 2013-09-23 20:50:35]

LGTM

Wait for Minux.

[dave_cheney.net, 2013-09-24 00:00:18]

Thanks rsc, this CL isn't ready for submission yet. I'm working on it today with
a hope of getting it submitted and the builder running again. 

> On 24 Sep 2013, at 6:50, rsc@golang.org wrote:
> 
> LGTM
> 
> Wait for Minux.
> 
> 
> https://codereview.appspot.com/13824044/

[dave_cheney.net, 2013-09-24 06:47:10]

Hello minux.ma@gmail.com, rsc@golang.org (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go

[dave_cheney.net, 2013-09-25 23:36:00]

On 2013/09/24 06:47:10, dfc wrote:
> Hello mailto:minux.ma@gmail.com, mailto:rsc@golang.org (cc:
mailto:golang-dev@googlegroups.com),
> 
> I'd like you to review this change to
> https://code.google.com/p/go

@minix, ping

[minux1, 2013-09-26 00:07:44]

i was working on fixing the build breakage, but failed as of now.

LGTM. OK, let's get this in first and then work on fixing the build.

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
File src/pkg/runtime/sys_freebsd_arm.s (right):

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
src/pkg/runtime/sys_freebsd_arm.s:13: #define SYS_BASE 0x0
we don't need this.

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
src/pkg/runtime/sys_freebsd_arm.s:153: // TODO(dfc) this looks differnt to
sys_linux_arm, why ?
do you want to retain the todo?

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
src/pkg/runtime/sys_freebsd_arm.s:240: MOVW R5, 12(R13)
add comment:
// the word at 8(R13) is skipped due to 64-bit argument alignment.

[dave_cheney.net, 2013-09-26 11:29:27]

Thanks for your review. Submitting.

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
File src/pkg/runtime/sys_freebsd_arm.s (right):

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
src/pkg/runtime/sys_freebsd_arm.s:13: #define SYS_BASE 0x0
On 2013/09/26 00:07:44, minux wrote:
> we don't need this.

I'd rather not remove it now in case I make a mistake in the numberings. I'll
take a note to fix it in a followup cl.

https://codereview.appspot.com/13824044/diff/37001/src/pkg/runtime/sys_freebs...
src/pkg/runtime/sys_freebsd_arm.s:153: // TODO(dfc) this looks differnt to
sys_linux_arm, why ?
On 2013/09/26 00:07:44, minux wrote:
> do you want to retain the todo?

No, we don't need that comment :)

[dave_cheney.net, 2013-09-26 11:36:16]

*** Submitted as https://code.google.com/p/go/source/detail?r=dd18f98c9aa5 ***

runtime, syscall: update freebsd/arm calling convention to match EABI

Fixes issue 6451.

There is still some breakages unrelated to the syscall change.

[root@beaglebone ~/go/src]# /root/go/pkg/tool/freebsd_arm/go_bootstrap version
go version devel freebsd/arm
a std@beaglebone ~/go/src]# /root/go/pkg/tool/freebsd_arm/go_bootstrap install -

fatal error: mark - finalizer inconsistency

runtime stack:
runtime.throw(0x3e80ac)
        /root/go/src/pkg/runtime/panic.c:464 +0x5c
addfinroots(0x2)
        /root/go/src/pkg/runtime/mgc0.c:1501 +0x74
runtime.walkfintab(0x6c200)
        /root/go/src/pkg/runtime/mfinal.c:216 +0xa0
addroots()
        /root/go/src/pkg/runtime/mgc0.c:1561 +0x188
gc(0x50632f78)
        /root/go/src/pkg/runtime/mgc0.c:2098 +0x19c
mgc(0x306170a0)
        /root/go/src/pkg/runtime/mgc0.c:2049 +0x30
runtime.mcall(0x3e97b0)
        /root/go/src/pkg/runtime/asm_arm.s:165 +0x3c

goroutine 1 [garbage collection]:
runtime.gc(0x0)
        /root/go/src/pkg/runtime/mgc0.c:2020 +0x1a0 fp=0x50632f80
runtime.mallocgc(0x680, 0x1b1971, 0x1)
        /root/go/src/pkg/runtime/malloc.goc:143 +0x210 fp=0x50632fbc
----- stack segment boundary -----
cnew(0x1b1970, 0x640, 0x1)
        /root/go/src/pkg/runtime/malloc.goc:718 +0xc4 fp=0x50626110
runtime.cnewarray(0x1b1970, 0x640)
        /root/go/src/pkg/runtime/malloc.goc:731 +0x3c fp=0x50626120
makeslice1(0x1ac6d0, 0x500, 0x640, 0x50626190)
        /root/go/src/pkg/runtime/slice.c:57 +0x50 fp=0x5062612c
growslice1(0x1ac6d0, 0x30714a00, 0x500, 0x500, 0x501, ...)
        /root/go/src/pkg/runtime/slice.c:113 +0x8c fp=0x50626144
runtime.growslice(0x1ac6d0, 0x30714a00, 0x500, 0x500, 0x1, ...)
        /root/go/src/pkg/runtime/slice.c:80 +0x19c fp=0x50626174
go/build.(*importReader).readByte(0x3070d1b0, 0xb384e)
        /root/go/src/pkg/go/build/read.go:43 +0xbc fp=0x506261b4
go/build.(*importReader).peekByte(0x3070d1b0, 0x3070d101, 0x3070d180)
        /root/go/src/pkg/go/build/read.go:89 +0x210 fp=0x506261d0
go/build.readComments(0x203e2560, 0x306f79a8, 0x306f79a8, 0x203e2560,
0x306f79a8, ...)
        /root/go/src/pkg/go/build/read.go:194 +0x84 fp=0x506261f4
go/build.(*Context).matchFile(0x3e9730, 0x306209c0, 0x13, 0x306c42b4, 0x5, ...)
        /root/go/src/pkg/go/build/build.go:812 +0x74c fp=0x5062629c
go/build.(*Context).Import(0x3e9730, 0x1f95c8, 0x1, 0x30620960, 0x13, ...)
        /root/go/src/pkg/go/build/build.go:580 +0xd64 fp=0x506268dc
go/build.(*Context).ImportDir(0x3e9730, 0x30620960, 0x13, 0x0, 0x24d901, ...)
        /root/go/src/pkg/go/build/build.go:397 +0x5c fp=0x50626904
main.func·021(0x30620960, 0x13, 0x203e2200, 0x30680330, 0x0, ...)
        /root/go/src/cmd/go/main.go:521 +0x2cc fp=0x5062696c
path/filepath.walk(0x30620960, 0x13, 0x203e2200, 0x30680330, 0x50626ae8, ...)
        /root/go/src/pkg/path/filepath/path.go:341 +0x5c fp=0x506269d8
path/filepath.walk(0x3067e720, 0x11, 0x203e2200, 0x30680210, 0x50626ae8, ...)
        /root/go/src/pkg/path/filepath/path.go:359 +0x308 fp=0x50626a44
path/filepath.Walk(0x3067e720, 0x11, 0x50626ae8, 0x1f9728, 0x1)
        /root/go/src/pkg/path/filepath/path.go:380 +0xb4 fp=0x50626a68
main.matchPackages(0xbfffedea, 0x3, 0x1b1190, 0x3067e600, 0x10)
        /root/go/src/cmd/go/main.go:530 +0x2c0 fp=0x50626b1c
main.allPackages(0xbfffedea, 0x3, 0x1fadc8, 0x3, 0x1)
        /root/go/src/cmd/go/main.go:474 +0x34 fp=0x50626b70
main.importPathsNoDotExpansion(0x30620018, 0x1, 0x1, 0x0, 0xffffffff, ...)
        /root/go/src/cmd/go/main.go:305 +0x2f8 fp=0x50626c04
main.importPaths(0x30620018, 0x1, 0x1, 0x3, 0x0, ...)
        /root/go/src/cmd/go/main.go:315 +0x44 fp=0x50626c88
main.packagesAndErrors(0x30620018, 0x1, 0x1, 0x50626d60, 0x90f44, ...)
        /root/go/src/cmd/go/pkg.go:798 +0x1bc fp=0x50626d1c
main.packagesForBuild(0x30620018, 0x1, 0x1, 0x53490, 0x0, ...)
        /root/go/src/cmd/go/pkg.go:818 +0x44 fp=0x50626dac
main.runInstall(0x3e46e0, 0x30620018, 0x1, 0x1)
        /root/go/src/cmd/go/build.go:311 +0x48 fp=0x50626e60
main.main()
        /root/go/src/cmd/go/main.go:161 +0x518 fp=0x50626f8c
runtime.main()
        /root/go/src/pkg/runtime/proc.c:222 +0x100 fp=0x50626fc0
runtime.goexit()
        /root/go/src/pkg/runtime/proc.c:1396 fp=0x50626fc0

goroutine 3 [syscall]:
os/signal.loop()
        /root/go/src/pkg/os/signal/signal_unix.go:21 +0x24
created by os/signal.init·1
        /root/go/src/pkg/os/signal/signal_unix.go:27 +0x48

R=minux.ma, rsc
CC=golang-dev
https://codereview.appspot.com/13824044