all: add support for FreeBSD / aarch64

[SylvainGarrigues]

Go 1.10 works for me on FreeBSD-CURRENT / arm, but I’d love an arm64 port.

[jsirianni]

I will plus this

[valpackett]

I made an attempt: https://github.com/myfreeweb/go/commit/04a920776cbee1428cb698503e1c99784475cf53
It compiles, and even does some syscalls, but crashes when starting the first thread.

I wonder if it's possible to take my patches to the standard library and use gccgo with them?

[ianlancetaylor]

@myfreeweb Patches like adding build tags here and there are likely the same for gccgo and gc. But gccgo has no equivalent to runtime/sys_freebsd_arm64.s.

[SylvainGarrigues]

Anyone working on this?

[peterjeremy]

I'm also interested in this but haven't looked to see how much effort would be involved.

[bsd-hacker]

I try.

"go version" is work, but src/make.bash not work.

# uname -a
FreeBSD pine64-01.os-hackers.jp 13.0-CURRENT FreeBSD 13.0-CURRENT r340361 GENERIC  arm64
# go version
go version devel +04a920776c Mon Jul 16 19:43:23 2018 +0300 freebsd/arm64

my fixes are,

diff --git a/src/runtime/sys_freebsd_arm64.s b/src/runtime/sys_freebsd_arm64.s
index 887c4a3ef1..d637e21a3a 100644
--- a/src/runtime/sys_freebsd_arm64.s
+++ b/src/runtime/sys_freebsd_arm64.s
@@ -13,7 +13,7 @@
 #define AT_FDCWD -100

 #define CLOCK_REALTIME 0
-#define CLOCK_MONOTONIC 1
+#define CLOCK_MONOTONIC 4

 #define SYS_exit 1
 #define SYS_read 3
@@ -57,27 +57,31 @@ TEXT runtime揃sys_umtx_op(SB),NOSPLIT,$0

 TEXT runtime揃thr_new(SB),NOSPLIT,$0
        MOVD param+0(FP), R0
-       MOVD size+8(FP), R1
-       MOVW $SYS_thr_new, R8
+       MOVW size+8(FP), R1
+       MOVD $SYS_thr_new, R8
        SVC
        MOVW    R0, ret+16(FP)
        RET

 TEXT runtime揃thr_start(SB),NOSPLIT,$0
        // set up g
-       MOVD    R10, g_m(R11)
-       MOVD    R11, g
-       //BL runtime揃stackcheck(SB)
+       MOVD    m_g0(R0), g
+       MOVD    R0, g_m(g)
+       //MOVD  R10, g_m(R11)
+       //MOVD  R11, g
+       //BL runtimestackcheck(SB)
        BL runtime揃mstart(SB)

-       MOVW $2, R8  // crash (not reached)
-       MOVW R8, (R8)
+       MOVD $2, R8  // crash (not reached)
+       MOVD R8, (R8)
        RET

 TEXT runtime揃exit(SB),NOSPLIT|NOFRAME,$0-4
        MOVW    code+0(FP), R0
        MOVD    $SYS_exit, R8
        SVC
+       MOVD    $0, R8
+       MOVD    R8, (R8)
        RET

 // func exitThread(wait *uint32)

[bsd-hacker]

I fix to pass argc/argv.
current diff:

diff --git a/src/runtime/rt0_freebsd_arm64.s b/src/runtime/rt0_freebsd_arm64.s
index db0e16886f..8745e922b8 100644
--- a/src/runtime/rt0_freebsd_arm64.s
+++ b/src/runtime/rt0_freebsd_arm64.s
@@ -5,8 +5,8 @@
 #include "textflag.h"

 TEXT _rt0_arm64_freebsd(SB),NOSPLIT|NOFRAME,$0
-       MOVD    0(RSP), R0      // argc
-       ADD     $8, RSP, R1     // argv
+       ADD     $8, R0, R1      // argv
+       MOVW    0(R0), R0       // argc
        BL      main(SB)

 // When building with -buildmode=c-shared, this symbol is called when the shared
@@ -35,7 +35,7 @@ TEXT _rt0_arm64_freebsd_lib(SB),NOSPLIT,$184
        // Initialize g as null in case of using g later e.g. sigaction in cgo_sigaction.go
        MOVD    ZR, g

-       MOVD    R0, _rt0_arm64_freebsd_lib_argc<>(SB)
+       MOVW    R0, _rt0_arm64_freebsd_lib_argc<>(SB)
        MOVD    R1, _rt0_arm64_freebsd_lib_argv<>(SB)

        // Synchronous initialization.
@@ -82,13 +82,13 @@ restore:
        RET

 TEXT _rt0_arm64_freebsd_lib_go(SB),NOSPLIT,$0
-       MOVD    _rt0_arm64_freebsd_lib_argc<>(SB), R0
+       MOVW    _rt0_arm64_freebsd_lib_argc<>(SB), R0
        MOVD    _rt0_arm64_freebsd_lib_argv<>(SB), R1
        MOVD    $runtime揃rt0_go(SB),R4
        B       (R4)

-DATA _rt0_arm64_freebsd_lib_argc<>(SB)/8, $0
-GLOBL _rt0_arm64_freebsd_lib_argc<>(SB),NOPTR, $8
+DATA _rt0_arm64_freebsd_lib_argc<>(SB)/4, $0
+GLOBL _rt0_arm64_freebsd_lib_argc<>(SB),NOPTR, $4
 DATA _rt0_arm64_freebsd_lib_argv<>(SB)/8, $0
 GLOBL _rt0_arm64_freebsd_lib_argv<>(SB),NOPTR, $8

diff --git a/src/runtime/sys_freebsd_arm64.s b/src/runtime/sys_freebsd_arm64.s
index 887c4a3ef1..e0509457ca 100644
--- a/src/runtime/sys_freebsd_arm64.s
+++ b/src/runtime/sys_freebsd_arm64.s
@@ -13,7 +13,7 @@
 #define AT_FDCWD -100

 #define CLOCK_REALTIME 0
-#define CLOCK_MONOTONIC 1
+#define CLOCK_MONOTONIC 4

 #define SYS_exit 1
 #define SYS_read 3
@@ -56,28 +56,30 @@ TEXT runtime揃sys_umtx_op(SB),NOSPLIT,$0
        RET

 TEXT runtime揃thr_new(SB),NOSPLIT,$0
-       MOVD param+0(FP), R0
-       MOVD size+8(FP), R1
-       MOVW $SYS_thr_new, R8
+       MOVD    param+0(FP), R0
+       MOVW    size+8(FP), R1
+       MOVD    $SYS_thr_new, R8
        SVC
        MOVW    R0, ret+16(FP)
        RET

 TEXT runtime揃thr_start(SB),NOSPLIT,$0
        // set up g
-       MOVD    R10, g_m(R11)
-       MOVD    R11, g
+       MOVD    m_g0(R0), g
+       MOVD    R0, g_m(g)
        //BL runtime揃stackcheck(SB)
        BL runtime揃mstart(SB)

-       MOVW $2, R8  // crash (not reached)
-       MOVW R8, (R8)
+       MOVD    $2, R8  // crash (not reached)
+       MOVD    R8, (R8)
        RET

 TEXT runtime揃exit(SB),NOSPLIT|NOFRAME,$0-4
        MOVW    code+0(FP), R0
        MOVD    $SYS_exit, R8
        SVC
+       MOVD    $0, R8  // crash (not reached)
+       MOVD    R8, (R8)
        RET

 // func exitThread(wait *uint32)