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141e3d8b59
- patch-syscall Use SYSCALL assembly instead of INT 0x80 for syscalls on amd64. Using INT 0x80 as syscall gate on amd64 is an accidential and undocumented feature of COMPAT_FREEBSD32. It allows to use 64-bit ABI, but run syscalls through i386 gate. Go used this "feature" to workaround a bug in FreeBSD 8, which is no longer relevant. The patch is exact e9ce76b0eca8fa95dddb90b0a72aadab58de2ffc from go repo. Now lang/go14 doesn't need COMPAT_FREEBSD32 to build and run. - patch-pipe2 The pipe2 syscall is present in all supported versions of FreeBSD, but pipe was removed from FreeBSD 11. With the patch go14 can be built and run on a system without COMPAT_FREEBSD10. Reviewed by: jlaffaye
48 lines
2.2 KiB
Text
48 lines
2.2 KiB
Text
--- src/runtime/sys_freebsd_amd64.s.orig 2017-03-17 20:08:29.000000000 +0000
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+++ src/runtime/sys_freebsd_amd64.s 2017-03-17 20:08:29.000000000 +0000
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@@ -9,31 +9,6 @@
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#include "zasm_GOOS_GOARCH.h"
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#include "textflag.h"
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-// FreeBSD 8, FreeBSD 9, and older versions that I have checked
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-// do not restore R10 on exit from a "restarted" system call
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-// if you use the SYSCALL instruction. This means that, for example,
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-// if a signal arrives while the wait4 system call is executing,
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-// the wait4 internally returns ERESTART, which makes the kernel
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-// back up the PC to execute the SYSCALL instruction a second time.
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-// However, since the kernel does not restore R10, the fourth
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-// argument to the system call has been lost. (FreeBSD 9 also fails
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-// to restore the fifth and sixth arguments, R8 and R9, although
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-// some earlier versions did restore those correctly.)
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-// The broken code is in fast_syscall in FreeBSD's amd64/amd64/exception.S.
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-// It restores only DI, SI, DX, AX, and RFLAGS on system call return.
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-// http://fxr.watson.org/fxr/source/amd64/amd64/exception.S?v=FREEBSD91#L399
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-//
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-// The INT $0x80 system call path (int0x80_syscall in FreeBSD's
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-// amd64/ia32/ia32_exception.S) does not have this problem,
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-// but it expects the third argument in R10. Instead of rewriting
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-// all the assembly in this file, #define SYSCALL to a safe simulation
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-// using INT $0x80.
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-//
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-// INT $0x80 is a little slower than SYSCALL, but correctness wins.
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-//
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-// See golang.org/issue/6372.
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-#define SYSCALL MOVQ R10, CX; INT $0x80
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-
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TEXT runtime·sys_umtx_op(SB),NOSPLIT,$0
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MOVQ addr+0(FP), DI
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MOVL mode+8(FP), SI
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--- src/syscall/asm_freebsd_amd64.s.orig 2017-03-17 20:20:07.000000000 +0000
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+++ src/syscall/asm_freebsd_amd64.s 2017-03-17 20:20:07.000000000 +0000
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@@ -12,11 +12,6 @@
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// System call support for AMD64, FreeBSD
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//
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-// The SYSCALL variant for invoking system calls is broken in FreeBSD.
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-// See comment at top of ../runtime/sys_freebsd_amd64.c and
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-// golang.org/issue/6372.
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-#define SYSCALL MOVQ R10, CX; INT $0x80
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-
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// func Syscall(trap int64, a1, a2, a3 int64) (r1, r2, err int64);
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// func Syscall6(trap int64, a1, a2, a3, a4, a5, a6 int64) (r1, r2, err int64);
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// func Syscall9(trap int64, a1, a2, a3, a4, a5, a6, a7, a8, a9 int64) (r1, r2, err int64)
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