From a566deace1d96cd517e79227937e3036baca7ee2 Mon Sep 17 00:00:00 2001
From: Akshat Kumar <seed@mail.nanosouffle.net>
Date: Fri, 8 Mar 2013 00:54:44 +0100
Subject: syscall: Plan 9: use lightweight errstr in entersyscall mode

Change 231af8ac63aa (CL 7314062) made runtime.enteryscall()
set m->mcache = nil, which means that we can no longer use
syscall.errstr in syscall.Syscall and syscall.Syscall6, since it
requires a new buffer to be allocated for holding the error string.
Instead, we use pre-allocated per-M storage to hold error strings
from syscalls made while in entersyscall mode, and call
runtime.findnull to calculate the lengths.

Fixes #4994.

R=rsc, rminnich, ality, dvyukov, rminnich, r
CC=golang-dev
https://golang.org/cl/7567043
---
 src/pkg/runtime/runtime.h | 1 +
 1 file changed, 1 insertion(+)

(limited to 'src/pkg/runtime/runtime.h')

diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index e44064f1ae..66bcf603bd 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -320,6 +320,7 @@ struct	M
 #endif
 #ifdef GOOS_plan9
 	int8*		notesig;
+	byte*	errstr;
 #endif
 	SEH*	seh;
 	uintptr	end[];
-- 
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