liblink, runtime: preliminary support for plan9/amd64
A TLS slot is reserved by _rt0_.*_plan9 as an automatic and
its address (which is static on Plan 9) is saved in the
global _privates symbol. The startup linkage now is exactly
like that from Plan 9 libc, and the way we access g is
exactly as if we'd have used privalloc(2).
Aside from making the code more standard, this change
drastically simplifies it, both for 386 and for amd64, and
makes the Plan 9 code in liblink common for both 386 and
amd64.
The amd64 runtime code was cleared of nxm assumptions, and
now runs on the standard Plan 9 kernel.
Note handling fixes will follow in a separate CL.
LGTM=rsc
R=golang-codereviews, rsc, bradfitz, dave
CC=0intro, ality, golang-codereviews, jas, minux.ma, mischief
https://golang.org/cl/101510049
diff --git a/src/pkg/runtime/sys_plan9_386.s b/src/pkg/runtime/sys_plan9_386.s
index 5a652ab..6a39012 100644
--- a/src/pkg/runtime/sys_plan9_386.s
+++ b/src/pkg/runtime/sys_plan9_386.s
@@ -101,7 +101,7 @@
MOVL BX, g_m(DX)
// Initialize procid from TOS struct.
- // TODO: Be explicit and insert a new MOVL _tos(SB), AX here.
+ MOVL _tos(SB), AX
MOVL 48(AX), AX // procid
MOVL AX, m_procid(BX) // save pid as m->procid
