commit 6965b01ea248cabb70c3749fd218b36089a21efb
author Alex Brainman <alex.brainman@gmail.com> Sat Nov 21 14:56:26 2020 +1100
committer Alex Brainman <alex.brainman@gmail.com> Tue Nov 24 07:07:06 2020 +0000
tree b066decdff387f9a8ac59fa04cbd1cb6042ea7ad
parent 7dc5d909fb465345bf1583eb978aaa56ca365f38

runtime: allow for usleep2HighRes to run without TLS setup

This change adjusts usleep2HighRes so it does not crash when TLS is
not configured. When g is not available, usleep2HighRes just calls
usleep2 instead.

Updates #8687

Change-Id: Idbb80f7b71d1da350a6a7df7c49154eb1ffe29a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/271907
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Simon Rozman <simon@rozman.si>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Trust: Alex Brainman <alex.brainman@gmail.com>

src/runtime/sys_windows_386.s

diff --git a/src/runtime/sys_windows_386.s b/src/runtime/sys_windows_386.s
index 2e5e828..ef8a3dd 100644
--- a/src/runtime/sys_windows_386.s
+++ b/src/runtime/sys_windows_386.s
@@ -415,12 +415,15 @@
 
 // Runs on OS stack. duration (in 100ns units) is in BX.
 TEXT runtime·usleep2HighRes(SB),NOSPLIT,$36
+	get_tls(CX)
+	CMPL	CX, $0
+	JE	gisnotset
+
 	// Want negative 100ns units.
 	NEGL	BX
 	MOVL	$-1, hi-4(SP)
 	MOVL	BX, lo-8(SP)
 
-	get_tls(CX)
 	MOVL	g(CX), CX
 	MOVL	g_m(CX), CX
 	MOVL	(m_mOS+mOS_highResTimer)(CX), CX
@@ -449,6 +452,12 @@
 
 	RET
 
+gisnotset:
+	// TLS is not configured. Call usleep2 instead.
+	MOVL	$runtime·usleep2(SB), AX
+	CALL	AX
+	RET
+
 // Runs on OS stack.
 TEXT runtime·switchtothread(SB),NOSPLIT,$0
 	MOVL	SP, BP

src/runtime/sys_windows_amd64.s

diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s
index e9ec99a..d1690ca 100644
--- a/src/runtime/sys_windows_amd64.s
+++ b/src/runtime/sys_windows_amd64.s
@@ -454,11 +454,14 @@
 
 // Runs on OS stack. duration (in 100ns units) is in BX.
 TEXT runtime·usleep2HighRes(SB),NOSPLIT|NOFRAME,$72
+	get_tls(CX)
+	CMPQ	CX, $0
+	JE	gisnotset
+
 	MOVQ	SP, AX
 	ANDQ	$~15, SP	// alignment as per Windows requirement
 	MOVQ	AX, 64(SP)
 
-	get_tls(CX)
 	MOVQ	g(CX), CX
 	MOVQ	g_m(CX), CX
 	MOVQ	(m_mOS+mOS_highResTimer)(CX), CX	// hTimer
@@ -484,6 +487,12 @@
 	MOVQ	64(SP), SP
 	RET
 
+gisnotset:
+	// TLS is not configured. Call usleep2 instead.
+	MOVQ	$runtime·usleep2(SB), AX
+	CALL	AX
+	RET
+
 // Runs on OS stack.
 TEXT runtime·switchtothread(SB),NOSPLIT|NOFRAME,$0
 	MOVQ	SP, AX