[PATCH 6/6] Cygwin: cygtls: Prompt system to switch tasks explicitly in lock()

[Takashi Yano]

This patch replaces pause instruction with SwitchToThread() call
in wait loop in lock() to increase the chance to unlock in other
threads.

Addresses: https://cygwin.com/pipermail/cygwin/2024-November/256744.html
Fixes: 61522196c715 ("* Merge in cygwin-64bit-branch.")
Reported-by: Christian Franke <Christian.Franke@t-online.de>
Reviewed-by:
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
---
 winsup/cygwin/scripts/gendef | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/scripts/gendef b/winsup/cygwin/scripts/gendef
index 720325fdd..d1bcc5318 100755
--- a/winsup/cygwin/scripts/gendef
+++ b/winsup/cygwin/scripts/gendef
@@ -115,6 +115,8 @@ EOF
 	.include "tlsoffsets"
 	.text
 
+	.global SwitchToThread
+
 	.seh_proc _sigfe_maybe
 _sigfe_maybe:					# stack is aligned on entry!
 	.seh_endprologue
@@ -334,7 +336,7 @@ _ZN7_cygtls4lockEv:
 	xchgl	%r11d,_cygtls.stacklock_p(%r12)	# try to acquire lock
 	testl   %r11d,%r11d
 	jz	2f
-	pause
+	call	SwitchToThread
 	jmp	1b
 2:	popq	%r12
 	ret
-- 
2.45.1