On Windows, page walking is known as __chkstk.

Reviewed-by: NAndy Polyakov <appro@openssl.org>

crypto/bn/asm/x86-mont.pl

@@ -88,6 +88,8 @@ $frame=32;				# size of above frame rounded up to 16n
 
 	&and	("esp",-64);		# align to cache line
 
+	# An OS-agnostic version of __chkstk.
+	#
 	# Some OSes (Windows) insist on stack being "wired" to
 	# physical memory in strictly sequential manner, i.e. if stack
 	# allocation spans two pages, then reference to farmost one can

crypto/bn/asm/x86_64-mont.pl

@@ -130,6 +130,8 @@ $code.=<<___;
 
 	mov	%r11,8(%rsp,$num,8)	# tp[num+1]=%rsp
 .Lmul_body:
+	# An OS-agnostic version of __chkstk.
+	#
 	# Some OSes (Windows) insist on stack being "wired" to
 	# physical memory in strictly sequential manner, i.e. if stack
 	# allocation spans two pages, then reference to farmost one can

crypto/bn/asm/x86_64-mont5.pl

@@ -115,6 +115,8 @@ $code.=<<___;
 
 	mov	%rax,8(%rsp,$num,8)	# tp[num+1]=%rsp
 .Lmul_body:
+	# An OS-agnostic version of __chkstk.
+	#
 	# Some OSes (Windows) insist on stack being "wired" to
 	# physical memory in strictly sequential manner, i.e. if stack
 	# allocation spans two pages, then reference to farmost one can