From a0d442c0d8bb6cb7b8f809a4cee243c5cdca8c1e Mon Sep 17 00:00:00 2001
From: "Jonathan T. Looney" <jtl@FreeBSD.org>
Date: Tue, 6 Mar 2018 14:18:45 +0000
Subject: [PATCH] Nudge lld to break the kernel read-only and read-write
 sections into separate 2M pages.  The binutils default for max-page-size and
 common-page-size used to produce this result.  By setting these values, we
 can nudge lld to also separate these sections into separate 2M pages.

Reviewed by:	jhb, kib
Discussed with:	emaste
Sponsored by:	Netflix
Differential Revision:	D14282
---
 sys/conf/kern.pre.mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 18f65e17047..0ddb35b1bb5 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -120,6 +120,10 @@ CFLAGS+=	${CONF_CFLAGS}
 LDFLAGS+=	-Wl,--build-id=sha1
 .endif
 
+.if ${MACHINE_CPUARCH} == "amd64"
+LDFLAGS+=	-Wl,-z max-page-size=2097152 -Wl,-z common-page-size=4096
+.endif
+
 NORMAL_C= ${CC} -c ${CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
 NORMAL_S= ${CC:N${CCACHE_BIN}} -c ${ASM_CFLAGS} ${WERROR} ${.IMPSRC}
 PROFILE_C= ${CC} -c ${CFLAGS} ${WERROR} ${.IMPSRC}