From 20d35d5817851df3a6d20e75df2e14a192b94940 Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Mon, 5 Aug 2024 15:19:21 -0600
Subject: [PATCH] loader: Add WITH/WITHOUT_LOADER_PXEBOOT build option

Make it possible to disable pxeboot. This loader will fail to build when
it's too large. When /boot/loader needs to be larger like that, this
options will disable a component whose build will fail. It is an explicit
option rather than implicit when things are too large to force the user to
make the explicit tradeoffs rather than wonder why they have a stale pxeboot
or other odd failure mode.

MFC After:		3 days
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D46212
---
 share/mk/src.opts.mk                       |  1 +
 stand/i386/Makefile                        |  2 +-
 tools/build/options/WITHOUT_LOADER_PXEBOOT | 10 +++++++++
 tools/build/options/WITH_LOADER_PXEBOOT    | 25 ++++++++++++++++++++++
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 tools/build/options/WITHOUT_LOADER_PXEBOOT
 create mode 100644 tools/build/options/WITH_LOADER_PXEBOOT

diff --git a/share/mk/src.opts.mk b/share/mk/src.opts.mk
index d7e246d10396..c10598246639 100644
--- a/share/mk/src.opts.mk
+++ b/share/mk/src.opts.mk
@@ -130,6 +130,7 @@ __DEFAULT_YES_OPTIONS = \
     LOADER_KBOOT \
     LOADER_LUA \
     LOADER_OFW \
+    LOADER_PXEBOOT \
     LOADER_UBOOT \
     LOCALES \
     LOCATE \
diff --git a/stand/i386/Makefile b/stand/i386/Makefile
index a08e956ef4f9..f9aedcc3a008 100644
--- a/stand/i386/Makefile
+++ b/stand/i386/Makefile
@@ -16,7 +16,7 @@ SUBDIR.${MK_LOADER_LUA}+= loader_lua
 SUBDIR.yes+=	loader_simp
 
 # special boot programs, 'self-extracting boot2+loader'
-SUBDIR.yes+=	pxeldr
+SUBDIR.${MK_LOADER_PXEBOOT}+=	pxeldr
 
 SUBDIR.${MK_LOADER_ZFS}+=	zfsboot gptzfsboot
 
diff --git a/tools/build/options/WITHOUT_LOADER_PXEBOOT b/tools/build/options/WITHOUT_LOADER_PXEBOOT
new file mode 100644
index 000000000000..e6b09381884e
--- /dev/null
+++ b/tools/build/options/WITHOUT_LOADER_PXEBOOT
@@ -0,0 +1,10 @@
+Do not build pxeboot on i386/amd64.
+When the pxeboot is too large, or unneeded, it may be disabled with this option.
+See
+.Va WITH_LOADER_PXEBOOT
+for how to adjust the defaults when you need both a larger
+.Pa /boot/loader
+and
+.Pa /boot/pxeboot
+.Pp
+This option only has an effect on x86.
diff --git a/tools/build/options/WITH_LOADER_PXEBOOT b/tools/build/options/WITH_LOADER_PXEBOOT
new file mode 100644
index 000000000000..01d4a0b86a66
--- /dev/null
+++ b/tools/build/options/WITH_LOADER_PXEBOOT
@@ -0,0 +1,25 @@
+Build pxeboot on i386/amd64.
+The PXE Boot loader package needs more space than we may have in the boot loader.
+If you need to increase
+.Va LOADERSIZE
+beyond 500000, then building
+.Xr pxeboot 8
+will fail.
+To allow a larger
+.Va LOADERSIZE
+for some environments, it may be necessary to disable pxeboot builds or adjust
+its defaults.
+You can set the default loader for pxeboot to use independently of the system
+default by setting
+.Va PXEBOOT_DEFAULT_INTERP
+to one of
+.Dq lua ,
+.Dq 4th ,
+or
+.Dq simp .
+The limit on the size of the loader used for
+.Xr pxeboot 8
+can be set independently with
+.Va PXEBOOTSIZE .
+.Pp
+This option only has an effect on x86.