kbuild: fix up substitutions in makefiles to allow for tristate checker

The tristate checker, like the Makefile.modbuiltin that preceded it,
relies on running the makefiles with some CONFIG_ variables set to
uppercase values ('Y' or 'M').  Large portions of the core build system
assume that these values are lowercase, but we mostly don't care about
those because they are only involved in actual building, and make
tristatecheck doesn't build anything (the parts that do need changing so
that recursion etc still worked were changed as part of the tristate
commit).

But some makefiles that are not part of the core build system also
contain assumptions that CONFIG_ variables are always lowercase (every
one of these was also broken wrt the old modules.builtin machinery, but
now this is part of a verifier, the problems are more obvious).  In most
cases this is just something like

obj-$(subst m,y,$(CONFIG_FOO)) += blah.o

to indicate that blah.o is always built in even if CONFIG_FOO is a
module.  There is a new macro to help this relatively common case, which
should now be rewritten as

obj-$(call always_built_in,$(CONFIG_FOO)) += blah.o

One other case we handle is that in net/dccp where things are built as
modules iff any member of some other set are modular; this is now
handled like so:

obj-$(call module_if_any_modular,$(CONFIG_IP_DCCP)$(CONFIG_IPV6)) += dccp_ipv6.o
dccp_ipv6-$(call module_if_any_modular,$(CONFIG_IP_DCCP)$(CONFIG_IPV6)) := ipv6.o

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>

drivers/Makefile

@@ -159,7 +159,7 @@ obj-$(CONFIG_SOUNDWIRE)		+= soundwire/
 
 # Virtualization drivers
 obj-$(CONFIG_VIRT_DRIVERS)	+= virt/
-obj-$(subst m,y,$(CONFIG_HYPERV))	+= hv/
+obj-$(call always_built_in,$(CONFIG_HYPERV))	+= hv/
 
 obj-$(CONFIG_PM_DEVFREQ)	+= devfreq/
 obj-$(CONFIG_EXTCON)		+= extcon/

drivers/hv/Makefile

@@ -13,4 +13,4 @@ hv_vmbus-$(CONFIG_HYPERV_TESTING)	+= hv_debugfs.o
 hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o
 
 # Code that must be built-in
-obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o
+obj-$(call always_built_in,$(CONFIG_HYPERV)) += hv_common.o

drivers/mmc/Makefile

@@ -4,4 +4,4 @@
 #
 
 obj-$(CONFIG_MMC)		+= core/
-obj-$(subst m,y,$(CONFIG_MMC))	+= host/
+obj-$(call always_built_in,$(CONFIG_MMC))	+= host/

drivers/net/wireless/silabs/wfx/Makefile

@@ -20,6 +20,6 @@ wfx-y := \
 	debug.o
 wfx-$(CONFIG_SPI) += bus_spi.o
 # When CONFIG_MMC == m, append to 'wfx-y' (and not to 'wfx-m')
-wfx-$(subst m,y,$(CONFIG_MMC)) += bus_sdio.o
+wfx-$(call always_built_in,$(CONFIG_MMC)) += bus_sdio.o
 
 obj-$(CONFIG_WFX) += wfx.o

drivers/s390/char/Makefile

@@ -34,7 +34,7 @@ obj-$(CONFIG_SCLP_VT220_TTY) += sclp_vt220.o
 
 obj-$(CONFIG_PCI) += sclp_pci.o
 
-obj-$(subst m,y,$(CONFIG_ZCRYPT)) += sclp_ap.o
+obj-$(call always_built_in,$(CONFIG_ZCRYPT)) += sclp_ap.o
 
 obj-$(CONFIG_VMLOGRDR) += vmlogrdr.o
 obj-$(CONFIG_VMCP) += vmcp.o

drivers/s390/crypto/Makefile

@@ -4,7 +4,7 @@
 #
 
 ap-objs := ap_bus.o ap_card.o ap_queue.o
-obj-$(subst m,y,$(CONFIG_ZCRYPT)) += ap.o
+obj-$(call always_built_in,$(CONFIG_ZCRYPT)) += ap.o
 # zcrypt_api.o and zcrypt_msgtype*.o depend on ap.o
 zcrypt-objs := zcrypt_api.o zcrypt_card.o zcrypt_queue.o
 zcrypt-objs += zcrypt_msgtype6.o zcrypt_msgtype50.o

net/8021q/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for the Linux VLAN layer.
 #
-obj-$(subst m,y,$(CONFIG_VLAN_8021Q))	+= vlan_core.o
+obj-$(call always_built_in,$(CONFIG_VLAN_8021Q))	+= vlan_core.o
 obj-$(CONFIG_VLAN_8021Q)		+= 8021q.o
 
 8021q-y					:= vlan.o vlan_dev.o vlan_netlink.o

net/Makefile

@@ -42,7 +42,7 @@ obj-$(CONFIG_PHONET)		+= phonet/
 ifneq ($(CONFIG_VLAN_8021Q),)
 obj-y				+= 8021q/
 endif
-obj-$(CONFIG_IP_DCCP)		+= dccp/
+obj-$(call always_built_in,$(CONFIG_IP_DCCP)) += dccp/
 obj-$(CONFIG_IP_SCTP)		+= sctp/
 obj-$(CONFIG_RDS)		+= rds/
 obj-$(CONFIG_WIRELESS)		+= wireless/

net/bridge/Makefile

@@ -12,10 +12,10 @@ bridge-y	:= br.o br_device.o br_fdb.o br_forward.o br_if.o br_input.o \
 
 bridge-$(CONFIG_SYSFS) += br_sysfs_if.o br_sysfs_br.o
 
-bridge-$(subst m,y,$(CONFIG_BRIDGE_NETFILTER)) += br_nf_core.o
+bridge-$(call always_built_in,$(CONFIG_BRIDGE_NETFILTER)) += br_nf_core.o
 
 br_netfilter-y := br_netfilter_hooks.o
-br_netfilter-$(subst m,y,$(CONFIG_IPV6)) += br_netfilter_ipv6.o
+br_netfilter-$(call always_built_in,$(CONFIG_IPV6)) += br_netfilter_ipv6.o
 obj-$(CONFIG_BRIDGE_NETFILTER) += br_netfilter.o
 
 bridge-$(CONFIG_BRIDGE_IGMP_SNOOPING) += br_multicast.o br_mdb.o br_multicast_eht.o

net/dccp/Makefile

@@ -17,8 +17,8 @@ dccp-$(CONFIG_IP_DCCP_TFRC_LIB) += ccids/lib/tfrc.o		\
 dccp_ipv4-y := ipv4.o
 
 # build dccp_ipv6 as module whenever either IPv6 or DCCP is a module
-obj-$(subst y,$(CONFIG_IP_DCCP),$(CONFIG_IPV6)) += dccp_ipv6.o
-dccp_ipv6-y := ipv6.o
+obj-$(call module_if_any_modular,$(CONFIG_IP_DCCP)$(CONFIG_IPV6)) += dccp_ipv6.o
+dccp_ipv6-$(call module_if_any_modular,$(CONFIG_IP_DCCP)$(CONFIG_IPV6)) := ipv6.o
 
 obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o
 

net/ipv6/Makefile

@@ -47,7 +47,7 @@ obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o ip6_icmp.o
 obj-$(CONFIG_INET) += output_core.o protocol.o \
 			ip6_offload.o tcpv6_offload.o exthdrs_offload.o
 
-obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
+obj-$(call always_built_in,$(CONFIG_IPV6)) += inet6_hashtables.o
 
 ifneq ($(CONFIG_IPV6),)
 obj-$(CONFIG_NET_UDP_TUNNEL) += ip6_udp_tunnel.o

net/l2tp/Makefile

@@ -8,11 +8,11 @@ obj-$(CONFIG_L2TP) += l2tp_core.o
 CFLAGS_l2tp_core.o += -I$(src)
 
 # Build l2tp as modules if L2TP is M
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_PPPOL2TP)) += l2tp_ppp.o
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip.o
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_V3)) += l2tp_netlink.o
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_ETH)) += l2tp_eth.o
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_DEBUGFS)) += l2tp_debugfs.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_PPPOL2TP))) += l2tp_ppp.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP))) += l2tp_ip.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_V3))) += l2tp_netlink.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_ETH))) += l2tp_eth.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_DEBUGFS))) += l2tp_debugfs.o
 ifneq ($(CONFIG_IPV6),)
-obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip6.o
+obj-$(subst Y,$(CONFIG_L2TP),$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP))) += l2tp_ip6.o
 endif

net/netfilter/Makefile

@@ -6,7 +6,7 @@ nf_conntrack-y	:= nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_exp
 		   nf_conntrack_proto_icmp.o \
 		   nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o
 
-nf_conntrack-$(subst m,y,$(CONFIG_IPV6)) += nf_conntrack_proto_icmpv6.o
+nf_conntrack-$(call always_built_in,$(CONFIG_IPV6)) += nf_conntrack_proto_icmpv6.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMEOUT) += nf_conntrack_timeout.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMESTAMP) += nf_conntrack_timestamp.o
 nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o

net/netlabel/Makefile

@@ -13,4 +13,4 @@ obj-y	+= netlabel_mgmt.o
 # protocol modules
 obj-y	+= netlabel_unlabeled.o
 obj-y	+= netlabel_cipso_v4.o
-obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o
+obj-$(call always_built_in,$(CONFIG_IPV6)) += netlabel_calipso.o

net/sctp/Makefile

@@ -21,4 +21,4 @@ sctp-$(CONFIG_SCTP_DBG_OBJCNT) += objcnt.o
 sctp-$(CONFIG_PROC_FS) += proc.o
 sctp-$(CONFIG_SYSCTL) += sysctl.o
 
-sctp-$(subst m,y,$(CONFIG_IPV6))	+= ipv6.o
+sctp-$(call always_built_in,$(CONFIG_IPV6))	+= ipv6.o

scripts/Kbuild.include

@@ -188,6 +188,21 @@ cmd_and_fixdep =                                                             \
 # and if so will execute $(rule_foo).
 if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
 
+# Usage. $(call always-built-in,CONFIG_VAR)
+# Expands to y if CONFIG_VAR is m, suitable for always-built-in pieces
+# of things that otherwise may be modular.
+always_built_in = $(subst M,Y,$(subst m,y,$(1)))
+
+# Usage, obj-$(call module_if_any_modular,$(CONATENATED)$(CONFIG)$(VARS))
+# Expands to m if any of the concatenated config vars are m, otherwise
+# y if any of them are y, otherwise n
+module_if_any_modular = $(strip \
+    $(if $(findstring m,$(subst M,m,$(1))), \
+        $(if $(findstring M,$(1)),M,m), \
+        $(if $(findstring y,$(subst Y,y,$(1))), \
+            $(if $(findstring Y,$(1)),Y,y), \
+            $(if $(findstring N,$(1)),N,n))))
+
 ###
 # why - tell why a target got built
 #       enabled by make V=2