s390: remove 31 bit support

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kbuild

@@ -4,6 +4,5 @@ obj-$(CONFIG_KVM)		+= kvm/
 obj-$(CONFIG_CRYPTO_HW)		+= crypto/
 obj-$(CONFIG_S390_HYPFS_FS)	+= hypfs/
 obj-$(CONFIG_APPLDATA_BASE)	+= appldata/
-obj-$(CONFIG_MATHEMU)		+= math-emu/
 obj-y				+= net/
 obj-$(CONFIG_PCI)		+= pci/

arch/s390/Kconfig

@@ -35,7 +35,7 @@ config GENERIC_BUG_RELATIVE_POINTERS
 	def_bool y
 
 config ARCH_DMA_ADDR_T_64BIT
-	def_bool 64BIT
+	def_bool y
 
 config GENERIC_LOCKBREAK
 	def_bool y if SMP && PREEMPT
@@ -59,7 +59,7 @@ config PCI_QUIRKS
 	def_bool n
 
 config ARCH_SUPPORTS_UPROBES
-	def_bool 64BIT
+	def_bool y
 
 config S390
 	def_bool y
@@ -110,19 +110,19 @@ config S390
 	select GENERIC_TIME_VSYSCALL
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 	select HAVE_ARCH_AUDITSYSCALL
-	select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
+	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
-	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
-	select HAVE_BPF_JIT if 64BIT && PACK_STACK
+	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_BPF_JIT if PACK_STACK
 	select HAVE_CMPXCHG_DOUBLE
 	select HAVE_CMPXCHG_LOCAL
 	select HAVE_DEBUG_KMEMLEAK
-	select HAVE_DYNAMIC_FTRACE if 64BIT
-	select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT
+	select HAVE_DYNAMIC_FTRACE
+	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_FTRACE_MCOUNT_RECORD
-	select HAVE_FUNCTION_GRAPH_TRACER if 64BIT
-	select HAVE_FUNCTION_TRACER if 64BIT
+	select HAVE_FUNCTION_GRAPH_TRACER
+	select HAVE_FUNCTION_TRACER
 	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_KERNEL_BZIP2
 	select HAVE_KERNEL_GZIP
@@ -132,7 +132,7 @@ config S390
 	select HAVE_KERNEL_XZ
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
-	select HAVE_KVM if 64BIT
+	select HAVE_KVM
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_MEMBLOCK_PHYS_MAP
@@ -141,7 +141,6 @@ config S390
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_SYSCALL_TRACEPOINTS
-	select HAVE_UID16 if 32BIT
 	select HAVE_VIRT_CPU_ACCOUNTING
 	select MODULES_USE_ELF_RELA
 	select NO_BOOTMEM
@@ -190,76 +189,66 @@ config HAVE_MARCH_Z13_FEATURES
 
 choice
 	prompt "Processor type"
-	default MARCH_G5
-
-config MARCH_G5
-	bool "System/390 model G5 and G6"
-	depends on !64BIT
-	help
-	  Select this to build a 31 bit kernel that works
-	  on all ESA/390 and z/Architecture machines.
+	default MARCH_Z900
 
 config MARCH_Z900
 	bool "IBM zSeries model z800 and z900"
-	select HAVE_MARCH_Z900_FEATURES if 64BIT
+	select HAVE_MARCH_Z900_FEATURES
 	help
 	  Select this to enable optimizations for model z800/z900 (2064 and
 	  2066 series). This will enable some optimizations that are not
 	  available on older ESA/390 (31 Bit) only CPUs.
 
 config MARCH_Z990
 	bool "IBM zSeries model z890 and z990"
-	select HAVE_MARCH_Z990_FEATURES if 64BIT
+	select HAVE_MARCH_Z990_FEATURES
 	help
 	  Select this to enable optimizations for model z890/z990 (2084 and
 	  2086 series). The kernel will be slightly faster but will not work
 	  on older machines.
 
 config MARCH_Z9_109
 	bool "IBM System z9"
-	select HAVE_MARCH_Z9_109_FEATURES if 64BIT
+	select HAVE_MARCH_Z9_109_FEATURES
 	help
 	  Select this to enable optimizations for IBM System z9 (2094 and
 	  2096 series). The kernel will be slightly faster but will not work
 	  on older machines.
 
 config MARCH_Z10
 	bool "IBM System z10"
-	select HAVE_MARCH_Z10_FEATURES if 64BIT
+	select HAVE_MARCH_Z10_FEATURES
 	help
 	  Select this to enable optimizations for IBM System z10 (2097 and
 	  2098 series). The kernel will be slightly faster but will not work
 	  on older machines.
 
 config MARCH_Z196
 	bool "IBM zEnterprise 114 and 196"
-	select HAVE_MARCH_Z196_FEATURES if 64BIT
+	select HAVE_MARCH_Z196_FEATURES
 	help
 	  Select this to enable optimizations for IBM zEnterprise 114 and 196
 	  (2818 and 2817 series). The kernel will be slightly faster but will
 	  not work on older machines.
 
 config MARCH_ZEC12
 	bool "IBM zBC12 and zEC12"
-	select HAVE_MARCH_ZEC12_FEATURES if 64BIT
+	select HAVE_MARCH_ZEC12_FEATURES
 	help
 	  Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
 	  2827 series). The kernel will be slightly faster but will not work on
 	  older machines.
 
 config MARCH_Z13
 	bool "IBM z13"
-	select HAVE_MARCH_Z13_FEATURES if 64BIT
+	select HAVE_MARCH_Z13_FEATURES
 	help
 	  Select this to enable optimizations for IBM z13 (2964 series).
 	  The kernel will be slightly faster but will not work on older
 	  machines.
 
 endchoice
 
-config MARCH_G5_TUNE
-	def_bool TUNE_G5 || MARCH_G5 && TUNE_DEFAULT
-
 config MARCH_Z900_TUNE
 	def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
 
@@ -298,9 +287,6 @@ config TUNE_DEFAULT
 	  Tune the generated code for the target processor for which the kernel
 	  will be compiled.
 
-config TUNE_G5
-	bool "System/390 model G5 and G6"
-
 config TUNE_Z900
 	bool "IBM zSeries model z800 and z900"
 
@@ -326,18 +312,10 @@ endchoice
 
 config 64BIT
 	def_bool y
-	prompt "64 bit kernel"
-	help
-	  Select this option if you have an IBM z/Architecture machine
-	  and want to use the 64 bit addressing mode.
-
-config 32BIT
-	def_bool y if !64BIT
 
 config COMPAT
 	def_bool y
 	prompt "Kernel support for 31 bit emulation"
-	depends on 64BIT
 	select COMPAT_BINFMT_ELF if BINFMT_ELF
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION
@@ -376,8 +354,7 @@ config NR_CPUS
 	int "Maximum number of CPUs (2-512)"
 	range 2 512
 	depends on SMP
-	default "32" if !64BIT
-	default "64" if 64BIT
+	default "64"
 	help
 	  This allows you to specify the maximum number of CPUs which this
 	  kernel will support. The maximum supported value is 512 and the
@@ -418,15 +395,6 @@ config SCHED_TOPOLOGY
 
 source kernel/Kconfig.preempt
 
-config MATHEMU
-	def_bool y
-	prompt "IEEE FPU emulation"
-	depends on MARCH_G5
-	help
-	  This option is required for IEEE compliant floating point arithmetic
-	  on older ESA/390 machines. Say Y unless you know your machine doesn't
-	  need this.
-
 source kernel/Kconfig.hz
 
 endmenu
@@ -437,7 +405,6 @@ config ARCH_SPARSEMEM_ENABLE
 	def_bool y
 	select SPARSEMEM_VMEMMAP_ENABLE
 	select SPARSEMEM_VMEMMAP
-	select SPARSEMEM_STATIC if !64BIT
 
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y
@@ -453,7 +420,6 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
 
 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
 	def_bool y
-	depends on 64BIT
 
 config FORCE_MAX_ZONEORDER
 	int
@@ -528,7 +494,6 @@ config QDIO
 
 menuconfig PCI
 	bool "PCI support"
-	depends on 64BIT
 	select HAVE_DMA_ATTRS
 	select PCI_MSI
 	help
@@ -598,7 +563,6 @@ config CHSC_SCH
 
 config SCM_BUS
 	def_bool y
-	depends on 64BIT
 	prompt "SCM bus driver"
 	help
 	  Bus driver for Storage Class Memory.
@@ -620,7 +584,7 @@ menu "Dump support"
 
 config CRASH_DUMP
 	bool "kernel crash dumps"
-	depends on 64BIT && SMP
+	depends on SMP
 	select KEXEC
 	help
 	  Generate crash dump after being started by kexec.
@@ -659,7 +623,7 @@ endmenu
 menu "Power Management"
 
 config ARCH_HIBERNATION_POSSIBLE
-	def_bool y if 64BIT
+	def_bool y
 
 source "kernel/power/Kconfig"
 
@@ -810,7 +774,6 @@ source "arch/s390/kvm/Kconfig"
 config S390_GUEST
 	def_bool y
 	prompt "s390 support for virtio devices"
-	depends on 64BIT
 	select TTY
 	select VIRTUALIZATION
 	select VIRTIO

arch/s390/Makefile

@@ -13,15 +13,6 @@
 # Copyright (C) 1994 by Linus Torvalds
 #
 
-ifndef CONFIG_64BIT
-LD_BFD		:= elf32-s390
-LDFLAGS		:= -m elf_s390
-KBUILD_CFLAGS	+= -m31
-KBUILD_AFLAGS	+= -m31
-UTS_MACHINE	:= s390
-STACK_SIZE	:= 8192
-CHECKFLAGS	+= -D__s390__ -msize-long
-else
 LD_BFD		:= elf64-s390
 LDFLAGS		:= -m elf64_s390
 KBUILD_AFLAGS_MODULE += -fPIC
@@ -31,11 +22,9 @@ KBUILD_AFLAGS	+= -m64
 UTS_MACHINE	:= s390x
 STACK_SIZE	:= 16384
 CHECKFLAGS	+= -D__s390__ -D__s390x__
-endif
 
 export LD_BFD
 
-mflags-$(CONFIG_MARCH_G5)     := -march=g5
 mflags-$(CONFIG_MARCH_Z900)   := -march=z900
 mflags-$(CONFIG_MARCH_Z990)   := -march=z990
 mflags-$(CONFIG_MARCH_Z9_109) := -march=z9-109
@@ -47,7 +36,6 @@ mflags-$(CONFIG_MARCH_Z13)   := -march=z13
 aflags-y += $(mflags-y)
 cflags-y += $(mflags-y)
 
-cflags-$(CONFIG_MARCH_G5_TUNE)		+= -mtune=g5
 cflags-$(CONFIG_MARCH_Z900_TUNE)	+= -mtune=z900
 cflags-$(CONFIG_MARCH_Z990_TUNE)	+= -mtune=z990
 cflags-$(CONFIG_MARCH_Z9_109_TUNE)	+= -mtune=z9-109
@@ -104,7 +92,7 @@ KBUILD_AFLAGS	+= $(aflags-y)
 OBJCOPYFLAGS	:= -O binary
 
 head-y		:= arch/s390/kernel/head.o
-head-y		+= arch/s390/kernel/$(if $(CONFIG_64BIT),head64.o,head31.o)
+head-y		+= arch/s390/kernel/head64.o
 
 # See arch/s390/Kbuild for content of core part of the kernel
 core-y		+= arch/s390/
@@ -129,9 +117,7 @@ zfcpdump:
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
 vdso_install:
-ifeq ($(CONFIG_64BIT),y)
 	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso64 $@
-endif
 	$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso32 $@
 
 archclean:

arch/s390/boot/compressed/Makefile

@@ -4,13 +4,11 @@
 # create a compressed vmlinux image from the original vmlinux
 #
 
-BITS := $(if $(CONFIG_64BIT),64,31)
-
 targets	:= vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2
 targets += vmlinux.bin.xz vmlinux.bin.lzma vmlinux.bin.lzo vmlinux.bin.lz4
-targets += misc.o piggy.o sizes.h head$(BITS).o
+targets += misc.o piggy.o sizes.h head64.o
 
-KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
+KBUILD_CFLAGS := -m64 -D__KERNEL__ $(LINUX_INCLUDE) -O2
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
 KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks
 KBUILD_CFLAGS += $(call cc-option,-mpacked-stack)
@@ -19,7 +17,7 @@ KBUILD_CFLAGS += $(call cc-option,-ffreestanding)
 GCOV_PROFILE := n
 
 OBJECTS := $(addprefix $(objtree)/arch/s390/kernel/, head.o sclp.o ebcdic.o)
-OBJECTS += $(obj)/head$(BITS).o $(obj)/misc.o $(obj)/piggy.o
+OBJECTS += $(obj)/head64.o $(obj)/misc.o $(obj)/piggy.o
 
 LDFLAGS_vmlinux := --oformat $(LD_BFD) -e startup -T
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(OBJECTS)
@@ -34,8 +32,8 @@ quiet_cmd_sizes = GEN $@
 $(obj)/sizes.h: vmlinux
 	$(call if_changed,sizes)
 
-AFLAGS_head$(BITS).o += -I$(obj)
-$(obj)/head$(BITS).o: $(obj)/sizes.h
+AFLAGS_head64.o += -I$(obj)
+$(obj)/head64.o: $(obj)/sizes.h
 
 CFLAGS_misc.o += -I$(obj)
 $(obj)/misc.o: $(obj)/sizes.h