[RFC PATCH 13/13] um: nommu: plug nommu code into build system

[Hajime Tazaki]

Add nommu kernel for um build.  defconfig is also provided.

Signed-off-by: Hajime Tazaki <thehajime at gmail.com>
Signed-off-by: Ricardo Koller <ricarkol at google.com>
---
 arch/um/Kconfig                         | 13 ++++-
 arch/um/configs/x86_64_nommu_defconfig  | 64 +++++++++++++++++++++++++
 arch/um/include/shared/common-offsets.h |  3 ++
 arch/x86/um/Makefile                    | 18 +++++++
 4 files changed, 96 insertions(+), 2 deletions(-)
 create mode 100644 arch/um/configs/x86_64_nommu_defconfig

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index c89575d05021..7e0d4285bd87 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -29,12 +29,15 @@ config UML
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
 	select TRACE_IRQFLAGS_SUPPORT
 	select TTY # Needed for line.c
-	select HAVE_ARCH_VMAP_STACK
+	select HAVE_ARCH_VMAP_STACK if MMU
 	select HAVE_RUST
 	select ARCH_HAS_UBSAN
+	select UACCESS_MEMCPY if !MMU
+	select GENERIC_STRNLEN_USER if !MMU
+	select GENERIC_STRNCPY_FROM_USER if !MMU
 
 config MMU
-	bool
+	bool "MMU-based Paged Memory Management Support"
 	default y
 
 config UML_DMA_EMULATION
@@ -187,8 +190,14 @@ config MAGIC_SYSRQ
 	  The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
 	  unless you really know what this hack does.
 
+config ARCH_FORCE_MAX_ORDER
+	int "Order of maximal physically contiguous allocations"
+	default "10" if MMU
+	default "16" if !MMU
+
 config KERNEL_STACK_ORDER
 	int "Kernel stack size order"
+	default 3 if !MMU
 	default 2 if 64BIT
 	range 2 10 if 64BIT
 	default 1 if !64BIT
diff --git a/arch/um/configs/x86_64_nommu_defconfig b/arch/um/configs/x86_64_nommu_defconfig
new file mode 100644
index 000000000000..c2e0fb546987
--- /dev/null
+++ b/arch/um/configs/x86_64_nommu_defconfig
@@ -0,0 +1,64 @@
+CONFIG_SYSVIPC=y
+CONFIG_POSIX_MQUEUE=y
+CONFIG_NO_HZ=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_BSD_PROCESS_ACCT=y
+CONFIG_IKCONFIG=y
+CONFIG_IKCONFIG_PROC=y
+CONFIG_LOG_BUF_SHIFT=14
+CONFIG_CGROUPS=y
+CONFIG_BLK_CGROUP=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CGROUP_CPUACCT=y
+# CONFIG_PID_NS is not set
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+# CONFIG_MMU is not set
+CONFIG_HOSTFS=y
+CONFIG_MAGIC_SYSRQ=y
+CONFIG_SSL=y
+CONFIG_NULL_CHAN=y
+CONFIG_PORT_CHAN=y
+CONFIG_PTY_CHAN=y
+CONFIG_TTY_CHAN=y
+CONFIG_CON_CHAN="pts"
+CONFIG_SSL_CHAN="pts"
+CONFIG_UML_SOUND=m
+CONFIG_UML_NET=y
+CONFIG_UML_NET_ETHERTAP=y
+CONFIG_UML_NET_TUNTAP=y
+CONFIG_UML_NET_SLIP=y
+CONFIG_UML_NET_DAEMON=y
+CONFIG_UML_NET_MCAST=y
+CONFIG_UML_NET_SLIRP=y
+CONFIG_MODULES=y
+CONFIG_MODULE_UNLOAD=y
+CONFIG_IOSCHED_BFQ=m
+CONFIG_BINFMT_MISC=m
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_BLK_DEV_UBD=y
+CONFIG_BLK_DEV_LOOP=m
+CONFIG_BLK_DEV_NBD=m
+CONFIG_DUMMY=m
+CONFIG_TUN=m
+CONFIG_PPP=m
+CONFIG_SLIP=m
+CONFIG_LEGACY_PTY_COUNT=32
+CONFIG_UML_RANDOM=y
+CONFIG_SOUND=m
+CONFIG_EXT4_FS=y
+CONFIG_REISERFS_FS=y
+CONFIG_QUOTA=y
+CONFIG_AUTOFS_FS=m
+CONFIG_ISO9660_FS=m
+CONFIG_JOLIET=y
+CONFIG_NLS=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_FRAME_WARN=1024
+CONFIG_IPV6=y
diff --git a/arch/um/include/shared/common-offsets.h b/arch/um/include/shared/common-offsets.h
index 579ed946a3a9..85a0e90a34b7 100644
--- a/arch/um/include/shared/common-offsets.h
+++ b/arch/um/include/shared/common-offsets.h
@@ -28,4 +28,7 @@ DEFINE(UML_CONFIG_64BIT, CONFIG_64BIT);
 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
 DEFINE(UML_CONFIG_UML_TIME_TRAVEL_SUPPORT, CONFIG_UML_TIME_TRAVEL_SUPPORT);
 #endif
+#ifdef CONFIG_MMU
+DEFINE(UML_CONFIG_MMU, CONFIG_MMU);
+#endif
 
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index 36e67fc97c22..d0a37634979b 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -32,6 +32,24 @@ obj-y += syscalls_64.o vdso/
 subarch-y = ../lib/csum-partial_64.o ../lib/memcpy_64.o \
 	../lib/memmove_64.o ../lib/memset_64.o
 
+
+# used by zpoline.c to translate syscall/sysenter instructions
+# note: only in x86_64 w/ !CONFIG_MMU
+ifneq ($(CONFIG_MMU),y)
+inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk
+inat_tables_maps = $(srctree)/arch/x86/lib/x86-opcode-map.txt
+quiet_cmd_inat_tables = GEN     $@
+      cmd_inat_tables = $(AWK) -f $(inat_tables_script) $(inat_tables_maps) > $@
+$(obj)/inat-tables.c: $(inat_tables_script) $(inat_tables_maps)
+	$(call cmd,inat_tables)
+targets += inat-tables.c
+$(obj)/../lib/inat.o: $(obj)/inat-tables.c
+subarch-y += ../lib/insn.o ../lib/inat.o
+
+
+obj-y += do_syscall_$(BITS).o entry_$(BITS).o zpoline.o
+endif
+
 endif
 
 subarch-$(CONFIG_MODULES) += ../kernel/module.o
-- 
2.43.0