Commit 42fda663 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: throw out CONFIG_MODE_TT 



This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.

Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a1ff5878

arch/um/Kconfig

+10 −54
Original line number Diff line number Diff line
@@ -62,55 +62,16 @@ config IRQ_RELEASE_METHOD 


menu "UML-specific options"



config MODE_TT

	bool "Tracing thread support (DEPRECATED)"

	default n

	depends on BROKEN

	help

	This option controls whether tracing thread support is compiled

	into UML. This option is largely obsolete, given that skas0 provides

	skas security and performance without needing to patch the host.

	It is safe to say 'N' here; saying 'Y' may cause additional problems

	with the resulting binary even if you run UML in SKAS mode, and running

	in TT mode is strongly *NOT RECOMMENDED*.



config STATIC_LINK

	bool "Force a static link"

	default n

	depends on !MODE_TT

	help

	If CONFIG_MODE_TT is disabled, then this option gives you the ability

	to force a static link of UML.  Normally, if only skas mode is built

	in to UML, it will be linked as a shared binary.  This is inconvenient

	for use in a chroot jail.  So, if you intend to run UML inside a

	chroot, and you disable CONFIG_MODE_TT, you probably want to say Y

	here.

	This option gives you the ability to force a static link of UML.

	Normally, UML is linked as a shared binary.  This is inconvenient for

	use in a chroot jail.  So, if you intend to run UML inside a chroot,

	you probably want to say Y here.

	Additionally, this option enables using higher memory spaces (up to

	2.75G) for UML - disabling CONFIG_MODE_TT and enabling this option leads

	to best results for this.



config KERNEL_HALF_GIGS

	int "Kernel address space size (in .5G units)"

	default "1"

	depends on MODE_TT

	help

        This determines the amount of address space that UML will allocate for

        its own, measured in half Gigabyte units.  The default is 1.

        Change this only if you need to boot UML with an unusually large amount

        of physical memory.



config MODE_SKAS

	bool "Separate Kernel Address Space support" if MODE_TT

	default y

	help

	This option controls whether skas (separate kernel address space)

	support is compiled in.

	Unless you have specific needs to use TT mode (which applies almost only

	to developers), you should say Y here.

	SKAS mode will make use of the SKAS3 patch if it is applied on the host

	(and your UML will run in SKAS3 mode), but if no SKAS patch is applied

	on the host it will run in SKAS0 mode, which is anyway faster than TT

	mode.

	2.75G) for UML.



source "arch/um/Kconfig.arch"

source "mm/Kconfig"
@@ -118,7 +79,7 @@ source "mm/Kconfig" 
config LD_SCRIPT_STATIC

	bool

	default y

	depends on MODE_TT || STATIC_LINK

	depends on STATIC_LINK



config LD_SCRIPT_DYN

	bool
@@ -220,7 +181,7 @@ config SMP 
	bool "Symmetric multi-processing support (EXPERIMENTAL)"

	default n

	#SMP_BROKEN is for x86_64.

	depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))

	depends on EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))

	help

	This option enables UML SMP support.

	It is NOT related to having a real SMP box. Not directly, at least.
@@ -258,11 +219,6 @@ config NEST_LEVEL 
        inside another UML, set CONFIG_NEST_LEVEL to one more than the host

        UML.



        Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to

        greater than one, then the guest UML should have its CONFIG_NEST_LEVEL

        set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.

        Only change this if you are running nested UMLs.



config HIGHMEM

	bool "Highmem support (EXPERIMENTAL)"

	depends on !64BIT && EXPERIMENTAL
@@ -271,9 +227,9 @@ config HIGHMEM 
	This was used to allow UML to run with big amounts of memory.

	Currently it is unstable, so if unsure say N.



	To use big amounts of memory, it is recommended to disable TT mode (i.e.

	CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -

	this should allow the guest to use up to 2.75G of memory.

	To use big amounts of memory, it is recommended enable static

	linking (i.e. CONFIG_STATIC_LINK) - this should allow the

	guest to use up to 2.75G of memory.



config KERNEL_STACK_ORDER

	int "Kernel stack size order"

arch/um/Kconfig.char

+0 −2
Original line number Diff line number Diff line
@@ -65,8 +65,6 @@ config XTERM_CHAN 
        This option enables support for attaching UML consoles and serial

        lines to xterms.  Each UML device so assigned will be brought up in

        its own xterm.

        If you disable this option, then CONFIG_PT_PROXY will be disabled as

        well, since UML's gdb currently requires an xterm.

        It is safe to say 'Y' here.



config NOCONFIG_CHAN

arch/um/Kconfig.debug

+2 −21
Original line number Diff line number Diff line
@@ -2,28 +2,9 @@ menu "Kernel hacking" 


source "lib/Kconfig.debug"



config CMDLINE_ON_HOST

	bool "Show command line arguments on the host in TT mode"

	depends on MODE_TT

	default !DEBUG_INFO

	help

	This controls whether arguments in guest processes should be shown on

	the host's ps output.

	Enabling this option hinders debugging on some recent GDB versions

	(because GDB gets "confused" when we do an execvp()). So probably you

	should disable it.



config PT_PROXY

	bool "Enable ptrace proxy"

	depends on XTERM_CHAN && DEBUG_INFO && MODE_TT

	help

	This option enables a debugging interface which allows gdb to debug

	the kernel without needing to actually attach to kernel threads.

	If you want to do kernel debugging, say Y here; otherwise say N.



config GPROF

	bool "Enable gprof support"

	depends on DEBUG_INFO && MODE_SKAS && !MODE_TT

	depends on DEBUG_INFO

	help

        This allows profiling of a User-Mode Linux kernel with the gprof

        utility.
@@ -36,7 +17,7 @@ config GPROF 


config GCOV

	bool "Enable gcov support"

	depends on DEBUG_INFO && MODE_SKAS

	depends on DEBUG_INFO

	help

        This option allows developers to retrieve coverage data from a UML

        session.

arch/um/Makefile

+5 −19
Original line number Diff line number Diff line
@@ -31,18 +31,9 @@ SYMLINK_HEADERS := $(foreach header,$(SYMLINK_HEADERS),include/asm-um/$(header)) 
ARCH_SYMLINKS = include/asm-um/arch $(ARCH_DIR)/include/sysdep $(ARCH_DIR)/os \

	$(SYMLINK_HEADERS) $(ARCH_DIR)/include/uml-config.h



um-modes-$(CONFIG_MODE_TT) += tt

um-modes-$(CONFIG_MODE_SKAS) += skas

MODE_INCLUDE	+= -I$(srctree)/$(ARCH_DIR)/include/skas



MODE_INCLUDE	+= $(foreach mode,$(um-modes-y),\

		   -I$(srctree)/$(ARCH_DIR)/include/$(mode))



MAKEFILES-INCL	+= $(foreach mode,$(um-modes-y),\

		   $(srctree)/$(ARCH_DIR)/Makefile-$(mode))



ifneq ($(MAKEFILES-INCL),)

  include $(MAKEFILES-INCL)

endif

include $(srctree)/$(ARCH_DIR)/Makefile-skas



ARCH_INCLUDE	:= -I$(ARCH_DIR)/include

ifneq ($(KBUILD_SRC),)
@@ -89,9 +80,8 @@ CFLAGS += $(call cc-option,-fno-unit-at-a-time,) 
# included; the values here are meaningless



CONFIG_NEST_LEVEL ?= 0

CONFIG_KERNEL_HALF_GIGS ?= 0



SIZE = (($(CONFIG_NEST_LEVEL) + $(CONFIG_KERNEL_HALF_GIGS)) * 0x20000000)

SIZE = ($(CONFIG_NEST_LEVEL) * 0x20000000)



PHONY += linux
@@ -124,7 +114,6 @@ CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) 
	$(call cc-option, -fno-stack-protector,) \

	$(call cc-option, -fno-stack-protector-all,)



CPP_MODE-$(CONFIG_MODE_TT) := -DMODE_TT

CONFIG_KERNEL_STACK_ORDER ?= 2

STACK_SIZE := $(shell echo $$[ 4096 * (1 << $(CONFIG_KERNEL_STACK_ORDER)) ] )
@@ -132,11 +121,8 @@ ifndef START 
  START = $(shell echo $$[ $(TOP_ADDR) - $(SIZE) ] )

endif



CPPFLAGS_vmlinux.lds = -U$(SUBARCH) \

	-DSTART=$(START) -DELF_ARCH=$(ELF_ARCH) \

	-DELF_FORMAT="$(ELF_FORMAT)" $(CPP_MODE-y) \

	-DKERNEL_STACK_SIZE=$(STACK_SIZE) \

	-DUNMAP_PATH=arch/um/sys-$(SUBARCH)/unmap.o

CPPFLAGS_vmlinux.lds = -U$(SUBARCH) -DSTART=$(START) -DELF_ARCH=$(ELF_ARCH) \

	-DELF_FORMAT="$(ELF_FORMAT)" -DKERNEL_STACK_SIZE=$(STACK_SIZE)



#The wrappers will select whether using "malloc" or the kernel allocator.

LINK_WRAPS = -Wl,--wrap,malloc -Wl,--wrap,free -Wl,--wrap,calloc

arch/um/Makefile-i386

+1 −5
Original line number Diff line number Diff line
@@ -2,11 +2,7 @@ core-y += arch/um/sys-i386/ arch/x86/crypto/ 


TOP_ADDR := $(CONFIG_TOP_ADDR)



ifeq ($(CONFIG_MODE_SKAS),y)

  ifneq ($(CONFIG_MODE_TT),y)

START := 0x8048000

  endif

endif



LDFLAGS			+= -m elf_i386

ELF_ARCH		:= $(SUBARCH)

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