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| author | Jeff Dike <jdike@addtoit.com> | 2008-02-08 04:22:07 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-08 09:22:42 -0800 |
| commit | 536788fe2d28e11db6aeda74207d95d750fb761f (patch) | |
| tree | 73df2d3a46c542c71d3a84c20c8fd1ce617386a3 /arch/um/Makefile | |
| parent | 2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4 (diff) | |
| download | linux-536788fe2d28e11db6aeda74207d95d750fb761f.tar.gz linux-536788fe2d28e11db6aeda74207d95d750fb761f.tar.bz2 linux-536788fe2d28e11db6aeda74207d95d750fb761f.zip | |
uml: runtime host VMSPLIT detection
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is
needed on i386 if UML is to run on hosts with varying VMSPLITs without
recompilation.
TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of
an include of pgtable.h from processor.h, which can cause include loops.
On i386, task_size is calculated early in boot by probing the address space in
a binary search to figure out where the boundary between usable and non-usable
memory is. This tries to make sure that a page that is considered to be in
userspace is, or can be made, read-write. I'm concerned about a system-global
VDSO page in kernel memory being hit and considered to be a userspace page.
On x86_64, task_size is just the old value of CONFIG_TOP_ADDR.
A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced
by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it
irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in
arch/um/Makefile are also gone.
I noticed and fixed a missing extern in os.h when adding os_get_task_size.
Note: This has been revised to fix the 32-bit UML on 64-bit host bug that
Miklos ran into.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/Makefile')
| -rw-r--r-- | arch/um/Makefile | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile index cb4af9bf2074..dbeab15e7bb7 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -79,13 +79,6 @@ KERNEL_DEFINES = $(strip -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask \ KBUILD_CFLAGS += $(KERNEL_DEFINES) KBUILD_CFLAGS += $(call cc-option,-fno-unit-at-a-time,) -# These are needed for clean and mrproper, since in that case .config is not -# included; the values here are meaningless - -CONFIG_NEST_LEVEL ?= 0 - -SIZE = ($(CONFIG_NEST_LEVEL) * 0x20000000) - PHONY += linux all: linux @@ -120,10 +113,6 @@ CFLAGS_NO_HARDENING := $(call cc-option, -fno-PIC,) $(call cc-option, -fno-pic,) CONFIG_KERNEL_STACK_ORDER ?= 2 STACK_SIZE := $(shell echo $$[ 4096 * (1 << $(CONFIG_KERNEL_STACK_ORDER)) ] ) -ifndef START - START = $(shell echo $$[ $(TOP_ADDR) - $(SIZE) ] ) -endif - CPPFLAGS_vmlinux.lds = -U$(SUBARCH) -DSTART=$(START) -DELF_ARCH=$(ELF_ARCH) \ -DELF_FORMAT="$(ELF_FORMAT)" -DKERNEL_STACK_SIZE=$(STACK_SIZE) |