From 536788fe2d28e11db6aeda74207d95d750fb761f Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Fri, 8 Feb 2008 04:22:07 -0800 Subject: 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 Cc: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/Makefile | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'arch/um/Makefile') diff --git a/arch/um/Makefile b/arch/um/Makefile index cb4af9b..dbeab15 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) -- cgit v1.1