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/Kconfig.i386 | 37 ------------------------------------- 1 file changed, 37 deletions(-) (limited to 'arch/um/Kconfig.i386') diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386 index e752646..3cd8a04 100644 --- a/arch/um/Kconfig.i386 +++ b/arch/um/Kconfig.i386 @@ -23,43 +23,6 @@ config SEMAPHORE_SLEEPERS bool default y -choice - prompt "Host memory split" - default HOST_VMSPLIT_3G - help - This is needed when the host kernel on which you run has a non-default - (like 2G/2G) memory split, instead of the customary 3G/1G. If you did - not recompile your own kernel but use the default distro's one, you can - safely accept the "Default split" option. - - It can be enabled on recent (>=2.6.16-rc2) vanilla kernels via - CONFIG_VM_SPLIT_*, or on previous kernels with special patches (-ck - patchset by Con Kolivas, or other ones) - option names match closely the - host CONFIG_VM_SPLIT_* ones. - - A lower setting (where 1G/3G is lowest and 3G/1G is higher) will - tolerate even more "normal" host kernels, but an higher setting will be - stricter. - - So, if you do not know what to do here, say 'Default split'. - -config HOST_VMSPLIT_3G - bool "Default split (3G/1G user/kernel host split)" -config HOST_VMSPLIT_3G_OPT - bool "3G/1G user/kernel host split (for full 1G low memory)" -config HOST_VMSPLIT_2G - bool "2G/2G user/kernel host split" -config HOST_VMSPLIT_1G - bool "1G/3G user/kernel host split" -endchoice - -config TOP_ADDR - hex - default 0xB0000000 if HOST_VMSPLIT_3G_OPT - default 0x78000000 if HOST_VMSPLIT_2G - default 0x40000000 if HOST_VMSPLIT_1G - default 0xC0000000 - config 3_LEVEL_PGTABLES bool "Three-level pagetables (EXPERIMENTAL)" default n -- cgit v1.1