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| author | Jeff Dike <jdike@addtoit.com> | 2008-02-08 13:22:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-08 18:22:42 +0100 |
| commit | 536788fe2d28e11db6aeda74207d95d750fb761f (patch) | |
| tree | 73df2d3a46c542c71d3a84c20c8fd1ce617386a3 /arch/um/Kconfig.i386 | |
| parent | CONFIG_HIGHPTE vs. sub-page page tables. (diff) | |
| download | linux-536788fe2d28e11db6aeda74207d95d750fb761f.tar.xz 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/Kconfig.i386')
| -rw-r--r-- | arch/um/Kconfig.i386 | 37 |
1 files changed, 0 insertions, 37 deletions
diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386 index e75264603d24..3cd8a04d66d8 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 |