|author||Jeff Dike <firstname.lastname@example.org>||2008-02-08 04:22:07 -0800|
|committer||Linus Torvalds <email@example.com>||2008-02-08 09:22:42 -0800|
|parent||CONFIG_HIGHPTE vs. sub-page page tables. (diff)|
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 <firstname.lastname@example.org> Cc: Miklos Szeredi <email@example.com> Signed-off-by: Andrew Morton <firstname.lastname@example.org> Signed-off-by: Linus Torvalds <email@example.com>
Diffstat (limited to '')
1 files changed, 0 insertions, 37 deletions
diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386
index e75264603d24..3cd8a04d66d8 100644
@@ -23,43 +23,6 @@ config SEMAPHORE_SLEEPERS
- prompt "Host memory split"
- default HOST_VMSPLIT_3G
- 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
- So, if you do not know what to do here, say 'Default split'.
- bool "Default split (3G/1G user/kernel host split)"
- bool "3G/1G user/kernel host split (for full 1G low memory)"
- bool "2G/2G user/kernel host split"
- bool "1G/3G user/kernel host split"
- default 0xB0000000 if HOST_VMSPLIT_3G_OPT
- default 0x78000000 if HOST_VMSPLIT_2G
- default 0x40000000 if HOST_VMSPLIT_1G
- default 0xC0000000
bool "Three-level pagetables (EXPERIMENTAL)"