diff options
| 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/include/os.h | |
| parent | 2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4 (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 <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/include/os.h')
| -rw-r--r-- | arch/um/include/os.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/um/include/os.h b/arch/um/include/os.h index 0b6b6273330..32c799e3a49 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -295,6 +295,9 @@ extern void maybe_sigio_broken(int fd, int read); extern int os_arch_prctl(int pid, int code, unsigned long *addr); /* tty.c */ -int get_pty(void); +extern int get_pty(void); + +/* sys-$ARCH/task_size.c */ +extern unsigned long os_get_task_size(void); #endif |