Commit Graph

4 Commits

Author SHA1 Message Date
Andy Lutomirski
48e08d0fb2 x86, entry: Switch stacks on a paranoid entry from userspace
This causes all non-NMI, non-double-fault kernel entries from
userspace to run on the normal kernel stack.  Double-fault is
exempt to minimize confusion if we double-fault directly from
userspace due to a bad kernel stack.

This is, suprisingly, simpler and shorter than the current code.  It
removes the IMO rather frightening paranoid_userspace path, and it
make sync_regs much simpler.

There is no risk of stack overflow due to this change -- the kernel
stack that we switch to is empty.

This will also enable us to create non-atomic sections within
machine checks from userspace, which will simplify memory failure
handling.  It will also allow the upcoming fsgsbase code to be
simplified, because it doesn't need to worry about usergs when
scheduling in paranoid_exit, as that code no longer exists.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
2015-01-02 10:22:45 -08:00
Luis R. Rodriguez
96ed4cd0aa x86/doc: Update documentation after file shuffling
While at it, also refer to the 32 bit entry file.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: linux-doc@vger.kernel.org
Cc: bpoirier@suse.de
Link: http://lkml.kernel.org/r/1418165684-6226-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-12-11 11:33:22 +01:00
Cesar Eduardo Barros
664ef2123f x86-64, doc: Remove int 0xcc from entry_64.S documentation
Commit 3ae36655b9 (x86-64: Rework vsyscall
emulation and add vsyscall= parameter) removed the special use of the
0xcc IDT vector.

Remove it from Documentation/x86/entry_64.txt also.

Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Acked-by: Andy Lutomirski <luto@MIT.EDU>
Link: http://lkml.kernel.org/r/1313447210-9149-1-git-send-email-cesarb@cesarb.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-08-16 08:04:08 -07:00
Andy Lutomirski
8b4777a4b5 x86-64: Document some of entry_64.S
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/fc134867cc550977cc996866129e11a16ba0f9ea.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-06-05 21:30:32 +02:00