x86-64: Modify copy_user_generic() alternatives mechanism
authorJan Beulich <JBeulich@novell.com>
Fri, 18 Dec 2009 16:12:56 +0000 (16:12 +0000)
committerIngo Molnar <mingo@elte.hu>
Wed, 30 Dec 2009 10:57:31 +0000 (11:57 +0100)
commit1b1d9258181bae199dc940f4bd0298126b9a73d9
treeb17ca149d943051fc76e79b75fc4b89c61b524a2
parent499a5f1efa0b0ac56ec5d060412aed84ae68e63e
x86-64: Modify copy_user_generic() alternatives mechanism

In order to avoid unnecessary chains of branches, rather than
implementing copy_user_generic() as a function consisting of
just a single (possibly patched) branch, instead properly deal
with patching call instructions in the alternative instructions
framework, and move the patching into the callers.

As a follow-on, one could also introduce something like
__EXPORT_SYMBOL_ALT() to avoid patching call sites in modules.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/alternative.h
arch/x86/include/asm/uaccess_64.h
arch/x86/kernel/alternative.c
arch/x86/kernel/x8664_ksyms_64.c
arch/x86/lib/copy_user_64.S