lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

x86-64: Modify copy_user_generic() alternatives mechanism

Browse Source 
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>
This commit is contained in:
Jan Beulich
2009-12-18 16:12:56 +00:00
committed by Ingo Molnar
parent 499a5f1efa
commit 1b1d925818
5 changed files with 31 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/lib/copy_user_64.S
View File

@ -90,12 +90,6 @@ ENTRY(_copy_from_user)
CFI_ENDPROC
ENDPROC(_copy_from_user)
ENTRY(copy_user_generic)
CFI_STARTPROC
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC
ENDPROC(copy_user_generic)
.section .fixup,"ax"
/* must zero dest */
ENTRY(bad_from_user)