x86-64: Modify memcpy()/memset() alternatives mechanism

In order to avoid unnecessary chains of branches, rather than
implementing memcpy()/memset()'s access to their alternative
implementations via a jump, patch the (larger) original function
directly.

The memcpy() part of this is slightly subtle: while alternative
instruction patching does itself use memcpy(), with the
replacement block being less than 64-bytes in size the main loop
of the original function doesn't get used for copying memcpy_c()
over memcpy(), and hence we can safely write over its beginning.

Also note that the CFI annotations are fine for both variants of
each of the functions.

Signed-off-by: Jan Beulich <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions