[PATCH 0/4] [GIT PULL][3.12] x86/jump-label: Clean ups and safety checks

Steven Rostedt
2013-08-07T16:51:16Z

Peter,

These 4 patches were taken from the patchset that did the 2-5 byte
jumps, but had nothing to do with the 2-5 byte jumps itself. They
were clean ups and safety checks that were needed for the jump code.
Although the 2-5 byte jump code is controversial, these cleanups are
not.

The first change is to use the default nops instead of a jmp to next
instruction in the jump label code.

The second is a boot time optimization that doesn't bother changing
the nops if the default nop is the same as the ideal nop.

The third patch adds safety checks like the ftrace function code has.
It makes sure the op code that is being changed is in fact the op code
we expect it to be.

The last patch will output the problem code if it fails the safety
check from patch three.

This is based off of tip/x86/jumplabel, which was equal to v3.11-rc1.

Please pull the latest tip/x86/jumplabel tree, which can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/x86/jumplabel

Head SHA1: fb40d7a8994a3cc7a1e1c1f3258ea8662a366916

Steven Rostedt (4):
x86/jump-label: Use best default nops for inital jump label calls
x86/jump-label: Do not bother updating nops if they are correct
x86/jump-label: Add safety checks to jump label conversions
x86/jump-label: Show where and what was wrong on errors

----
arch/x86/include/asm/jump_label.h | 9 +++--
arch/x86/kernel/jump_label.c | 70 ++++++++++++++++++++++++++++++++++---
2 files changed, 73 insertions(+), 6 deletions(-)