linux/arch/powerpc/include
Anton Blanchard cc1adb5f32 powerpc/pseries: Use jump labels for hcall tracepoints
hcall tracepoints add quite a few instructions to our hcall path:

plpar_hcall:
	mr      r2,r2
	mfcr    r0
	stw     r0,8(r1)
	b       164		<---- start
	ld      r12,0(r2)
	std     r12,32(r1)
	cmpdi   r12,0
	beq     164		<---- end
...

We have an unconditional branch that gets noped out during boot and
a load/compare/branch. We also store the tracepoint value to the
stack for the hcall_exit path to use.

By using jump labels we can simplify this to just a single nop that
gets replaced with a branch when the tracepoint is enabled:

plpar_hcall:
	mr      r2,r2
	mfcr    r0
	stw     r0,8(r1)
	nop			<----
...

If jump labels are not enabled, we fall back to the old method.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-11 16:05:58 +10:00
..
asm powerpc/pseries: Use jump labels for hcall tracepoints 2014-07-11 16:05:58 +10:00
uapi/asm powerpc: Add AT_HWCAP2 to indicate V.CRYPTO category support 2014-06-11 16:31:20 +10:00