Using LOAD_REG_IMMEDIATE to get the address of kernel symbols
generates 5 instructions where LOAD_REG_ADDR can do it in one,
and will generate R_PPC64_ADDR16_* relocations in the output when
we get to making the kernel as a position-independent executable,
which we'd rather not have to handle. This changes various bits
of assembly code to use LOAD_REG_ADDR when we need to get the
address of a symbol, or to use suitable position-independent code
for cases where we can't access the TOC for various reasons, or
if we're not running at the address we were linked at.
It also cleans up a few minor things; there's no reason to save and
restore SRR0/1 around RTAS calls, __mmu_off can get the return
address from LR more conveniently than the caller can supply it in
R4 (and we already assume elsewhere that EA == RA if the MMU is on
in early boot), and enable_64b_mode was using 5 instructions where
2 would do.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Without this patch, on an idle system I get:
cpu-power-0:21.638
cpu-power-1:27.102
cpu-power-2:29.343
cpu-power-3:25.784
Total: 103.8W
With this patch:
cpu-power-0:11.730
cpu-power-1:17.185
cpu-power-2:18.547
cpu-power-3:17.528
Total: 65.0W
If I lower HZ to 100, I can get it as low as:
cpu-power-0:10.938
cpu-power-1:16.021
cpu-power-2:17.245
cpu-power-3:16.145
Total: 60.2W
Another (older) Quad G5 went from 54W to 39W at HZ=250.
Coming back out of Deep Nap takes 40-70 cycles longer than coming back
from just Nap (which already takes quite a while). I don't think it'll
be a performance issue (interrupt latency on an idle system), but in
case someone does measurements feel free to report them.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cleanup CPU inits a bit more, Geoff Levand already did some earlier.
* Move CPU state save to cpu_setup, since cpu_setup is only ever done
on cpu 0 on 64-bit and save is never done more than once.
* Rename __restore_cpu_setup to __restore_cpu_ppc970 and add
function pointers to the cputable to use instead. Powermac always
has 970 so no need to check there.
* Rename __970_cpu_preinit to __cpu_preinit_ppc970 and check PVR before
calling it instead of in it, it's too early to use cputable.
* Rename pSeries_secondary_smp_init to generic_secondary_smp_init since
everyone but powermac and iSeries use it.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Rename cpu_setup_power4.S to cpu_setup_ppc970.S, since that's
really what it is.
No functional or other changes.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Paul Mackerras
Olof Johansson