This moves all the CPU feature bits that are only used on 32-bit
machines to the top 20 bits of the CPU feature word and arranges
for them to be defined only in 32-bit builds. The features that
are common to 32-bit and 64-bit machines are moved to bits 0-11
of the CPU feature word. This means that for 64-bit platforms,
bits 44-63 can now be used for new features that only exist on
64-bit machines. (These bit numbers are counting from the right,
i.e. the LSB is bit 0.)
Because CPU_FTR_L3_DISABLE_NAP moved from the low 16 bits to the high
16 bits, we have to adjust some assembly code. Also, CPU_FTR_EMB_HV
moved from the high 16 bits to the low 16 bits.
Note that CPU_FTR_REAL_LE only applies to 64-bit chips, because only
64-bit chips (POWER6, 7, 8, 9) have a true little-endian mode that is
a CPU execution mode as opposed to being a page attribute.
With this we now have 20 free CPU feature bits on 64-bit machines.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Some of those functions try to adjust the CPU features, for example
to remove NAP support on some revisions. However, they seem to use
r5 as an index into the CPU table entry, which might have been right
a long time ago but no longer is. r4 is the right register to use.
This probably caused some off behaviours on some PowerMac variants
using 750cx or 7455 processor revisions.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@kernel.org
The kernel uses SPRG registers for various purposes, typically in
low level assembly code as scratch registers or to hold per-cpu
global infos such as the PACA or the current thread_info pointer.
We want to be able to easily shuffle the usage of those registers
as some implementations have specific constraints realted to some
of them, for example, some have userspace readable aliases, etc..
and the current choice isn't always the best.
This patch should not change any code generation, and replaces the
usage of SPRN_SPRGn everywhere in the kernel with a named replacement
and adds documentation next to the definition of the names as to
what those are used for on each processor family.
The only parts that still use the original numbers are bits of KVM
or suspend/resume code that just blindly needs to save/restore all
the SPRGs.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Currently the kernel expects the additional four IBAT and DBAT registers
to be available, but doesn't enable these registers on 745x CPUs, which
have them disabled after reset. Thus set the HIGH_BAT_EN bit in HID0
register, if the corresponding MMU feature is defined.
Signed-off-by: Gerhard Pircher <gerhard_pircher@gmx.net>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Complete workaround for DTLB errata in e300c2/c3/c4 processors.
Due to the bug, the hardware-implemented LRU algorythm always goes to way
1 of the TLB. This fix implements the proposed software workaround in
form of a LRW table for chosing the TLB-way.
Based on patch from David Jander <david@protonic.nl>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
603 CPUs have the same issue that some 750 CPUs have in that they can crash
in funny ways if a store from an FPU register instruction is executed on a
register that has never been initialized since power on. This patch fixes
it by making sure all FP registers have been properly initialized at kernel
boot.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Also renamed temp.c to tau_6xx.c (for thermal assist unit) and updated
the Kconfig option description and help text for CONFIG_TAU.
Signed-off-by: Paul Mackerras <paulus@samba.org>
