We are running low on CPU feature bits, so we only want to use them when
it's really necessary.
CPU_FTR_SUBCORE is only used in one place, and only in C, so we don't
need it in order to make asm patching work. It can only be set on
"Power8" CPUs, which in practice means POWER8, POWER8E and POWER8NVL.
There are no plans to implement it on future CPUs, but if there ever
were we could retrofit it then.
Although KVM uses subcores, it never looks at the CPU feature, it either
looks at the ISA level or the threads_per_subcore value.
So drop the CPU feature and do a PVR check instead. Drop the device tree
"subcore" feature as we no longer support doing anything with it, and we
will drop it from skiboot too.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The ibm,powerpc-cpu-features device tree binding describes CPU features with
ASCII names and extensible compatibility, privilege, and enablement metadata
that allows improved flexibility and compatibility with new hardware.
The interface is described in detail in ibm,powerpc-cpu-features.txt in this
patch.
Currently this code is not enabled by default, and there are no released
firmwares that provide the binding.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Power9 DD1 does not implement SAO. Although it's not widely used, its presence
or absence is visible to user space via arch_validate_prot() so it's moderately
important that we get the value right.
Fixes: 7dccfbc325 ("powerpc/book3s: Add a cpu table entry for different POWER9 revs")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Power9 does not implement the icswx instruction. This CPU feature is not visible
to userspace and is only used in the CONFIG_PPC_ICSWX code, which is generally
not enabled, and can only be triggered by other code using icswx, which should
not happen on Power9 systems in the first place. So impact should be minimal.
Fixes: c3ab300ea5 ("powerpc: Add POWER9 cputable entry")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
During a machine check, the 8xx provides indication of
whether the check is due to data or instruction access, so
let's display it.
Lets also move 8xx specific handling into the new handler.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <oss@buserror.net>
We do binary patching of asm code using CPU features, which is a
one-time operation, done during early boot. However checks of CPU
features in C code are currently done at run time, even though the set
of CPU features can never change after boot.
We can optimise this by using jump labels to implement cpu_has_feature(),
meaning checks in C code are binary patched into a single nop or branch.
For a C sequence along the lines of:
if (cpu_has_feature(FOO))
return 2;
The generated code before is roughly:
ld r9,-27640(r2)
ld r9,0(r9)
lwz r9,32(r9)
cmpwi cr7,r9,0
bge cr7, 1f
li r3,2
blr
1: ...
After (true):
nop
li r3,2
blr
After (false):
b 1f
li r3,2
blr
1: ...
mpe: Rename MAX_CPU_FEATURES as we already have a #define with that
name, and define it simply as a constant, rather than doing tricks with
sizeof and NULL pointers. Rename the array to cpu_feature_keys. Use the
kconfig we added to guard it. Add BUILD_BUG_ON() if the feature is not a
compile time constant. Rewrite the change log.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We plan to use jump label for cpu_has_feature(). In order to implement
this we need to include the linux/jump_label.h in asm/cputable.h.
Unfortunately if we do that it leads to an include loop. The root of the
problem seems to be that reg.h needs cputable.h (for CPU_FTRs), and then
cputable.h via jump_label.h eventually pulls in hw_irq.h which needs
reg.h (for MSR_EE).
So move cpu_has_feature() to a separate file on its own.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Rename to cpu_has_feature.h and flesh out change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In later patches, we will be switching CPU and MMU feature checks to
use static keys.
For checks in early boot before jump label is initialized we need a
variant of [cpu|mmu]_has_feature() that doesn't use jump labels.
So create those called, unimaginatively, early_[cpu|mmu]_has_feature().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The intention is that the result is only used as a boolean, so enforce
that by changing the return type to bool.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Various e500 core have different cache architecture, so they
need different cache flush operations. Therefore, add a callback
function cpu_flush_caches to the struct cpu_spec. The cache flush
operation for the specific kind of e500 is selected at init time.
The callback function will flush all caches inside the current cpu.
Signed-off-by: Chenhui Zhao <chenhui.zhao@freescale.com>
Signed-off-by: Tang Yuantian <Yuantian.Tang@feescale.com>
Signed-off-by: Scott Wood <oss@buserror.net>
Add a cputable entry for POWER9. More code is required to actually
boot and run on a POWER9 but this gets the base piece in which we can
start building on.
Copies over from POWER8 except for:
- Adds a new CPU_FTR_ARCH_300 bit to start hanging new architecture
features from (in subsequent patches).
- Advertises new user features bits PPC_FEATURE2_ARCH_3_00 &
HAS_IEEE128 when on POWER9.
- Drops CPU_FTR_SUBCORE.
- Drops PMU code and machine check.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Subcores isn't really part of the 2.07 architecture but currently we
turn it on using the 2.07 feature bit. Subcores is really a POWER8
specific feature.
This adds a new CPU_FTR bit just for subcores and moves the subcore
init code over to use this.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Freescale updates from Scott:
"Highlights include more 8xx optimizations, an e6500 hugetlb optimization,
QMan device tree nodes, t1024/t1023 support, and various fixes and
cleanup."
This patch changes the syscall handler to doom (tabort) active
transactions when a syscall is made and return very early without
performing the syscall and keeping side effects to a minimum (no CPU
accounting or system call tracing is performed). Also included is a
new HWCAP2 bit, PPC_FEATURE2_HTM_NOSC, to indicate this
behaviour to userspace.
Currently, the system call instruction automatically suspends an
active transaction which causes side effects to persist when an active
transaction fails.
This does change the kernel's behaviour, but in a way that was
documented as unsupported. It doesn't reduce functionality as
syscalls will still be performed after tsuspend; it just requires that
the transaction be explicitly suspended. It also provides a
consistent interface and makes the behaviour of user code
substantially the same across powerpc and platforms that do not
support suspended transactions (e.g. x86 and s390).
Performance measurements using
http://ozlabs.org/~anton/junkcode/null_syscall.c indicate the cost of
a normal (non-aborted) system call increases by about 0.25%.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch implements PAGE_EXEC capability on the 8xx.
All pages PP exec bits are set to 000, which means Execute for
Supervisor and no Execute for User.
Then we use the APG to say whether accesses are according to Page
rules, "all Supervisor" rules (Exec for all) and
"all User" rules (Exec for noone)
Therefore, we define 4 APG groups. msb is _PAGE_EXEC,
lsb is _PAGE_USER. MI_AP is initialised as follows:
GP0 (00) => Not User, no exec => 11 (all accesses performed as user)
GP1 (01) => User but no exec => 11 (all accesses performed as user)
GP2 (10) => Not User, exec => 01 (rights according to page definition)
GP3 (11) => User, exec => 00 (all accesses performed as supervisor)
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[scottwood: comments: s/exec/data/ on data side, and s/pages/pages'/]
Signed-off-by: Scott Wood <scottwood@freescale.com>
The flush_tlb hook in cpu_spec was introduced as a generic function hook
to invalidate TLBs. But the current implementation of flush_tlb hook
takes IS (invalidation selector) as an argument which is architecture
dependent. Hence, It is not right to have a generic routine where caller
has to pass non-generic argument.
This patch fixes this and makes flush_tlb hook as high level API.
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We removed the last usage of CPU_FTR_IABR in commit 1ad7d70562
"powerpc/xmon: Enable HW instruction breakpoint on POWER8".
Mark it as free.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In commit fb5a515704 "Remove platforms/wsp and associated pieces" we
removed the last user of CPU_FTRS_A2, so we should remove it too.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We potentially clear CPU_FTR_HVMODE at runtime in __init_hvmode_206(),
so we must make sure it's not set in CPU_FTRS_ALWAYS.
This doesn't hurt us in practice at the moment, because we don't support
compiling only for CPUs that support CPU_FTR_HVMODE.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We have been a bit slack about updating the CPU_FTRS_POSSIBLE and
CPU_FTRS_ALWAYS masks. When we added POWER8, and also POWER8E we forgot
to update the ALWAYS mask. And when we added POWER8_DD1 we forgot to
update both the POSSIBLE and ALWAYS masks.
Luckily this hasn't caused any actual bugs AFAICS. Failing to update the
ALWAYS mask just forgoes a potential optimisation opportunity. Failing
to update the POSSIBLE mask for POWER8_DD1 is also OK because it only
removes a bit rather than adding any.
Regardless they should all be in both masks so as to avoid any future
bugs when the set of ALWAYS/POSSIBLE bits changes, or the masks
themselves change.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Neuling <mikey@neuling.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Scott writes:
Highlights include e6500 hardware threading support, an e6500 TLB erratum
workaround, corenet error reporting, support for a new board, and some
minor fixes.
The general idea is that each core will release all of its
threads into the secondary thread startup code, which will
eventually wait in the secondary core holding area, for the
appropriate bit in the PACA to be set. The kick_cpu function
pointer will set that bit in the PACA, and thus "release"
the core/thread to boot. We also need to do a few things that
U-Boot normally does for CPUs (like enable branch prediction).
Signed-off-by: Andy Fleming <afleming@freescale.com>
[scottwood@freescale.com: various changes, including only enabling
threads if Linux wants to kick them]
Signed-off-by: Scott Wood <scottwood@freescale.com>
We have a strange #define in cputable.h called CLASSIC_PPC.
Although it is defined for 32 & 64bit, it's only used for 32bit and
it's basically a duplicate of CONFIG_PPC_BOOK3S_32, so let's use
the latter.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Although the name CONFIG_POWER4 suggests that it controls support for
power4 cpus, this symbol is actually misnamed.
It is a historical wart from the powermac code, which used to support
building a 32-bit kernel for power4. CONFIG_POWER4 was used in that
context to guard code that was 64-bit only.
In the powermac code we can just use CONFIG_PPC64 instead, and in other
places it is a synonym for CONFIG_PPC_BOOK3S_64.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Now that we have dropped power3 support we can remove CONFIG_POWER3. The
usage in pgtable_32.c was already dead code as CONFIG_POWER3 was not
selectable on PPC32.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We now only support cpus that use an SLB, so we don't need an MMU
feature to indicate that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We inadvertently broke power3 support back in 3.4 with commit
f5339277eb "powerpc: Remove FW_FEATURE ISERIES from arch code".
No one noticed until at least 3.9.
By then we'd also broken it with the optimised memcpy, copy_to/from_user
and clear_user routines. We don't want to add any more complexity to
those just to support ancient cpus, so it seems like it's a good time to
drop support for power3 and earlier.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These processors do not currently support doorbell IPIs, so remove them
from the feature list if we are at DD 1.xx for the 0x004d part.
This fixes a regression caused by d4e58e5928 (powerpc/powernv: Enable
POWER8 doorbell IPIs). With that patch the kernel would hang at boot
when calling smp_call_function_many, as the doorbell would not be
received by the target CPUs:
.smp_call_function_many+0x2bc/0x3c0 (unreliable)
.on_each_cpu_mask+0x30/0x100
.cpuidle_register_driver+0x158/0x1a0
.cpuidle_register+0x2c/0x110
.powernv_processor_idle_init+0x23c/0x2c0
.do_one_initcall+0xd4/0x260
.kernel_init_freeable+0x25c/0x33c
.kernel_init+0x1c/0x120
.ret_from_kernel_thread+0x58/0x7c
Fixes: d4e58e5928 (powerpc/powernv: Enable POWER8 doorbell IPIs)
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Some power8 revisions have a hardware bug where we can lose a
Performance Monitor (PMU) exception under certain circumstances.
We will be adding a workaround for this case, see the next commit for
details. The observed behaviour is that writing PMAO doesn't cause an
exception as we would expect, hence the name of the feature.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch introduces flush_tlb operation in cpu_spec structure. This will
help us to invoke appropriate CPU-side flush tlb routine. This patch
adds the foundation to invoke CPU specific flush routine for respective
architectures. Currently this patch introduce flush_tlb for p7 and p8.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch adds the early machine check function pointer in cputable for
CPU specific early machine check handling. The early machine handle routine
will be called in real mode to handle SLB and TLB errors. We can not reuse
the existing machine_check hook because it is always invoked in kernel
virtual mode and we would already be in trouble if we get SLB or TLB errors.
This patch just sets up a mechanism to invoke CPU specific handler. The
subsequent patches will populate the function pointer.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Erratum A-006598 says that 64-bit mftb is not atomic -- it's subject
to a similar race condition as doing mftbu/mftbl on 32-bit. The lower
half of timebase is updated before the upper half; thus, we can share
the workaround for a similar bug on Cell. This workaround involves
looping if the lower half of timebase is zero, thus avoiding the need
for a scratch register (other than CR0). This workaround must be
avoided when the timebase is frozen, such as during the timebase sync
code.
This deals with kernel and vdso accesses, but other userspace accesses
will of course need to be fixed elsewhere.
Signed-off-by: Scott Wood <scottwood@freescale.com>
When introducing support for DABRX in 4474ef0, we broke older 32-bit CPUs
that don't have that register.
Some CPUs have a DABR but not DABRX. Configuration are:
- No 32bit CPUs have DABRX but some have DABR.
- POWER4+ and below have the DABR but no DABRX.
- 970 and POWER5 and above have DABR and DABRX.
- POWER8 has DAWR, hence no DABRX.
This introduces CPU_FTR_DABRX and sets it on appropriate CPUs. We use
the top 64 bits for CPU FTR bits since only 64 bit CPUs have this.
Processors that don't have the DABRX will still work as they will fall
back to software filtering these breakpoints via perf_exclude_event().
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reported-by: "Gorelik, Jacob (335F)" <jacob.gorelik@jpl.nasa.gov>
cc: stable@vger.kernel.org (v3.9 only)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Also, make HTM's presence dependent on the .config option.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We are getting low on cpu feature bits. So rather than add a separate bit for
every new Power8 feature, add a bit for arch 2.07 server catagory and use that
instead.
Hijack the value we had for BCTAR, but swap the value with CFAR so that all the
ARCH defines are together.
Note we don't touch CPU_FTR_TM, because it is conditionally enabled if
the kernel is built with TM support.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
From Kumar Gala:
<<
Add support for T4 and B4 SoC families from Freescale, e6500 altivec
support, some various board fixes and other minor cleanups.
>>
We are currently out of free bits in AT_HWCAP. With POWER8, we have
several hardware features that we need to advertise.
Tested on POWER and x86.
Signed-off-by: Michael Neuling <michael@neuling.org>
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The e6500 core adds support for AltiVec on a Book-E class processor.
Connect up all the various exception handling code and build config
mechanisms to allow user spaces apps to utilize AltiVec.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch adds support for enabling and context switching the Target
Address Register in Power8. The TAR is a new special purpose register
that can be used for computed branches with the bctar[l] (branch
conditional to TAR) instruction in the same manner as the count and link
registers.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
.. and add it to POWER8 cpu features.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This frees up 7 bits for crazy new CPU features.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
These are 32 bit, so no need to have a bunch of wasted 0s.
The 0s saved here can be put to better use elsewhere, like at the end of my pay
check.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[PATCH 2/6] powerpc: Enable PPR save/restore
SMT thread status register (PPR) is used to set thread priority. This patch
enables PPR save/restore feature (CPU_FTR_HAS_PPR) on POWER7 and POWER8 systems.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This patch actually hooks up doorbell interrupts on POWER8:
- Select the PPC_DOORBELL Kconfig option from PPC_PSERIES
- Add the doorbell CPU feature bit to POWER8
- We define a new pSeries_cause_ipi_mux() function that issues a
doorbell interrupt if the recipient is another thread within the same
core as the sender. If the recipient is in a different core it falls
back to using XICS to deliver the IPI as before.
- During pSeries_smp_probe() at boot, we check if doorbell interrupts
are supported. If they are we set the cause_ipi function pointer to
the above mentioned function, otherwise we leave it as whichever XICS
cause_ipi function was determined by xics_smp_probe().
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
Michael Ellerman