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While the handling of fsl,pq3-gpio and fsl,mpc8572-gpio is done in the
same driver and the two hardly differ, the latter controller needs a
workaround for an erratum in the gpio_get callback. To make this
difference more explicit remove fsl,pq3-gpio from the list of
compatibles for mpc8572 machines.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Add 1588 timer node in files:
arch/powerpc/boot/dts/bsc9131rdb.dtsi
arch/powerpc/boot/dts/bsc9132qds.dtsi
arch/powerpc/boot/dts/p1010rdb.dtsi
arch/powerpc/boot/dts/p1020rdb-pd.dts
arch/powerpc/boot/dts/p1021rdb-pc.dtsi
arch/powerpc/boot/dts/p1022ds.dtsi
arch/powerpc/boot/dts/p1025twr.dtsi
For P2020RDB-PC, registers' values should be calculated
based on default 1588 reference clock(300MHz) not 250MHz,
and fix this in file:
arch/powerpc/boot/dts/p2020rdb-pc.dtsi
Signed-off-by: Yangbo Lu <yangbo.lu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Core reset may cause issue if using the proxy mode of MPIC.
Use the mixed mode of MPIC if enabling CPU hotplug.
Signed-off-by: Chenhui Zhao <chenhui.zhao@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
- Re-enable CONFIG_SCSI_DH in our defconfigs
- Remove unused os_area_db_id_video_mode
- cxl: fix leak of IRQ names in cxl_free_afu_irqs() from Andrew
- cxl: fix leak of ctx->irq_bitmap when releasing context via kernel API from Andrew
- cxl: fix leak of ctx->mapping when releasing kernel API contexts from Andrew
- cxl: Workaround malformed pcie packets on some cards from Philippe
- cxl: Fix number of allocated pages in SPA from Christophe Lombard
- Fix checkstop in native_hpte_clear() with lockdep from Cyril
- Panic on unhandled Machine Check on powernv from Daniel
- selftests/powerpc: Fix build failure of load_unaligned_zeropad test
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Merge tag 'powerpc-4.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- Re-enable CONFIG_SCSI_DH in our defconfigs
- Remove unused os_area_db_id_video_mode
- cxl: fix leak of IRQ names in cxl_free_afu_irqs() from Andrew
- cxl: fix leak of ctx->irq_bitmap when releasing context via kernel API from Andrew
- cxl: fix leak of ctx->mapping when releasing kernel API contexts from Andrew
- cxl: Workaround malformed pcie packets on some cards from Philippe
- cxl: Fix number of allocated pages in SPA from Christophe Lombard
- Fix checkstop in native_hpte_clear() with lockdep from Cyril
- Panic on unhandled Machine Check on powernv from Daniel
- selftests/powerpc: Fix build failure of load_unaligned_zeropad test
* tag 'powerpc-4.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
selftests/powerpc: Fix build failure of load_unaligned_zeropad test
powerpc/powernv: Panic on unhandled Machine Check
powerpc: Fix checkstop in native_hpte_clear() with lockdep
cxl: Fix number of allocated pages in SPA
cxl: Workaround malformed pcie packets on some cards
cxl: fix leak of ctx->mapping when releasing kernel API contexts
cxl: fix leak of ctx->irq_bitmap when releasing context via kernel API
cxl: fix leak of IRQ names in cxl_free_afu_irqs()
powerpc/ps3: Remove unused os_area_db_id_video_mode
powerpc/configs: Re-enable CONFIG_SCSI_DH
For the machine check interrupt that happens while we are in the guest,
kvm layer attempts the recovery, and then delivers the machine check interrupt
directly to the guest if recovery fails. On successful recovery we go back to
normal functioning of the guest. But there can be cases where a machine check
interrupt can happen with MSR(RI=0) while we are in the guest. This means
MC interrupt is unrecoverable and we have to deliver a machine check to the
guest since the machine check interrupt might have trashed valid values in
SRR0/1. The current implementation do not handle this case, causing guest
to crash with Bad kernel stack pointer instead of machine check oops message.
[26281.490060] Bad kernel stack pointer 3fff9ccce5b0 at c00000000000490c
[26281.490434] Oops: Bad kernel stack pointer, sig: 6 [#1]
[26281.490472] SMP NR_CPUS=2048 NUMA pSeries
This patch fixes this issue by checking MSR(RI=0) in KVM layer and forwarding
unrecoverable interrupt to guest which then panics with proper machine check
Oops message.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The kernel log buffer is often much longer than the size of a terminal
so paginate it's output.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The paca display is already more than 24 lines, which can be problematic
if you have an old school 80x24 terminal, or more likely you are on a
virtual terminal which does not scroll for whatever reason.
This patch adds a new command "#", which takes a single (hex) numeric
argument: lines per page. It will cause the output of "dp" and "dpa"
to be broken into pages, if necessary.
Sample output:
0:mon> # 10
0:mon> dp1
paca for cpu 0x1 @ c00000000fdc0480:
possible = yes
present = yes
online = yes
lock_token = 0x8000 (0x8)
paca_index = 0x1 (0xa)
kernel_toc = 0xc000000000eb2400 (0x10)
kernelbase = 0xc000000000000000 (0x18)
kernel_msr = 0xb000000000001032 (0x20)
emergency_sp = 0xc00000003ffe8000 (0x28)
mc_emergency_sp = 0xc00000003ffe4000 (0x2e0)
in_mce = 0x0 (0x2e8)
data_offset = 0x7f170000 (0x30)
hw_cpu_id = 0x8 (0x38)
cpu_start = 0x1 (0x3a)
kexec_state = 0x0 (0x3b)
[Hit a key (a:all, q:truncate, any:next page)]
0:mon>
__current = 0xc00000007e696620 (0x290)
kstack = 0xc00000007e6ebe30 (0x298)
stab_rr = 0xb (0x2a0)
saved_r1 = 0xc00000007ef37860 (0x2a8)
trap_save = 0x0 (0x2b8)
soft_enabled = 0x0 (0x2ba)
irq_happened = 0x1 (0x2bb)
io_sync = 0x0 (0x2bc)
irq_work_pending = 0x0 (0x2bd)
nap_state_lost = 0x0 (0x2be)
0:mon>
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
[mpe: Use bool, make some variables static]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
of_get_next_parent can be used to simplify the while() loop and
avoid the need of a temp variable.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
of_get_next_parent can be used to simplify the while() loop and
avoid the need of a temp variable.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In commit 3c8464a9b12bf83807b6e2c896d7e7b633e1cae7 ("powerpc:
Delete old PrPMC 280/2800 support") we got rid of most of the C
code, and the Makefile/Kconfig hooks, but it seems I left the
platform's DTS file orphaned in the tree as well as the boot code.
Here we get rid of them both.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
.exit.text is discarded at run time and there are some references from
that to .exit.data, so we need to discard .exit.data at run time as well.
Fixes these errors:
`.exit.data' referenced in section `.exit.text' of drivers/built-in.o: defined in discarded section `.exit.data' of drivers/built-in.o
`.exit.data' referenced in section `.exit.text' of drivers/built-in.o: defined in discarded section `.exit.data' of drivers/built-in.o
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
No need to have two atomic opertions (update and fetch/check) when
decreasing PE's number of passed devices as one atomic operation
is enough.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Export pcibios_free_controller(), so it can be used by the cxl module to
free virtual PHBs.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch provides individual system call numbers for the following
System V IPC system calls, on PowerPC, so that they do not need to be
multiplexed:
* semop, semget, semctl, semtimedop
* msgsnd, msgrcv, msgget, msgctl
* shmat, shmdt, shmget, shmctl
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Now that pseries selects PCI_MSI && PCI, EEH will always be true, and
therefore CONFIG_PSERIES_MSI will always be true. So drop it, and move
msi.o to obj-y.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Make it entirely clear in the Makefile that we always build the pci
related files by moving them to obj-y.
Note that CONFIG_EEH is now always enabled on pseries, because it
depends on PSERIES && PCI.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Now that we always have CONFIG_PCI=y for pseries, we can stop guarding
code with CONFIG_PCI ifdefs.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The pseries build with PCI=n looks to have been broken for at least 5
years, and no one's noticed or cared.
Following the obvious breakages backward, the first commit I can find
that builds is the parent of 2eb4afb69ff3 ("powerpc/pci: Move pseries
code into pseries platform specific area") from April 2009.
A distro would never ship a PCI=n kernel, so it is only useful for folks
building custom kernels. Also on KVM the virtio devices appear on PCI,
so it would only be useful if you were building kernels specifically to
run on PowerVM and with no PCI devices.
The added code complexity, and testing load (which we've clearly not
been doing), is not justified by the small reduction in kernel size for
such a niche use case.
So just make PCI non-optional on pseries.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Fix couple of cases where we shift left a 32-bit
value thus might get truncated results on 64-bit
targets.
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Suggested-by: Scott Wood <scotttwood@freescale.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Emulate TMCFG0 TMRN register exposing one HW thread per vcpu.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
[Laurentiu.Tudor@freescale.com: rebased on latest kernel, use
define instead of hardcoded value, moved code in own function]
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Acked-by: Scott Wood <scotttwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The function can return negative value.
The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].
[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The register is not currently used in the base kernel
but will be in a forthcoming kvm patch.
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The struct irq_domain contains a "struct device_node *" field
(of_node) that is almost the only link between the irqdomain
and the device tree infrastructure.
In order to prepare for the removal of that field, convert all
users to use irq_domain_get_of_node() instead.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-and-tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Graeme Gregory <graeme@xora.org.uk>
Cc: Jake Oshins <jakeo@microsoft.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/1444737105-31573-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We need to properly identify whether a hugepage is an explicit or
a transparent hugepage in follow_huge_addr(). We used to depend
on hugepage shift argument to do that. But in some case that can
result in wrong results. For ex:
On finding a transparent hugepage we set hugepage shift to PMD_SHIFT.
But we can end up clearing the thp pte, via pmdp_huge_get_and_clear.
We do prevent reusing the pfn page via the usage of
kick_all_cpus_sync(). But that happens after we updated the pte to 0.
Hence in follow_huge_addr() we can find hugepage shift set, but transparent
huge page check fail for a thp pte.
NOTE: We fixed a variant of this race against thp split in commit
691e95fd7396905a38d98919e9c150dbc3ea21a3
("powerpc/mm/thp: Make page table walk safe against thp split/collapse")
Without this patch, we may hit the BUG_ON(flags & FOLL_GET) in
follow_page_mask occasionally.
In the long term, we may want to switch ppc64 64k page size config to
enable CONFIG_ARCH_WANT_GENERAL_HUGETLB
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
After commit e2b3d202d1dba8f3546ed28224ce485bc50010be
("powerpc: Switch 16GB and 16MB explicit hugepages to a
different page table format"), we don't need to support
is_hugepd() for 64K page size.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
All unrecovered machine check errors on PowerNV should cause an
immediate panic. There are 2 reasons that this is the right policy:
it's not safe to continue, and we're already trying to reboot.
Firstly, if we go through the recovery process and do not successfully
recover, we can't be sure about the state of the machine, and it is
not safe to recover and proceed.
Linux knows about the following sources of Machine Check Errors:
- Uncorrectable Errors (UE)
- Effective - Real Address Translation (ERAT)
- Segment Lookaside Buffer (SLB)
- Translation Lookaside Buffer (TLB)
- Unknown/Unrecognised
In the SLB, TLB and ERAT cases, we can further categorise these as
parity errors, multihit errors or unknown/unrecognised.
We can handle SLB errors by flushing and reloading the SLB. We can
handle TLB and ERAT multihit errors by flushing the TLB. (It appears
we may not handle TLB and ERAT parity errors: I will investigate
further and send a followup patch if appropriate.)
This leaves us with uncorrectable errors. Uncorrectable errors are
usually the result of ECC memory detecting an error that it cannot
correct, but they also crop up in the context of PCI cards failing
during DMA writes, and during CAPI error events.
There are several types of UE, and there are 3 places a UE can occur:
Skiboot, the kernel, and userspace. For Skiboot errors, we have the
facility to make some recoverable. For userspace, we can simply kill
(SIGBUS) the affected process. We have no meaningful way to deal with
UEs in kernel space or in unrecoverable sections of Skiboot.
Currently, these unrecovered UEs fall through to
machine_check_expection() in traps.c, which calls die(), which OOPSes
and sends SIGBUS to the process. This sometimes allows us to stumble
onwards. For example we've seen UEs kill the kernel eehd and
khugepaged. However, the process killed could have held a lock, or it
could have been a more important process, etc: we can no longer make
any assertions about the state of the machine. Similarly if we see a
UE in skiboot (and again we've seen this happen), we're not in a
position where we can make any assertions about the state of the
machine.
Likewise, for unknown or unrecognised errors, we're not able to say
anything about the state of the machine.
Therefore, if we have an unrecovered MCE, the most appropriate thing
to do is to panic.
The second reason is that since e784b6499d9c ("powerpc/powernv: Invoke
opal_cec_reboot2() on unrecoverable machine check errors."), we
attempt a special OPAL reboot on an unhandled MCE. This is so the
hardware can record error data for later debugging.
The comments in that commit assert that we are heading down the panic
path anyway. At the moment this is not always true. With UEs in kernel
space, for instance, they are marked as recoverable by the hardware,
so if the attempt to reboot failed (e.g. old Skiboot), we wouldn't
panic() but would simply die() and OOPS. It doesn't make sense to be
staggering on if we've just tried to reboot: we should panic().
Explicitly panic() on unrecovered MCEs on PowerNV.
Update the comments appropriately.
This fixes some hangs following EEH events on cxlflash setups.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
pi_buff is being memset before it is sanity checked. Move the
memset after the null pi_buff sanity check to avoid an oops.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
native_hpte_clear() is called in real mode from two places:
- Early in boot during htab initialisation if firmware assisted dump is
active.
- Late in the kexec path.
In both contexts there is no need to disable interrupts are they are
already disabled. Furthermore, locking around the tlbie() is only required
for pre POWER5 hardware.
On POWER5 or newer hardware concurrent tlbie()s work as expected and on pre
POWER5 hardware concurrent tlbie()s could result in deadlock. This code
would only be executed at crashdump time, during which all bets are off,
concurrent tlbie()s are unlikely and taking locks is unsafe therefore the
best course of action is to simply do nothing. Concurrent tlbie()s are not
possible in the first case as secondary CPUs have not come up yet.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For some reason, only the little-endian flavor of
powerpc provided the zero_bytemask() implementation.
Reported-by: Michal Sojka <sojkam1@fel.cvut.cz>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Enable the "wake-on-filer" (aka. wake on user defined packet)
wake on lan capability for the eTSEC ethernet nodes.
Cc: Li Yang <leoli@freescale.com>
Cc: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
arch/tile added word-at-a-time.h after the patch that added generic-y
entries; the generic-y entry is now stale.
arch/h8300 is newer than the generic-y patch for word-at-a-time.h,
and needs a generic-y entry.
arch/powerpc seems to have gotten a generic-y entry by mistake in
the first patch; this change removes it.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Always include a timeout when waiting for secondary cpus to enter OPAL
in the kexec path, rather than only when crashing.
Signed-off-by: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The derive_parent() has similar semantics to what we have in newly introduced
of_helpers module. The replacement reduces code base and propagates the actual
error code to the caller.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In case we have node without '/' strrchr() returns NULL which might lead to
crash. Replace strrchr() by kbasename() and modify condition to avoid such
behaviour.
Suggested-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The helper kstrndup() will do the same in one line.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In case we have a full node name like /foo/bar and /foo is not found the
parent_path left unfreed. So, free a memory before return to a caller.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Extract a new module to share the code between other modules.
There is no functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull strscpy string copy function implementation from Chris Metcalf.
Chris sent this during the merge window, but I waffled back and forth on
the pull request, which is why it's going in only now.
The new "strscpy()" function is definitely easier to use and more secure
than either strncpy() or strlcpy(), both of which are horrible nasty
interfaces that have serious and irredeemable problems.
strncpy() has a useless return value, and doesn't NUL-terminate an
overlong result. To make matters worse, it pads a short result with
zeroes, which is a performance disaster if you have big buffers.
strlcpy(), by contrast, is a mis-designed "fix" for strlcpy(), lacking
the insane NUL padding, but having a differently broken return value
which returns the original length of the source string. Which means
that it will read characters past the count from the source buffer, and
you have to trust the source to be properly terminated. It also makes
error handling fragile, since the test for overflow is unnecessarily
subtle.
strscpy() avoids both these problems, guaranteeing the NUL termination
(but not excessive padding) if the destination size wasn't zero, and
making the overflow condition very obvious by returning -E2BIG. It also
doesn't read past the size of the source, and can thus be used for
untrusted source data too.
So why did I waffle about this for so long?
Every time we introduce a new-and-improved interface, people start doing
these interminable series of trivial conversion patches.
And every time that happens, somebody does some silly mistake, and the
conversion patch to the improved interface actually makes things worse.
Because the patch is mindnumbing and trivial, nobody has the attention
span to look at it carefully, and it's usually done over large swatches
of source code which means that not every conversion gets tested.
So I'm pulling the strscpy() support because it *is* a better interface.
But I will refuse to pull mindless conversion patches. Use this in
places where it makes sense, but don't do trivial patches to fix things
that aren't actually known to be broken.
* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
tile: use global strscpy() rather than private copy
string: provide strscpy()
Make asm/word-at-a-time.h available on all architectures
As we need to add further flags to the bpf_prog structure, lets migrate
both bools to a bitfield representation. The size of the base structure
(excluding insns) remains unchanged at 40 bytes.
Add also tags for the kmemchecker, so that it doesn't throw false
positives. Even in case gcc would generate suboptimal code, it's not
being accessed in performance critical paths.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
'nvram_create_os_partition' should be 'nvram_create_partition'.
Use __func__ to have it right, as done elsewhere in this file.
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If 'nvram_write_header' fails, then 'new_part' should be freed, otherwise,
there is a memory leak.
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This add helper virt_to_pfn and remove the opencoded usage of the
same.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc has a link register (lr) used for calling functions. We "bl
<func>" to call a function, and "blr" to return back to the call site.
The lr is only a single register, so if we call another function from
inside this function (ie. nested calls), software must save away the
lr on the software stack before calling the new function. Before
returning (ie. before the "blr"), the lr is restored by software from
the software stack.
This makes branch prediction quite difficult for the processor as it
will only know the branch target just before the "blr".
To help with this, modern powerpc processors keep a (non-architected)
hardware stack of lr called a "link stack". When a "bl <func>" is
run, the lr is pushed onto this stack. When a "blr" is called, the
branch predictor pops the lr value from the top of the link stack, and
uses it to predict the branch target. Hence the processor pipeline
knows a lot earlier the branch target.
This works great but there are some cases where you call "bl" but
without a matching "blr". Once such case is when trying to determine
the program counter (which can't be read directly). Here you "bl+4;
mflr" to get the program counter. If you do this, the link stack will
get out of sync with reality, causing the branch predictor to
mis-predict subsequent function returns.
To avoid this, modern micro-architectures have a special case of bl.
Using the form "bcl 20,31,+4", ensures the processor doesn't push to
the link stack.
The 32 and 64 bit variants of __get_datapage() use a "bl; mflr" to
determine the loaded address of the VDSO. The current versions of
these attempt to use this special bl variant.
Unfortunately they use +8 rather than the required +4. Hence the
current code results in the link stack getting out of sync with
reality and hence the resulting performance degradation.
This patch moves it to bcl+4 by moving __kernel_datapage_offset out of
__get_datapage().
With this patch, running a gettimeofday() (which uses
__get_datapage()) microbenchmark we get a decent bump in performance
on POWER7/8.
For the benchmark in tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
POWER8:
64bit gets ~4% improvement
32bit gets ~9% improvement
POWER7:
64bit gets ~7% improvement
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reported-by: Aaron Sawdey <sawdey@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
