We move the function itself to pseries/firmware.c and call it along
with almost all other flat device-tree parsers from early_init_devtree()
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Move #ifdefs into the header by providing pseries_probe_fw_features()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Instead of punching a hole in the linear mapping, just use normal
cachable memory, and apply the flush sequence documented in the
CPC625 (aka U3) user manual.
This allows us to remove quite a bit of code related to the early
allocation of the DART and the hole in the linear mapping. We can
also get rid of the copy of the DART for suspend/resume as the
original memory can just be saved/restored now, as long as we
properly sync the caches.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Integrate dart_init() fix to return ENODEV when DART disabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
32 and 64-bit do a similar set of calls early on, we move it all to
a single common function to make the boot code more readable.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
It is seldom used in the kernel code and can be easily replaced by
either RELOCATABLE or PPC32. So there is no reason to keep a separate
kernel option for this.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This makes it easy to verify we are not overloading the bits.
No functionality change by this patch.
mpe: Cleanup more. Completely fixup whitespace, convert all UL values to
ASM_CONST(), and replace all occurrences of 63-x with the actual shift.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We add a tlb flush variant, to flush LPID mappings.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This update the machine dep callback such that we can use the same
callback to register process table. The interface is updated such that
we can easily call H_REGISTER_PROC_TBL hcall. The HCALL itself is
introduced in a later patch.
No functionality change introduced by this patch.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Update the PID switch as per ISA doc. slbia is needed in radix to
invalidate any implementation specific lookaside information.
We use the .long format due to build errors with the below compiler
version.
gcc (Ubuntu 5.3.1-14ubuntu2.1) 5.3.1 20160413
GNU assembler (GNU Binutils for Ubuntu) 2.26
CC arch/powerpc/mm//mmu_context_book3s64.o
{standard input}: Assembler messages:
{standard input}:506: Error: junk at end of line: `0x7'
scripts/Makefile.build:291: recipe for target 'arch/powerpc/mm//mmu_context_book3s64.o' failed
make[1]: *** [arch/powerpc/mm//mmu_context_book3s64.o] Error 1
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
As per ISA, we need to do this only for architecture version 2.02 and
earlier. This continued to work even for 2.07. But let's not do this for
anything after 2.02. ISA 3.0 requires these top bits to be not cleared.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently we depend on mmu_has_feature to evalute to zero based on
MMU_FTRS_POSSIBLE mask. In a later patch, we want to update
radix_enabled() to runtime update the conditional operation to a jump
instruction. This implies we cannot depend on MMU_FTRS_POSSIBLE mask.
Instead define radix_enabled to return 0 if RADIX_MMU is not enabled.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PowerISA 3.0 requires the MMU mode (radix vs. hash) of the hypervisor
to be mirrored in the LPCR register, in addition to the partition table.
This is done to avoid fetching from the table when deciding, among other
things, how to perform transitions to HV mode on some interrupts.
So let's set it up appropriately
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The .longs with the shifts are harder to read, use more meaningful names
for the opcodes. PPC_TLBIE_5 is introduced for the 5 opcode variation of
the instruction due to an existing op-code for the 2 opcode variant.
Signed-off-by: Balbir Singh <bsingharora@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 have some obsolete code in pnv_pci_p7ioc_tce_invalidate()
to handle some internal lab tools that have stopped being
useful a long time ago. Remove that along with the definition
and test for the TCE_PCI_SWINV_* flags whose value is basically
always the same.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Replace the old generic opal_call_realmode() with proper per-call
wrappers similar to the normal ones and convert callers.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds a new XICS backend that uses OPAL calls, which can be
used when we don't have native support for the platform interrupt
controller.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Calling this function with interrupts soft-disabled will cause
a replay of the external interrupt vector when they are re-enabled.
This will be used by the OPAL XICS backend (and latter by the native
XIVE code) to handle EOI signaling that there are more interrupts to
fetch from the hardware since the hardware won't issue another HW
interrupt in that case.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This will be delivering external interrupts from the XIVE to the
Hypervisor. We treat it as a normal external interrupt for the
lazy irq disable code (so it will be replayed as a 0x500) and
route it to do_IRQ.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
OPAL provides an emulated XICS interrupt controller to
use as a fallback on newer processors that don't have a
XICS. It's meant as a way to provide backward compatibility
with future processors. Add the corresponding interfaces.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER ISA v3 defines a new idle processor core mechanism. In summary,
a) new instruction named stop is added. This instruction replaces
instructions like nap, sleep, rvwinkle.
b) new per thread SPR named Processor Stop Status and Control Register
(PSSCR) is added which controls the behavior of stop instruction.
PSSCR layout:
----------------------------------------------------------
| PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
----------------------------------------------------------
0 4 41 42 43 44 48 54 56 60
PSSCR key fields:
Bits 0:3 - Power-Saving Level Status. This field indicates the lowest
power-saving state the thread entered since stop instruction was last
executed.
Bit 42 - Enable State Loss
0 - No state is lost irrespective of other fields
1 - Allows state loss
Bits 44:47 - Power-Saving Level Limit
This limits the power-saving level that can be entered into.
Bits 60:63 - Requested Level
Used to specify which power-saving level must be entered on executing
stop instruction
This patch adds support for stop instruction and PSSCR handling.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
- tm: Always reclaim in start_thread() for exec() class syscalls from Cyril Bur
- tm: Avoid SLB faults in treclaim/trecheckpoint when RI=0 from Michael Neuling
- eeh: Fix wrong argument passed to eeh_rmv_device() from Gavin Shan
- Initialise pci_io_base as early as possible from Darren Stevens
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Merge tag 'powerpc-4.7-5' into next
Pull in the fixes we sent during 4.7, we have code we want to merge into
next that depends on some of them.
powernv marks it's halt and restart calls as __noreturn. However,
ppc_md does not have this annotation. Add the annotation to ppc_md,
and then to every halt/restart function that is missing it.
Additionally, I have verified that all of these functions do not
return. Occasionally I have added a spin loop to be sure.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The cxl driver will use infrastructure from pnv_php to handle device tree
updates when switching bi-modal CAPI cards into CAPI mode.
To enable this, export pnv_php_find_slot() and
pnv_php_set_slot_power_state(), and add corresponding declarations, as well
as the definition of struct pnv_php_slot, to asm/pnv-pci.h.
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds support for the peer model of the cxl kernel api to the
PowerNV PHB, in which physical function 0 represents the cxl function on
the card (an XSL in the case of the CX4), which other physical functions
will use for memory access and interrupt services. It is referred to as
the peer model as these functions are peers of one another, as opposed
to the Virtual PHB model which forms a hierarchy.
This patch exports APIs to enable the peer mode, check if a PCI device
is attached to a PHB in this mode, and to set and get the peer AFU for
this mode.
The cxl driver will enable this mode for supported cards by calling
pnv_cxl_enable_phb_kernel_api(). This will set a flag in the PHB to note
that this mode is enabled, and switch out it's controller_ops for the
cxl version.
The cxl version of the controller_ops struct implements it's own
versions of the enable_device_hook and release_device to handle
refcounting on the peer AFU and to allocate a default context for the
device.
Once enabled, the cxl kernel API may not be disabled on a PHB. Currently
there is no safe way to disable cxl mode short of a reboot, so until
that changes there is no reason to support the disable path.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On some environments (prototype machines, some simulators, etc...)
there is no functional interrupt source to signal completion, so
we rely on the fairly slow OPAL heartbeat.
In a number of cases, the calls complete very quickly or even
immediately. We've observed that it helps a lot to wakeup the OPAL
heartbeat thread before waiting for event in those cases, it will
call OPAL immediately to collect completions for anything that
finished fast enough.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-By: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Power ISAv3 adds a large decrementer (LD) mode which increases the size
of the decrementer register. The size of the enlarged decrementer
register is between 32 and 64 bits with the exact size being dependent
on the implementation. When in LD mode, reads are sign extended to 64
bits and a decrementer exception is raised when the high bit is set (i.e
the value goes below zero). Writes however are truncated to the physical
register width so some care needs to be taken to ensure that the high
bit is not set when reloading the decrementer. This patch adds support
for using the LD inside the host kernel on processors that support it.
When LD mode is supported firmware will supply the ibm,dec-bits property
for CPU nodes to allow the kernel to determine the maximum decrementer
value. Enabling LD mode is a hypervisor privileged operation so the kernel
can only enable it manually when running in hypervisor mode. Guests that
support LD mode can request it using the "ibm,client-architecture-support"
firmware call (not implemented in this patch) or some other platform
specific method. If this property is not supplied then the traditional
decrementer width of 32 bit is assumed and LD mode will not be enabled.
This patch was based on initial work by Jack Miller.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Calling ISA 3.0 instructions copy, copy_first, paste and paste_last
generates an alignment fault when copying or pasting unaligned
data (128 byte). We catch this and send SIGBUS to the userspace
process that caused it.
We do not emulate these because paste may contain additional metadata
when pasting to a co-processor and paste_last is the synchronisation
point for preceding copy/paste sequences.
Thanks to Michael Neuling <mikey@neuling.org> for his help.
Signed-off-by: Chris Smart <chris@distroguy.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit d6a9996e84 ("powerpc/mm: vmalloc abstraction in preparation for
radix") turned kernel memory and IO addresses from #defined constants to
variables initialised at runtime.
On PA6T (pasemi) systems the setup_arch() machine call initialises the
onboard PCI-e root-ports, and uses pci_io_base to do this, which is now
before its value has been set, resulting in a panic early in boot before
console IO is initialised.
Move the pci_io_base initialisation to the same place as vmalloc ranges
are set (hash__early_init_mmu()/radix__early_init_mmu()) - this is the
earliest possible place we can initialise it.
Fixes: d6a9996e84 ("powerpc/mm: vmalloc abstraction in preparation for radix")
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Darren Stevens <darren@stevens-zone.net>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Add #ifdef CONFIG_PCI, massage change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Implement new character device driver to allow access from user space
to the operator panel display present on IBM Power Systems machines
with FSPs.
This will allow status information to be presented on the display which
is visible to a user.
The driver implements a character buffer which a user can read/write
by accessing the device (/dev/op_panel). This buffer is then displayed on
the operator panel display. Any attempt to write past the last character
position will have no effect and attempts to write more characters than
the size of the display will be truncated. The device may only be accessed
by a single process at a time.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
An opal_msg of type OPAL_MSG_ASYNC_COMP contains the return code in the
params[1] struct member. However this isn't intuitive or obvious when
reading the code and requires that a user look at the skiboot
documentation or opal-api.h to verify this.
Add an inline function to get the return code from an opal_msg and update
call sites accordingly.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
PPC64 eBPF JIT compiler.
Enable with:
echo 1 > /proc/sys/net/core/bpf_jit_enable
or
echo 2 > /proc/sys/net/core/bpf_jit_enable
... to see the generated JIT code. This can further be processed with
tools/net/bpf_jit_disasm.
With CONFIG_TEST_BPF=m and 'modprobe test_bpf':
test_bpf: Summary: 305 PASSED, 0 FAILED, [297/297 JIT'ed]
... on both ppc64 BE and LE.
The details of the approach are documented through various comments in
the code.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Since we will be using the rotate immediate instructions for extended
BPF JIT, let's introduce macros for the same. And since the shift
immediate operations use the rotate immediate instructions, let's redo
those macros to use the newly introduced instructions.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This exports 4 functions, which base on the corresponding OPAL
APIs to get/set PCI slot status. Those functions are going to
be used by PowerNV PCI hotplug driver:
pnv_pci_get_device_tree() opal_get_device_tree()
pnv_pci_get_presence_state() opal_pci_get_presence_state()
pnv_pci_get_power_state() opal_pci_get_power_state()
pnv_pci_set_power_state() opal_pci_set_power_state()
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This introduces pnv_pci_get_slot_id() to get the hotpluggable PCI
slot ID from the corresponding device node. It will be used by
hotplug driver.
Requested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The reset and poll functionality from (OPAL) firmware supports
PHB and PCI slot at same time. They are identified by ID. This
supports PCI slot ID by:
* Rename the argument name for opal_pci_reset() and opal_pci_poll()
accordingly
* Rename pnv_eeh_phb_poll() to pnv_eeh_poll() and adjust its argument
name.
* One macro is added to produce PCI slot ID.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The pdn (struct pci_dn) instances are allocated from memblock or
bootmem when creating PCI controller (hoses) in setup_arch(). PCI
hotplug, which will be supported by proceeding patches, releases
PCI device nodes and their corresponding pdn on unplugging event.
The memory chunks for pdn instances allocated from memblock or
bootmem are hard to reused after being released.
This delays creating pdn by pci_devs_phb_init() from setup_arch()
to core_initcall() so that they are allocated from slab. The memory
consumed by pdn can be released to system without problem during
PCI unplugging time. It indicates that pci_dn is unavailable in
setup_arch() and the the fixup on pdn (like AGP's) can't be carried
out that time. We have to do that in pcibios_root_bridge_prepare()
on maple/pasemi/powermac platforms where/when the pdn is available.
pcibios_root_bridge_prepare is called from subsys_initcall() which
is executed after core_initcall() so the code flow does not change.
At the mean while, the EEH device is created when pdn is populated,
meaning pdn and EEH device have same life cycle. In turn, we needn't
call eeh_dev_init() to create EEH device explicitly.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This overrides pcibios_setup_bridge() that is called to update PCI
bridge windows when PCI resource assignment is completed, to assign
PE and setup various (resource) mapping for the PE in subsequent
patches.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This enables new registers, LMRR and LMSER, that can trigger an EBB in
userspace code when a monitored load (via the new ldmx instruction)
loads memory from a monitored space. This facility is controlled by a
new FSCR bit, LM.
This patch disables the FSCR LM control bit on task init and enables
that bit when a load monitor facility unavailable exception is taken
for using it. On context switch, this bit is then used to determine
whether the two relevant registers are saved and restored. This is
done lazily for performance reasons.
Signed-off-by: Jack Miller <jack@codezen.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This fixes a few issues with FSCR init and switching.
In commit 152d523e63 ("powerpc: Create context switch helpers
save_sprs() and restore_sprs()") we moved the setting of the FSCR
register from inside an CPU_FTR_ARCH_207S section to inside just a
CPU_FTR_ARCH_DSCR section. Hence we are setting FSCR on POWER6/7 where
the FSCR doesn't exist. This is harmless but we shouldn't do it.
Also, we can simplify the FSCR context switch. We don't need to go
through the calculation involving dscr_inherit. We can just restore
what we saved last time.
We also set an initial value in INIT_THREAD, so that pid 1 which is
cloned from that gets a sane value.
Based on patch by Jack Miller.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
ISA 3.0 updated it to be encoded as Radix tree size = 2^(RTS + 31). We
have it encoded as 2^(RTS + 28). Add a helper with the correct encoding
and use it instead of opencoding.
Fixes: 2bfd65e45e ("powerpc/mm/radix: Add radix callbacks for early init routines")
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds support for using CAPP DMA mode, which is required for XSL
based cards such as the Mellanox CX4 to function.
This is currently an RFC as it depends on the corresponding support to
be merged into skiboot first, which was submitted here:
http://patchwork.ozlabs.org/patch/625582/
In the event that the skiboot on the system does not have the above
support, it will indicate as such in the kernel log and abort the init
process.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Sparse picked up a number of functions that are implemented in C and
then only referred to in asm code.
This introduces asm-prototypes.h, which provides a place for
prototypes of these functions.
This silences some sparse warnings.
Signed-off-by: Daniel Axtens <dja@axtens.net>
[mpe: Add include guards, clean up copyright & GPL text]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
There is an ordering issue with spin_unlock_wait() on powerpc, because
the spin_lock primitive is an ACQUIRE and an ACQUIRE is only ordering
the load part of the operation with memory operations following it.
Therefore the following event sequence can happen:
CPU 1 CPU 2 CPU 3
================== ==================== ==============
spin_unlock(&lock);
spin_lock(&lock):
r1 = *lock; // r1 == 0;
o = object; o = READ_ONCE(object); // reordered here
object = NULL;
smp_mb();
spin_unlock_wait(&lock);
*lock = 1;
smp_mb();
o->dead = true; < o = READ_ONCE(object); > // reordered upwards
if (o) // true
BUG_ON(o->dead); // true!!
To fix this, we add a "nop" ll/sc loop in arch_spin_unlock_wait() on
ppc, the "nop" ll/sc loop reads the lock
value and writes it back atomically, in this way it will synchronize the
view of the lock on CPU1 with that on CPU2. Therefore in the scenario
above, either CPU2 will fail to get the lock at first or CPU1 will see
the lock acquired by CPU2, both cases will eliminate this bug. This is a
similar idea as what Will Deacon did for ARM64 in:
d86b8da04d ("arm64: spinlock: serialise spin_unlock_wait against concurrent lockers")
Furthermore, if the "nop" ll/sc figures out the lock is locked, we
actually don't need to do the "nop" ll/sc trick again, we can just do a
normal load+check loop for the lock to be released, because in that
case, spin_unlock_wait() is called when someone is holding the lock, and
the store part of the "nop" ll/sc happens before the lock release of the
current lock holder:
"nop" ll/sc -> spin_unlock()
and the lock release happens before the next lock acquisition:
spin_unlock() -> spin_lock() <next holder>
which means the "nop" ll/sc happens before the next lock acquisition:
"nop" ll/sc -> spin_unlock() -> spin_lock() <next holder>
With a smp_mb() preceding spin_unlock_wait(), the store of object is
guaranteed to be observed by the next lock holder:
STORE -> smp_mb() -> "nop" ll/sc
-> spin_unlock() -> spin_lock() <next holder>
This patch therefore fixes the issue and also cleans the
arch_spin_unlock_wait() a little bit by removing superfluous memory
barriers in loops and consolidating the implementations for PPC32 and
PPC64 into one.
Suggested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
[mpe: Inline the "nop" ll/sc loop and set EH=0, munge change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We're approaching 20 locations where we need to check for ELF ABI v2.
That's fine, except the logic is a bit awkward, because we have to check
that _CALL_ELF is defined and then what its value is.
So check it once in asm/types.h and define PPC64_ELF_ABI_v2 when ELF ABI
v2 is detected.
We also have a few places where what we're really trying to check is
that we are using the 64-bit v1 ABI, ie. function descriptors. So also
add a #define for that, which simplifies several checks.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A number of our assembly implementations of string functions do not
align their hot loops. I was going to align them manually, but I
realised that they are are almost instruction for instruction
identical to what gcc produces, with the advantage that gcc does
align them.
In light of that, let's just remove the assembly versions.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With commit e58e87adc8 "powerpc/mm: Update _PAGE_KERNEL_RO" we now
use all the three PPP bits. The top bit is now used to have a PPP value
of 0b110 which will be mapped to kernel read only. When updating the
hpte entry use right mask such that we update the 63rd bit (top 'P' bit)
too.
Prior to e58e87adc8 we didn't support KERNEL_RO at all (it was ==
KERNEL_RW), so this isn't a regression as such.
Fixes: e58e87adc8 ("powerpc/mm: Update _PAGE_KERNEL_RO")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Even though a tlb_flush() does a flush with invalidate all cache,
we can end up doing an RCU page table free before calling tlb_flush().
That means we can have page walk cache entries even after we free the
page table pages. This can result in us doing wrong page table walk.
Avoid this by doing pwc flush on every page table free. We can't batch
the pwc flush, because the rcu call back function where we free the
page table pages doesn't have information of the mmu gather. Thus we
have to do a pwc on every page table page freed.
Note: I also removed the dummy tlb_flush_pgtable call functions for
hash 32.
Fixes: 1a472c9dba ("powerpc/mm/radix: Add tlbflush routines")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
