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We originally added asm-prototypes.h in commit 42f5b4cacd78 ("powerpc:
Introduce asm-prototypes.h"). It's purpose was for prototypes of C
functions that are only called from asm, in order to fix sparse
warnings about missing prototypes.
A few months later Nick added a different use case in
commit 4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm")
for C prototypes for exported asm functions. This is basically the
inverse of our original usage.
Since then we've added various prototypes to asm-prototypes.h for both
reasons, meaning we now need to unstitch it all.
Dispatch prototypes of C functions into relevant headers and keep
only the prototypes for functions defined in assembly.
For the time being, leave prom_init() there because moving it
into asm/prom.h or asm/setup.h conflicts with
drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowrom.o
This will be fixed later by untaggling asm/pci.h and asm/prom.h
or by renaming the function in shadowrom.c
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/62d46904eca74042097acf4cb12c175e3067f3d1.1646413435.git.christophe.leroy@csgroup.eu
Last call to sys_swapcontext() from ASM was removed by
commit fbcee2ebe8ed ("powerpc/32: Always save non volatile GPRs at
syscall entry")
sys_debug_setcontext() prototype not needed anymore since
commit f3675644e172 ("powerpc/syscalls: signal_{32, 64} - switch
to SYSCALL_DEFINE")
sys_switch_endian() prototype not needed anymore since
commit 81dac8177862 ("powerpc/64: Make sys_switch_endian() traceable")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Keep _mcount() prototype to avoid modpost errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3ed660a585df2080ea8412ec20fbf652f5bf013a.1646413435.git.christophe.leroy@csgroup.eu
Include a testcase to check if the sysfs files for energy and frequency
related have its related attribute files exist and populated
Signed-off-by: Pratik R. Sampat <psampat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220217105321.52941-3-psampat@linux.ibm.com
Adds a syscall interface to represent the energy and frequency related
PAPR attributes on the system using the new H_CALL
"H_GET_ENERGY_SCALE_INFO".
H_GET_EM_PARMS H_CALL was previously responsible for exporting this
information in the lparcfg, however the H_GET_EM_PARMS H_CALL
will be deprecated P10 onwards.
The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format:
hcall(
uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
uint64 flags, // Per the flag request
uint64 firstAttributeId,// The attribute id
uint64 bufferAddress, // Guest physical address of the output buffer
uint64 bufferSize // The size in bytes of the output buffer
);
As specified in PAPR+ v2.11, section 14.14.3.
This H_CALL can query either all the attributes at once with
firstAttributeId = 0, flags = 0 as well as query only one attribute
at a time with firstAttributeId = id, flags = 1.
The output buffer consists of the following
1. number of attributes - 8 bytes
2. array offset to the data location - 8 bytes
3. version info - 1 byte
4. A data array of size num attributes, which contains the following:
a. attribute ID - 8 bytes
b. attribute value in number - 8 bytes
c. attribute name in string - 64 bytes
d. attribute value in string - 64 bytes
The new H_CALL exports information in direct string value format, hence
a new interface has been introduced in
/sys/firmware/papr/energy_scale_info to export this information to
userspace so that the firmware can add new values without the need for
the kernel to be changed.
The H_CALL returns the name, numeric value and string value (if exists)
The format of exposing the sysfs information is as follows:
/sys/firmware/papr/energy_scale_info/
|-- <id>/
|-- desc
|-- value
|-- value_desc (if exists)
|-- <id>/
|-- desc
|-- value
|-- value_desc (if exists)
...
The energy information that is exported is useful for userspace tools
such as powerpc-utils. Currently these tools infer the
"power_mode_data" value in the lparcfg, which in turn is obtained from
the to be deprecated H_GET_EM_PARMS H_CALL.
On future platforms, such userspace utilities will have to look at the
data returned from the new H_CALL being populated in this new sysfs
interface and report this information directly without the need of
interpretation.
Signed-off-by: Pratik R. Sampat <psampat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220217105321.52941-2-psampat@linux.ibm.com
In realmode mce handler we use irq_work_queue() to defer
the processing of mce events, irq_work_queue() can only
be called when translation is enabled because it touches
memory outside RMA, hence we enable translation before
calling irq_work_queue and disable on return, though it
is not safe to do in realmode.
To avoid this, program the decrementer and call the event
processing functions from timer handler.
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com
To avoid ambiguity, modify the strings in real address error
logging messages to "foreign/control memory" from "foreign",
Since the error discriptions in P9 user manual and P10 user
manual are different for same type of errors.
P9 User Manual for MCE:
DSISR:59 Host real address to foreign space during translation.
DSISR:60 Host real address to foreign space on a load or store
access.
P10 User Manual for MCE:
DSISR:59 D-side tablewalk used a host real address in the
control memory address range.
DSISR:60 D-side operand access to control memory address space.
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220107141428.67862-3-ganeshgr@linux.ibm.com
Add test for real address or control memory address access
error handling, using NX-GZIP engine.
The error is injected by accessing the control memory address
using illegal instruction, on successful handling the process
attempting to access control memory address using illegal
instruction receives SIGBUS.
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220107141428.67862-2-ganeshgr@linux.ibm.com
Add support to parse and log control memory access
error for pseries. These changes are made according to
PAPR v2.11 10.3.2.2.12.
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220107141428.67862-1-ganeshgr@linux.ibm.com
In bpf_jit_build_body(), the mapping of TMP_REG_1 and TMP_REG_2's bpf
register to ppc register is evalulated at every use despite not
changing. Instead, determine the ppc register once and store the result.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[Rebased, converted additional usage sites]
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0944e2f0fa6dd254ea401f1c946fb6c9a5294278.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
When calling BPF helpers, we load the function address to call into a
register. This can result in upto 5 instructions. Optimize this by
instead using the kernel toc in r2 and adjusting offset to the BPF
helper. This works since all BPF helpers are part of kernel text, and
all BPF programs/functions utilize the kernel TOC.
Further more:
- load the actual function entry address in elf v1, rather than loading
it through the function descriptor address.
- load the Local Entry Point (LEP) in elf v2 skipping TOC setup.
- consolidate code across elf abi v1 and v2 by using r12 on both.
Reported-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1233c7544e60dcb021c52b1f840b0f21a87b33ed.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
BPF helpers always reside in core kernel and all BPF programs use the
kernel TOC. As such, there is no need to load the TOC before calling
helpers or other BPF functions. Drop code to do the same.
Add a check to ensure we don't proceed if this assumption ever changes
in future.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a3cd3da4d24d95d845cd10382b1af083600c9074.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
In preparation for using kernel TOC, load the same in r2 on entry. With
elfv1, the kernel TOC is already setup by our caller.
We adjust the number of instructions to skip on a tail call accordingly.
We get rid of the #ifdef in bpf_jit_emit_tail_call() since
FUNCTION_DESCR_SIZE is itself under a #ifdef.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/18a05a4ceec14a8617c9dd4b7128d0afa83fd14e.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
In preparation for preserving kernel toc in r2, switch BPF_REG_AX from
r2 to r12. r12 is not used by bpf JIT except during external helper/bpf
calls, or with BPF_NOSPEC. These sequences aren't emitted when
BPF_REG_AX is used for constant blinding and other purposes.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e109f98617eacb4512c17a48525e94eda42889e6.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
In some scenarios, it is possible that the program epilogue is outside
the branch range for a BPF_EXIT instruction. Instead of rejecting such
programs, emit epilogue as an alternate exit point from the program.
Track the location of the same so that subsequent exits can take either
of the two paths.
Reported-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/33aa2e92645a92712be23b18035a2c6dcb92ff8d.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
PPC_BCC() emits two instructions to accommodate scenarios where we need
to branch outside the range of a conditional branch. PPC_BCC_SHORT()
emits a single branch instruction and can be used when the branch is
known to be within a conditional branch range.
Convert some of the uses of PPC_BCC() in the powerpc BPF JIT over to
PPC_BCC_SHORT() where we know the branch range.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/edbca01377d1d5f472868bf6d8962b0a0d85b96f.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
During the first pass, addrs[] is still being populated. So, all
branches to following instructions will appear to be going to the start
of the JIT program. Ignore branch range validation for such instructions
and assume those to be in range. Branch range validation will happen
during the second pass after addrs[] is setup properly.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bc517413d11636e20dbfc88503dad14bcbe391e2.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
Paul reported a warning with DEBUG_ATOMIC_SLEEP=y:
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:256
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0
preempt_count: 0, expected: 0
...
Call Trace:
dump_stack_lvl+0xa0/0xec (unreliable)
__might_resched+0x2f4/0x310
kmem_cache_alloc+0x220/0x4b0
__pud_alloc+0x74/0x1d0
hash__map_kernel_page+0x2cc/0x390
do_patch_instruction+0x134/0x4a0
arch_jump_label_transform+0x64/0x78
__jump_label_update+0x148/0x180
static_key_enable_cpuslocked+0xd0/0x120
static_key_enable+0x30/0x50
check_kvm_guest+0x60/0x88
pSeries_smp_probe+0x54/0xb0
smp_prepare_cpus+0x3e0/0x430
kernel_init_freeable+0x20c/0x43c
kernel_init+0x30/0x1a0
ret_from_kernel_thread+0x5c/0x64
Peter pointed out that this is because do_patch_instruction() has
disabled interrupts, but then map_patch_area() calls map_kernel_page()
then hash__map_kernel_page() which does a sleeping memory allocation.
We only see the warning in KVM guests with SMT enabled, which is not
particularly common, or on other platforms if CONFIG_KPROBES is
disabled, also not common. The reason we don't see it in most
configurations is that another path that happens to have interrupts
enabled has allocated the required page tables for us, eg. there's a
path in kprobes init that does that. That's just pure luck though.
As Christophe suggested, the simplest solution is to do a dummy
map/unmap when we initialise the patching, so that any required page
table levels are pre-allocated before the first call to
do_patch_instruction(). This works because the unmap doesn't free any
page tables that were allocated by the map, it just clears the PTE,
leaving the page table levels there for the next map.
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Debugged-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220223015821.473097-1-mpe@ellerman.id.au
Since commit 46ddcb3950a2 ("powerpc/mm: Show if a bad page fault on data
is read or write.") we use page_fault_is_write(regs->dsisr) in
__bad_page_fault() to determine if the fault is for a read or write, and
change the message printed accordingly.
But SLB faults, aka Data Segment Interrupts, don't set DSISR (Data
Storage Interrupt Status Register) to a useful value. All ISA versions
from v2.03 through v3.1 specify that the Data Segment Interrupt sets
DSISR "to an undefined value". As far as I can see there's no mention of
SLB faults setting DSISR in any BookIV content either.
This manifests as accesses that should be a read being incorrectly
reported as writes, for example, using the xmon "dump" command:
0:mon> d 0x5deadbeef0000000
5deadbeef0000000
[359526.415354][ C6] BUG: Unable to handle kernel data access on write at 0x5deadbeef0000000
[359526.415611][ C6] Faulting instruction address: 0xc00000000010a300
cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf400]
pc: c00000000010a300: mread+0x90/0x190
If we disassemble the PC, we see a load instruction:
0:mon> di c00000000010a300
c00000000010a300 89490000 lbz r10,0(r9)
We can also see in exceptions-64s.S that the data_access_slb block
doesn't set IDSISR=1, which means it doesn't load DSISR into pt_regs. So
the value we're using to determine if the fault is a read/write is some
stale value in pt_regs from a previous page fault.
Rework the printing logic to separate the SLB fault case out, and only
print read/write in the cases where we can determine it.
The result looks like eg:
0:mon> d 0x5deadbeef0000000
5deadbeef0000000
[ 721.779525][ C6] BUG: Unable to handle kernel data access at 0x5deadbeef0000000
[ 721.779697][ C6] Faulting instruction address: 0xc00000000014cbe0
cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390]
0:mon> d 0
0000000000000000
[ 742.793242][ C6] BUG: Kernel NULL pointer dereference at 0x00000000
[ 742.793316][ C6] Faulting instruction address: 0xc00000000014cbe0
cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390]
Fixes: 46ddcb3950a2 ("powerpc/mm: Show if a bad page fault on data is read or write.")
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20220222113449.319193-1-mpe@ellerman.id.au
'gtm' will *always* be set by list_for_each_entry().
It is incorrect to assume that the iterator value will be NULL if the
list is empty.
Instead of checking the pointer it should be checked if
the list is empty.
Fixes: 83ff9dcf375c ("powerpc/sysdev: implement FSL GTM support")
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220228142434.576226-1-jakobkoschel@gmail.com
Since the VAS windows belong to the VAS hardware resource, the
hypervisor expects the partition to close them on source partition
and reopen them after the partition migrated on the destination
machine.
This handler is called before pseries_suspend() to close these
windows and again invoked after migration. All active windows
for both default and QoS types will be closed and mark them
inactive and reopened after migration with this handler.
During the migration, the user space receives paste instruction
failure if it issues copy/paste on these inactive windows.
The current migration implementation does not freeze the user
space and applications can continue to open VAS windows while
migration is in progress. So when the migration_in_progress flag
is set, VAS open window API returns -EBUSY.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/05e45ff4f8babd2490ccb7ae923884f4aa21a7e5.camel@linux.ibm.com
VAS is a hardware engine stays on the chip. So when the partition
migrates, all VAS windows on the source system have to be closed
and reopen them on the destination after migration.
The kernel has to consider both DLPAR CPU and migration events to
take action on VAS windows. So using VAS_WIN_NO_CRED_CLOSE and
VAS_WIN_MIGRATE_CLOSE status bits and windows will be reopened
after migration only after both status bits are cleared.
This patch make changes to the current reconfig_open/close_windows
functions to support migration:
- Set VAS_WIN_MIGRATE_CLOSE to the window status when closes and
reopen windows with the same status during resume.
- Continue to close all windows even if deallocate HCALL failed
(should not happen) since no way to stop migration with the
current LPM implementation.
- If the DLPAR CPU event happens while migration is in progress,
set VAS_WIN_NO_CRED_CLOSE to the window status. Close window
happens with the first event (migration or DLPAR) and Reopen
window happens only with the last event (migration or DLPAR).
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0aad580387cb58379496b4cbbd7c5596e9ea70be.camel@linux.ibm.com
The coprocessor capabilities struct is used to get default and
QoS capabilities from the hypervisor during init, DLPAR event and
migration. So instead of allocating this struct for each event,
define global struct and reuse it which allows the migration code
to avoid adding an error path.
Also disable copy/paste feature flag if any capabilities HCALL
is failed.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/57da6a270fcb9308cd57be7c88037029343080f7.camel@linux.ibm.com
pseries supports two types of credits - Default (uses normal priority
FIFO) and Qality of service (QoS uses high priority FIFO). The user
decides the number of QoS credits and sets this value with HMC
interface. The total credits for QoS capabilities can be changed
dynamically with HMC interface which invokes drmgr to communicate
to the kernel.
This patch creats 'update_total_credits' entry for QoS capabilities
so that drmgr command can write the new target QoS credits in sysfs.
Instead of using this value, the kernel gets the new QoS capabilities
from the hypervisor whenever update_total_credits is updated to make
sure sync with the QoS target credits in the hypervisor.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b01ef31a0f964686d00243e7de7f09c73c07e69e.camel@linux.ibm.com
The hypervisor provides the available VAS GZIP capabilities such
as default or QoS window type and the target available credits in
each type. This patch creates sysfs entries and exports the target,
used and the available credits for each feature.
This interface can be used by the user space to determine the credits
usage or to set the target credits in the case of QoS type (for DLPAR).
/sys/devices/vas/vas0/gzip/default_capabilities (default GZIP capabilities)
nr_total_credits /* Total credits available. Can be
/* changed with DLPAR operation */
nr_used_credits /* Used credits */
/sys/devices/vas/vas0/gzip/qos_capabilities (QoS GZIP capabilities)
nr_total_credits
nr_used_credits
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/702d8b626ebfac2b52f4995eebeafe1c9a6fcb75.camel@linux.ibm.com
VAS windows can be closed in the hypervisor due to lost credits
when the core is removed and the kernel gets fault for NX
requests on these inactive windows. If the NX requests are
issued on these inactive windows, OS gets page faults and the
paste failure will be returned to the user space. If the lost
credits are available later with core add, reopen these windows
and set them active. Later when the OS sees page faults on these
active windows, it creates mapping on the new paste address.
Then the user space can continue to use these windows and send
HW compression requests to NX successfully.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d9f360e21355e6826142c81146acfa9b60bc7ecc.camel@linux.ibm.com
The hypervisor assigns vas credits (windows) for each LPAR based
on the number of cores configured in that system. The OS is
expected to release credits when cores are removed, and may
allocate more when cores are added. So there is a possibility of
using excessive credits (windows) in the LPAR and the hypervisor
expects the system to close the excessive windows so that NX load
can be equally distributed across all LPARs in the system.
When the OS closes the excessive windows in the hypervisor,
it sets the window status inactive and invalidates window
virtual address mapping. The user space receives paste instruction
failure if any NX requests are issued on the inactive window.
Then the user space can use with the available open windows or
retry NX requests until this window active again.
This patch also adds the notifier for core removal/add to close
windows in the hypervisor if the system lost credits (core
removal) and reopen windows in the hypervisor when the previously
lost credits are available.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/108928f9c00a48cc6a722315d482d07cf66acf5a.camel@linux.ibm.com
The paste address mapping is done with mmap() after the window is
opened with ioctl. The partition has to close VAS windows in the
hypervisor if it lost credits due to DLPAR core removal. But the
kernel marks these windows inactive until the previously lost
credits are available later. If the window is inactive due to
DLPAR after this mmap(), the paste instruction returns failure
until the the OS reopens this window again.
Before the user space issuing mmap(), there is a possibility of
happening DLPAR core removal event which causes the corresponding
window inactive. So if the window is not active, return mmap()
failure with -EACCES and expects the user space reissue mmap()
when the window is active or open a new window when the credit
is available.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bbb203c26b324534e25658cb1dbbcb5160a2f93a.camel@linux.ibm.com
The VAS window may not be active if the system looses credits and
the NX generates page fault when it receives request on unmap
paste address.
The kernel handles the fault by remap new paste address if the
window is active again, Otherwise return the paste instruction
failure if the executed instruction that caused the fault was
a paste.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/492b9aefd593061d51dda67ee4d2fc449c000dce.camel@linux.ibm.com
The user space opens VAS windows and issues NX requests by pasting
CRB on the corresponding paste address mmap. When the system lost
credits due to core removal, the kernel has to close the window in
the hypervisor and make the window inactive by unmapping this paste
address. Also the OS has to handle NX request page faults if the user
space issue NX requests.
This handler maps the new paste address with the same VMA when the
window is active again (due to core add with DLPAR). Otherwise
returns paste failure.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3956e1c1fdfde69127055ff1c0256c7d71104030.camel@linux.ibm.com
The kernel sets the VAS window with PID when it is opened in
the hypervisor. During DLPAR operation, windows can be closed and
reopened in the hypervisor when the credit is available. So saves
this PID in pseries_vas_window struct when the window is opened
initially and reuse it later during DLPAR operation.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a57cbe6d292fe49ad55a0b49c5679d6a24d8fe73.camel@linux.ibm.com
nr_total/nr_used_credits provides credits usage to user space
via sysfs and the same interface can be used on PowerNV in
future. Changed with proper naming so that applicable on both
pseries and PowerNV.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f4313e9f198ee4f8d4fa4d015d8d1873e17851e6.camel@linux.ibm.com
Merge a topic branch we are maintaining with some cross-architecture
changes to function descriptor handling and their use in LKDTM.
From Christophe's cover letter:
Fix LKDTM for PPC64/IA64/PARISC
PPC64/IA64/PARISC have function descriptors. LKDTM doesn't work on those
three architectures because LKDTM messes up function descriptors with
functions.
This series does some cleanup in the three architectures and refactors
function descriptors so that it can then easily use it in a generic way
in LKDTM.
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian
2.37.90.20220207) the following build error shows up:
{standard input}: Assembler messages:
{standard input}:10576: Error: unrecognized opcode: `stbcx.'
{standard input}:10680: Error: unrecognized opcode: `lharx'
{standard input}:10694: Error: unrecognized opcode: `lbarx'
Rework to add assembler directives [1] around the instruction. The
problem with this might be that we can trick a power6 into
single-stepping through an stbcx. for instance, and it will execute that
in kernel mode.
[1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo
Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code")
Cc: stable@vger.kernel.org # v4.14+
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220224162215.3406642-3-anders.roxell@linaro.org
