1
0
Fork 0
Commit Graph

20919 Commits (bcf7f2d3fcec8a47ddfee6d8801ab57162922480)

Author SHA1 Message Date
Christophe Leroy 6958fbd52e powerpc/603: Always fault when _PAGE_ACCESSED is not set
commit 11522448e6 upstream.

The kernel expects pte_young() to work regardless of CONFIG_SWAP.

Make sure a minor fault is taken to set _PAGE_ACCESSED when it
is not already set, regardless of the selection of CONFIG_SWAP.

Fixes: 84de6ab0e9 ("powerpc/603: don't handle PAGE_ACCESSED in TLB miss handlers.")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a44367744de54e2315b2f1a8cbbd7f88488072e0.1602342806.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-18 19:20:33 +01:00
Qian Cai d261d0bd90 powerpc/eeh_cache: Fix a possible debugfs deadlock
[ Upstream commit fd552e0542 ]

Lockdep complains that a possible deadlock below in
eeh_addr_cache_show() because it is acquiring a lock with IRQ enabled,
but eeh_addr_cache_insert_dev() needs to acquire the same lock with IRQ
disabled. Let's just make eeh_addr_cache_show() acquire the lock with
IRQ disabled as well.

        CPU0                    CPU1
        ----                    ----
   lock(&pci_io_addr_cache_root.piar_lock);
                                local_irq_disable();
                                lock(&tp->lock);
                                lock(&pci_io_addr_cache_root.piar_lock);
   <Interrupt>
     lock(&tp->lock);

  *** DEADLOCK ***

  lock_acquire+0x140/0x5f0
  _raw_spin_lock_irqsave+0x64/0xb0
  eeh_addr_cache_insert_dev+0x48/0x390
  eeh_probe_device+0xb8/0x1a0
  pnv_pcibios_bus_add_device+0x3c/0x80
  pcibios_bus_add_device+0x118/0x290
  pci_bus_add_device+0x28/0xe0
  pci_bus_add_devices+0x54/0xb0
  pcibios_init+0xc4/0x124
  do_one_initcall+0xac/0x528
  kernel_init_freeable+0x35c/0x3fc
  kernel_init+0x24/0x148
  ret_from_kernel_thread+0x5c/0x80

  lock_acquire+0x140/0x5f0
  _raw_spin_lock+0x4c/0x70
  eeh_addr_cache_show+0x38/0x110
  seq_read+0x1a0/0x660
  vfs_read+0xc8/0x1f0
  ksys_read+0x74/0x130
  system_call_exception+0xf8/0x1d0
  system_call_common+0xe8/0x218

Fixes: 5ca85ae631 ("powerpc/eeh_cache: Add a way to dump the EEH address cache")
Signed-off-by: Qian Cai <cai@redhat.com>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201028152717.8967-1-cai@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-18 19:20:18 +01:00
Michael Neuling 415043c3ec powerpc: Fix undetected data corruption with P9N DD2.1 VSX CI load emulation
commit 1da4a0272c upstream.

__get_user_atomic_128_aligned() stores to kaddr using stvx which is a
VMX store instruction, hence kaddr must be 16 byte aligned otherwise
the store won't occur as expected.

Unfortunately when we call __get_user_atomic_128_aligned() in
p9_hmi_special_emu(), the buffer we pass as kaddr (ie. vbuf) isn't
guaranteed to be 16B aligned. This means that the write to vbuf in
__get_user_atomic_128_aligned() has the bottom bits of the address
truncated. This results in other local variables being
overwritten. Also vbuf will not contain the correct data which results
in the userspace emulation being wrong and hence undetected user data
corruption.

In the past we've been mostly lucky as vbuf has ended up aligned but
this is fragile and isn't always true. CONFIG_STACKPROTECTOR in
particular can change the stack arrangement enough that our luck runs
out.

This issue only occurs on POWER9 Nimbus <= DD2.1 bare metal.

The fix is to align vbuf to a 16 byte boundary.

Fixes: 5080332c2c ("powerpc/64s: Add workaround for P9 vector CI load issue")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201013043741.743413-1-mikey@neuling.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:31 +01:00
Christophe Leroy 94e27f1369 powerpc/powermac: Fix low_sleep_handler with KUAP and KUEP
commit 2c637d2df4 upstream.

low_sleep_handler() has an hardcoded restore of segment registers
that doesn't take KUAP and KUEP into account.

Use head_32's load_segment_registers() routine instead.

Fixes: a68c31fc01 ("powerpc/32s: Implement Kernel Userspace Access Protection")
Fixes: 31ed2b13c4 ("powerpc/32s: Implement Kernel Userspace Execution Prevention.")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21b05f7298c1b18f73e6e5b4cd5005aafa24b6da.1599820109.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:31 +01:00
Mahesh Salgaonkar 61ed8c1b94 powerpc/powernv/elog: Fix race while processing OPAL error log event.
commit aea948bb80 upstream.

Every error log reported by OPAL is exported to userspace through a
sysfs interface and notified using kobject_uevent(). The userspace
daemon (opal_errd) then reads the error log and acknowledges the error
log is saved safely to disk. Once acknowledged the kernel removes the
respective sysfs file entry causing respective resources to be
released including kobject.

However it's possible the userspace daemon may already be scanning
elog entries when a new sysfs elog entry is created by the kernel.
User daemon may read this new entry and ack it even before kernel can
notify userspace about it through kobject_uevent() call. If that
happens then we have a potential race between
elog_ack_store->kobject_put() and kobject_uevent which can lead to
use-after-free of a kernfs object resulting in a kernel crash. eg:

  BUG: Unable to handle kernel data access on read at 0x6b6b6b6b6b6b6bfb
  Faulting instruction address: 0xc0000000008ff2a0
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
  CPU: 27 PID: 805 Comm: irq/29-opal-elo Not tainted 5.9.0-rc2-gcc-8.2.0-00214-g6f56a67bcbb5-dirty #363
  ...
  NIP kobject_uevent_env+0xa0/0x910
  LR  elog_event+0x1f4/0x2d0
  Call Trace:
    0x5deadbeef0000122 (unreliable)
    elog_event+0x1f4/0x2d0
    irq_thread_fn+0x4c/0xc0
    irq_thread+0x1c0/0x2b0
    kthread+0x1c4/0x1d0
    ret_from_kernel_thread+0x5c/0x6c

This patch fixes this race by protecting the sysfs file
creation/notification by holding a reference count on kobject until we
safely send kobject_uevent().

The function create_elog_obj() returns the elog object which if used
by caller function will end up in use-after-free problem again.
However, the return value of create_elog_obj() function isn't being
used today and there is no need as well. Hence change it to return
void to make this fix complete.

Fixes: 774fea1a38 ("powerpc/powernv: Read OPAL error log and export it through sysfs")
Cc: stable@vger.kernel.org # v3.15+
Reported-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Rework the logic to use a single return, reword comments, add oops]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201006122051.190176-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:31 +01:00
Aneesh Kumar K.V 7850dd0851 powerpc/memhotplug: Make lmb size 64bit
commit 301d2ea657 upstream.

Similar to commit 89c140bbae ("pseries: Fix 64 bit logical memory block panic")
make sure different variables tracking lmb_size are updated to be 64 bit.

This was found by code audit.

Cc: stable@vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201007114836.282468-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:31 +01:00
Joel Stanley 3fa03b7f21 powerpc: Warn about use of smt_snooze_delay
commit a02f6d4235 upstream.

It's not done anything for a long time. Save the percpu variable, and
emit a warning to remind users to not expect it to do anything.

This uses pr_warn_once instead of pr_warn_ratelimit as testing
'ppc64_cpu --smt=off' on a 24 core / 4 SMT system showed the warning
to be noisy, as the online/offline loop is slow.

Fixes: 3fa8cad82b ("powerpc/pseries/cpuidle: smt-snooze-delay cleanup.")
Cc: stable@vger.kernel.org # v3.14
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902000012.3440389-1-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:31 +01:00
Andrew Donnellan 240baebeda powerpc/rtas: Restrict RTAS requests from userspace
commit bd59380c5b upstream.

A number of userspace utilities depend on making calls to RTAS to retrieve
information and update various things.

The existing API through which we expose RTAS to userspace exposes more
RTAS functionality than we actually need, through the sys_rtas syscall,
which allows root (or anyone with CAP_SYS_ADMIN) to make any RTAS call they
want with arbitrary arguments.

Many RTAS calls take the address of a buffer as an argument, and it's up to
the caller to specify the physical address of the buffer as an argument. We
allocate a buffer (the "RMO buffer") in the Real Memory Area that RTAS can
access, and then expose the physical address and size of this buffer in
/proc/powerpc/rtas/rmo_buffer. Userspace is expected to read this address,
poke at the buffer using /dev/mem, and pass an address in the RMO buffer to
the RTAS call.

However, there's nothing stopping the caller from specifying whatever
address they want in the RTAS call, and it's easy to construct a series of
RTAS calls that can overwrite arbitrary bytes (even without /dev/mem
access).

Additionally, there are some RTAS calls that do potentially dangerous
things and for which there are no legitimate userspace use cases.

In the past, this would not have been a particularly big deal as it was
assumed that root could modify all system state freely, but with Secure
Boot and lockdown we need to care about this.

We can't fundamentally change the ABI at this point, however we can address
this by implementing a filter that checks RTAS calls against a list
of permitted calls and forces the caller to use addresses within the RMO
buffer.

The list is based off the list of calls that are used by the librtas
userspace library, and has been tested with a number of existing userspace
RTAS utilities. For compatibility with any applications we are not aware of
that require other calls, the filter can be turned off at build time.

Cc: stable@vger.kernel.org
Reported-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200820044512.7543-1-ajd@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:30 +01:00
Aneesh Kumar K.V 73597ab2a9 powerpc/drmem: Make lmb_size 64 bit
commit ec72024e35 upstream.

Similar to commit 89c140bbae ("pseries: Fix 64 bit logical memory block panic")
make sure different variables tracking lmb_size are updated to be 64 bit.

This was found by code audit.

Cc: stable@vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201007114836.282468-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:43:30 +01:00
Fabiano Rosas 9b58c55ba8 KVM: PPC: Book3S HV: Do not allocate HPT for a nested guest
[ Upstream commit 05e6295dc7 ]

The current nested KVM code does not support HPT guests. This is
informed/enforced in some ways:

- Hosts < P9 will not be able to enable the nested HV feature;

- The nested hypervisor MMU capabilities will not contain
  KVM_CAP_PPC_MMU_HASH_V3;

- QEMU reflects the MMU capabilities in the
  'ibm,arch-vec-5-platform-support' device-tree property;

- The nested guest, at 'prom_parse_mmu_model' ignores the
  'disable_radix' kernel command line option if HPT is not supported;

- The KVM_PPC_CONFIGURE_V3_MMU ioctl will fail if trying to use HPT.

There is, however, still a way to start a HPT guest by using
max-compat-cpu=power8 at the QEMU machine options. This leads to the
guest being set to use hash after QEMU calls the KVM_PPC_ALLOCATE_HTAB
ioctl.

With the guest set to hash, the nested hypervisor goes through the
entry path that has no knowledge of nesting (kvmppc_run_vcpu) and
crashes when it tries to execute an hypervisor-privileged (mtspr
HDEC) instruction at __kvmppc_vcore_entry:

root@L1:~ $ qemu-system-ppc64 -machine pseries,max-cpu-compat=power8 ...

<snip>
[  538.543303] CPU: 83 PID: 25185 Comm: CPU 0/KVM Not tainted 5.9.0-rc4 #1
[  538.543355] NIP:  c00800000753f388 LR: c00800000753f368 CTR: c0000000001e5ec0
[  538.543417] REGS: c0000013e91e33b0 TRAP: 0700   Not tainted  (5.9.0-rc4)
[  538.543470] MSR:  8000000002843033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE>  CR: 22422882  XER: 20040000
[  538.543546] CFAR: c00800000753f4b0 IRQMASK: 3
               GPR00: c0080000075397a0 c0000013e91e3640 c00800000755e600 0000000080000000
               GPR04: 0000000000000000 c0000013eab19800 c000001394de0000 00000043a054db72
               GPR08: 00000000003b1652 0000000000000000 0000000000000000 c0080000075502e0
               GPR12: c0000000001e5ec0 c0000007ffa74200 c0000013eab19800 0000000000000008
               GPR16: 0000000000000000 c00000139676c6c0 c000000001d23948 c0000013e91e38b8
               GPR20: 0000000000000053 0000000000000000 0000000000000001 0000000000000000
               GPR24: 0000000000000001 0000000000000001 0000000000000000 0000000000000001
               GPR28: 0000000000000001 0000000000000053 c0000013eab19800 0000000000000001
[  538.544067] NIP [c00800000753f388] __kvmppc_vcore_entry+0x90/0x104 [kvm_hv]
[  538.544121] LR [c00800000753f368] __kvmppc_vcore_entry+0x70/0x104 [kvm_hv]
[  538.544173] Call Trace:
[  538.544196] [c0000013e91e3640] [c0000013e91e3680] 0xc0000013e91e3680 (unreliable)
[  538.544260] [c0000013e91e3820] [c0080000075397a0] kvmppc_run_core+0xbc8/0x19d0 [kvm_hv]
[  538.544325] [c0000013e91e39e0] [c00800000753d99c] kvmppc_vcpu_run_hv+0x404/0xc00 [kvm_hv]
[  538.544394] [c0000013e91e3ad0] [c0080000072da4fc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[  538.544472] [c0000013e91e3af0] [c0080000072d61b8] kvm_arch_vcpu_ioctl_run+0x310/0x420 [kvm]
[  538.544539] [c0000013e91e3b80] [c0080000072c7450] kvm_vcpu_ioctl+0x298/0x778 [kvm]
[  538.544605] [c0000013e91e3ce0] [c0000000004b8c2c] sys_ioctl+0x1dc/0xc90
[  538.544662] [c0000013e91e3dc0] [c00000000002f9a4] system_call_exception+0xe4/0x1c0
[  538.544726] [c0000013e91e3e20] [c00000000000d140] system_call_common+0xf0/0x27c
[  538.544787] Instruction dump:
[  538.544821] f86d1098 60000000 60000000 48000099 e8ad0fe8 e8c500a0 e9264140 75290002
[  538.544886] 7d1602a6 7cec42a6 40820008 7d0807b4 <7d164ba6> 7d083a14 f90d10a0 480104fd
[  538.544953] ---[ end trace 74423e2b948c2e0c ]---

This patch makes the KVM_PPC_ALLOCATE_HTAB ioctl fail when running in
the nested hypervisor, causing QEMU to abort.

Reported-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:21 +01:00
Nicholas Piggin 7d59323cff powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
[ Upstream commit 66acd46080 ]

powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:13 +01:00
Oliver O'Halloran dc17b990ee powerpc/powernv/smp: Fix spurious DBG() warning
[ Upstream commit f6bac19cf6 ]

When building with W=1 we get the following warning:

 arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
 arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
 	empty body in an ‘if’ statement [-Werror=empty-body]
   276 |      cpu, srr1);
       |                ^
 cc1: all warnings being treated as errors

The full context is this block:

 if (srr1 && !generic_check_cpu_restart(cpu))
 	DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
 			cpu, srr1);

When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:13 +01:00
Ganesh Goudar 5ef1279abc powerpc/pseries: Avoid using addr_to_pfn in real mode
[ Upstream commit 4ff753feab ]

When an UE or memory error exception is encountered the MCE handler
tries to find the pfn using addr_to_pfn() which takes effective
address as an argument, later pfn is used to poison the page where
memory error occurred, recent rework in this area made addr_to_pfn
to run in real mode, which can be fatal as it may try to access
memory outside RMO region.

Have two helper functions to separate things to be done in real mode
and virtual mode without changing any functionality. This also fixes
the following error as the use of addr_to_pfn is now moved to virtual
mode.

Without this change following kernel crash is seen on hitting UE.

[  485.128036] Oops: Kernel access of bad area, sig: 11 [#1]
[  485.128040] LE SMP NR_CPUS=2048 NUMA pSeries
[  485.128047] Modules linked in:
[  485.128067] CPU: 15 PID: 6536 Comm: insmod Kdump: loaded Tainted: G OE 5.7.0 #22
[  485.128074] NIP:  c00000000009b24c LR: c0000000000398d8 CTR: c000000000cd57c0
[  485.128078] REGS: c000000003f1f970 TRAP: 0300   Tainted: G OE (5.7.0)
[  485.128082] MSR:  8000000000001003 <SF,ME,RI,LE>  CR: 28008284  XER: 00000001
[  485.128088] CFAR: c00000000009b190 DAR: c0000001fab00000 DSISR: 40000000 IRQMASK: 1
[  485.128088] GPR00: 0000000000000001 c000000003f1fbf0 c000000001634300 0000b0fa01000000
[  485.128088] GPR04: d000000002220000 0000000000000000 00000000fab00000 0000000000000022
[  485.128088] GPR08: c0000001fab00000 0000000000000000 c0000001fab00000 c000000003f1fc14
[  485.128088] GPR12: 0000000000000008 c000000003ff5880 d000000002100008 0000000000000000
[  485.128088] GPR16: 000000000000ff20 000000000000fff1 000000000000fff2 d0000000021a1100
[  485.128088] GPR20: d000000002200000 c00000015c893c50 c000000000d49b28 c00000015c893c50
[  485.128088] GPR24: d0000000021a0d08 c0000000014e5da8 d0000000021a0818 000000000000000a
[  485.128088] GPR28: 0000000000000008 000000000000000a c0000000017e2970 000000000000000a
[  485.128125] NIP [c00000000009b24c] __find_linux_pte+0x11c/0x310
[  485.128130] LR [c0000000000398d8] addr_to_pfn+0x138/0x170
[  485.128133] Call Trace:
[  485.128135] Instruction dump:
[  485.128138] 3929ffff 7d4a3378 7c883c36 7d2907b4 794a1564 7d294038 794af082 3900ffff
[  485.128144] 79291f24 790af00e 78e70020 7d095214 <7c69502a> 2fa30000 419e011c 70690040
[  485.128152] ---[ end trace d34b27e29ae0e340 ]---

Fixes: 9ca766f989 ("powerpc/64s/pseries: machine check convert to use common event code")
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724063946.21378-1-ganeshgr@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:58:00 +01:00
Vasant Hegde 72ccbd1481 powerpc/powernv/dump: Fix race while processing OPAL dump
[ Upstream commit 0a43ae3e2b ]

Every dump reported by OPAL is exported to userspace through a sysfs
interface and notified using kobject_uevent(). The userspace daemon
(opal_errd) then reads the dump and acknowledges that the dump is
saved safely to disk. Once acknowledged the kernel removes the
respective sysfs file entry causing respective resources to be
released including kobject.

However it's possible the userspace daemon may already be scanning
dump entries when a new sysfs dump entry is created by the kernel.
User daemon may read this new entry and ack it even before kernel can
notify userspace about it through kobject_uevent() call. If that
happens then we have a potential race between
dump_ack_store->kobject_put() and kobject_uevent which can lead to
use-after-free of a kernfs object resulting in a kernel crash.

This patch fixes this race by protecting the sysfs file
creation/notification by holding a reference count on kobject until we
safely send kobject_uevent().

The function create_dump_obj() returns the dump object which if used
by caller function will end up in use-after-free problem again.
However, the return value of create_dump_obj() function isn't being
used today and there is no need as well. Hence change it to return
void to make this fix complete.

Fixes: c7e64b9ce0 ("powerpc/powernv Platform dump interface")
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201017164210.264619-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:58:00 +01:00
Kajol Jain ebe1a014d7 powerpc/perf/hv-gpci: Fix starting index value
[ Upstream commit 0f9866f7e8 ]

Commit 9e9f601084 ("powerpc/perf/{hv-gpci, hv-common}: generate
requests with counters annotated") adds a framework for defining
gpci counters.
In this patch, they adds starting_index value as '0xffffffffffffffff'.
which is wrong as starting_index is of size 32 bits.

Because of this, incase we try to run hv-gpci event we get error.

In power9 machine:

command#: perf stat -e hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
          -C 0 -I 1000
event syntax error: '..bie_count_and_time_tlbie_instructions_issued/'
                                  \___ value too big for format, maximum is 4294967295

This patch fix this issue and changes starting_index value to '0xffffffff'

After this patch:

command#: perf stat -e hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/ -C 0 -I 1000
     1.000085786              1,024      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
     2.000287818              1,024      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/
     2.439113909             17,408      hv_gpci/system_tlbie_count_and_time_tlbie_instructions_issued/

Fixes: 9e9f601084 ("powerpc/perf/{hv-gpci, hv-common}: generate requests with counters annotated")
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201003074943.338618-1-kjain@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:51 +01:00
Athira Rajeev 271e53005a powerpc/perf: Exclude pmc5/6 from the irrelevant PMU group constraints
[ Upstream commit 3b6c3adbb2 ]

PMU counter support functions enforces event constraints for group of
events to check if all events in a group can be monitored. Incase of
event codes using PMC5 and PMC6 ( 500fa and 600f4 respectively ), not
all constraints are applicable, say the threshold or sample bits. But
current code includes pmc5 and pmc6 in some group constraints (like
IC_DC Qualifier bits) which is actually not applicable and hence
results in those events not getting counted when scheduled along with
group of other events. Patch fixes this by excluding PMC5/6 from
constraints which are not relevant for it.

Fixes: 7ffd948 ("powerpc/perf: factor out power8 pmu functions")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1600672204-1610-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:51 +01:00
Nicholas Piggin 557c184df3 powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm
[ Upstream commit a665eec0a2 ]

Commit 0cef77c779 ("powerpc/64s/radix: flush remote CPUs out of
single-threaded mm_cpumask") added a mechanism to trim the mm_cpumask of
a process under certain conditions. One of the assumptions is that
mm_users would not be incremented via a reference outside the process
context with mmget_not_zero() then go on to kthread_use_mm() via that
reference.

That invariant was broken by io_uring code (see previous sparc64 fix),
but I'll point Fixes: to the original powerpc commit because we are
changing that assumption going forward, so this will make backports
match up.

Fix this by no longer relying on that assumption, but by having each CPU
check the mm is not being used, and clearing their own bit from the mask
only if it hasn't been switched-to by the time the IPI is processed.

This relies on commit 38cf307c1f ("mm: fix kthread_use_mm() vs TLB
invalidate") and ARCH_WANT_IRQS_OFF_ACTIVATE_MM to disable irqs over mm
switch sequences.

Fixes: 0cef77c779 ("powerpc/64s/radix: flush remote CPUs out of single-threaded mm_cpumask")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Depends-on: 38cf307c1f ("mm: fix kthread_use_mm() vs TLB invalidate")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-5-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Finn Thain 148d4f4dc7 powerpc/tau: Disable TAU between measurements
[ Upstream commit e63d6fb563 ]

Enabling CONFIG_TAU_INT causes random crashes:

Unrecoverable exception 1700 at c0009414 (msr=1000)
Oops: Unrecoverable exception, sig: 6 [#1]
BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-pmac-00043-gd5f545e1a8593 #5
NIP:  c0009414 LR: c0009414 CTR: c00116fc
REGS: c0799eb8 TRAP: 1700   Not tainted  (5.7.0-pmac-00043-gd5f545e1a8593)
MSR:  00001000 <ME>  CR: 22000228  XER: 00000100

GPR00: 00000000 c0799f70 c076e300 00800000 0291c0ac 00e00000 c076e300 00049032
GPR08: 00000001 c00116fc 00000000 dfbd3200 ffffffff 007f80a8 00000000 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c075ce04
GPR24: c075ce04 dfff8880 c07b0000 c075ce04 00080000 00000001 c079ef98 c079ef5c
NIP [c0009414] arch_cpu_idle+0x24/0x6c
LR [c0009414] arch_cpu_idle+0x24/0x6c
Call Trace:
[c0799f70] [00000001] 0x1 (unreliable)
[c0799f80] [c0060990] do_idle+0xd8/0x17c
[c0799fa0] [c0060ba4] cpu_startup_entry+0x20/0x28
[c0799fb0] [c072d220] start_kernel+0x434/0x44c
[c0799ff0] [00003860] 0x3860
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX 3d20c07b XXXXXXXX XXXXXXXX XXXXXXXX 7c0802a6
XXXXXXXX XXXXXXXX XXXXXXXX 4e800421 XXXXXXXX XXXXXXXX XXXXXXXX 7d2000a6
---[ end trace 3a0c9b5cb216db6b ]---

Resolve this problem by disabling each THRMn comparator when handling
the associated THRMn interrupt and by disabling the TAU entirely when
updating THRMn thresholds.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5a0ba3dc5612c7aac596727331284a3676c08472.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Finn Thain 72407b8d08 powerpc/tau: Check processor type before enabling TAU interrupt
[ Upstream commit 5e3119e15f ]

According to Freescale's documentation, MPC74XX processors have an
erratum that prevents the TAU interrupt from working, so don't try to
use it when running on those processors.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c281611544768e758bd58fe812cf702a5bd2d042.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Finn Thain 68a8ec0b02 powerpc/tau: Remove duplicated set_thresholds() call
[ Upstream commit 420ab2bc75 ]

The commentary at the call site seems to disagree with the code. The
conditional prevents calling set_thresholds() via the exception handler,
which appears to crash. Perhaps that's because it immediately triggers
another TAU exception. Anyway, calling set_thresholds() from TAUupdate()
is redundant because tau_timeout() does so.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d7c7ee33232cf72a6a6bbb6ef05838b2e2b113c0.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Finn Thain c0578b423b powerpc/tau: Convert from timer to workqueue
[ Upstream commit b1c6a0a10b ]

Since commit 19dbdcb803 ("smp: Warn on function calls from softirq
context") the Thermal Assist Unit driver causes a warning like the
following when CONFIG_SMP is enabled.

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 0 at kernel/smp.c:428 smp_call_function_many_cond+0xf4/0x38c
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-pmac #3
  NIP:  c00b37a8 LR: c00b3abc CTR: c001218c
  REGS: c0799c60 TRAP: 0700   Not tainted  (5.7.0-pmac)
  MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 42000224  XER: 00000000
  GPR00: c00b3abc c0799d18 c076e300 c079ef5c c0011fec 00000000 00000000 00000000
  GPR08: 00000100 00000100 00008000 ffffffff 42000224 00000000 c079d040 c079d044
  GPR16: 00000001 00000000 00000004 c0799da0 c079f054 c07a0000 c07a0000 00000000
  GPR24: c0011fec 00000000 c079ef5c c079ef5c 00000000 00000000 00000000 00000000
  NIP [c00b37a8] smp_call_function_many_cond+0xf4/0x38c
  LR [c00b3abc] on_each_cpu+0x38/0x68
  Call Trace:
  [c0799d18] [ffffffff] 0xffffffff (unreliable)
  [c0799d68] [c00b3abc] on_each_cpu+0x38/0x68
  [c0799d88] [c0096704] call_timer_fn.isra.26+0x20/0x7c
  [c0799d98] [c0096b40] run_timer_softirq+0x1d4/0x3fc
  [c0799df8] [c05b4368] __do_softirq+0x118/0x240
  [c0799e58] [c0039c44] irq_exit+0xc4/0xcc
  [c0799e68] [c000ade8] timer_interrupt+0x1b0/0x230
  [c0799ea8] [c0013520] ret_from_except+0x0/0x14
  --- interrupt: 901 at arch_cpu_idle+0x24/0x6c
      LR = arch_cpu_idle+0x24/0x6c
  [c0799f70] [00000001] 0x1 (unreliable)
  [c0799f80] [c0060990] do_idle+0xd8/0x17c
  [c0799fa0] [c0060ba8] cpu_startup_entry+0x24/0x28
  [c0799fb0] [c072d220] start_kernel+0x434/0x44c
  [c0799ff0] [00003860] 0x3860
  Instruction dump:
  8129f204 2f890000 40beff98 3d20c07a 8929eec4 2f890000 40beff88 0fe00000
  81220000 552805de 550802ef 4182ff84 <0fe00000> 3860ffff 7f65db78 7f44d378
  ---[ end trace 34a886e47819c2eb ]---

Don't call on_each_cpu() from a timer callback, call it from a worker
thread instead.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bb61650bea4f4c91fb8e24b9a6f130a1438651a7.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Finn Thain 0305488040 powerpc/tau: Use appropriate temperature sample interval
[ Upstream commit 66943005cc ]

According to the MPC750 Users Manual, the SITV value in Thermal
Management Register 3 is 13 bits long. The present code calculates the
SITV value as 60 * 500 cycles. This would overflow to give 10 us on
a 500 MHz CPU rather than the intended 60 us. (But according to the
Microprocessor Datasheet, there is also a factor of 266 that has to be
applied to this value on certain parts i.e. speed sort above 266 MHz.)
Always use the maximum cycle count, as recommended by the Datasheet.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/896f542e5f0f1d6cf8218524c2b67d79f3d69b3c.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:49 +01:00
Aneesh Kumar K.V a2087c04a2 powerpc/book3s64/hash/4k: Support large linear mapping range with 4K
[ Upstream commit 7746406baa ]

With commit: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel
regions in the same 0xc range"), we now split the 64TB address range
into 4 contexts each of 16TB. That implies we can do only 16TB linear
mapping.

On some systems, eg. Power9, memory attached to nodes > 0 will appear
above 16TB in the linear mapping. This resulted in kernel crash when
we boot such systems in hash translation mode with 4K PAGE_SIZE.

This patch updates the kernel mapping such that we now start supporting upto
61TB of memory with 4K. The kernel mapping now looks like below 4K PAGE_SIZE
and hash translation.

    vmalloc start     = 0xc0003d0000000000
    IO start          = 0xc0003e0000000000
    vmemmap start     = 0xc0003f0000000000

Our MAX_PHYSMEM_BITS for 4K is still 64TB even though we can only map 61TB.
We prevent bolt mapping anything outside 61TB range by checking against
H_VMALLOC_START.

Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Reported-by: Cameron Berkenpas <cam@neo-zeon.de>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200608070904.387440-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:48 +01:00
Scott Cheloha 935950e319 pseries/drmem: don't cache node id in drmem_lmb struct
[ Upstream commit e5e179aa3a ]

At memory hot-remove time we can retrieve an LMB's nid from its
corresponding memory_block.  There is no need to store the nid
in multiple locations.

Note that lmb_to_memblock() uses find_memory_block() to get the
corresponding memory_block.  As find_memory_block() runs in sub-linear
time this approach is negligibly slower than what we do at present.

In exchange for this lookup at hot-remove time we no longer need to
call memory_add_physaddr_to_nid() during drmem_init() for each LMB.
On powerpc, memory_add_physaddr_to_nid() is a linear search, so this
spares us an O(n^2) initialization during boot.

On systems with many LMBs that initialization overhead is palpable and
disruptive.  For example, on a box with 249854 LMBs we're seeing
drmem_init() take upwards of 30 seconds to complete:

[   53.721639] drmem: initializing drmem v2
[   80.604346] watchdog: BUG: soft lockup - CPU#65 stuck for 23s! [swapper/0:1]
[   80.604377] Modules linked in:
[   80.604389] CPU: 65 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc2+ #4
[   80.604397] NIP:  c0000000000a4980 LR: c0000000000a4940 CTR: 0000000000000000
[   80.604407] REGS: c0002dbff8493830 TRAP: 0901   Not tainted  (5.6.0-rc2+)
[   80.604412] MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 44000248  XER: 0000000d
[   80.604431] CFAR: c0000000000a4a38 IRQMASK: 0
[   80.604431] GPR00: c0000000000a4940 c0002dbff8493ac0 c000000001904400 c0003cfffffede30
[   80.604431] GPR04: 0000000000000000 c000000000f4095a 000000000000002f 0000000010000000
[   80.604431] GPR08: c0000bf7ecdb7fb8 c0000bf7ecc2d3c8 0000000000000008 c00c0002fdfb2001
[   80.604431] GPR12: 0000000000000000 c00000001e8ec200
[   80.604477] NIP [c0000000000a4980] hot_add_scn_to_nid+0xa0/0x3e0
[   80.604486] LR [c0000000000a4940] hot_add_scn_to_nid+0x60/0x3e0
[   80.604492] Call Trace:
[   80.604498] [c0002dbff8493ac0] [c0000000000a4940] hot_add_scn_to_nid+0x60/0x3e0 (unreliable)
[   80.604509] [c0002dbff8493b20] [c000000000087c10] memory_add_physaddr_to_nid+0x20/0x60
[   80.604521] [c0002dbff8493b40] [c0000000010d4880] drmem_init+0x25c/0x2f0
[   80.604530] [c0002dbff8493c10] [c000000000010154] do_one_initcall+0x64/0x2c0
[   80.604540] [c0002dbff8493ce0] [c0000000010c4aa0] kernel_init_freeable+0x2d8/0x3a0
[   80.604550] [c0002dbff8493db0] [c000000000010824] kernel_init+0x2c/0x148
[   80.604560] [c0002dbff8493e20] [c00000000000b648] ret_from_kernel_thread+0x5c/0x74
[   80.604567] Instruction dump:
[   80.604574] 392918e8 e9490000 e90a000a e92a0000 80ea000c 1d080018 3908ffe8 7d094214
[   80.604586] 7fa94040 419d00dc e9490010 714a0088 <2faa0008> 409e00ac e9490000 7fbe5040
[   89.047390] drmem: 249854 LMB(s)

With a patched kernel on the same machine we're no longer seeing the
soft lockup.  drmem_init() now completes in negligible time, even when
the LMB count is large.

Fixes: b2d3b5ee66 ("powerpc/pseries: Track LMB nid instead of using device tree")
Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200811015115.63677-1-cheloha@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:47 +01:00
Nathan Lynch eb327e9863 powerpc/pseries: explicitly reschedule during drmem_lmb list traversal
[ Upstream commit 9d6792ffe1 ]

The drmem lmb list can have hundreds of thousands of entries, and
unfortunately lookups take the form of linear searches. As long as
this is the case, traversals have the potential to monopolize the CPU
and provoke lockup reports, workqueue stalls, and the like unless
they explicitly yield.

Rather than placing cond_resched() calls within various
for_each_drmem_lmb() loop blocks in the code, put it in the iteration
expression of the loop macro itself so users can't omit it.

Introduce a drmem_lmb_next() iteration helper function which calls
cond_resched() at a regular interval during array traversal. Each
iteration of the loop in DLPAR code paths can involve around ten RTAS
calls which can each take up to 250us, so this ensures the check is
performed at worst every few milliseconds.

Fixes: 6c6ea53725 ("powerpc/mm: Separate ibm, dynamic-memory data from DT format")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200813151131.2070161-1-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:47 +01:00
Nicholas Mc Guire 22d8bebf63 powerpc/icp-hv: Fix missing of_node_put() in success path
[ Upstream commit d3e669f31e ]

Both of_find_compatible_node() and of_find_node_by_type() will return
a refcounted node on success - thus for the success path the node must
be explicitly released with a of_node_put().

Fixes: 0b05ac6e24 ("powerpc/xics: Rewrite XICS driver")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1530691407-3991-1-git-send-email-hofrat@osadl.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:46 +01:00
Nicholas Mc Guire d2575bf272 powerpc/pseries: Fix missing of_node_put() in rng_init()
[ Upstream commit 67c3e59443 ]

The call to of_find_compatible_node() returns a node pointer with
refcount incremented thus it must be explicitly decremented here
before returning.

Fixes: a489043f46 ("powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1530522496-14816-1-git-send-email-hofrat@osadl.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-29 09:57:46 +01:00
Paul Mackerras ad9940e377 KVM: PPC: Book3S HV: Close race with page faults around memslot flushes
[ Upstream commit 11362b1bef ]

There is a potential race condition between hypervisor page faults
and flushing a memslot.  It is possible for a page fault to read the
memslot before a memslot is updated and then write a PTE to the
partition-scoped page tables after kvmppc_radix_flush_memslot has
completed.  (Note that this race has never been explicitly observed.)

To close this race, it is sufficient to increment the MMU sequence
number while the kvm->mmu_lock is held.  That will cause
mmu_notifier_retry() to return true, and the page fault will then
return to the guest without inserting a PTE.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:18:05 +02:00
Nicholas Piggin 7c972122ca powerpc/traps: Make unrecoverable NMIs die instead of panic
[ Upstream commit 265d6e588d ]

System Reset and Machine Check interrupts that are not recoverable due
to being nested or interrupting when RI=0 currently panic. This is not
necessary, and can often just kill the current context and recover.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Link: https://lore.kernel.org/r/20200508043408.886394-16-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:18:01 +02:00
Anju T Sudhakar 685a1e317a powerpc/perf: Implement a global lock to avoid races between trace, core and thread imc events.
[ Upstream commit a36e8ba60b ]

IMC(In-memory Collection Counters) does performance monitoring in
two different modes, i.e accumulation mode(core-imc and thread-imc events),
and trace mode(trace-imc events). A cpu thread can either be in
accumulation-mode or trace-mode at a time and this is done via the LDBAR
register in POWER architecture. The current design does not address the
races between thread-imc and trace-imc events.

Patch implements a global id and lock to avoid the races between
core, trace and thread imc events. With this global id-lock
implementation, the system can either run core, thread or trace imc
events at a time. i.e. to run any core-imc events, thread/trace imc events
should not be enabled/monitored.

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200313055238.8656-1-anju@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:52 +02:00
Gustavo Romero 5d09e3edf5 KVM: PPC: Book3S HV: Treat TM-related invalid form instructions on P9 like the valid ones
[ Upstream commit 1dff3064c7 ]

On P9 DD2.2 due to a CPU defect some TM instructions need to be emulated by
KVM. This is handled at first by the hardware raising a softpatch interrupt
when certain TM instructions that need KVM assistance are executed in the
guest. Althought some TM instructions per Power ISA are invalid forms they
can raise a softpatch interrupt too. For instance, 'tresume.' instruction
as defined in the ISA must have bit 31 set (1), but an instruction that
matches 'tresume.' PO and XO opcode fields but has bit 31 not set (0), like
0x7cfe9ddc, also raises a softpatch interrupt. Similarly for 'treclaim.'
and 'trechkpt.' instructions with bit 31 = 0, i.e. 0x7c00075c and
0x7c0007dc, respectively. Hence, if a code like the following is executed
in the guest it will raise a softpatch interrupt just like a 'tresume.'
when the TM facility is enabled ('tabort. 0' in the example is used only
to enable the TM facility):

int main() { asm("tabort. 0; .long 0x7cfe9ddc;"); }

Currently in such a case KVM throws a complete trace like:

[345523.705984] WARNING: CPU: 24 PID: 64413 at arch/powerpc/kvm/book3s_hv_tm.c:211 kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.705985] Modules linked in: kvm_hv(E) xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp ip6table_mangle ip6table_nat
iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ebtable_filter ebtables ip6table_filter
ip6_tables iptable_filter bridge stp llc sch_fq_codel ipmi_powernv at24 vmx_crypto ipmi_devintf ipmi_msghandler
ibmpowernv uio_pdrv_genirq kvm opal_prd uio leds_powernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp
libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456
async_raid6_recov async_memcpy async_pq async_xor async_tx libcrc32c xor raid6_pq raid1 raid0 multipath linear tg3
crct10dif_vpmsum crc32c_vpmsum ipr [last unloaded: kvm_hv]
[345523.706030] CPU: 24 PID: 64413 Comm: CPU 0/KVM Tainted: G        W   E     5.5.0+ #1
[345523.706031] NIP:  c0080000072cb9c0 LR: c0080000072b5e80 CTR: c0080000085c7850
[345523.706034] REGS: c000000399467680 TRAP: 0700   Tainted: G        W   E      (5.5.0+)
[345523.706034] MSR:  900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>  CR: 24022428  XER: 00000000
[345523.706042] CFAR: c0080000072b5e7c IRQMASK: 0
                GPR00: c0080000072b5e80 c000000399467910 c0080000072db500 c000000375ccc720
                GPR04: c000000375ccc720 00000003fbec0000 0000a10395dda5a6 0000000000000000
                GPR08: 000000007cfe9ddc 7cfe9ddc000005dc 7cfe9ddc7c0005dc c0080000072cd530
                GPR12: c0080000085c7850 c0000003fffeb800 0000000000000001 00007dfb737f0000
                GPR16: c0002001edcca558 0000000000000000 0000000000000000 0000000000000001
                GPR20: c000000001b21258 c0002001edcca558 0000000000000018 0000000000000000
                GPR24: 0000000001000000 ffffffffffffffff 0000000000000001 0000000000001500
                GPR28: c0002001edcc4278 c00000037dd80000 800000050280f033 c000000375ccc720
[345523.706062] NIP [c0080000072cb9c0] kvmhv_p9_tm_emulation+0x68/0x620 [kvm_hv]
[345523.706065] LR [c0080000072b5e80] kvmppc_handle_exit_hv.isra.53+0x3e8/0x798 [kvm_hv]
[345523.706066] Call Trace:
[345523.706069] [c000000399467910] [c000000399467940] 0xc000000399467940 (unreliable)
[345523.706071] [c000000399467950] [c000000399467980] 0xc000000399467980
[345523.706075] [c0000003994679f0] [c0080000072bd1c4] kvmhv_run_single_vcpu+0xa1c/0xb80 [kvm_hv]
[345523.706079] [c000000399467ac0] [c0080000072bd8e0] kvmppc_vcpu_run_hv+0x5b8/0xb00 [kvm_hv]
[345523.706087] [c000000399467b90] [c0080000085c93cc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[345523.706095] [c000000399467bb0] [c0080000085c582c] kvm_arch_vcpu_ioctl_run+0x244/0x420 [kvm]
[345523.706101] [c000000399467c40] [c0080000085b7498] kvm_vcpu_ioctl+0x3d0/0x7b0 [kvm]
[345523.706105] [c000000399467db0] [c0000000004adf9c] ksys_ioctl+0x13c/0x170
[345523.706107] [c000000399467e00] [c0000000004adff8] sys_ioctl+0x28/0x80
[345523.706111] [c000000399467e20] [c00000000000b278] system_call+0x5c/0x68
[345523.706112] Instruction dump:
[345523.706114] 419e0390 7f8a4840 409d0048 6d497c00 2f89075d 419e021c 6d497c00 2f8907dd
[345523.706119] 419e01c0 6d497c00 2f8905dd 419e00a4 <0fe00000> 38210040 38600000 ebc1fff0

and then treats the executed instruction as a 'nop'.

However the POWER9 User's Manual, in section "4.6.10 Book II Invalid
Forms", informs that for TM instructions bit 31 is in fact ignored, thus
for the TM-related invalid forms ignoring bit 31 and handling them like the
valid forms is an acceptable way to handle them. POWER8 behaves the same
way too.

This commit changes the handling of the cases here described by treating
the TM-related invalid forms that can generate a softpatch interrupt
just like their valid forms (w/ bit 31 = 1) instead of as a 'nop' and by
gently reporting any other unrecognized case to the host and treating it as
illegal instruction instead of throwing a trace and treating it as a 'nop'.

Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Acked-By: Michael Neuling <mikey@neuling.org>
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:44 +02:00
Alexey Kardashevskiy f211830829 powerpc/book3s64: Fix error handling in mm_iommu_do_alloc()
[ Upstream commit c4b78169e3 ]

The last jump to free_exit in mm_iommu_do_alloc() happens after page
pointers in struct mm_iommu_table_group_mem_t were already converted to
physical addresses. Thus calling put_page() on these physical addresses
will likely crash.

This moves the loop which calculates the pageshift and converts page
struct pointers to physical addresses later after the point when
we cannot fail; thus eliminating the need to convert pointers back.

Fixes: eb9d7a62c3 ("powerpc/mm_iommu: Fix potential deadlock")
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191223060351.26359-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:38 +02:00
Oliver O'Halloran 821bf0bf65 powerpc/eeh: Only dump stack once if an MMIO loop is detected
[ Upstream commit 4e0942c030 ]

Many drivers don't check for errors when they get a 0xFFs response from an
MMIO load. As a result after an EEH event occurs a driver can get stuck in
a polling loop unless it some kind of internal timeout logic.

Currently EEH tries to detect and report stuck drivers by dumping a stack
trace after eeh_dev_check_failure() is called EEH_MAX_FAILS times on an
already frozen PE. The value of EEH_MAX_FAILS was chosen so that a dump
would occur every few seconds if the driver was spinning in a loop. This
results in a lot of spurious stack traces in the kernel log.

Fix this by limiting it to printing one stack trace for each PE freeze. If
the driver is truely stuck the kernel's hung task detector is better suited
to reporting the probelm anyway.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191016012536.22588-1-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:28 +02:00
Michael Ellerman 75a1c45694 powerpc/64s: Always disable branch profiling for prom_init.o
[ Upstream commit 6266a4dadb ]

Otherwise the build fails because prom_init is calling symbols it's
not allowed to, eg:

  Error: External symbol 'ftrace_likely_update' referenced from prom_init.c
  make[3]: *** [arch/powerpc/kernel/Makefile:197: arch/powerpc/kernel/prom_init_check] Error 1

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191106051129.7626-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:15 +02:00
Alexey Kardashevskiy 5ed6a7e1a7 powerpc/dma: Fix dma_map_ops::get_required_mask
commit 437ef802e0 upstream.

There are 2 problems with it:
  1. "<" vs expected "<<"
  2. the shift number is an IOMMU page number mask, not an address
  mask as the IOMMU page shift is missing.

This did not hit us before f1565c24b5 ("powerpc: use the generic
dma_ops_bypass mode") because we had additional code to handle bypass
mask so this chunk (almost?) never executed.However there were
reports that aacraid does not work with "iommu=nobypass".

After f1565c24b5, aacraid (and probably others which call
dma_get_required_mask() before setting the mask) was unable to enable
64bit DMA and fall back to using IOMMU which was known not to work,
one of the problems is double free of an IOMMU page.

This fixes DMA for aacraid, both with and without "iommu=nobypass" in
the kernel command line. Verified with "stress-ng -d 4".

Fixes: 6a5c7be5e4 ("powerpc: Override dma_get_required_mask by platform hook and ops")
Cc: stable@vger.kernel.org # v3.2+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200908015106.79661-1-aik@ozlabs.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-23 12:40:46 +02:00
Aneesh Kumar K.V 600cafd55b powerpc/book3s64/radix: Fix boot failure with large amount of guest memory
[ Upstream commit 103a8542cb ]

If the hypervisor doesn't support hugepages, the kernel ends up allocating a large
number of page table pages. The early page table allocation was wrongly
setting the max memblock limit to ppc64_rma_size with radix translation
which resulted in boot failure as shown below.

Kernel panic - not syncing:
early_alloc_pgtable: Failed to allocate 16777216 bytes align=0x1000000 nid=-1 from=0x0000000000000000 max_addr=0xffffffffffffffff
 CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-24.9-default+ #2
 Call Trace:
 [c0000000016f3d00] [c0000000007c6470] dump_stack+0xc4/0x114 (unreliable)
 [c0000000016f3d40] [c00000000014c78c] panic+0x164/0x418
 [c0000000016f3dd0] [c000000000098890] early_alloc_pgtable+0xe0/0xec
 [c0000000016f3e60] [c0000000010a5440] radix__early_init_mmu+0x360/0x4b4
 [c0000000016f3ef0] [c000000001099bac] early_init_mmu+0x1c/0x3c
 [c0000000016f3f10] [c00000000109a320] early_setup+0x134/0x170

This was because the kernel was checking for the radix feature before we enable the
feature via mmu_features. This resulted in the kernel using hash restrictions on
radix.

Rework the early init code such that the kernel boot with memblock restrictions
as imposed by hash. At that point, the kernel still hasn't finalized the
translation the kernel will end up using.

We have three different ways of detecting radix.

1. dt_cpu_ftrs_scan -> used only in case of PowerNV
2. ibm,pa-features -> Used when we don't use cpu_dt_ftr_scan
3. CAS -> Where we negotiate with hypervisor about the supported translation.

We look at 1 or 2 early in the boot and after that, we look at the CAS vector to
finalize the translation the kernel will use. We also support a kernel command
line option (disable_radix) to switch to hash.

Update the memblock limit after mmu_early_init_devtree() if the kernel is going
to use radix translation. This forces some of the memblock allocations we do before
mmu_early_init_devtree() to be within the RMA limit.

Fixes: 2bfd65e45e ("powerpc/mm/radix: Add radix callbacks for early init routines")
Reported-by: Shirisha Ganta <shiganta@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200828100852.426575-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-23 12:40:39 +02:00
Linus Torvalds 087b6cb17d vgacon: remove software scrollback support
commit 973c096f6a upstream.

Yunhai Zhang recently fixed a VGA software scrollback bug in commit
ebfdfeeae8 ("vgacon: Fix for missing check in scrollback handling"),
but that then made people look more closely at some of this code, and
there were more problems on the vgacon side, but also the fbcon software
scrollback.

We don't really have anybody who maintains this code - probably because
nobody actually _uses_ it any more.  Sure, people still use both VGA and
the framebuffer consoles, but they are no longer the main user
interfaces to the kernel, and haven't been for decades, so these kinds
of extra features end up bitrotting and not really being used.

So rather than try to maintain a likely unused set of code, I'll just
aggressively remove it, and see if anybody even notices.  Maybe there
are people who haven't jumped on the whole GUI badnwagon yet, and think
it's just a fad.  And maybe those people use the scrollback code.

If that turns out to be the case, we can resurrect this again, once
we've found the sucker^Wmaintainer for it who actually uses it.

Reported-by: NopNop Nop <nopitydays@gmail.com>
Tested-by: Willy Tarreau <w@1wt.eu>
Cc: 张云海 <zhangyunhai@nsfocus.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-17 13:47:54 +02:00
Alexey Kardashevskiy df2a6a4a9d powerpc/perf: Fix crashes with generic_compat_pmu & BHRB
commit b460b51241 upstream.

The bhrb_filter_map ("The Branch History Rolling Buffer") callback is
only defined in raw CPUs' power_pmu structs. The "architected" CPUs
use generic_compat_pmu, which does not have this callback, and crashes
occur if a user tries to enable branch stack for an event.

This add a NULL pointer check for bhrb_filter_map() which behaves as
if the callback returned an error.

This does not add the same check for config_bhrb() as the only caller
checks for cpuhw->bhrb_users which remains zero if bhrb_filter_map==0.

Fixes: be80e758d0 ("powerpc/perf: Add generic compat mode pmu driver")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200602025612.62707-1-aik@ozlabs.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03 11:27:05 +02:00
Athira Rajeev 7d44b707aa powerpc/perf: Fix soft lockups due to missed interrupt accounting
[ Upstream commit 17899eaf88 ]

Performance monitor interrupt handler checks if any counter has
overflown and calls record_and_restart() in core-book3s which invokes
perf_event_overflow() to record the sample information. Apart from
creating sample, perf_event_overflow() also does the interrupt and
period checks via perf_event_account_interrupt().

Currently we record information only if the SIAR (Sampled Instruction
Address Register) valid bit is set (using siar_valid() check) and
hence the interrupt check.

But it is possible that we do sampling for some events that are not
generating valid SIAR, and hence there is no chance to disable the
event if interrupts are more than max_samples_per_tick. This leads to
soft lockup.

Fix this by adding perf_event_account_interrupt() in the invalid SIAR
code path for a sampling event. ie if SIAR is invalid, just do
interrupt check and don't record the sample information.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596717992-7321-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03 11:27:01 +02:00
Arnd Bergmann e77f71c634 powerpc/spufs: add CONFIG_COREDUMP dependency
[ Upstream commit b648a5132c ]

The kernel test robot pointed out a slightly different error message
after recent commit 5456ffdee6 ("powerpc/spufs: simplify spufs core
dumping") to spufs for a configuration that never worked:

   powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_proxydma_info_dump':
>> file.c:(.text+0x4c68): undefined reference to `.dump_emit'
   powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_dma_info_dump':
   file.c:(.text+0x4d70): undefined reference to `.dump_emit'
   powerpc64-linux-ld: arch/powerpc/platforms/cell/spufs/file.o: in function `.spufs_wbox_info_dump':
   file.c:(.text+0x4df4): undefined reference to `.dump_emit'

Add a Kconfig dependency to prevent this from happening again.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200706132302.3885935-1-arnd@arndb.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03 11:26:48 +02:00
Alexey Kardashevskiy 1dc0ed1821 powerpc/xive: Ignore kmemleak false positives
[ Upstream commit f0993c839e ]

xive_native_provision_pages() allocates memory and passes the pointer to
OPAL so kmemleak cannot find the pointer usage in the kernel memory and
produces a false positive report (below) (even if the kernel did scan
OPAL memory, it is unable to deal with __pa() addresses anyway).

This silences the warning.

unreferenced object 0xc000200350c40000 (size 65536):
  comm "qemu-system-ppc", pid 2725, jiffies 4294946414 (age 70776.530s)
  hex dump (first 32 bytes):
    02 00 00 00 50 00 00 00 00 00 00 00 00 00 00 00  ....P...........
    01 00 08 07 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000081ff046c>] xive_native_alloc_vp_block+0x120/0x250
    [<00000000d555d524>] kvmppc_xive_compute_vp_id+0x248/0x350 [kvm]
    [<00000000d69b9c9f>] kvmppc_xive_connect_vcpu+0xc0/0x520 [kvm]
    [<000000006acbc81c>] kvm_arch_vcpu_ioctl+0x308/0x580 [kvm]
    [<0000000089c69580>] kvm_vcpu_ioctl+0x19c/0xae0 [kvm]
    [<00000000902ae91e>] ksys_ioctl+0x184/0x1b0
    [<00000000f3e68bd7>] sys_ioctl+0x48/0xb0
    [<0000000001b2c127>] system_call_exception+0x124/0x1f0
    [<00000000d2b2ee40>] system_call_common+0xe8/0x214

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612043303.84894-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03 11:26:42 +02:00
Michael Ellerman 669fc3b38c powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
commit 0828137e8f upstream.

__init_FSCR() was added originally in commit 2468dcf641 ("powerpc:
Add support for context switching the TAR register") (Feb 2013), and
only set FSCR_TAR.

At that point FSCR (Facility Status and Control Register) was not
context switched, so the setting was permanent after boot.

Later we added initialisation of FSCR_DSCR to __init_FSCR(), in commit
54c9b2253d ("powerpc: Set DSCR bit in FSCR setup") (Mar 2013), again
that was permanent after boot.

Then commit 2517617e0d ("powerpc: Fix context switch DSCR on
POWER8") (Aug 2013) added a limited context switch of FSCR, just the
FSCR_DSCR bit was context switched based on thread.dscr_inherit. That
commit said "This clears the H/FSCR DSCR bit initially", but it
didn't, it left the initialisation of FSCR_DSCR in __init_FSCR().
However the initial context switch from init_task to pid 1 would clear
FSCR_DSCR because thread.dscr_inherit was 0.

That commit also introduced the requirement that FSCR_DSCR be clear
for user processes, so that we can take the facility unavailable
interrupt in order to manage dscr_inherit.

Then in commit 152d523e63 ("powerpc: Create context switch helpers
save_sprs() and restore_sprs()") (Dec 2015) FSCR was added to
thread_struct. However it still wasn't fully context switched, we just
took the existing value and set FSCR_DSCR if the new thread had
dscr_inherit set. FSCR was still initialised at boot to FSCR_DSCR |
FSCR_TAR, but that value was not propagated into the thread_struct, so
the initial context switch set FSCR_DSCR back to 0.

Finally commit b57bd2de8c ("powerpc: Improve FSCR init and context
switching") (Jun 2016) added a full context switch of the FSCR, and
added an initialisation of init_task.thread.fscr to FSCR_TAR |
FSCR_EBB, but omitted FSCR_DSCR.

The end result is that swapper runs with FSCR_DSCR set because of the
initialisation in __init_FSCR(), but no other processes do, they use
the value from init_task.thread.fscr.

Having FSCR_DSCR set for swapper allows it to access SPR 3 from
userspace, but swapper never runs userspace, so it has no useful
effect. It's also confusing to have the value initialised in two
places to two different values.

So remove FSCR_DSCR from __init_FSCR(), this at least gets us to the
point where there's a single value of FSCR, even if it's still set in
two places.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200527145843.2761782-1-mpe@ellerman.id.au
Cc: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03 11:26:39 +02:00
Will Deacon e1818ffcca KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
commit fdfe7cbd58 upstream.

The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.

Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.

Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-2-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-26 10:41:08 +02:00
Vasant Hegde 13b1fc60ec powerpc/pseries: Do not initiate shutdown when system is running on UPS
commit 90a9b102ed upstream.

As per PAPR we have to look for both EPOW sensor value and event
modifier to identify the type of event and take appropriate action.

In LoPAPR v1.1 section 10.2.2 includes table 136 "EPOW Action Codes":

  SYSTEM_SHUTDOWN 3

  The system must be shut down. An EPOW-aware OS logs the EPOW error
  log information, then schedules the system to be shut down to begin
  after an OS defined delay internal (default is 10 minutes.)

Then in section 10.3.2.2.8 there is table 146 "Platform Event Log
Format, Version 6, EPOW Section", which includes the "EPOW Event
Modifier":

  For EPOW sensor value = 3
  0x01 = Normal system shutdown with no additional delay
  0x02 = Loss of utility power, system is running on UPS/Battery
  0x03 = Loss of system critical functions, system should be shutdown
  0x04 = Ambient temperature too high
  All other values = reserved

We have a user space tool (rtas_errd) on LPAR to monitor for
EPOW_SHUTDOWN_ON_UPS. Once it gets an event it initiates shutdown
after predefined time. It also starts monitoring for any new EPOW
events. If it receives "Power restored" event before predefined time
it will cancel the shutdown. Otherwise after predefined time it will
shutdown the system.

Commit 79872e3546 ("powerpc/pseries: All events of
EPOW_SYSTEM_SHUTDOWN must initiate shutdown") changed our handling of
the "on UPS/Battery" case, to immediately shutdown the system. This
breaks existing setups that rely on the userspace tool to delay
shutdown and let the system run on the UPS.

Fixes: 79872e3546 ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Massage change log and add PAPR references]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200820061844.306460-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-26 10:41:06 +02:00
Anton Blanchard 54f44e3af2 pseries: Fix 64 bit logical memory block panic
commit 89c140bbae upstream.

Booting with a 4GB LMB size causes us to panic:

  qemu-system-ppc64: OS terminated: OS panic:
      Memory block size not suitable: 0x0

Fix pseries_memory_block_size() to handle 64 bit LMBs.

Cc: stable@vger.kernel.org
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200715000820.1255764-1-anton@ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-21 13:05:28 +02:00
Michael Ellerman 9ba5f37fa3 powerpc: Fix circular dependency between percpu.h and mmu.h
commit 0c83b277ad upstream.

Recently random.h started including percpu.h (see commit
f227e3ec3b ("random32: update the net random state on interrupt and
activity")), which broke corenet64_smp_defconfig:

  In file included from /linux/arch/powerpc/include/asm/paca.h:18,
                   from /linux/arch/powerpc/include/asm/percpu.h:13,
                   from /linux/include/linux/random.h:14,
                   from /linux/lib/uuid.c:14:
  /linux/arch/powerpc/include/asm/mmu.h:139:22: error: unknown type name 'next_tlbcam_idx'
    139 | DECLARE_PER_CPU(int, next_tlbcam_idx);

This is due to a circular header dependency:
  asm/mmu.h includes asm/percpu.h, which includes asm/paca.h, which
  includes asm/mmu.h

Which means DECLARE_PER_CPU() isn't defined when mmu.h needs it.

We can fix it by moving the include of paca.h below the include of
asm-generic/percpu.h.

This moves the include of paca.h out of the #ifdef __powerpc64__, but
that is OK because paca.h is almost entirely inside #ifdef
CONFIG_PPC64 anyway.

It also moves the include of paca.h out of the #ifdef CONFIG_SMP,
which could possibly break something, but seems to have no ill
effects.

Fixes: f227e3ec3b ("random32: update the net random state on interrupt and activity")
Cc: stable@vger.kernel.org # v5.8
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804130558.292328-1-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-21 13:05:24 +02:00
Michael Ellerman 9de20a6c4d powerpc: Allow 4224 bytes of stack expansion for the signal frame
commit 63dee5df43 upstream.

We have powerpc specific logic in our page fault handling to decide if
an access to an unmapped address below the stack pointer should expand
the stack VMA.

The code was originally added in 2004 "ported from 2.4". The rough
logic is that the stack is allowed to grow to 1MB with no extra
checking. Over 1MB the access must be within 2048 bytes of the stack
pointer, or be from a user instruction that updates the stack pointer.

The 2048 byte allowance below the stack pointer is there to cover the
288 byte "red zone" as well as the "about 1.5kB" needed by the signal
delivery code.

Unfortunately since then the signal frame has expanded, and is now
4224 bytes on 64-bit kernels with transactional memory enabled. This
means if a process has consumed more than 1MB of stack, and its stack
pointer lies less than 4224 bytes from the next page boundary, signal
delivery will fault when trying to expand the stack and the process
will see a SEGV.

The total size of the signal frame is the size of struct rt_sigframe
(which includes the red zone) plus __SIGNAL_FRAMESIZE (128 bytes on
64-bit).

The 2048 byte allowance was correct until 2008 as the signal frame
was:

struct rt_sigframe {
        struct ucontext    uc;                           /*     0  1440 */
        /* --- cacheline 11 boundary (1408 bytes) was 32 bytes ago --- */
        long unsigned int          _unused[2];           /*  1440    16 */
        unsigned int               tramp[6];             /*  1456    24 */
        struct siginfo *           pinfo;                /*  1480     8 */
        void *                     puc;                  /*  1488     8 */
        struct siginfo     info;                         /*  1496   128 */
        /* --- cacheline 12 boundary (1536 bytes) was 88 bytes ago --- */
        char                       abigap[288];          /*  1624   288 */

        /* size: 1920, cachelines: 15, members: 7 */
        /* padding: 8 */
};

1920 + 128 = 2048

Then in commit ce48b21007 ("powerpc: Add VSX context save/restore,
ptrace and signal support") (Jul 2008) the signal frame expanded to
2304 bytes:

struct rt_sigframe {
        struct ucontext    uc;                           /*     0  1696 */	<--
        /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */
        long unsigned int          _unused[2];           /*  1696    16 */
        unsigned int               tramp[6];             /*  1712    24 */
        struct siginfo *           pinfo;                /*  1736     8 */
        void *                     puc;                  /*  1744     8 */
        struct siginfo     info;                         /*  1752   128 */
        /* --- cacheline 14 boundary (1792 bytes) was 88 bytes ago --- */
        char                       abigap[288];          /*  1880   288 */

        /* size: 2176, cachelines: 17, members: 7 */
        /* padding: 8 */
};

2176 + 128 = 2304

At this point we should have been exposed to the bug, though as far as
I know it was never reported. I no longer have a system old enough to
easily test on.

Then in 2010 commit 320b2b8de1 ("mm: keep a guard page below a
grow-down stack segment") caused our stack expansion code to never
trigger, as there was always a VMA found for a write up to PAGE_SIZE
below r1.

That meant the bug was hidden as we continued to expand the signal
frame in commit 2b0a576d15 ("powerpc: Add new transactional memory
state to the signal context") (Feb 2013):

struct rt_sigframe {
        struct ucontext    uc;                           /*     0  1696 */
        /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */
        struct ucontext    uc_transact;                  /*  1696  1696 */	<--
        /* --- cacheline 26 boundary (3328 bytes) was 64 bytes ago --- */
        long unsigned int          _unused[2];           /*  3392    16 */
        unsigned int               tramp[6];             /*  3408    24 */
        struct siginfo *           pinfo;                /*  3432     8 */
        void *                     puc;                  /*  3440     8 */
        struct siginfo     info;                         /*  3448   128 */
        /* --- cacheline 27 boundary (3456 bytes) was 120 bytes ago --- */
        char                       abigap[288];          /*  3576   288 */

        /* size: 3872, cachelines: 31, members: 8 */
        /* padding: 8 */
        /* last cacheline: 32 bytes */
};

3872 + 128 = 4000

And commit 573ebfa660 ("powerpc: Increase stack redzone for 64-bit
userspace to 512 bytes") (Feb 2014):

struct rt_sigframe {
        struct ucontext    uc;                           /*     0  1696 */
        /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */
        struct ucontext    uc_transact;                  /*  1696  1696 */
        /* --- cacheline 26 boundary (3328 bytes) was 64 bytes ago --- */
        long unsigned int          _unused[2];           /*  3392    16 */
        unsigned int               tramp[6];             /*  3408    24 */
        struct siginfo *           pinfo;                /*  3432     8 */
        void *                     puc;                  /*  3440     8 */
        struct siginfo     info;                         /*  3448   128 */
        /* --- cacheline 27 boundary (3456 bytes) was 120 bytes ago --- */
        char                       abigap[512];          /*  3576   512 */	<--

        /* size: 4096, cachelines: 32, members: 8 */
        /* padding: 8 */
};

4096 + 128 = 4224

Then finally in 2017, commit 1be7107fbe ("mm: larger stack guard
gap, between vmas") exposed us to the existing bug, because it changed
the stack VMA to be the correct/real size, meaning our stack expansion
code is now triggered.

Fix it by increasing the allowance to 4224 bytes.

Hard-coding 4224 is obviously unsafe against future expansions of the
signal frame in the same way as the existing code. We can't easily use
sizeof() because the signal frame structure is not in a header. We
will either fix that, or rip out all the custom stack expansion
checking logic entirely.

Fixes: ce48b21007 ("powerpc: Add VSX context save/restore, ptrace and signal support")
Cc: stable@vger.kernel.org # v2.6.27+
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Tested-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724092528.1578671-2-mpe@ellerman.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-21 13:05:24 +02:00
Christophe Leroy 2150c25b76 powerpc/ptdump: Fix build failure in hashpagetable.c
commit 7c466b0807 upstream.

H_SUCCESS is only defined when CONFIG_PPC_PSERIES is defined.

!= H_SUCCESS means != 0. Modify the test accordingly.

Fixes: 65e701b2d2 ("powerpc/ptdump: drop non vital #ifdefs")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/795158fc1d2b3dff3bf7347881947a887ea9391a.1592227105.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-21 13:05:24 +02:00
Michael Ellerman 3e95f258a1 powerpc/boot: Fix CONFIG_PPC_MPC52XX references
[ Upstream commit e5eff89657 ]

Commit 866bfc75f4 ("powerpc: conditionally compile platform-specific
serial drivers") made some code depend on CONFIG_PPC_MPC52XX, which
doesn't exist.

Fix it to use CONFIG_PPC_MPC52xx.

Fixes: 866bfc75f4 ("powerpc: conditionally compile platform-specific serial drivers")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131728.1643966-7-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-19 08:16:17 +02:00
Michael Ellerman 69a797a045 powerpc/32s: Fix CONFIG_BOOK3S_601 uses
[ Upstream commit df4d4ef224 ]

We have two uses of CONFIG_BOOK3S_601, which doesn't exist. Fix them
to use CONFIG_PPC_BOOK3S_601 which is the correct symbol.

Fixes: 12c3f1fd87 ("powerpc/32s: get rid of CPU_FTR_601 feature")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131728.1643966-5-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-19 08:16:17 +02:00