This makes it easy to update the region mapping in the later patch
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Allocate subpage protect related variables only if we use the feature.
This helps in reducing the hash related mm context struct by around 4K

Before the patch
sizeof(struct hash_mm_context)  = 8288

After the patch
sizeof(struct hash_mm_context) = 4160
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently, our mm_context_t on book3s64 include all hash specific
context details like slice mask and subpage protection details. We
can skip allocating these with radix translation. This will help us to save
8K per mm_context with radix translation.

With the patch applied we have

sizeof(mm_context_t)  = 136
sizeof(struct hash_mm_context)  = 8288
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Avoid #ifdef in generic code. Also enables us to do this specific to
MMU translation mode on book3s64
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We want to switch to allocating them runtime only when hash translation is
enabled. Add helpers so that both book3s and nohash can be adapted to
upcoming change easily.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Book3s64 always have PPC_MM_SLICES enabled. So remove the unncessary #ifdef
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The current value of MAX_PHYSMEM_BITS cannot work with 32 bit configs.
We used to have MAX_PHYSMEM_BITS not defined without SPARSEMEM and 32
bit configs never expected a value to be set for MAX_PHYSMEM_BITS.

Dependent code such as zsmalloc derived the right values based on other
fields. Instead of finding a value that works with different configs,
use new values only for book3s_64. For 64 bit booke, use the definition
of MAX_PHYSMEM_BITS as per commit a7df61a0 ("[PATCH] ppc64: Increase sparsemem defaults")
That change was done in 2005 and hopefully will work with book3e 64.

Fixes: 8bc08689 ("powerpc/mm: Only define MAX_PHYSMEM_BITS in SPARSEMEM configurations")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch implements Kernel Userspace Access Protection for
book3s/32.

Due to limitations of the processor page protection capabilities,
the protection is only against writing. read protection cannot be
achieved using page protection.

The previous patch modifies the page protection so that RW user
pages are RW for Key 0 and RO for Key 1, and it sets Key 0 for
both user and kernel.

This patch changes userspace segment registers are set to Ku 0
and Ks 1. When kernel needs to write to RW pages, the associated
segment register is then changed to Ks 0 in order to allow write
access to the kernel.

In order to avoid having the read all segment registers when
locking/unlocking the access, some data is kept in the thread_struct
and saved on stack on exceptions. The field identifies both the
first unlocked segment and the first segment following the last
unlocked one. When no segment is unlocked, it contains value 0.

As the hash_page() function is not able to easily determine if a
protfault is due to a bad kernel access to userspace, protfaults
need to be handled by handle_page_fault when KUAP is set.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Drop allow_read/write_to/from_user() as they're now in kup.h,
      and adapt allow_user_access() to do nothing when to == NULL]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch prepares Kernel Userspace Access Protection for
book3s/32.

Due to limitations of the processor page protection capabilities,
the protection is only against writing. read protection cannot be
achieved using page protection.

book3s/32 provides the following values for PP bits:

PP00 provides RW for Key 0 and NA for Key 1
PP01 provides RW for Key 0 and RO for Key 1
PP10 provides RW for all
PP11 provides RO for all

Today PP10 is used for RW pages and PP11 for RO pages, and user
segment register's Kp and Ks are set to 1. This patch modifies
page protection to use PP01 for RW pages and sets user segment
registers to Kp 0 and Ks 0.

This will allow to setup Userspace write access protection by
settng Ks to 1 in the following patch.

Kernel space segment registers remain unchanged.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

To implement Kernel Userspace Execution Prevention, this patch
sets NX bit on all user segments on kernel entry and clears NX bit
on all user segments on kernel exit.

Note that powerpc 601 doesn't have the NX bit, so KUEP will not
work on it. A warning is displayed at startup.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds Kernel Userspace Access Protection on the 8xx.

When a page is RO or RW, it is set RO or RW for Key 0 and NA
for Key 1.

Up to now, the User group is defined with Key 0 for both User and
Supervisor.

By changing the group to Key 0 for User and Key 1 for Supervisor,
this patch prevents the Kernel from being able to access user data.

At exception entry, the kernel saves SPRN_MD_AP in the regs struct,
and reapply the protection. At exception exit it restores SPRN_MD_AP
with the value saved on exception entry.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Drop allow_read/write_to/from_user() as they're now in kup.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds Kernel Userspace Execution Prevention on the 8xx.

When a page is Executable, it is set Executable for Key 0 and NX
for Key 1.

Up to now, the User group is defined with Key 0 for both User and
Supervisor.

By changing the group to Key 0 for User and Key 1 for Supervisor,
this patch prevents the Kernel from being able to execute user code.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Since the 8xx implements hardware page table walk assistance,
the PGD entries always point to a 4k aligned page, so the 2 upper
bits of the APG are not clobbered anymore and remain 0. Therefore
only APG0 and APG1 are used and need a definition. We set the
other APG to the lowest permission level.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds ASM macros for saving, restoring and checking
the KUAP state, and modifies setup_32 to call them on exceptions
from kernel.

The macros are defined as empty by default for when CONFIG_PPC_KUAP
is not selected and/or for platforms which don't handle (yet) KUAP.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

syscalls are from user only, so we can account time without checking
whether returning to kernel or user as it will only be user.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When KUAP is enabled we have logic to detect page faults that occur
outside of a valid user access region and are blocked by the AMR.

What we don't have at the moment is logic to detect a fault *within* a
valid user access region, that has been incorrectly blocked by AMR.
This is not meant to ever happen, but it can if we incorrectly
save/restore the AMR, or if the AMR was overwritten for some other
reason.

Currently if that happens we assume it's just a regular fault that
will be corrected by handling the fault normally, so we just return.
But there is nothing the fault handling code can do to fix it, so the
fault just happens again and we spin forever, leading to soft lockups.

So add some logic to detect that case and WARN() if we ever see it.
Arguably it should be a BUG(), but it's more polite to fail the access
and let the kernel continue, rather than taking down the box. There
should be no data integrity issue with failing the fault rather than
BUG'ing, as we're just going to disallow an access that should have
been allowed.

To make the code a little easier to follow, unroll the condition at
the end of bad_kernel_fault() and comment each case, before adding the
call to bad_kuap_fault().
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Kernel Userspace Access Prevention utilises a feature of the Radix MMU
which disallows read and write access to userspace addresses. By
utilising this, the kernel is prevented from accessing user data from
outside of trusted paths that perform proper safety checks, such as
copy_{to/from}_user() and friends.

Userspace access is disabled from early boot and is only enabled when
performing an operation like copy_{to/from}_user(). The register that
controls this (AMR) does not prevent userspace from accessing itself,
so there is no need to save and restore when entering and exiting
userspace.

When entering the kernel from the kernel we save AMR and if it is not
blocking user access (because eg. we faulted doing a user access) we
reblock user access for the duration of the exception (ie. the page
fault) and then restore the AMR when returning back to the kernel.

This feature can be tested by using the lkdtm driver (CONFIG_LKDTM=y)
and performing the following:

  # (echo ACCESS_USERSPACE) > [debugfs]/provoke-crash/DIRECT

If enabled, this should send SIGSEGV to the thread.

We also add paranoid checking of AMR in switch and syscall return
under CONFIG_PPC_KUAP_DEBUG.
Co-authored-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

__patch_instruction() is called in early boot, and uses
__put_user_size(), which includes the allow/prevent calls to enforce
KUAP, which could either be called too early, or in the Radix case,
forced to use "early_" versions of functions just to safely handle
this one case.

__put_user_asm() does not do this, and thus is safe to use both in
early boot, and later on since in this case it should only ever be
touching kernel memory.

__patch_instruction() was previously refactored to use
__put_user_size() in order to be able to return -EFAULT, which would
allow the kernel to patch instructions in userspace, which should
never happen. This has the functional change of causing faults on
userspace addresses if KUAP is turned on, which should never happen in
practice.

A future enhancement could be to double check the patch address is
definitely allowed to be tampered with by the kernel.
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Execution protection already exists on radix, this just refactors
the radix init to provide the KUEP setup function instead.

Thus, the only functional change is that it can now be disabled.
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Some platforms (i.e. Radix MMU) need per-CPU initialisation for KUP.

Any platforms that only want to do KUP initialisation once
globally can just check to see if they're running on the boot CPU, or
check if whatever setup they need has already been performed.

Note that this is only for 64-bit.
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch implements a framework for Kernel Userspace Access
Protection.

Then subarches will have the possibility to provide their own
implementation by providing setup_kuap() and
allow/prevent_user_access().

Some platforms will need to know the area accessed and whether it is
accessed from read, write or both. Therefore source, destination and
size and handed over to the two functions.

mpe: Rename to allow/prevent rather than unlock/lock, and add
read/write wrappers. Drop the 32-bit code for now until we have an
implementation for it. Add kuap to pt_regs for 64-bit as well as
32-bit. Don't split strings, use pr_crit_ratelimited().
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds a skeleton for Kernel Userspace Execution Prevention.

Then subarches implementing it have to define CONFIG_PPC_HAVE_KUEP
and provide setup_kuep() function.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Don't split strings, use pr_crit_ratelimited()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds a skeleton for Kernel Userspace Protection
functionnalities like Kernel Userspace Access Protection and Kernel
Userspace Execution Prevention

The subsequent implementation of KUAP for radix makes use of a MMU
feature in order to patch out assembly when KUAP is disabled or
unsupported. This won't work unless there's an entry point for KUP
support before the feature magic happens, so for PPC64 setup_kup() is
called early in setup.

On PPC32, feature_fixup() is done too early to allow the same.
Suggested-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

In order to implement KUAP (Kernel Userspace Access Protection) on
Power9 we will be using the AMR, and therefore indirectly the
UAMOR/AMOR.

So save/restore these regs in the idle code.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Without restoring the IAMR after idle, execution prevention on POWER9
with Radix MMU is overwritten and the kernel can freely execute
userspace without faulting.

This is necessary when returning from any stop state that modifies
user state, as well as hypervisor state.

To test how this fails without this patch, load the lkdtm driver and
do the following:

  $ echo EXEC_USERSPACE > /sys/kernel/debug/provoke-crash/DIRECT

which won't fault, then boot the kernel with powersave=off, where it
will fault. Applying this patch will fix this.

Fixes: 3b10d009 ("powerpc/mm/radix: Prevent kernel execution of user space")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Changing the NUMA associations for CPUs and memory at runtime is
basically unsupported by the core mm, scheduler etc. We see all manner
of crashes, warnings and instability when the pseries code tries to do
this. Disable this behavior by default, and document the switch a bit.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When booted with "topology_updates=no", or when "off" is written to
/proc/powerpc/topology_updates, NUMA reassignments are inhibited for
PRRN and VPHN events. However, migration and suspend unconditionally
re-enable reassignments via start_topology_update(). This is
incoherent.

Check the topology_updates_enabled flag in
start/stop_topology_update() so that callers of those APIs need not be
aware of whether reassignments are enabled. This allows the
administrative decision on reassignments to remain in force across
migrations and suspensions.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

sparse complains a lot about opal-call.c:

  arch/powerpc/platforms/powernv/opal-call.c:128:1: warning: symbol 'opal_invalid_call' was not declared. Should it be static?
  arch/powerpc/platforms/powernv/opal-call.c:129:1: warning: symbol 'opal_console_write' was not declared. Should it be static?
  arch/powerpc/platforms/powernv/opal-call.c:130:1: warning: symbol 'opal_console_read' was not declared. Should it be static?

Those symbols are forward declared in opal.h, but we can't include that
because the function signatures in opal.h are different. So instead, just
add an extra forward declaration to the OPAL_CALL macro to shut sparse up.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This code was filling a 64K buffer from /dev/urandom in order to
compute a CRC over (on average half of) it by two different methods,
comparing the CRCs, and repeating.

This is not a remotely security-critical application, so use the far
faster and cheaper prandom_u32() generator.

And, while we're at it, only fill as much of the buffer as we plan to use.
Signed-off-by: George Spelvin <lkml@sdf.org>
Acked-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Remove duplicate headers inclusions.
Signed-off-by: Jagadeesh Pagadala <jagdsh.linux@gmail.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The call to of_find_compatible_node() returns a node pointer with
refcount incremented thus it must be explicitly decremented after the
last usage.

irq_domain_add_linear() also calls of_node_get() to increase refcount,
so irq_domain() will not be affected when it is released.

Detected by coccinelle.

Fixes: a8db8cf0 ("irq_domain: Replace irq_alloc_host() with revmap-specific initializers")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Peng Hao <peng.hao2@zte.com.cn>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add support to hwpoison the pages upon hitting machine check
exception.

This patch queues the address where UE is hit to percpu array
and schedules work to plumb it into memory poison infrastructure.
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
[mpe: Combine #ifdefs, drop PPC_BIT8(), and empty inline stub]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add an of_node_put() when a tested device node is not available.

Fixes: c026c987 ("powerpc/83xx: Do not configure or probe disabled FSL DR USB controllers")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Paul McKenney attempted to update all email addresses @linux.vnet.ibm.com
to @linux.ibm.com in commit 1dfddcdb
("MAINTAINERS: Update from @linux.vnet.ibm.com to @linux.ibm.com"), but
some still remained.

We update the remaining email addresses in MAINTAINERS, hopefully finally
catching all cases for good.

Fixes: 1dfddcdb ("MAINTAINERS: Update from @linux.vnet.ibm.com to @linux.ibm.com")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The file arch/powerpc/include/uapi/asm/vas.h was considered but
never merged and should be removed from the MAINTAINERS file.

While here, add missing email address.
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The commit 4c5d87db ("powerpc/pseries: PAPR persistent memory
support") set a local variable "count" in dlpar_hp_pmem() but never
use it.

  arch/powerpc/platforms/pseries/pmem.c: In function 'dlpar_hp_pmem':
  arch/powerpc/platforms/pseries/pmem.c:109:6: warning: variable 'count' set but not used
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The commit b7d6bf4f ("powerpc/pseries/pci: Remove obsolete SW
invalidate") left 2 variables unused.

  arch/powerpc/platforms/pseries/iommu.c:108:17: warning: variable 'tces' set but not used
    __be64 *tcep, *tces;
                   ^~~~

  arch/powerpc/platforms/pseries/iommu.c:132:17: warning: variable 'tces' set but not used
    __be64 *tcep, *tces;
                   ^~~~

Also, the commit 68c0449e ("powerpc/pseries/iommu: Use memory@
nodes in max RAM address calculation") set "ranges" in
ddw_memory_hotplug_max() but never use it.

  arch/powerpc/platforms/pseries/iommu.c: In function 'ddw_memory_hotplug_max':
  arch/powerpc/platforms/pseries/iommu.c:948:7: warning: variable 'ranges' set but not used
     int ranges, n_mem_addr_cells, n_mem_size_cells, len;
         ^~~~~~
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

pte_unmap() compiles away on some powerpc platforms, so silence the
warnings below by making it a static inline function.

  mm/memory.c: In function 'copy_pte_range':
  mm/memory.c:820:24: warning: variable 'orig_dst_pte' set but not used
  mm/memory.c:820:9: warning: variable 'orig_src_pte' set but not used
  mm/madvise.c: In function 'madvise_free_pte_range':
  mm/madvise.c:318:9: warning: variable 'orig_pte' set but not used
  mm/swap_state.c: In function 'swap_ra_info':
  mm/swap_state.c:634:15: warning: variable 'orig_pte' set but not used
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

resize_hpt_for_hotplug() reports a warning when it cannot
resize the hash page table ("Unable to resize hash page
table to target order") but in some cases it's not a problem
and can make user thinks something has not worked properly.

This patch moves the warning to arch_remove_memory() to
only report the problem when it is needed.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add radix_enabled() check to avoid SLB preload with radix translation.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>