Commit Graph

1647 Commits

Author SHA1 Message Date
Michael Ellerman
8434f0892e Merge branch 'topic/ppc-kvm' into next
Bring in the commit to rename find_linux_pte_or_hugepte() which touches
arch and KVM code, and might need to be merged with the kvmppc tree to
avoid conflicts.
2017-08-17 23:14:17 +10:00
Aneesh Kumar K.V
94171b19c3 powerpc/mm: Rename find_linux_pte_or_hugepte()
Add newer helpers to make the function usage simpler. It is always
recommended to use find_current_mm_pte() for walking the page table.
If we cannot use find_current_mm_pte(), it should be documented why
the said usage of __find_linux_pte() is safe against a parallel THP
split.

For now we have KVM code using __find_linux_pte(). This is because kvm
code ends up calling __find_linux_pte() in real mode with MSR_EE=0 but
with PACA soft_enabled = 1. We may want to fix that later and make
sure we keep the MSR_EE and PACA soft_enabled in sync. When we do that
we can switch kvm to use find_linux_pte().

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-17 23:13:46 +10:00
Aneesh Kumar K.V
79cc38ded1 powerpc/mm/hugetlb: Add support for reserving gigantic huge pages via kernel command line
With commit aa888a7497 ("hugetlb: support larger than MAX_ORDER") we added
support for allocating gigantic hugepages via kernel command line. Switch
ppc64 arch specific code to use that.

W.r.t FSL support, we now limit our allocation range using BOOTMEM_ALLOC_ACCESSIBLE.

We use the kernel command line to do reservation of hugetlb pages on powernv
platforms. On pseries hash mmu mode the supported gigantic huge page size is
16GB and that can only be allocated with hypervisor assist. For pseries the
command line option doesn't do the allocation. Instead pseries does gigantic
hugepage allocation based on hypervisor hint that is specified via
"ibm,expected#pages" property of the memory node.

Cc: Scott Wood <oss@buserror.net>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-16 14:56:12 +10:00
Christophe Leroy
ca8afd4046 powerpc/hugetlb: fix page rights verification in gup_hugepte()
gup_hugepte() checks if pages are present and readable, and
when  'write' is set, also checks if the pages are writable.

Initially this was done by checking if _PAGE_PRESENT and
_PAGE_READ were set. In addition, _PAGE_WRITE was verified for write
accesses.

The problem is that we have to handle the three following cases:
1/ The target defines __PAGE_READ and __PAGE_WRITE
2/ The target defines __PAGE_RW
3/ The target defines __PAGE_RO

In case 1/, this is obvious
In case 2/, __PAGE_READ is defined as 0 and __PAGE_WRITE as __PAGE_RW
so it works as well.
But in case 3, __PAGE_RW is defined as 0, which means __PAGE_WRITE is 0
and then the test returns true (page writable) in all cases.

A first correction was attempted in commit 6b8cb66a6a ("powerpc: Fix
usage of _PAGE_RO in hugepage"), but that fix is wrong:
instead of checking that the page is writable when write is requested,
it checks that the page is NOT writable when write is NOT requested.

This patch adds a new pte_read() helper to check whether a page is
readable or not. This avoids handling all possible cases in
gup_hugepte().

Then gup_hugepte() is modified to use pte_present(), pte_read()
and pte_write() instead of the raw flags.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:58 +10:00
Christophe Leroy
4cfac2f9c7 powerpc/mm: Simplify __set_fixmap()
__set_fixmap() uses __fix_to_virt() then does the boundary checks
by it self. Instead, we can use fix_to_virt() which does the
verification at build time. For this, we need to use it inline
so that GCC can see the real value of idx at buildtime.

In the meantime, we remove the 'fixmaps' variable.
This variable is set but has never been used from the beginning
(commit 2c419bdeca ("[POWERPC] Port fixmap from x86 and use
for kmap_atomic"))

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:58 +10:00
Christophe Leroy
86b19520e7 powerpc/mm: declare some local functions static
get_pteptr() and __mapin_ram_chunk() are only used locally,
so define them static

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:57 +10:00
Christophe Leroy
95902e6c88 powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32
This patch implements STRICT_KERNEL_RWX on PPC32.

As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings
in order to allow page protection setup at the level of each page.

As BAT/LTLB mappings are deactivated, there might be a performance
impact.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:57 +10:00
Christophe Leroy
3184cc4b6f powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32
As seen below, allthough the init sections have been freed, the
associated memory area is still marked as executable in the
page tables.

~ dmesg
[    5.860093] Freeing unused kernel memory: 592K (c0570000 - c0604000)

~ cat /sys/kernel/debug/kernel_page_tables
---[ Start of kernel VM ]---
0xc0000000-0xc0497fff        4704K  rw  X  present dirty accessed shared
0xc0498000-0xc056ffff         864K  rw     present dirty accessed shared
0xc0570000-0xc059ffff         192K  rw  X  present dirty accessed shared
0xc05a0000-0xc7ffffff      125312K  rw     present dirty accessed shared
---[ vmalloc() Area ]---

This patch fixes that.

The implementation is done by reusing the change_page_attr()
function implemented for CONFIG_DEBUG_PAGEALLOC

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:56 +10:00
Christophe Leroy
e611939fc8 powerpc/mm: Ensure change_page_attr() doesn't invalidate pinned TLBs
__change_page_attr() uses flush_tlb_page().
flush_tlb_page() uses tlbie instruction, which also invalidates
pinned TLBs, which is not what we expect.

This patch modifies the implementation to use flush_tlb_kernel_range()
instead. This will make use of tlbia which will preserve pinned TLBs.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:56 +10:00
Christophe Leroy
346bcc4d33 powerpc/8xx: mark init functions with __init
setup_initial_memory_limit() is only called during init.
mmu_patch_cmp_limit() is only called from 8xx_mmu.c

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:54 +10:00
Christophe Leroy
a3059b0ca0 powerpc/8xx: Make pinning of ITLBs optional
As stated in a comment in head_8xx.S, today we "Always pin the first
8 MB ITLB to prevent ITLB misses while mucking around with SRR0/SRR1
in asm".

This issue has just been cleared by the preceding patch, therefore
we can make this pinning optional (on by default) and independent
of DATA pinning.

This patch also makes pinning of IMMR independent of pinning of DATA.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:53 +10:00
Christophe Leroy
eef784bbe7 powerpc/8xx: Ensures RAM mapped with LTLB is seen as block mapped on 8xx.
On the 8xx, the RAM mapped with LTLBs must be seen as block mapped,
just like areas mapped with BATs on standard PPC32.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-15 22:55:52 +10:00
Michael Ellerman
7559952e1f powerpc/mm: Fix section mismatch warning in early_check_vec5()
early_check_vec5() is called from and calls __init routines, so should
also be __init.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 23:40:51 +10:00
Christophe Leroy
4915349b10 powerpc/8xx: Use symbolic names for DSISR bits in DSI
Use symbolic names for DSISR bits in DSI

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 23:32:20 +10:00
Christophe Leroy
968159c003 powerpc/8xx: Getting rid of remaining use of CONFIG_8xx
Two config options exist to define powerpc MPC8xx:
* CONFIG_PPC_8xx
* CONFIG_8xx

arch/powerpc/platforms/Kconfig.cputype has contained the following
comment about CONFIG_8xx item for some years:
"# this is temp to handle compat with arch=ppc"

arch/powerpc is now the only place with remaining use of
CONFIG_8xx: get rid of them.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 23:32:12 +10:00
Suraj Jitindar Singh
7cd2a8695e powerpc/mm: Properly invalidate when setting process table base
The host process table base is stored in the partition table by calling
the function native_register_process_table(). Currently this just sets
the entry in memory and is missing a subsequent cache invalidation
instruction. Any update to the partition table should be followed by a
cache invalidation instruction specifying invalidation of the caching of
any partition table entries (RIC = 2, PRS = 0).

We already have a function to update the partition table with the
required cache invalidation instructions - mmu_partition_table_set_entry().
Update the native_register_process_table() function to call
mmu_partition_table_set_entry(), this ensures all appropriate
invalidation will be performed.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Use a local for patb0 to clean it up slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-10 22:30:03 +10:00
Michael Ellerman
21a0e8c14b powerpc/mm/hash64: Make vmalloc 56T on hash
On 64-bit book3s, with the hash MMU, we currently define the kernel
virtual space (vmalloc, ioremap etc.), to be 16T in size. This is a
leftover from pre v3.7 when our user VM was also 16T.

Of that 16T we split it 50/50, with half used for PCI IO and ioremap
and the other 8T for vmalloc.

We never bothered to make it any bigger because 8T of vmalloc ought to
be enough for anybody. But it turns out that's not true, the per cpu
allocator wants large amounts of vmalloc space, not to make large
allocations, but to allow a large stride between allocations, because
we use pcpu_embed_first_chunk().

With a bit of juggling we can increase the entire kernel virtual space
to 64T. The only real complication is the check of the address in the
SLB miss handler, see the comment in the code.

Although we could continue to split virtual space 50/50 as we do now,
no one seems to be running out of PCI IO or ioremap space. So instead
keep that as 8T, and use the remaining 56T for vmalloc.

In future we should be able to increase the kernel virtual space to
512T, the code already supports that, it just needs testing on older
hardware.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2017-08-08 19:37:05 +10:00
Michael Ellerman
b5048de04b powerpc/mm/slb: Move comment next to the code it's referring to
There is a comment in slb_allocate() referring to the load of
paca->vmalloc_sllp, but it's several lines prior in the assembly.
We're about to change this code, and we want to add another comment,
so move the comment immediately prior to the instruction it's talking
about.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-08 19:37:04 +10:00
Michael Ellerman
63ee9b2ff9 powerpc/mm/book3s64: Make KERN_IO_START a variable
Currently KERN_IO_START is defined as:

 #define KERN_IO_START  (KERN_VIRT_START + (KERN_VIRT_SIZE >> 1))

Although it looks like a constant, both the components are actually
variables, to allow us to have a different value between Radix and
Hash with a single kernel.

However that still requires both Radix and Hash to place the kernel IO
region at the same location relative to the start and end of the
kernel virtual region (namely 1/2 way through it), and we'd like to
change that.

So split KERN_IO_START out into its own variable, and initialise it
for Radix and Hash. In the medium term we should be able to
reconsolidate this, by doing a more involved rearrangement of the
location of the regions.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-08 19:37:04 +10:00
Benjamin Herrenschmidt
6ff4d3e966 powerpc: Remove old unused icswx based coprocessor support
We have a whole pile of unused code to maintain the ACOP register,
allocate coprocessor PIDs and handle ACOP faults. This mechanism
was used for the HFI adapter on POWER7 which is dead and gone and
whose driver never went upstream. It was used on some A2 core based
stuff that also never saw the light of day.

Take out all that code.

There is still some POWER8 coprocessor code that uses icswx but it's
kernel only and thus doesn't use any of that infrastructure.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:52 +10:00
Benjamin Herrenschmidt
8f5ca0b319 powerpc/mm: Cleanup check for stack expansion
When hitting below a VM_GROWSDOWN vma (typically growing the stack),
we check whether it's a valid stack-growing instruction and we
check the distance to GPR1. This is largely open coded with lots
of comments, so move it out to a helper.

While at it, make store_update_sp a boolean.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:51 +10:00
Benjamin Herrenschmidt
f43bb27ebf powerpc/mm: Don't lose "major" fault indication on retry
If the first iteration returns VM_FAULT_MAJOR but the second
one doesn't, we fail to account the fault as a major fault.

This fixes it and brings the code in line with x86.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:51 +10:00
Benjamin Herrenschmidt
bd0d63f809 powerpc/mm: Move page fault VMA access checks to a helper
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:51 +10:00
Benjamin Herrenschmidt
d2e0d2c51a powerpc/mm: Set fault flags earlier
Move out the code that sets FAULT_FLAG_WRITE so the block that check
access permissions can be extracted. While at it also set
FAULT_FLAG_INSTRUCTION which will be used for protection keys.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:50 +10:00
Benjamin Herrenschmidt
b15021d994 powerpc/mm: Add a bunch of (un)likely annotations to do_page_fault
Mostly for the failure cases

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:50 +10:00
Benjamin Herrenschmidt
11ccdd33d6 powerpc/mm: Move/simplify faulthandler_disabled() and !mm check
Do the check before we re-enable interrupts and clean the code
up a bit.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:49 +10:00
Benjamin Herrenschmidt
2865d08dd9 powerpc/mm: Move the DSISR_PROTFAULT sanity check
This has a page of comment explaining what's going on right in
the middle of do_page_fault() which makes things a bit hard to
follow. Move it to a helper instead. Also do the test earlier
as there's no point waiting until after we found the VMA.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:49 +10:00
Benjamin Herrenschmidt
04aafdc601 powerpc/mm: Cosmetic fix to page fault accounting
No need to break those lines, they aren't that long

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:48 +10:00
Benjamin Herrenschmidt
3da026480a powerpc/mm: Move CMO accounting out of do_page_fault into a helper
It makes do_page_fault() more readable. No functional change.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:48 +10:00
Benjamin Herrenschmidt
b5c8f0fd59 powerpc/mm: Rework mm_fault_error()
First, handle the normal retry failure in do_page_fault itself,
since it's a simple return statement. That allows us to remove
the "continue" special return code from mm_fault_error().

Once that's done, we can have an implementation much closer to
x86 where we only call mm_fault_error() if VM_FAULT_ERROR is set
and directly return.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:47 +10:00
Benjamin Herrenschmidt
c3350602e8 powerpc/mm: Make bad_area* helper functions
Instead of goto labels, instead call those functions and return.

This gets us closer to x86 and allows us to shring do_page_fault()
even more.

The main difference with x86 is that those function return a value
which we then return from do_page_fault(). That value is our
return value from do_page_fault() which we use to generate
kernel faults.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:47 +10:00
Benjamin Herrenschmidt
d3ca587404 powerpc/mm: Fix reporting of kernel execute faults
We currently test for is_exec and DSISR_PROTFAULT but that doesn't
make sense as this is the wrong error bit to test for an execute
permission failure.

In fact, we had code that would return early if we had an exec
fault in kernel mode so I think that was just dead code anyway.

Finally the location of that test is awkward and prevents further
simplifications.

So instead move that test into a helper along with the existing
early test for kernel exec faults and out of range accesses,
and put it all in a "bad_kernel_fault()" helper. While at it
test the correct error bits.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:46 +10:00
Benjamin Herrenschmidt
65d47fd4a3 powerpc/mm: Simplify returns from __do_page_fault
Now that we moved the exception state handling to a wrapper, we can
just directly return rather than "goto bail"

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:46 +10:00
Benjamin Herrenschmidt
bb4be50e61 powerpc/mm: Move debugger check to notify_page_fault()
unclutters the main path

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:46 +10:00
Benjamin Herrenschmidt
f3d96e698e powerpc/mm: Overhaul handling of bad page faults
A bad page fault is when the HW signals an error such as a bad
copy/paste, an AMO error, or some other type of error that will
not be fixed by updating the PTE.

Use a helper page_fault_is_bad() to check for bad page faults thus
removing the per-processor family open-coding in __do_page_fault()
and trigger a SIGBUS rather than a SIGSEGV which is more appropriate.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:45 +10:00
Benjamin Herrenschmidt
e6c8290a89 powerpc/mm: Move error_code checks for bad faults earlier
There's no point looking for the VMA etc.. when we already know
we are going to fail.

This adds some code to set "code" for the si_code but that will
be gone in subsequent patches.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:44 +10:00
Benjamin Herrenschmidt
41b464e5e5 powerpc/mm: Move out definition of CPU specific is_write bits
Define a common page_fault_is_write() helper and use it

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:44 +10:00
Benjamin Herrenschmidt
d300627c6a powerpc/6xx: Handle DABR match before calling do_page_fault
On legacy 6xx 32-bit procesors, we checked for the DABR match bit
in DSISR from do_page_fault(), in the middle of a pile of ifdef's
because all other CPU types do it in assembly prior to calling
do_page_fault. Fix that.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Add #ifdef CONFIG_6xx]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:26 +10:00
Benjamin Herrenschmidt
c433ec0455 powerpc/mm: Pre-filter SRR1 bits before do_page_fault()
By filtering the relevant SRR1 bits in the assembly rather than
in do_page_fault() itself, we avoid a conditional branch (since we
already come from different path for data and instruction faults).

This will allow more simplifications later

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-02 13:11:07 +10:00
Benjamin Herrenschmidt
7afad422ac powerpc/mm: Move exception_enter/exit to a do_page_fault wrapper
This will allow simplifying the returns from do_page_fault

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-02 13:11:07 +10:00
Benjamin Herrenschmidt
424de9c6e3 powerpc/mm/radix: Avoid flushing the PWC on every flush_tlb_range
We do that because it's used by THP pmd collapsing, so use
instead a dedicated flush function.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-02 13:11:06 +10:00
Benjamin Herrenschmidt
a46cc7a90f powerpc/mm/radix: Improve TLB/PWC flushes
At the moment we have to rather sub-optimal flushing behaviours:

 - flush_tlb_mm() will flush the PWC which is unnecessary (for example
   when doing a fork)

 - A large unmap will call flush_tlb_pwc() multiple times causing us
   to perform that fairly expensive operation repeatedly. This happens
   often in batches of 3 on every new process.

So we change flush_tlb_mm() to only flush the TLB, and we use the
existing "need_flush_all" flag in struct mmu_gather to indicate
that the PWC needs flushing.

Unfortunately, flush_tlb_range() still needs to do a full flush
for now as it's used by the THP collapsing. We will fix that later.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-02 13:11:06 +10:00
Benjamin Herrenschmidt
5ce5fe14ed powerpc/mm/radix: Improve _tlbiel_pid to be usable for PWC flushes
The PWC flush only needs a single set call, just like the
full (RIC=2) flush.

This will allow us to get rid of the dedicated _tlbiel_pwc()

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-02 13:11:05 +10:00
Michael Ellerman
bb272221e9 Linux v4.13-rc1
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Merge tag 'v4.13-rc1' into fixes

The fixes branch is based off a random pre-rc1 commit, because we had
some fixes that needed to go in before rc1 was released.

However we now need to fix some code that went in after that point, but
before rc1, so merge rc1 to get that code into fixes so we can fix it!
2017-07-31 20:20:29 +10:00
Rui Teng
23493c1219 powerpc/mm: Fix check of multiple 16G pages from device tree
The offset of hugepage block will not be 16G, if the expected
page is more than one. Calculate the totol size instead of the
hardcode value.

Fixes: 4792adbac9 ("powerpc: Don't use a 16G page if beyond mem= limits")
Signed-off-by: Rui Teng <rui.teng@linux.vnet.ibm.com>
Tested-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-31 16:56:58 +10:00
Aneesh Kumar K.V
0da12a7a81 powerpc/mm/hash: Free the subpage_prot_table correctly
Fixes: dad6f37c26 ("powerpc: subpage_protect: Increase the array size to take care of 64TB")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-27 13:05:50 +10:00
Benjamin Herrenschmidt
a25bd72bad powerpc/mm/radix: Workaround prefetch issue with KVM
There's a somewhat architectural issue with Radix MMU and KVM.

When coming out of a guest with AIL (Alternate Interrupt Location, ie,
MMU enabled), we start executing hypervisor code with the PID register
still containing whatever the guest has been using.

The problem is that the CPU can (and will) then start prefetching or
speculatively load from whatever host context has that same PID (if
any), thus bringing translations for that context into the TLB, which
Linux doesn't know about.

This can cause stale translations and subsequent crashes.

Fixing this in a way that is neither racy nor a huge performance
impact is difficult. We could just make the host invalidations always
use broadcast forms but that would hurt single threaded programs for
example.

We chose to fix it instead by partitioning the PID space between guest
and host. This is possible because today Linux only use 19 out of the
20 bits of PID space, so existing guests will work if we make the host
use the top half of the 20 bits space.

We additionally add support for a property to indicate to Linux the
size of the PID register which will be useful if we eventually have
processors with a larger PID space available.

There is still an issue with malicious guests purposefully setting the
PID register to a value in the hosts PID range. Hopefully future HW
can prevent that, but in the meantime, we handle it with a pair of
kludges:

 - On the way out of a guest, before we clear the current VCPU in the
   PACA, we check the PID and if it's outside of the permitted range
   we flush the TLB for that PID.

 - When context switching, if the mm is "new" on that CPU (the
   corresponding bit was set for the first time in the mm cpumask), we
   check if any sibling thread is in KVM (has a non-NULL VCPU pointer
   in the PACA). If that is the case, we also flush the PID for that
   CPU (core).

This second part is needed to handle the case where a process is
migrated (or starts a new pthread) on a sibling thread of the CPU
coming out of KVM, as there's a window where stale translations can
exist before we detect it and flush them out.

A future optimization could be added by keeping track of whether the
PID has ever been used and avoid doing that for completely fresh PIDs.
We could similarily mark PIDs that have been the subject of a global
invalidation as "fresh". But for now this will do.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Rework the asm to build with CONFIG_PPC_RADIX_MMU=n, drop
      unneeded include of kvm_book3s_asm.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-26 16:41:52 +10:00
Aneesh Kumar K.V
7e7dc66adc powerpc/mm: Build fix for non SPARSEMEM_VMEMAP config
We can use pfn_to_page() in realmode for other configs. Hence remove the
CONFIG_FLATMEM ifdef.

Fixes: 8e0861fa3c ("powerpc: Prepare to support kernel handling of IOMMU map/unmap")
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Also fix up the #endif comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-24 22:39:08 +10:00
Linus Torvalds
10fc95547f powerpc fixes for 4.13 #3
A handful of fixes, mostly for new code.
 
 Some reworking of the new STRICT_KERNEL_RWX support to make sure we also remove
 executable permission from __init memory before it's freed.
 
 A fix to some recent optimisations to the hypercall entry where we were
 clobbering r12, this was breaking nested guests (PR KVM).
 
 A fix for the recent patch to opal_configure_cores(). This could break booting
 on bare metal Power8 boxes if the kernel was built without
 CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG.
 
 And finally a workaround for spurious PMU interrupts on Power9 DD2.
 
 Thanks to:
   Nicholas Piggin, Anton Blanchard, Balbir Singh.
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Merge tag 'powerpc-4.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "A handful of fixes, mostly for new code:

   - some reworking of the new STRICT_KERNEL_RWX support to make sure we
     also remove executable permission from __init memory before it's
     freed.

   - a fix to some recent optimisations to the hypercall entry where we
     were clobbering r12, this was breaking nested guests (PR KVM).

   - a fix for the recent patch to opal_configure_cores(). This could
     break booting on bare metal Power8 boxes if the kernel was built
     without CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG.

   - .. and finally a workaround for spurious PMU interrupts on Power9
     DD2.

  Thanks to: Nicholas Piggin, Anton Blanchard, Balbir Singh"

* tag 'powerpc-4.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y
  powerpc/mm/hash: Refactor hash__mark_rodata_ro()
  powerpc/mm/radix: Refactor radix__mark_rodata_ro()
  powerpc/64s: Fix hypercall entry clobbering r12 input
  powerpc/perf: Avoid spurious PMU interrupts after idle
  powerpc/powernv: Fix boot on Power8 bare metal due to opal_configure_cores()
2017-07-21 13:54:37 -07:00
Michael Ellerman
029d9252b1 powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y
Currently even with STRICT_KERNEL_RWX we leave the __init text marked
executable after init, which is bad.

Add a hook to mark it NX (no-execute) before we free it, and implement
it for radix and hash.

Note that we use __init_end as the end address, not _einittext,
because overlaps_kernel_text() uses __init_end, because there are
additional executable sections other than .init.text between
__init_begin and __init_end.

Tested on radix and hash with:

  0:mon> p $__init_begin
  *** 400 exception occurred

Fixes: 1e0fc9d1eb ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-18 19:54:24 +10:00
Michael Ellerman
fa7f9189e0 powerpc/mm/hash: Refactor hash__mark_rodata_ro()
Move the core logic into a helper, so we can use it for changing other
permissions.

We also change the logic to align start down, and end up. This means
calling the function with a range will expand that range to be at
least 1 mmu_linear_psize page in size. We need that so we can use it
on __init_begin ...  __init_end which is not a full page in size.

This should always work for _stext/__init_begin, because we align
__init_begin to _stext + 16M in the linker script.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-18 18:51:35 +10:00
Michael Ellerman
b134bd9028 powerpc/mm/radix: Refactor radix__mark_rodata_ro()
Move the core logic into a helper, so we can use it for changing permissions
other than _PAGE_WRITE.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-18 18:51:34 +10:00
Linus Torvalds
deed9deb62 powerpc fixes for 4.13 #2
Nothing that really stands out, just a bunch of fixes that have come in in the
 last couple of weeks.
 
 None of these are actually fixes for code that is new in 4.13. It's roughly half
 older bugs, with fixes going to stable, and half fixes/updates for Power9.
 
 Thanks to:
   Aneesh Kumar K.V, Anton Blanchard, Balbir Singh, Benjamin Herrenschmidt,
   Madhavan Srinivasan, Michael Neuling, Nicholas Piggin, Oliver O'Halloran.
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Merge tag 'powerpc-4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Nothing that really stands out, just a bunch of fixes that have come
  in in the last couple of weeks.

  None of these are actually fixes for code that is new in 4.13. It's
  roughly half older bugs, with fixes going to stable, and half
  fixes/updates for Power9.

  Thanks to: Aneesh Kumar K.V, Anton Blanchard, Balbir Singh, Benjamin
  Herrenschmidt, Madhavan Srinivasan, Michael Neuling, Nicholas Piggin,
  Oliver O'Halloran"

* tag 'powerpc-4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64: Fix atomic64_inc_not_zero() to return an int
  powerpc: Fix emulation of mfocrf in emulate_step()
  powerpc: Fix emulation of mcrf in emulate_step()
  powerpc/perf: Add POWER9 alternate PM_RUN_CYC and PM_RUN_INST_CMPL events
  powerpc/perf: Fix SDAR_MODE value for continous sampling on Power9
  powerpc/asm: Mark cr0 as clobbered in mftb()
  powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9
  powerpc/mm/radix: Synchronize updates to the process table
  powerpc/mm/radix: Properly clear process table entry
  powerpc/powernv: Tell OPAL about our MMU mode on POWER9
  powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR
2017-07-14 15:33:15 -07:00
Rik van Riel
0a782dc31f powerpc,mmap: properly account for stack randomization in mmap_base
When RLIMIT_STACK is, for example, 256MB, the current code results in a
gap between the top of the task and mmap_base of 256MB, failing to take
into account the amount by which the stack address was randomized.  In
other words, the stack gets less than RLIMIT_STACK space.

Ensure that the gap between the stack and mmap_base always takes stack
randomization and the stack guard gap into account.

Inspired by Daniel Micay's linux-hardened tree.

Link: http://lkml.kernel.org/r/20170622200033.25714-4-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Florian Weimer <fweimer@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00
Benjamin Herrenschmidt
3a6a04706f powerpc/mm/radix: Synchronize updates to the process table
When writing to the process table, we need to ensure the store is
visible to a subsequent access by the MMU. We assume we never have
the PID active while doing the update, so a ptesync/isync pair
should hopefully be a big enough hammer for our purpose.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-10 21:26:31 +10:00
Benjamin Herrenschmidt
c6bb0b8d42 powerpc/mm/radix: Properly clear process table entry
On radix, the process table entry we want to clear when destroying a
context is entry 0, not entry 1. This has no *immediate* consequence
on Power9, but it can cause other bugs to become worse.

Fixes: 7e381c0ff6 ("powerpc/mm/radix: Add mmu context handling callback for radix")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-10 21:24:34 +10:00
Linus Torvalds
d691b7e7d1 powerpc updates for 4.13
Highlights include:
 
  - Support for STRICT_KERNEL_RWX on 64-bit server CPUs.
 
  - Platform support for FSP2 (476fpe) board
 
  - Enable ZONE_DEVICE on 64-bit server CPUs.
 
  - Generic & powerpc spin loop primitives to optimise busy waiting
 
  - Convert VDSO update function to use new update_vsyscall() interface
 
  - Optimisations to hypercall/syscall/context-switch paths
 
  - Improvements to the CPU idle code on Power8 and Power9.
 
 As well as many other fixes and improvements.
 
 Thanks to:
   Akshay Adiga, Andrew Donnellan, Andrew Jeffery, Anshuman Khandual, Anton
   Blanchard, Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe
   Lombard, Colin Ian King, Dan Carpenter, Gautham R. Shenoy, Hari Bathini, Ian
   Munsie, Ivan Mikhaylov, Javier Martinez Canillas, Madhavan Srinivasan,
   Masahiro Yamada, Matt Brown, Michael Neuling, Michal Suchanek, Murilo
   Opsfelder Araujo, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul
   Mackerras, Pavel Machek, Russell Currey, Santosh Sivaraj, Stephen Rothwell,
   Thiago Jung Bauermann, Yang Li.
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Merge tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Highlights include:

   - Support for STRICT_KERNEL_RWX on 64-bit server CPUs.

   - Platform support for FSP2 (476fpe) board

   - Enable ZONE_DEVICE on 64-bit server CPUs.

   - Generic & powerpc spin loop primitives to optimise busy waiting

   - Convert VDSO update function to use new update_vsyscall() interface

   - Optimisations to hypercall/syscall/context-switch paths

   - Improvements to the CPU idle code on Power8 and Power9.

  As well as many other fixes and improvements.

  Thanks to: Akshay Adiga, Andrew Donnellan, Andrew Jeffery, Anshuman
  Khandual, Anton Blanchard, Balbir Singh, Benjamin Herrenschmidt,
  Christophe Leroy, Christophe Lombard, Colin Ian King, Dan Carpenter,
  Gautham R. Shenoy, Hari Bathini, Ian Munsie, Ivan Mikhaylov, Javier
  Martinez Canillas, Madhavan Srinivasan, Masahiro Yamada, Matt Brown,
  Michael Neuling, Michal Suchanek, Murilo Opsfelder Araujo, Naveen N.
  Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pavel Machek,
  Russell Currey, Santosh Sivaraj, Stephen Rothwell, Thiago Jung
  Bauermann, Yang Li"

* tag 'powerpc-4.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits)
  powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs
  powerpc/mm/radix: Implement STRICT_RWX/mark_rodata_ro() for Radix
  powerpc/mm/hash: Implement mark_rodata_ro() for hash
  powerpc/vmlinux.lds: Align __init_begin to 16M
  powerpc/lib/code-patching: Use alternate map for patch_instruction()
  powerpc/xmon: Add patch_instruction() support for xmon
  powerpc/kprobes/optprobes: Use patch_instruction()
  powerpc/kprobes: Move kprobes over to patch_instruction()
  powerpc/mm/radix: Fix execute permissions for interrupt_vectors
  powerpc/pseries: Fix passing of pp0 in updatepp() and updateboltedpp()
  powerpc/64s: Blacklist rtas entry/exit from kprobes
  powerpc/64s: Blacklist functions invoked on a trap
  powerpc/64s: Un-blacklist system_call() from kprobes
  powerpc/64s: Move system_call() symbol to just after setting MSR_EE
  powerpc/64s: Blacklist system_call() and system_call_common() from kprobes
  powerpc/64s: Convert .L__replay_interrupt_return to a local label
  powerpc64/elfv1: Only dereference function descriptor for non-text symbols
  cxl: Export library to support IBM XSL
  powerpc/dts: Use #include "..." to include local DT
  powerpc/perf/hv-24x7: Aggregate result elements on POWER9 SMT8
  ...
2017-07-07 13:55:45 -07:00
Punit Agrawal
7868a2087e mm/hugetlb: add size parameter to huge_pte_offset()
A poisoned or migrated hugepage is stored as a swap entry in the page
tables.  On architectures that support hugepages consisting of
contiguous page table entries (such as on arm64) this leads to ambiguity
in determining the page table entry to return in huge_pte_offset() when
a poisoned entry is encountered.

Let's remove the ambiguity by adding a size parameter to convey
additional information about the requested address.  Also fixup the
definition/usage of huge_pte_offset() throughout the tree.

Link: http://lkml.kernel.org/r/20170522133604.11392-4-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com> (odd fixer:METAG ARCHITECTURE)
Cc: Ralf Baechle <ralf@linux-mips.org> (supporter:MIPS)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:34 -07:00
Aneesh Kumar K.V
40692eb5ee powerpc/mm/hugetlb: add support for 1G huge pages
POWER9 supports hugepages of size 2M and 1G in radix MMU mode.  This
patch enables the usage of 1G page size for hugetlbfs.  This also update
the helper such we can do 1G page allocation at runtime.

We still don't enable 1G page size on DD1 version.  This is to avoid
doing workaround mentioned in commit 6d3a0379eb ("powerpc/mm: Add
radix__tlb_flush_pte_p9_dd1()").

Link: http://lkml.kernel.org/r/1494995292-4443-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:33 -07:00
Aneesh Kumar K.V
28c057160e powerpc/mm/hugetlb: remove follow_huge_addr for powerpc
With generic code now handling hugetlb entries at pgd level and also
supporting hugepage directory format, we can now remove the powerpc
sepcific follow_huge_addr implementation.

Link: http://lkml.kernel.org/r/1494926612-23928-9-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:33 -07:00
Aneesh Kumar K.V
50791e6de0 powerpc/hugetlb: add follow_huge_pd implementation for ppc64
Link: http://lkml.kernel.org/r/1494926612-23928-8-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:33 -07:00
Michal Hocko
3d79a728f9 mm, memory_hotplug: replace for_device by want_memblock in arch_add_memory
arch_add_memory gets for_device argument which then controls whether we
want to create memblocks for created memory sections.  Simplify the
logic by telling whether we want memblocks directly rather than going
through pointless negation.  This also makes the api easier to
understand because it is clear what we want rather than nothing telling
for_device which can mean anything.

This shouldn't introduce any functional change.

Link: http://lkml.kernel.org/r/20170515085827.16474-13-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:32 -07:00
Michal Hocko
f1dd2cd13c mm, memory_hotplug: do not associate hotadded memory to zones until online
The current memory hotplug implementation relies on having all the
struct pages associate with a zone/node during the physical hotplug
phase (arch_add_memory->__add_pages->__add_section->__add_zone).  In the
vast majority of cases this means that they are added to ZONE_NORMAL.
This has been so since 9d99aaa31f ("[PATCH] x86_64: Support memory
hotadd without sparsemem") and it wasn't a big deal back then because
movable onlining didn't exist yet.

Much later memory hotplug wanted to (ab)use ZONE_MOVABLE for movable
onlining 511c2aba8f ("mm, memory-hotplug: dynamic configure movable
memory and portion memory") and then things got more complicated.
Rather than reconsidering the zone association which was no longer
needed (because the memory hotplug already depended on SPARSEMEM) a
convoluted semantic of zone shifting has been developed.  Only the
currently last memblock or the one adjacent to the zone_movable can be
onlined movable.  This essentially means that the online type changes as
the new memblocks are added.

Let's simulate memory hot online manually
  $ echo 0x100000000 > /sys/devices/system/memory/probe
  $ grep . /sys/devices/system/memory/memory32/valid_zones
  Normal Movable

  $ echo $((0x100000000+(128<<20))) > /sys/devices/system/memory/probe
  $ grep . /sys/devices/system/memory/memory3?/valid_zones
  /sys/devices/system/memory/memory32/valid_zones:Normal
  /sys/devices/system/memory/memory33/valid_zones:Normal Movable

  $ echo $((0x100000000+2*(128<<20))) > /sys/devices/system/memory/probe
  $ grep . /sys/devices/system/memory/memory3?/valid_zones
  /sys/devices/system/memory/memory32/valid_zones:Normal
  /sys/devices/system/memory/memory33/valid_zones:Normal
  /sys/devices/system/memory/memory34/valid_zones:Normal Movable

  $ echo online_movable > /sys/devices/system/memory/memory34/state
  $ grep . /sys/devices/system/memory/memory3?/valid_zones
  /sys/devices/system/memory/memory32/valid_zones:Normal
  /sys/devices/system/memory/memory33/valid_zones:Normal Movable
  /sys/devices/system/memory/memory34/valid_zones:Movable Normal

This is an awkward semantic because an udev event is sent as soon as the
block is onlined and an udev handler might want to online it based on
some policy (e.g.  association with a node) but it will inherently race
with new blocks showing up.

This patch changes the physical online phase to not associate pages with
any zone at all.  All the pages are just marked reserved and wait for
the onlining phase to be associated with the zone as per the online
request.  There are only two requirements

	- existing ZONE_NORMAL and ZONE_MOVABLE cannot overlap

	- ZONE_NORMAL precedes ZONE_MOVABLE in physical addresses

the latter one is not an inherent requirement and can be changed in the
future.  It preserves the current behavior and made the code slightly
simpler.  This is subject to change in future.

This means that the same physical online steps as above will lead to the
following state: Normal Movable

  /sys/devices/system/memory/memory32/valid_zones:Normal Movable
  /sys/devices/system/memory/memory33/valid_zones:Normal Movable

  /sys/devices/system/memory/memory32/valid_zones:Normal Movable
  /sys/devices/system/memory/memory33/valid_zones:Normal Movable
  /sys/devices/system/memory/memory34/valid_zones:Normal Movable

  /sys/devices/system/memory/memory32/valid_zones:Normal Movable
  /sys/devices/system/memory/memory33/valid_zones:Normal Movable
  /sys/devices/system/memory/memory34/valid_zones:Movable

Implementation:
The current move_pfn_range is reimplemented to check the above
requirements (allow_online_pfn_range) and then updates the respective
zone (move_pfn_range_to_zone), the pgdat and links all the pages in the
pfn range with the zone/node.  __add_pages is updated to not require the
zone and only initializes sections in the range.  This allowed to
simplify the arch_add_memory code (s390 could get rid of quite some of
code).

devm_memremap_pages is the only user of arch_add_memory which relies on
the zone association because it only hooks into the memory hotplug only
half way.  It uses it to associate the new memory with ZONE_DEVICE but
doesn't allow it to be {on,off}lined via sysfs.  This means that this
particular code path has to call move_pfn_range_to_zone explicitly.

The original zone shifting code is kept in place and will be removed in
the follow up patch for an easier review.

Please note that this patch also changes the original behavior when
offlining a memory block adjacent to another zone (Normal vs.  Movable)
used to allow to change its movable type.  This will be handled later.

[richard.weiyang@gmail.com: simplify zone_intersects()]
  Link: http://lkml.kernel.org/r/20170616092335.5177-1-richard.weiyang@gmail.com
[richard.weiyang@gmail.com: remove duplicate call for set_page_links]
  Link: http://lkml.kernel.org/r/20170616092335.5177-2-richard.weiyang@gmail.com
[akpm@linux-foundation.org: remove unused local `i']
Link: http://lkml.kernel.org/r/20170515085827.16474-12-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # For s390 bits
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:32 -07:00
Michal Hocko
1b862aecfb mm, memory_hotplug: get rid of is_zone_device_section
Device memory hotplug hooks into regular memory hotplug only half way.
It needs memory sections to track struct pages but there is no
need/desire to associate those sections with memory blocks and export
them to the userspace via sysfs because they cannot be onlined anyway.

This is currently expressed by for_device argument to arch_add_memory
which then makes sure to associate the given memory range with
ZONE_DEVICE.  register_new_memory then relies on is_zone_device_section
to distinguish special memory hotplug from the regular one.  While this
works now, later patches in this series want to move __add_zone outside
of arch_add_memory path so we have to come up with something else.

Add want_memblock down the __add_pages path and use it to control
whether the section->memblock association should be done.
arch_add_memory then just trivially want memblock for everything but
for_device hotplug.

remove_memory_section doesn't need is_zone_device_section either.  We
can simply skip all the memblock specific cleanup if there is no
memblock for the given section.

This shouldn't introduce any functional change.

Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06 16:24:32 -07:00
Balbir Singh
7614ff3272 powerpc/mm/radix: Implement STRICT_RWX/mark_rodata_ro() for Radix
The Radix linear mapping code (create_physical_mapping()) tries to use
the largest page size it can at each step. Currently the only reason
it steps down to a smaller page size is if the start addr is
unaligned (never happens in practice), or the end of memory is not
aligned to a huge page boundary.

To support STRICT_RWX we need to break the mapping at __init_begin,
so that the text and rodata prior to that can be marked R_X and the
regular pages after can be marked RW.

Having done that we can now implement mark_rodata_ro() for Radix,
knowing that we won't need to split any mappings.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Split down to PAGE_SIZE, not 2MB, rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-04 11:37:39 +10:00
Balbir Singh
cd65d69713 powerpc/mm/hash: Implement mark_rodata_ro() for hash
With hash we update the bolted pte to mark it read-only. We rely
on the MMU_FTR_KERNEL_RO to generate the correct permissions
for read-only text. The radix implementation just prints a warning
in this implementation

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Make the warning louder when we don't have MMU_FTR_KERNEL_RO]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-04 11:35:16 +10:00
Linus Torvalds
9a9594efe5 Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug updates from Thomas Gleixner:
 "This update is primarily a cleanup of the CPU hotplug locking code.

  The hotplug locking mechanism is an open coded RWSEM, which allows
  recursive locking. The main problem with that is the recursive nature
  as it evades the full lockdep coverage and hides potential deadlocks.

  The rework replaces the open coded RWSEM with a percpu RWSEM and
  establishes full lockdep coverage that way.

  The bulk of the changes fix up recursive locking issues and address
  the now fully reported potential deadlocks all over the place. Some of
  these deadlocks have been observed in the RT tree, but on mainline the
  probability was low enough to hide them away."

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  cpu/hotplug: Constify attribute_group structures
  powerpc: Only obtain cpu_hotplug_lock if called by rtasd
  ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init
  cpu/hotplug: Remove unused check_for_tasks() function
  perf/core: Don't release cred_guard_mutex if not taken
  cpuhotplug: Link lock stacks for hotplug callbacks
  acpi/processor: Prevent cpu hotplug deadlock
  sched: Provide is_percpu_thread() helper
  cpu/hotplug: Convert hotplug locking to percpu rwsem
  s390: Prevent hotplug rwsem recursion
  arm: Prevent hotplug rwsem recursion
  arm64: Prevent cpu hotplug rwsem recursion
  kprobes: Cure hotplug lock ordering issues
  jump_label: Reorder hotplug lock and jump_label_lock
  perf/tracing/cpuhotplug: Fix locking order
  ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()
  PCI: Replace the racy recursion prevention
  PCI: Use cpu_hotplug_disable() instead of get_online_cpus()
  perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()
  x86/perf: Drop EXPORT of perf_check_microcode
  ...
2017-07-03 18:08:06 -07:00
Balbir Singh
7f6d498ed3 powerpc/mm/radix: Fix execute permissions for interrupt_vectors
Commit 9abcc981de ("powerpc/mm/radix: Only add X for pages
overlapping kernel text") changed the linear mapping on Radix to only
mark the kernel text executable.

However if the kernel is run relocated, for example as a kdump kernel,
then the exception vectors are split from the kernel text, ie. they
remain at real address 0.

We tend to get away with it, because the kernel itself will usually be
below 1G, which means the 1G page at 0-1G is marked executable and
everything works OK. However if the kernel is loaded above 1G, or the
system has less than 1G in total (meaning we can't use a 1G page),
then the exception vectors will not be marked executable and the
kernel will fail to boot.

Fix it by also checking if the address range overlaps the exception
vectors when deciding if we should add PAGE_KERNEL_X.

Fixes: 9abcc981de ("powerpc/mm/radix: Only add X for pages overlapping kernel text")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Combine with the existing check, rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-03 23:12:19 +10:00
Michael Ellerman
218ea31039 Merge branch 'fixes' into next
Merge our fixes branch, a few of them are tripping people up while
working on top of next, and we also have a dependency between the CXL
fixes and new CXL code we want to merge into next.
2017-07-03 23:05:43 +10:00
Anton Blanchard
1b644f57b3 powerpc/mm: Wire up hpte_removebolted for powernv
Adds support for removing bolted (i.e kernel linear mapping) mappings on
powernv. This is needed to support memory hot unplug operations which
are required for the teardown of DAX/PMEM devices.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:28 +10:00
Oliver O'Halloran
ebd3119793 powerpc/mm: Add devmap support for ppc64
Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S.  This
is used to differentiate device backed memory from transparent huge
pages since they are handled in more or less the same manner by the core
mm code.

Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:28 +10:00
Oliver O'Halloran
b584c25440 powerpc/vmemmap: Add altmap support
Adds support to powerpc for the altmap feature of ZONE_DEVICE memory. An
altmap is a driver provided region that is used to provide the backing
storage for the struct pages of ZONE_DEVICE memory. In situations where
large amount of ZONE_DEVICE memory is being added to the system the
altmap reduces pressure on main system memory by allowing the mm/
metadata to be stored on the device itself rather in main memory.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:27 +10:00
Oliver O'Halloran
d7d9b612f1 powerpc/vmemmap: Reshuffle vmemmap_free()
Removes an indentation level and shuffles some code around to make the
following patch cleaner. No functional changes.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:26 +10:00
Oliver O'Halloran
7a849a6cf3 powerpc/hugetlbfs: Export HPAGE_SHIFT
Export it so it can be referenced inside a module.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:25 +10:00
Nicholas Piggin
4e287e655e powerpc: use spin loop primitives in some functions
Use the different spin loop primitives in some simple powerpc
spin loops, including those which will spin as a common case.

This will help to test the spin loop primitives before more
conversions are done.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add some includes of <linux/processor.h>]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:24 +10:00
Anshuman Khandual
39e4675183 powerpc/mm: Add comments on vmemmap physical mapping
Adds some explaination on how the vmemmap based struct page layout's
physical mapping is allocated and tracked through linked list. It
also keeps note of a possible race condition.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-28 13:08:17 +10:00
Anshuman Khandual
b0f36c10de powerpc/mm: Add comments to the vmemmap layout
Add some explaination to the layout of vmemmap virtual address
space and how physical page mapping is only used for valid PFNs
present at any point on the system.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-28 13:08:17 +10:00
Benjamin Herrenschmidt
74e27c6af5 powerpc: Only do ERAT invalidate on radix context switch on P9 DD1
From: Michael Neuling <mikey@neuling.org>

On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
register will implicitly invalidate the user space ERAT entries
and leave the kernel ones alone. Thus the only thing needed is
an isync() to synchronize this with subsequent uaccess's

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-27 14:15:54 +10:00
Balbir Singh
0428491cba powerpc/mm: Trace tlbie(l) instructions
Add a trace point for tlbie(l) (Translation Lookaside Buffer Invalidate
Entry (Local)) instructions.

The tlbie instruction has changed over the years, so not all versions
accept the same operands. Use the ISA v3 field operands because they are
the most verbose, we may change them in future.

Example output:

  qemu-system-ppc-5371  [016]  1412.369519: tlbie:
  	tlbie with lpid 0, local 1, rb=67bd8900174c11c1, rs=0, ric=0 prs=0 r=0

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Add some missing trace_tlbie()s, reword change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-23 21:14:49 +10:00
Thiago Jung Bauermann
3e401f7a2e powerpc: Only obtain cpu_hotplug_lock if called by rtasd
Calling arch_update_cpu_topology from a CPU hotplug state machine callback
hits a deadlock because the function tries to get a read lock on
cpu_hotplug_lock while the state machine still holds a write lock on it.

Since all callers of arch_update_cpu_topology except rtasd already hold
cpu_hotplug_lock, this patch changes the function to use
stop_machine_cpuslocked and creates a separate function for rtasd which
still tries to obtain the lock.

Michael Bringmann investigated the bug and provided a detailed analysis
of the deadlock on this previous RFC for an alternate solution:

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com
Link: https://patchwork.ozlabs.org/patch/771293/
2017-06-23 09:32:11 +02:00
Michael Ellerman
fd88b945c1 powerpc/64s: Rename slb_allocate_realmode() to slb_allocate()
As for slb_miss_realmode(), rename slb_allocate_realmode() to avoid
confusion over whether it runs in real or virtual mode - it runs in
both.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
2017-06-21 16:18:33 +10:00
Nicholas Piggin
d59afffdf0 powerpc/64s: Preserve r3 in slb_allocate_realmode()
One fewer registers clobbered by this function means the SLB miss
handler can save one fewer.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-20 22:18:25 +10:00
Hugh Dickins
1be7107fbe mm: larger stack guard gap, between vmas
Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 21:50:20 +08:00
Michael Ellerman
9abcc981de powerpc/mm/radix: Only add X for pages overlapping kernel text
Currently we map the whole linear mapping with PAGE_KERNEL_X. Instead we
should check if the page overlaps the kernel text and only then add
PAGE_KERNEL_X.

Note that we still use 1G pages if they're available, so this will
typically still result in a 1G executable page at KERNELBASE. So this fix is
primarily useful for catching stray branches to high linear mapping addresses.

Without this patch, we can execute at 1G in xmon using:

  0:mon> m c000000040000000
  c000000040000000  00 l
  c000000040000000  00000000 01006038
  c000000040000004  00000000 2000804e
  c000000040000008  00000000 x
  0:mon> di c000000040000000
  c000000040000000  38600001      li      r3,1
  c000000040000004  4e800020      blr
  0:mon> p c000000040000000
  return value is 0x1

After we get a 400 as expected:

  0:mon> p c000000040000000
  *** 400 exception occurred

Fixes: 2bfd65e45e ("powerpc/mm/radix: Add radix callbacks for early init routines")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
2017-06-15 16:34:39 +10:00
Aneesh Kumar K.V
92d9dfda8b powerpc/mm/4k: Limit 4k page size config to 64TB virtual address space
Supporting 512TB requires us to do a order 3 allocation for level 1 page
table (pgd). This results in page allocation failures with certain workloads.
For now limit 4k linux page size config to 64TB.

Fixes: f6eedbba7a ("powerpc/mm/hash: Increase VA range to 128TB")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-08 20:42:56 +10:00
Christophe Leroy
4386c096c2 powerpc/mm: Rename map_page() to map_kernel_page() on 32-bit
These two functions implement the same semantics, so unify their naming so we
can share code that calls them. The longer name is more descriptive so use it.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-05 19:59:03 +10:00
Balbir Singh
d2485644c7 powerpc/mm/hugetlb: Add support for page accounting
Add __GFP_ACCOUNT to __hugepte_alloc()

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-05 19:03:12 +10:00
Balbir Singh
abd667be15 powerpc/mm/book(e)(3s)/32: Add page table accounting
Add support in pte_alloc_one() and pgd_alloc() by
passing __GFP_ACCOUNT in the flags

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-05 19:03:11 +10:00
Balbir Singh
de3b87611d powerpc/mm/book(e)(3s)/64: Add page table accounting
Introduce a helper pgtable_gfp_flags() which
just returns the current gfp flags and adds
__GFP_ACCOUNT to account for page table allocation.
The generic helper is added to include/asm/pgalloc.h
and has two variants - WARNING ugly bits ahead

1. If the header is included from a module, no check
for mm == &init_mm is done, since init_mm is not
exported
2. For kernel includes, the check is done and required
see (3e79ec7 arch: x86: charge page tables to kmemcg)

The fundamental assumption is that no module should be
doing pgd/pud/pmd and pte alloc's on behalf of init_mm
directly.

NOTE: This adds an overhead to pmd/pud/pgd allocations
similar to x86.  The other alternative was to implement
pmd_alloc_kernel/pud_alloc_kernel and pgd_alloc_kernel
with their offset variants.

For 4k page size, pte_alloc_one no longer calls
pte_alloc_one_kernel.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-05 19:03:10 +10:00
Balbir Singh
c5cee6421c powerpc/mm/hash: Do a local flush if possible when no batch is active
Currently in hpte_need_flush() if there is no batch pending we always do a
global TLB flush, which is inefficient if the mm has never run on another
thread.

Instead do the same check that __flush_tlb_pending() does and check if a local
flush is sufficient when batch->active is false. Instead of open-coding it we
use mm_is_thread_local().

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Don't use a local, just inline mm_is_thread_local()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-05 19:02:55 +10:00
Christophe Leroy
92aa2fe039 powerpc/mm: The 8xx doesn't call do_page_fault() for breakpoints
The 8xx has a dedicated exception for breakpoints, that directly
calls do_break()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:20:12 +10:00
Christophe Leroy
da929f6af4 powerpc/mm: Evaluate user_mode(regs) only once in do_page_fault()
Analysis of the assembly code shows that when using user_mode(regs),
at least the 'andi.' is redone all the time, and also
the 'lwz ,132(r31)' most of the time. With the new form, the 'is_user'
is mapped to cr4, then all further use of is_user results in just
things like 'beq cr4,218 <do_page_fault+0x218>'

Without the patch:

  50:	81 1e 00 84 	lwz     r8,132(r30)
  54:	71 09 40 00 	andi.   r9,r8,16384
  58:	40 82 00 0c 	bne     64 <do_page_fault+0x64>

  84:	81 3e 00 84 	lwz     r9,132(r30)
  8c:	71 2a 40 00 	andi.   r10,r9,16384
  90:	41 a2 01 64 	beq     1f4 <do_page_fault+0x1f4>

  d4:	81 3e 00 84 	lwz     r9,132(r30)
  dc:	71 28 40 00 	andi.   r8,r9,16384
  e0:	41 82 02 08 	beq     2e8 <do_page_fault+0x2e8>

 108:	81 3e 00 84 	lwz     r9,132(r30)
 110:	71 28 40 00 	andi.   r8,r9,16384
 118:	41 82 02 28 	beq     340 <do_page_fault+0x340>

 1e4:	81 3e 00 84 	lwz     r9,132(r30)
 1e8:	71 2a 40 00 	andi.   r10,r9,16384
 1ec:	40 82 01 68 	bne     354 <do_page_fault+0x354>

 228:	81 3e 00 84 	lwz     r9,132(r30)
 22c:	71 28 40 00 	andi.   r8,r9,16384
 230:	41 82 ff c4 	beq     1f4 <do_page_fault+0x1f4>

 288:	71 2a 40 00 	andi.   r10,r9,16384
 294:	41 a2 fe 60 	beq     f4 <do_page_fault+0xf4>

 50c:	81 3e 00 84 	lwz     r9,132(r30)
 514:	71 2a 40 00 	andi.   r10,r9,16384
 518:	40 a2 fc e0 	bne     1f8 <do_page_fault+0x1f8>

 534:	81 3e 00 84 	lwz     r9,132(r30)
 53c:	71 2a 40 00 	andi.   r10,r9,16384
 540:	41 82 fc b8 	beq     1f8 <do_page_fault+0x1f8>

This patch creates a local var called 'is_user' which contains the
result of user_mode(regs)

With the patch:

  20:	81 03 00 84 	lwz     r8,132(r3)
  48:	55 09 97 fe 	rlwinm  r9,r8,18,31,31
  58:	2e 09 00 00 	cmpwi   cr4,r9,0
  5c:	40 92 00 0c 	bne     cr4,68 <do_page_fault+0x68>

  88:	41 b2 01 90 	beq     cr4,218 <do_page_fault+0x218>

  d4:	40 92 01 d0 	bne     cr4,2a4 <do_page_fault+0x2a4>

 120:	41 b2 00 f8 	beq     cr4,218 <do_page_fault+0x218>

 138:	41 b2 ff a0 	beq     cr4,d8 <do_page_fault+0xd8>

 1d4:	40 92 00 e0 	bne     cr4,2b4 <do_page_fault+0x2b4>

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:19:45 +10:00
Christophe Leroy
97a011e69b powerpc/mm: Remove a redundant test in do_page_fault()
The result of (trap == 0x400) is already in is_exec.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:18:34 +10:00
Christophe Leroy
e8de85ca32 powerpc/mm: Only call store_updates_sp() on stores in do_page_fault()
Function store_updates_sp() checks whether the faulting
instruction is a store updating r1. Therefore we can limit its calls
to store exceptions.

This patch is an improvement of commit a7a9dcd882 ("powerpc: Avoid
taking a data miss on every userspace instruction miss")

With the same microbenchmark app, run with 500 as argument, on an
MPC885 we get:

Before this patch: 152000 DTLB misses
After this patch:  147000 DTLB misses

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:10:24 +10:00
Christophe Leroy
9affa9e228 powerpc/mm: Remove __this_fixmap_does_not_exist()
This function has not been used since commit 9494a1e842
("powerpc: use generic fixmap.h)

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:09:53 +10:00
Balbir Singh
e63739b168 powerpc/mm/ptdump: Dump the first entry of the linear mapping as well
The check in hpte_find() should be < and not <= for PAGE_OFFSET

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-02 19:09:52 +10:00
Michael Ellerman
bfb9956ab4 powerpc/mm: Fix crash in page table dump with huge pages
The page table dump code doesn't know about huge pages, so currently
it crashes (or walks random memory, usually leading to a crash), if it
finds a huge page. On Book3S we only see huge pages in the Linux page
tables when we're using the P9 Radix MMU.

Teaching the code to properly handle huge pages is a bit more involved,
so for now just prevent the crash.

Cc: stable@vger.kernel.org # v4.10+
Fixes: 8eb07b1870 ("powerpc/mm: Dump linux pagetables")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-05-17 11:56:33 +10:00
Stephen Boyd
ad61dd303a scripts/spelling.txt: add regsiter -> register spelling mistake
This typo is quite common.  Fix it and add it to the spelling file so
that checkpatch catches it earlier.

Link: http://lkml.kernel.org/r/20170317011131.6881-2-sboyd@codeaurora.org
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:13 -07:00
Linus Torvalds
7246f60068 powerpc updates for 4.12 part 1.
Highlights include:
 
  - Larger virtual address space on 64-bit server CPUs. By default we use a 128TB
    virtual address space, but a process can request access to the full 512TB by
    passing a hint to mmap().
 
  - Support for the new Power9 "XIVE" interrupt controller.
 
  - TLB flushing optimisations for the radix MMU on Power9.
 
  - Support for CAPI cards on Power9, using the "Coherent Accelerator Interface
    Architecture 2.0".
 
  - The ability to configure the mmap randomisation limits at build and runtime.
 
  - Several small fixes and cleanups to the kprobes code, as well as support for
    KPROBES_ON_FTRACE.
 
  - Major improvements to handling of system reset interrupts, correctly treating
    them as NMIs, giving them a dedicated stack and using a new hypervisor call
    to trigger them, all of which should aid debugging and robustness.
 
 Many fixes and other minor enhancements.
 
 Thanks to:
   Alastair D'Silva, Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
   Aneesh Kumar K.V, Anshuman Khandual, Anton Blanchard, Balbir Singh, Ben
   Hutchings, Benjamin Herrenschmidt, Bhupesh Sharma, Chris Packham, Christian
   Zigotzky, Christophe Leroy, Christophe Lombard, Daniel Axtens, David Gibson,
   Gautham R. Shenoy, Gavin Shan, Geert Uytterhoeven, Guilherme G. Piccoli,
   Hamish Martin, Hari Bathini, Kees Cook, Laurent Dufour, Madhavan Srinivasan,
   Mahesh J Salgaonkar, Mahesh Salgaonkar, Masami Hiramatsu, Matt Brown, Matthew
   R. Ochs, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran,
   Pan Xinhui, Paul Mackerras, Rashmica Gupta, Russell Currey, Sukadev
   Bhattiprolu, Thadeu Lima de Souza Cascardo, Tobin C. Harding, Tyrel Datwyler,
   Uma Krishnan, Vaibhav Jain, Vipin K Parashar, Yang Shi.
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Merge tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Highlights include:

   - Larger virtual address space on 64-bit server CPUs. By default we
     use a 128TB virtual address space, but a process can request access
     to the full 512TB by passing a hint to mmap().

   - Support for the new Power9 "XIVE" interrupt controller.

   - TLB flushing optimisations for the radix MMU on Power9.

   - Support for CAPI cards on Power9, using the "Coherent Accelerator
     Interface Architecture 2.0".

   - The ability to configure the mmap randomisation limits at build and
     runtime.

   - Several small fixes and cleanups to the kprobes code, as well as
     support for KPROBES_ON_FTRACE.

   - Major improvements to handling of system reset interrupts,
     correctly treating them as NMIs, giving them a dedicated stack and
     using a new hypervisor call to trigger them, all of which should
     aid debugging and robustness.

   - Many fixes and other minor enhancements.

  Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Alistair Popple,
  Andrew Donnellan, Aneesh Kumar K.V, Anshuman Khandual, Anton
  Blanchard, Balbir Singh, Ben Hutchings, Benjamin Herrenschmidt,
  Bhupesh Sharma, Chris Packham, Christian Zigotzky, Christophe Leroy,
  Christophe Lombard, Daniel Axtens, David Gibson, Gautham R. Shenoy,
  Gavin Shan, Geert Uytterhoeven, Guilherme G. Piccoli, Hamish Martin,
  Hari Bathini, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mahesh J
  Salgaonkar, Mahesh Salgaonkar, Masami Hiramatsu, Matt Brown, Matthew
  R. Ochs, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Oliver
  O'Halloran, Pan Xinhui, Paul Mackerras, Rashmica Gupta, Russell
  Currey, Sukadev Bhattiprolu, Thadeu Lima de Souza Cascardo, Tobin C.
  Harding, Tyrel Datwyler, Uma Krishnan, Vaibhav Jain, Vipin K Parashar,
  Yang Shi"

* tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (214 commits)
  powerpc/64s: Power9 has no LPCR[VRMASD] field so don't set it
  powerpc/powernv: Fix TCE kill on NVLink2
  powerpc/mm/radix: Drop support for CPUs without lockless tlbie
  powerpc/book3s/mce: Move add_taint() later in virtual mode
  powerpc/sysfs: Move #ifdef CONFIG_HOTPLUG_CPU out of the function body
  powerpc/smp: Document irq enable/disable after migrating IRQs
  powerpc/mpc52xx: Don't select user-visible RTAS_PROC
  powerpc/powernv: Document cxl dependency on special case in pnv_eeh_reset()
  powerpc/eeh: Clean up and document event handling functions
  powerpc/eeh: Avoid use after free in eeh_handle_special_event()
  cxl: Mask slice error interrupts after first occurrence
  cxl: Route eeh events to all drivers in cxl_pci_error_detected()
  cxl: Force context lock during EEH flow
  powerpc/64: Allow CONFIG_RELOCATABLE if COMPILE_TEST
  powerpc/xmon: Teach xmon oops about radix vectors
  powerpc/mm/hash: Fix off-by-one in comment about kernel contexts ids
  powerpc/pseries: Enable VFIO
  powerpc/powernv: Fix iommu table size calculation hook for small tables
  powerpc/powernv: Check kzalloc() return value in pnv_pci_table_alloc
  powerpc: Add arch/powerpc/tools directory
  ...
2017-05-05 11:36:44 -07:00
Michael Ellerman
3c9ac2bcc3 powerpc/mm/radix: Drop support for CPUs without lockless tlbie
Currently the radix TLB code includes support for CPUs that do *not*
have MMU_FTR_LOCKLESS_TLBIE. On those CPUs we are required to take a
global spinlock before issuing a tlbie.

Radix can only be built for 64-bit Book3s CPUs, and of those, only
POWER4, 970, Cell and PA6T do not have MMU_FTR_LOCKLESS_TLBIE. Although
it's possible to build a kernel with Radix support that can also boot on
those CPUs, we happen to know that in reality none of those CPUs support
the Radix MMU, so the code can never actually run on those CPUs.

So remove the native_tlbie_lock in the Radix TLB code.

Note that there is another lock of the same name in the hash code, which
is unaffected by this patch.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-05-03 20:45:45 +10:00