One fix going back to stable, for a bug on 32-bit introduced when we added
support for THREAD_INFO_IN_TASK.
A fix for a typo in a recent rework of our hugetlb code that leads to crashes on
64-bit when using hugetlbfs with a 4K PAGE_SIZE.
Two fixes for our recent rework of the address layout on 64-bit hash CPUs, both
only triggered when userspace tries to access addresses outside the user or
kernel address ranges.
Finally a fix for a recently introduced double free in an error path in our
cacheinfo code.
Thanks to:
Aneesh Kumar K.V, Christophe Leroy, Sachin Sant, Tobin C. Harding.
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Merge tag 'powerpc-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix going back to stable, for a bug on 32-bit introduced when we
added support for THREAD_INFO_IN_TASK.
A fix for a typo in a recent rework of our hugetlb code that leads to
crashes on 64-bit when using hugetlbfs with a 4K PAGE_SIZE.
Two fixes for our recent rework of the address layout on 64-bit hash
CPUs, both only triggered when userspace tries to access addresses
outside the user or kernel address ranges.
Finally a fix for a recently introduced double free in an error path
in our cacheinfo code.
Thanks to: Aneesh Kumar K.V, Christophe Leroy, Sachin Sant, Tobin C.
Harding"
* tag 'powerpc-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/cacheinfo: Remove double free
powerpc/mm/hash: Fix get_region_id() for invalid addresses
powerpc/mm: Drop VM_BUG_ON in get_region_id()
powerpc/mm: Fix crashes with hugepages & 4K pages
powerpc/32s: fix flush_hash_pages() on SMP
Accesses by userspace to random addresses outside the user or kernel
address range will generate an SLB fault. When we handle that fault we
classify the effective address into several classes, eg. user, kernel
linear, kernel virtual etc.
For addresses that are completely outside of any valid range, we
should not insert an SLB entry at all, and instead immediately an
exception.
In the past this was handled in two ways. Firstly we would check the
top nibble of the address (using REGION_ID(ea)) and that would tell us
if the address was user (0), kernel linear (c), kernel virtual (d), or
vmemmap (f). If the address didn't match any of these it was invalid.
Then for each type of address we would do a secondary check. For the
user region we check against H_PGTABLE_RANGE, for kernel linear we
would mask the top nibble of the address and then check the address
against MAX_PHYSMEM_BITS.
As part of commit 0034d395f8 ("powerpc/mm/hash64: Map all the kernel
regions in the same 0xc range") we replaced REGION_ID() with
get_region_id() and changed the masking of the top nibble to only mask
the top two bits, which introduced a bug.
Addresses less than (4 << 60) are still handled correctly, they are
either less than (1 << 60) in which case they are subject to the
H_PGTABLE_RANGE check, or they are correctly checked against
MAX_PHYSMEM_BITS.
However addresses from (4 << 60) to ((0xc << 60) - 1), are incorrectly
treated as kernel linear addresses in get_region_id(). Then the top
two bits are cleared by EA_MASK in slb_allocate_kernel() and the
address is checked against MAX_PHYSMEM_BITS, which it passes due to
the masking. The end result is we incorrectly insert SLB entries for
those addresses.
That is not actually catastrophic, having inserted the SLB entry we
will then go on to take a page fault for the address and at that point
we detect the problem and report it as a bad fault.
Still we should not be inserting those entries, or treating them as
kernel linear addresses in the first place. So fix get_region_id() to
detect addresses in that range and return an invalid region id, which
we cause use to not insert an SLB entry and directly report an
exception.
Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Drop change to EA_MASK for now, rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We call get_region_id() without validating the ea value. That means
with a wrong ea value we hit the BUG as below.
kernel BUG at arch/powerpc/include/asm/book3s/64/hash.h:129!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
CPU: 0 PID: 3937 Comm: access_tests Not tainted 5.1.0
....
NIP [c00000000007ba20] do_slb_fault+0x70/0x320
LR [c00000000000896c] data_access_slb_common+0x15c/0x1a0
Fix this by removing the VM_BUG_ON. All callers make sure the returned
region id is valid and error out otherwise.
Fixes: 0034d395f8 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Reported-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On systems without CONTIG_ALLOC activated but that support gigantic pages,
boottime reserved gigantic pages can not be freed at all. This patch
simply enables the possibility to hand back those pages to memory
allocator.
Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: David S. Miller <davem@davemloft.net> [sparc]
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When implementing the KUAP support on Radix we fixed one case where
mmu_has_feature() was being called too early in boot via
__put_user_size().
However since then some new code in linux-next has created a new path
via which we can end up calling mmu_has_feature() too early.
On P9 this leads to crashes early in boot if we have both PPC_KUAP and
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG enabled. Our early boot code
calls printk() which calls probe_kernel_read(), that does a
__copy_from_user_inatomic() which calls into set_kuap() and that uses
mmu_has_feature().
At that point in boot we haven't patched MMU features yet so the debug
code in mmu_has_feature() complains, and calls printk(). At that point
we recurse, eg:
...
dump_stack+0xdc
probe_kernel_read+0x1a4
check_pointer+0x58
...
printk+0x40
dump_stack_print_info+0xbc
dump_stack+0x8
probe_kernel_read+0x1a4
probe_kernel_read+0x19c
check_pointer+0x58
...
printk+0x40
cpufeatures_process_feature+0xc8
scan_cpufeatures_subnodes+0x380
of_scan_flat_dt_subnodes+0xb4
dt_cpu_ftrs_scan_callback+0x158
of_scan_flat_dt+0xf0
dt_cpu_ftrs_scan+0x3c
early_init_devtree+0x360
early_setup+0x9c
And so on for infinity, symptom is a dead system.
Even more fun is what happens when using the hash MMU (ie. p8 or p9
with Radix disabled), and when we don't have
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG enabled. With the debug disabled
we don't check if static keys have been initialised, we just rely on
the jump label. But the jump label defaults to true so we just whack
the AMR even though Radix is not enabled.
Clearing the AMR is fine, but after we've done the user copy we write
(0b11 << 62) into AMR. When using hash that makes all pages with key
zero no longer readable or writable. All kernel pages implicitly have
key zero, and so all of a sudden the kernel can't read or write any of
its memory. Again dead system.
In the medium term we have several options for fixing this.
probe_kernel_read() doesn't need to touch AMR at all, it's not doing a
user access after all, but it uses __copy_from_user_inatomic() just
because it's easy, we could fix that.
It would also be safe to default to not writing to the AMR during
early boot, until we've detected features. But it's not clear that
flipping all the MMU features to static_key_false won't introduce
other bugs.
But for now just switch to early_mmu_has_feature() in set_kuap(), that
avoids all the problems with jump labels. It adds the overhead of a
global lookup and test, but that's probably trivial compared to the
writes to the AMR anyway.
Fixes: 890274c2dc ("powerpc/64s: Implement KUAP for Radix MMU")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Russell Currey <ruscur@russell.cc>
When we add KASAN shadow area, KVIRT_TOP can't be anymore fixed
at 0xfe000000.
This patch uses FIXADDR_START to define KVIRT_TOP.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
pmd_pgtable() is identical on the 4 subarches, refactor it.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
pgtable_cache[] is the same for the 4 subarches, lets make it common.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Functions pte_alloc_one(), pte_alloc_one_kernel(), pte_free(),
pte_free_kernel() are identical for the four subarches.
This patch moves their definition in a common place.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
pte_alloc_one_kernel() and pte_alloc_one() are simple calls to
pte_fragment_alloc(), so they are good candidates for inlining as
already done on PPC64.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
pgtable_t is now identical for all subarches, move it to the
top level asm/mmu.h
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This has never been called (since Kernel has been in git at least),
drop it.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Introduce a subarch specific helper check_and_get_huge_psize()
to check the huge page sizes and cleanup the ifdef mess in
add_huge_page_size()
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patchs adds a subarch helper to populate hugepd.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Three subarches support hugepages:
- fsl book3e
- book3s/64
- 8xx
This patch splits asm/hugetlb.h to reduce the #ifdef mess.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch defines a subarch specific SLB_ADDR_LIMIT_DEFAULT
to remove the #ifdefs around the setup of mm->context.slb_addr_limit
It also generalises the use of mm_ctx_set_slb_addr_limit() helper.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Now that slice_mask_for_size() is in mmu.h, the mm_ctx_slice_mask_xxx()
are not needed anymore, so drop them. Note that the 8xx ones where
not used anyway.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Move slice_mask_for_size() into subarch mmu.h
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Retain the BUG_ON()s, rather than converting to VM_BUG_ON()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The region actually point to linear map. Rename the #define to
clarify thati.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This reduces multiple comparisons in get_region_id to a bit shift operation.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch maps vmalloc, IO and vmemap regions in the 0xc address range
instead of the current 0xd and 0xf range. This brings the mapping closer
to radix translation mode.
With hash 64K page size each of this region is 512TB whereas with 4K config
we are limited by the max page table range of 64TB and hence there regions
are of 16TB size.
The kernel mapping is now:
On 4K hash
kernel_region_map_size = 16TB
kernel vmalloc start = 0xc000100000000000
kernel IO start = 0xc000200000000000
kernel vmemmap start = 0xc000300000000000
64K hash, 64K radix and 4k radix:
kernel_region_map_size = 512TB
kernel vmalloc start = 0xc008000000000000
kernel IO start = 0xc00a000000000000
kernel vmemmap start = 0xc00c000000000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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>
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 a7df61a0e2 ("[PATCH] ppc64: Increase sparsemem defaults")
That change was done in 2005 and hopefully will work with book3e 64.
Fixes: 8bc0868998 ("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>
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>
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>
Add comments describing the size in bytes of the various levels of the
page table tree, and the size of the virtual address space mapped by
each level, to make it clear what the sizes are without having to also
look up other definitions.
The code that calculates the sizes actually uses sizeof(pgd_t) etc.,
so in theory these comments could skew vs the code, but the size of
pgd_t etc. is unlikely to change very often.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
One fix to prevent runtime allocation of 16GB pages when running in a VM (as
opposed to bare metal), because it doesn't work.
A small fix to our recently added KCOV support to exempt some more code from
being instrumented.
Plus a few minor build fixes, a small dead code removal and a defconfig update.
Thanks to:
Alexey Kardashevskiy, Aneesh Kumar K.V, Christophe Leroy, Jason Yan, Joel
Stanley, Mahesh Salgaonkar, Mathieu Malaterre.
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Merge tag 'powerpc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix to prevent runtime allocation of 16GB pages when running in a
VM (as opposed to bare metal), because it doesn't work.
A small fix to our recently added KCOV support to exempt some more
code from being instrumented.
Plus a few minor build fixes, a small dead code removal and a
defconfig update.
Thanks to: Alexey Kardashevskiy, Aneesh Kumar K.V, Christophe Leroy,
Jason Yan, Joel Stanley, Mahesh Salgaonkar, Mathieu Malaterre"
* tag 'powerpc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s: Include <asm/nmi.h> header file to fix a warning
powerpc/powernv: Fix compile without CONFIG_TRACEPOINTS
powerpc/mm: Disable kcov for SLB routines
powerpc: remove dead code in head_fsl_booke.S
powerpc/configs: Sync skiroot defconfig
powerpc/hugetlb: Don't do runtime allocation of 16G pages in LPAR configuration
Notable changes:
- Enable THREAD_INFO_IN_TASK to move thread_info off the stack.
- A big series from Christoph reworking our DMA code to use more of the generic
infrastructure, as he said:
"This series switches the powerpc port to use the generic swiotlb and
noncoherent dma ops, and to use more generic code for the coherent direct
mapping, as well as removing a lot of dead code."
- Increase our vmalloc space to 512T with the Hash MMU on modern CPUs, allowing
us to support machines with larger amounts of total RAM or distance between
nodes.
- Two series from Christophe, one to optimise TLB miss handlers on 6xx, and
another to optimise the way STRICT_KERNEL_RWX is implemented on some 32-bit
CPUs.
- Support for KCOV coverage instrumentation which means we can run syzkaller
and discover even more bugs in our code.
And as always many clean-ups, reworks and minor fixes etc.
Thanks to:
Alan Modra, Alexey Kardashevskiy, Alistair Popple, Andrea Arcangeli, Andrew
Donnellan, Aneesh Kumar K.V, Aravinda Prasad, Balbir Singh, Brajeswar Ghosh,
Breno Leitao, Christian Lamparter, Christian Zigotzky, Christophe Leroy,
Christoph Hellwig, Corentin Labbe, Daniel Axtens, David Gibson, Diana Craciun,
Firoz Khan, Gustavo A. R. Silva, Igor Stoppa, Joe Lawrence, Joel Stanley,
Jonathan Neuschäfer, Jordan Niethe, Laurent Dufour, Madhavan Srinivasan, Mahesh
Salgaonkar, Mark Cave-Ayland, Masahiro Yamada, Mathieu Malaterre, Matteo Croce,
Meelis Roos, Michael W. Bringmann, Nathan Chancellor, Nathan Fontenot, Nicholas
Piggin, Nick Desaulniers, Nicolai Stange, Oliver O'Halloran, Paul Mackerras,
Peter Xu, PrasannaKumar Muralidharan, Qian Cai, Rashmica Gupta, Reza Arbab,
Robert P. J. Day, Russell Currey, Sabyasachi Gupta, Sam Bobroff, Sandipan Das,
Sergey Senozhatsky, Souptick Joarder, Stewart Smith, Tyrel Datwyler, Vaibhav
Jain, YueHaibing.
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Merge tag 'powerpc-5.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Notable changes:
- Enable THREAD_INFO_IN_TASK to move thread_info off the stack.
- A big series from Christoph reworking our DMA code to use more of
the generic infrastructure, as he said:
"This series switches the powerpc port to use the generic swiotlb
and noncoherent dma ops, and to use more generic code for the
coherent direct mapping, as well as removing a lot of dead
code."
- Increase our vmalloc space to 512T with the Hash MMU on modern
CPUs, allowing us to support machines with larger amounts of total
RAM or distance between nodes.
- Two series from Christophe, one to optimise TLB miss handlers on
6xx, and another to optimise the way STRICT_KERNEL_RWX is
implemented on some 32-bit CPUs.
- Support for KCOV coverage instrumentation which means we can run
syzkaller and discover even more bugs in our code.
And as always many clean-ups, reworks and minor fixes etc.
Thanks to: Alan Modra, Alexey Kardashevskiy, Alistair Popple, Andrea
Arcangeli, Andrew Donnellan, Aneesh Kumar K.V, Aravinda Prasad, Balbir
Singh, Brajeswar Ghosh, Breno Leitao, Christian Lamparter, Christian
Zigotzky, Christophe Leroy, Christoph Hellwig, Corentin Labbe, Daniel
Axtens, David Gibson, Diana Craciun, Firoz Khan, Gustavo A. R. Silva,
Igor Stoppa, Joe Lawrence, Joel Stanley, Jonathan Neuschäfer, Jordan
Niethe, Laurent Dufour, Madhavan Srinivasan, Mahesh Salgaonkar, Mark
Cave-Ayland, Masahiro Yamada, Mathieu Malaterre, Matteo Croce, Meelis
Roos, Michael W. Bringmann, Nathan Chancellor, Nathan Fontenot,
Nicholas Piggin, Nick Desaulniers, Nicolai Stange, Oliver O'Halloran,
Paul Mackerras, Peter Xu, PrasannaKumar Muralidharan, Qian Cai,
Rashmica Gupta, Reza Arbab, Robert P. J. Day, Russell Currey,
Sabyasachi Gupta, Sam Bobroff, Sandipan Das, Sergey Senozhatsky,
Souptick Joarder, Stewart Smith, Tyrel Datwyler, Vaibhav Jain,
YueHaibing"
* tag 'powerpc-5.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (200 commits)
powerpc/32: Clear on-stack exception marker upon exception return
powerpc: Remove export of save_stack_trace_tsk_reliable()
powerpc/mm: fix "section_base" set but not used
powerpc/mm: Fix "sz" set but not used warning
powerpc/mm: Check secondary hash page table
powerpc: remove nargs from __SYSCALL
powerpc/64s: Fix unrelocated interrupt trampoline address test
powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables
powerpc/fsl: Fix the flush of branch predictor.
powerpc/powernv: Make opal log only readable by root
powerpc/xmon: Fix opcode being uninitialized in print_insn_powerpc
powerpc/powernv: move OPAL call wrapper tracing and interrupt handling to C
powerpc/64s: Fix data interrupts vs d-side MCE reentrancy
powerpc/64s: Prepare to handle data interrupts vs d-side MCE reentrancy
powerpc/64s: system reset interrupt preserve HSRRs
powerpc/64s: Fix HV NMI vs HV interrupt recoverability test
powerpc/mm/hash: Handle mmap_min_addr correctly in get_unmapped_area topdown search
powerpc/hugetlb: Handle mmap_min_addr correctly in get_unmapped_area callback
selftests/powerpc: Remove duplicate header
powerpc sstep: Add support for modsd, modud instructions
...
NestMMU requires us to mark the pte invalid and flush the tlb when we do
a RW upgrade of pte. We fixed a variant of this in the fault path in
bd5050e38a ("powerpc/mm/radix: Change pte relax sequence to handle
nest MMU hang").
Link: http://lkml.kernel.org/r/20190116085035.29729-6-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NestMMU requires us to mark the pte invalid and flush the tlb when we do
a RW upgrade of pte. We fixed a variant of this in the fault path in
bd5050e38a ("powerpc/mm/radix: Change pte relax sequence to handle
nest MMU hang").
Do the same for mprotect upgrades.
Hugetlb is handled in the next patch.
Link: http://lkml.kernel.org/r/20190116085035.29729-4-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We added runtime allocation of 16G pages in commit 4ae279c2c9
("powerpc/mm/hugetlb: Allow runtime allocation of 16G.") That was done
to enable 16G allocation on PowerNV and KVM config. In case of KVM
config, we mostly would have the entire guest RAM backed by 16G
hugetlb pages for this to work. PAPR do support partial backing of
guest RAM with hugepages via ibm,expected#pages node of memory node in
the device tree. This means rest of the guest RAM won't be backed by
16G contiguous pages in the host and hence a hash page table insertion
can fail in such case.
An example error message will look like
hash-mmu: mm: Hashing failure ! EA=0x7efc00000000 access=0x8000000000000006 current=readback
hash-mmu: trap=0x300 vsid=0x67af789 ssize=1 base psize=14 psize 14 pte=0xc000000400000386
readback[12260]: unhandled signal 7 at 00007efc00000000 nip 00000000100012d0 lr 000000001000127c code 2
This patch address that by preventing runtime allocation of 16G
hugepages in LPAR config. To allocate 16G hugetlb one need to kernel
command line hugepagesz=16G hugepages=<number of 16G pages>
With radix translation mode we don't run into this issue.
This change will prevent runtime allocation of 16G hugetlb pages on
kvm with hash translation mode. However, with the current upstream it
was observed that 16G hugetlbfs backed guest doesn't boot at all.
We observe boot failure with the below message:
[131354.647546] KVM: map_vrma at 0 failed, ret=-4
That means this patch is not resulting in an observable regression.
Once we fix the boot issue with 16G hugetlb backed memory, we need to
use ibm,expected#pages memory node attribute to indicate 16G page
reservation to the guest. This will also enable partial backing of
guest RAM with 16G pages.
Fixes: 4ae279c2c9 ("powerpc/mm/hugetlb: Allow runtime allocation of 16G.")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When activating CONFIG_THREAD_INFO_IN_TASK, linux/sched.h includes
asm/current.h. This generates a circular dependency. To avoid that,
asm/processor.h shall not be included in mmu-hash.h.
In order to do that, this patch moves into a new header called
asm/task_size_64/32.h all the TASK_SIZE related constants, which can
then be included in mmu-hash.h directly.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Split out all the TASK_SIZE constants not just 64-bit ones]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Today, STRICT_KERNEL_RWX is based on the use of regular pages
to map kernel pages.
On Book3s 32, it has three consequences:
- Using pages instead of BAT for mapping kernel linear memory severely
impacts performance.
- Exec protection is not effective because no-execute cannot be set at
page level (except on 603 which doesn't have hash tables)
- Write protection is not effective because PP bits do not provide RO
mode for kernel-only pages (except on 603 which handles it in software
via PAGE_DIRTY)
On the 603+, we have:
- Independent IBAT and DBAT allowing limitation of exec parts.
- NX bit can be set in segment registers to forbit execution on memory
mapped by pages.
- RO mode on DBATs even for kernel-only blocks.
On the 601, there is nothing much we can do other than warn the user
about it, because:
- BATs are common to instructions and data.
- BAT do not provide RO mode for kernel-only blocks.
- segment registers don't have the NX bit.
In order to use IBAT for exec protection, this patch:
- Aligns _etext to BAT block sizes (128kb)
- Set NX bit in kernel segment register (Except on vmalloc area when
CONFIG_MODULES is selected)
- Maps kernel text with IBATs.
In order to use DBAT for exec protection, this patch:
- Aligns RW DATA to BAT block sizes (4M)
- Maps kernel RO area with write prohibited DBATs
- Maps remaining memory with remaining DBATs
Here is what we get with this patch on a 832x when activating
STRICT_KERNEL_RWX:
Symbols:
c0000000 T _stext
c0680000 R __start_rodata
c0680000 R _etext
c0800000 T __init_begin
c0800000 T _sinittext
~# cat /sys/kernel/debug/block_address_translation
---[ Instruction Block Address Translation ]---
0: 0xc0000000-0xc03fffff 0x00000000 Kernel EXEC coherent
1: 0xc0400000-0xc05fffff 0x00400000 Kernel EXEC coherent
2: 0xc0600000-0xc067ffff 0x00600000 Kernel EXEC coherent
3: -
4: -
5: -
6: -
7: -
---[ Data Block Address Translation ]---
0: 0xc0000000-0xc07fffff 0x00000000 Kernel RO coherent
1: 0xc0800000-0xc0ffffff 0x00800000 Kernel RW coherent
2: 0xc1000000-0xc1ffffff 0x01000000 Kernel RW coherent
3: 0xc2000000-0xc3ffffff 0x02000000 Kernel RW coherent
4: 0xc4000000-0xc7ffffff 0x04000000 Kernel RW coherent
5: 0xc8000000-0xcfffffff 0x08000000 Kernel RW coherent
6: 0xd0000000-0xdfffffff 0x10000000 Kernel RW coherent
7: -
~# cat /sys/kernel/debug/segment_registers
---[ User Segments ]---
0x00000000-0x0fffffff Kern key 1 User key 1 VSID 0xa085d0
0x10000000-0x1fffffff Kern key 1 User key 1 VSID 0xa086e1
0x20000000-0x2fffffff Kern key 1 User key 1 VSID 0xa087f2
0x30000000-0x3fffffff Kern key 1 User key 1 VSID 0xa08903
0x40000000-0x4fffffff Kern key 1 User key 1 VSID 0xa08a14
0x50000000-0x5fffffff Kern key 1 User key 1 VSID 0xa08b25
0x60000000-0x6fffffff Kern key 1 User key 1 VSID 0xa08c36
0x70000000-0x7fffffff Kern key 1 User key 1 VSID 0xa08d47
0x80000000-0x8fffffff Kern key 1 User key 1 VSID 0xa08e58
0x90000000-0x9fffffff Kern key 1 User key 1 VSID 0xa08f69
0xa0000000-0xafffffff Kern key 1 User key 1 VSID 0xa0907a
0xb0000000-0xbfffffff Kern key 1 User key 1 VSID 0xa0918b
---[ Kernel Segments ]---
0xc0000000-0xcfffffff Kern key 0 User key 1 No Exec VSID 0x000ccc
0xd0000000-0xdfffffff Kern key 0 User key 1 No Exec VSID 0x000ddd
0xe0000000-0xefffffff Kern key 0 User key 1 No Exec VSID 0x000eee
0xf0000000-0xffffffff Kern key 0 User key 1 No Exec VSID 0x000fff
Aligning _etext to 128kb allows to map up to 32Mb text with 8 IBATs:
16Mb + 8Mb + 4Mb + 2Mb + 1Mb + 512kb + 256kb + 128kb (+ 128kb) = 32Mb
(A 9th IBAT is unneeded as 32Mb would need only a single 32Mb block)
Aligning data to 4M allows to map up to 512Mb data with 8 DBATs:
16Mb + 8Mb + 4Mb + 4Mb + 32Mb + 64Mb + 128Mb + 256Mb = 512Mb
Because some processors only have 4 BATs and because some targets need
DBATs for mapping other areas, the following patch will allow to
modify _etext and data alignment.
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>
setibat() and clearibat() allows to manipulate IBATs independently
of DBATs.
update_bats() allows to update bats after init. This is done
with MMU off.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
For pages without _PAGE_USER, PP field is 00
For pages with _PAGE_USER, PP field is 10 for RW and 11 for RO.
This patch sets _PAGE_USER to 0x002 and _PAGE_RW to 0x001
is order to simplify TLB handling by reducing amount of shifts.
The location of _PAGE_PRESENT and _PAGE_HASHPTE doesn't matter
as they are only SW related flags.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When updating page tables, we need to make sure we fill the page table
entry valid bits. We do this by or'ing in one of PGD/PUD/PMD_VAL_BITS.
The page table 'set' interfaces allow updating the raw value of page
table entries without setting the valid bits, so remove those
interfaces to avoid incorrect usage in future.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Reword commit message based on mailing list discussion]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch updates the kernel non-linear virtual map to 512TB when
we're built with 64K page size and are using the hash MMU. We allocate
one context for the vmalloc region and hence the max virtual area size
is limited by the context map size (512TB for 64K and 64TB for 4K page
size).
This patch fixes boot failures with large amounts of system RAM where
we need large vmalloc space to handle per cpu allocations.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
In v4.20 we changed our pgd/pud_present() to check for _PAGE_PRESENT
rather than just checking that the value is non-zero, e.g.:
static inline int pgd_present(pgd_t pgd)
{
- return !pgd_none(pgd);
+ return (pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
}
Unfortunately this is broken on big endian, as the result of the
bitwise & is truncated to int, which is always zero because
_PAGE_PRESENT is 0x8000000000000000ul. This means pgd_present() and
pud_present() are always false at compile time, and the compiler
elides the subsequent code.
Remarkably with that bug present we are still able to boot and run
with few noticeable effects. However under some work loads we are able
to trigger a warning in the ext4 code:
WARNING: CPU: 11 PID: 29593 at fs/ext4/inode.c:3927 .ext4_set_page_dirty+0x70/0xb0
CPU: 11 PID: 29593 Comm: debugedit Not tainted 4.20.0-rc1 #1
...
NIP .ext4_set_page_dirty+0x70/0xb0
LR .set_page_dirty+0xa0/0x150
Call Trace:
.set_page_dirty+0xa0/0x150
.unmap_page_range+0xbf0/0xe10
.unmap_vmas+0x84/0x130
.unmap_region+0xe8/0x190
.__do_munmap+0x2f0/0x510
.__vm_munmap+0x80/0x110
.__se_sys_munmap+0x14/0x30
system_call+0x5c/0x70
The fix is simple, we need to convert the result of the bitwise & to
an int before returning it.
Thanks to Erhard, Jan Kara and Aneesh for help with debugging.
Fixes: da7ad366b4 ("powerpc/mm/book3s: Update pmd_present to look at _PAGE_PRESENT bit")
Cc: stable@vger.kernel.org # v4.20+
Reported-by: Erhard F. <erhard_f@mailbox.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With support for split pmd lock, we use pmd page pmd_huge_pte pointer
to store the deposited page table. In those config when we move page
tables we need to make sure we move the deposited page table to the
correct pmd page. Otherwise this can result in crash when we withdraw
of deposited page table because we can find the pmd_huge_pte NULL.
eg:
__split_huge_pmd+0x1070/0x1940
__split_huge_pmd+0xe34/0x1940 (unreliable)
vma_adjust_trans_huge+0x110/0x1c0
__vma_adjust+0x2b4/0x9b0
__split_vma+0x1b8/0x280
__do_munmap+0x13c/0x550
sys_mremap+0x220/0x7e0
system_call+0x5c/0x70
Fixes: 675d995297 ("powerpc/book3s64: Enable split pmd ptlock.")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linus Torvalds