The kernel calls these functions on CPU online and hence they must not
be marked __init.
Otherwise if the memory they occupied has been reused the system can
crash in various ways. Sachin reported it caused his LPAR to
spontaneously restart with no other output. With xmon enabled it may
drop into xmon with a dump like:
cpu 0x1: Vector: 700 (Program Check) at [c000000003c5fcb0]
pc: 00000000011e0a78
lr: 00000000011c51d4
sp: c000000003c5ff50
msr: 8000000000081001
current = 0xc000000002c12b00
paca = 0xc000000003cff280 irqmask: 0x03 irq_happened: 0x01
pid = 0, comm = swapper/1
...
[c000000003c5ff50] 0000000000087c38 (unreliable)
[c000000003c5ff70] 000000000003870c
[c000000003c5ff90] 000000000000d108
Fixes: 3b47b7549e ("powerpc/book3s64/kuap: Move KUAP related function outside radix")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Expand change log with details and xmon output]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201214080121.358567-1-aneesh.kumar@linux.ibm.com
PTE_FLAGS_OFFSET is defined in asm/page_32.h and used only
in hash_low.S
And PTE_FLAGS_OFFSET nullity depends on CONFIG_PTE_64BIT
Instead of tests like #if (PTE_FLAGS_OFFSET != 0), use
CONFIG_PTE_64BIT related code.
Also move the definition of PTE_FLAGS_OFFSET into hash_low.S
directly, that improves readability.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f5bc21db7a33dab55924734e6060c2e9daed562e.1606247495.git.christophe.leroy@csgroup.eu
All hugetlb range freeing functions have a verification like the following,
which only differs by the mask used, depending on the page table level.
start &= MASK;
if (start < floor)
return;
if (ceiling) {
ceiling &= MASK;
if (! ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
Refactor that into a helper function which takes the mask as
an argument, returning true when [start;end[ is not fully
contained inside [floor;ceiling[
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/16a571bb32eb6e8cd44bda484c8d81cd8a25e6d7.1604668827.git.christophe.leroy@csgroup.eu
Exception fixup doesn't require the heady full regs saving,
do it from do_page_fault() directly.
For that, split bad_page_fault() in two parts.
As bad_page_fault() can also be called from other places than
handle_page_fault(), it will still perform exception fixup and
fallback on __bad_page_fault().
handle_page_fault() directly calls __bad_page_fault() as the
exception fixup will now be done by do_page_fault()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bd07d6fef9237614cd6d318d8f19faeeadaa816b.1607491748.git.christophe.leroy@csgroup.eu
search_exception_tables() is an heavy operation, we have to avoid it.
When KUAP is selected, we'll know the fault has been blocked by KUAP.
When it is blocked by KUAP, check whether we are in an expected
userspace access place. If so, emit a warning to spot something is
going work. Otherwise, just remain silent, it will likely Oops soon.
When KUAP is not selected, it behaves just as if the address was
already in the TLBs and no fault was generated.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9870f01e293a5a76c4f4e4ddd4a6b0f63038c591.1607491748.git.christophe.leroy@csgroup.eu
The verification and message introduced by commit 374f3f5979
("powerpc/mm/hash: Handle user access of kernel address gracefully")
applies to all platforms, it should not be limited to BOOK3S.
Make the BOOK3S version of sanity_check_fault() the one for all,
and bail out earlier if not BOOK3S.
Fixes: 374f3f5979 ("powerpc/mm/hash: Handle user access of kernel address gracefully")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/fe199d5af3578d3bf80035d203a94d742a7a28af.1607491748.git.christophe.leroy@csgroup.eu
There is no big poing in not pinning kernel text anymore, as now
we can keep pinned TLB even with things like DEBUG_PAGEALLOC.
Remove CONFIG_PIN_TLB_TEXT, making it always right.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Drop ifdef around mmu_pin_tlb() to fix build errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/203b89de491e1379f1677a2685211b7c32adfff0.1606231483.git.christophe.leroy@csgroup.eu
On hash 32 bits, handling minor protection faults like unsetting
dirty flag is heavy if done from the normal page_fault processing,
because it implies hash table software lookup for flushing the entry
and then a DSI is taken anyway to add the entry back.
When KUAP was implemented, as explained in commit a68c31fc01
("powerpc/32s: Implement Kernel Userspace Access Protection"),
protection faults has been diverted from hash_page() because
hash_page() was not able to identify a KUAP fault.
Implement KUAP verification in hash_page(), by clearing write
permission when the access is a kernel access and Ks is 1.
This works regardless of the address because kernel segments always
have Ks set to 0 while user segments have Ks set to 0 only
when kernel write to userspace is granted.
Then protection faults can be handled by hash_page() even for KUAP.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8a4ffe4798e9ea32aaaccdf85e411bb1beed3500.1605542955.git.christophe.leroy@csgroup.eu
flush_range() handle both the MMU_FTR_HPTE_TABLE case and
the other case.
The non MMU_FTR_HPTE_TABLE case is trivial as it is only a call
to _tlbie()/_tlbia() which is not worth a dedicated function.
Make flush_range() a hash specific and call it from tlbflush.h based
on mmu_has_feature(MMU_FTR_HPTE_TABLE).
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/132ab19aae52abc8e06ab524ec86d4229b5b9c3d.1603348103.git.christophe.leroy@csgroup.eu
flush_tlb_mm() and flush_tlb_page() handle both the MMU_FTR_HPTE_TABLE
case and the other case.
The non MMU_FTR_HPTE_TABLE case is trivial as it is only a call
to _tlbie()/_tlbia() which is not worth a dedicated function.
Make flush_tlb_mm() and flush_tlb_page() hash specific and call
them from tlbflush.h based on mmu_has_feature(MMU_FTR_HPTE_TABLE).
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/11e932ded41ba6d9b251d89b7afa33cc060d3aa4.1603348103.git.christophe.leroy@csgroup.eu
_tlbie() and _tlbia() are used only on 603 cores while the
other functions are used only on cores having a hash table.
Move them into a new file named nohash_low.S
Add mmu_hash_lock var is used by both, it needs to go
in a common file.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9a265b1b17a64153463d361280cb4b43eb1266a4.1603348103.git.christophe.leroy@csgroup.eu
We now have an early hash table on hash MMU, so no need to check
Hash var to know if the Hash table is set of not.
Use mmu_has_feature(MMU_FTR_HPTE_TABLE) instead. This will allow
optimisation via jump_label.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/f1766631a9e014b6433f1a3c12c726ddfce34220.1603348103.git.christophe.leroy@csgroup.eu
This partially reverts commit eb232b1624 ("powerpc/book3s64/kuap: Improve
error reporting with KUAP") and update the fault handler to print
[ 55.022514] Kernel attempted to access user page (7e6725b70000) - exploit attempt? (uid: 0)
[ 55.022528] BUG: Unable to handle kernel data access on read at 0x7e6725b70000
[ 55.022533] Faulting instruction address: 0xc000000000e8b9bc
[ 55.022540] Oops: Kernel access of bad area, sig: 11 [#1]
....
when the kernel access userspace address without unlocking AMR.
bad_kuap_fault() is added as part of commit 5e5be3aed2 ("powerpc/mm: Detect
bad KUAP faults") to catch userspace access incorrectly blocked by AMR. Hence
retain the full stack dump there even with hash translation. Also, add a comment
explaining the difference between hash and radix.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201208031539.84878-1-aneesh.kumar@linux.ibm.com
There is no defconfig selecting CONFIG_E200, and no platform.
e200 is an earlier version of booke, a predecessor of e500,
with some particularities like an unified cache instead of both an
instruction cache and a data cache.
Remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Scott Wood <oss@buserror.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/34ebc3ba2c768d97f363bd5f2deea2356e9ae127.1605589460.git.christophe.leroy@csgroup.eu
SPRN_SPRG_PGDIR is there mainly to speedup SW TLB miss handlers
for powerpc 603.
We need to free SPRN_SPRG2 to reduce the mess with CONFIG_VMAP_STACK.
In hash_page(), reading PGDIR from thread_struct will be in the noise
performance wise.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4adca19b7120cdf619956768ed09e74fc6a558f3.1606285014.git.christophe.leroy@csgroup.eu
Since commit 2b279c0348 ("powerpc/32s: Allow mapping with BATs with
DEBUG_PAGEALLOC"), there is no real situation where mapping without
BATs is required.
In order to simplify memory handling, always map kernel text
and rodata with BATs even when "nobats" kernel parameter is set.
Also fix the 603 TLB miss exceptions that don't require anymore
kernel page table if DEBUG_PAGEALLOC.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/da51f7ec632825a4ce43290a904aad61648408c0.1606285013.git.christophe.leroy@csgroup.eu
With hash translation use DSISR_KEYFAULT to identify a wrong access.
With Radix we look at the AMR value and type of fault.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-17-aneesh.kumar@linux.ibm.com
Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of userspace.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-15-aneesh.kumar@linux.ibm.com
On fork, we inherit from the parent and on exec, we should switch to default_amr values.
Also, avoid changing the AMR register value within the kernel. The kernel now runs with
different AMR values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-13-aneesh.kumar@linux.ibm.com
This patch updates kernel hash page table entries to use storage key 3
for its mapping. This implies all kernel access will now use key 3 to
control READ/WRITE. The patch also prevents the allocation of key 3 from
userspace and UAMOR value is updated such that userspace cannot modify key 3.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-9-aneesh.kumar@linux.ibm.com
This is in preparation to adding support for kuap with hash translation.
In preparation for that rename/move kuap related functions to
non radix names. Also move the feature bit closer to MMU_FTR_KUEP.
MMU_FTR_KUEP is renamed to MMU_FTR_BOOK3S_KUEP to indicate the feature
is only relevant to BOOK3S_64
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-8-aneesh.kumar@linux.ibm.com
The next set of patches adds support for kuep with hash translation.
In preparation for that rename/move kuap related functions to
non radix names.
Also set MMU_FTR_KUEP and add the missing isync().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-7-aneesh.kumar@linux.ibm.com
The next set of patches adds support for kuap with hash translation.
In preparation for that rename/move kuap related functions to
non radix names.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-6-aneesh.kumar@linux.ibm.com
This patch consolidates UAMOR update across pkey, kuap and kuep features.
The boot cpu initialize UAMOR via pkey init and both radix/hash do the
secondary cpu UAMOR init in early_init_mmu_secondary.
We don't check for mmu_feature in radix secondary init because UAMOR
is a supported SPRN with all CPUs supporting radix translation.
The old code was not updating UAMOR if we had smap disabled and smep enabled.
This change handles that case.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-5-aneesh.kumar@linux.ibm.com
The config CONFIG_PPC_PKEY is used to select the base support that is
required for PPC_MEM_KEYS, KUAP, and KUEP. Adding this dependency
reduces the code complexity(in terms of #ifdefs) and enables us to
move some of the initialization code to pkeys.c
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-4-aneesh.kumar@linux.ibm.com
Since ISA v3.0, SLB no longer uses the slb_cache, and stab_rr is no
longer correlated with SLB allocation. Move those to pre-3.0.
While here, improve some alignments and reduce whitespace.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201128070728.825934-9-npiggin@gmail.com
Let's revert what we did in case something goes wrong and we return an
error - as already done on arm64 and s390x.
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201111145322.15793-8-david@redhat.com
The single caller (arch_remove_linear_mapping()) prints a proper
warning when this function fails. No need to eventually crash the
kernel - let's drop this WARN_ON.
Suggested-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201111145322.15793-7-david@redhat.com
