KUEP implements the update of user segment registers.
Move it into mmu-hash.h in order to use it from other places.
And inline kuep_lock() and kuep_unlock(). Inlining kuep_lock() is
important for system_call_exception(), otherwise system_call_exception()
has to save into stack the system call parameters that are used just
after, and doing that takes more instructions than kuep_lock() itself.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/24591ca480d14a62ef910e38a5273d551262c4a2.1622708530.git.christophe.leroy@csgroup.eu
'struct ppc_inst' is an internal representation of an instruction, but
in-memory instructions are and will remain a table of 'u32' forever.
Replace all 'struct ppc_inst *' used for locating an instruction in
memory by 'u32 *'. This removes a lot of undue casts to 'struct
ppc_inst *'.
It also helps locating ab-use of 'struct ppc_inst' dereference.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Fix ppc_inst_next(), use u32 instead of unsigned int]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7062722b087228e42cbd896e39bfdf526d6a340a.1621516826.git.christophe.leroy@csgroup.eu
Rather than partition the guest PID space + flush a rogue guest PID to
work around this problem, instead fix it by always disabling the MMU when
switching in or out of guest MMU context in HV mode.
This may be a bit less efficient, but it is a lot less complicated and
allows the P9 path to trivally implement the workaround too. Newer CPUs
are not subject to this issue.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-22-npiggin@gmail.com
A bunch of PPC files are missing the inclusion of linux/of.h and
linux/irqdomain.h, relying on transitive inclusion from another
file.
As we are about to break this dependency, make sure these dependencies
are explicit.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Merge more updates from Andrew Morton:
"The remainder of the main mm/ queue.
143 patches.
Subsystems affected by this patch series (all mm): pagecache, hugetlb,
userfaultfd, vmscan, compaction, migration, cma, ksm, vmstat, mmap,
kconfig, util, memory-hotplug, zswap, zsmalloc, highmem, cleanups, and
kfence"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (143 commits)
kfence: use power-efficient work queue to run delayed work
kfence: maximize allocation wait timeout duration
kfence: await for allocation using wait_event
kfence: zero guard page after out-of-bounds access
mm/process_vm_access.c: remove duplicate include
mm/mempool: minor coding style tweaks
mm/highmem.c: fix coding style issue
btrfs: use memzero_page() instead of open coded kmap pattern
iov_iter: lift memzero_page() to highmem.h
mm/zsmalloc: use BUG_ON instead of if condition followed by BUG.
mm/zswap.c: switch from strlcpy to strscpy
arm64/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
x86/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
mm,memory_hotplug: add kernel boot option to enable memmap_on_memory
acpi,memhotplug: enable MHP_MEMMAP_ON_MEMORY when supported
mm,memory_hotplug: allocate memmap from the added memory range
mm,memory_hotplug: factor out adjusting present pages into adjust_present_page_count()
mm,memory_hotplug: relax fully spanned sections check
drivers/base/memory: introduce memory_block_{online,offline}
mm/memory_hotplug: remove broken locking of zone PCP structures during hot remove
...
Merge misc updates from Andrew Morton:
"A few misc subsystems and some of MM.
175 patches.
Subsystems affected by this patch series: ia64, kbuild, scripts, sh,
ocfs2, kfifo, vfs, kernel/watchdog, and mm (slab-generic, slub,
kmemleak, debug, pagecache, msync, gup, memremap, memcg, pagemap,
mremap, dma, sparsemem, vmalloc, documentation, kasan, initialization,
pagealloc, and memory-failure)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (175 commits)
mm/memory-failure: unnecessary amount of unmapping
mm/mmzone.h: fix existing kernel-doc comments and link them to core-api
mm: page_alloc: ignore init_on_free=1 for debug_pagealloc=1
net: page_pool: use alloc_pages_bulk in refill code path
net: page_pool: refactor dma_map into own function page_pool_dma_map
SUNRPC: refresh rq_pages using a bulk page allocator
SUNRPC: set rq_page_end differently
mm/page_alloc: inline __rmqueue_pcplist
mm/page_alloc: optimize code layout for __alloc_pages_bulk
mm/page_alloc: add an array-based interface to the bulk page allocator
mm/page_alloc: add a bulk page allocator
mm/page_alloc: rename alloced to allocated
mm/page_alloc: duplicate include linux/vmalloc.h
mm, page_alloc: avoid page_to_pfn() in move_freepages()
mm/Kconfig: remove default DISCONTIGMEM_MANUAL
mm: page_alloc: dump migrate-failed pages
mm/mempolicy: fix mpol_misplaced kernel-doc
mm/mempolicy: rewrite alloc_pages_vma documentation
mm/mempolicy: rewrite alloc_pages documentation
mm/mempolicy: rename alloc_pages_current to alloc_pages
...
The memory ordering comment no longer applies, because mm_ctx_id is
no longer used anywhere. At best always been difficult to follow.
It's better to consider the load on which the slbmte depends on, which
the MMU depends on before it can start loading TLBs, rather than a
store which may or may not have a subsequent dependency chain to the
slbmte.
So update the comment and we use the load of the mm's user context ID.
This is much more analogous the radix ordering too, which is good.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210421151733.212858-1-npiggin@gmail.com
Define macros to list ppc interrupt types in interttupt.h, replace the
reference of the trap hex values with these macros.
Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S,
arch/powerpc/kernel/exceptions-64s.S, arch/powerpc/kernel/head_*.S,
arch/powerpc/kernel/head_booke.h and arch/powerpc/include/asm/kvm_asm.h.
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
[mpe: Resolve conflicts in nmi_disables_ftrace(), fix 40x build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1618398033-13025-1-git-send-email-sxwjean@me.com
The lkp bot pointed out that with W=1 we get:
arch/powerpc/mm/book3s64/radix_pgtable.c:183:6: error: no previous
prototype for 'radix__change_memory_range'
Which is really saying that it could be static, make it so.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
flush_dcache_page() is only a few lines, it is worth
inlining.
ia64, csky, mips, openrisc and riscv have a similar
flush_dcache_page() and inline it.
On pmac32_defconfig, we get a small size reduction.
On ppc64_defconfig, we get a very small size increase.
In both case that's in the noise (less than 0.1%).
text data bss dec hex filename
18991155 5934744 1497624 26423523 19330e3 vmlinux64.before
18994829 59367321497624 26429185 1934701 vmlinux64.after
9150963 2467502 184548 11803013 b41985 vmlinux32.before
9149689 2467302 184548 11801539 b413c3 vmlinux32.after
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/21c417488b70b7629dae316539fb7bb8bdef4fdd.1617895813.git.christophe.leroy@csgroup.eu
__flush_dcache_icache() is usable for non HIGHMEM pages on
every platform.
It is only for HIGHMEM pages that BOOKE needs kmap() and
BOOK3S needs flush_dcache_icache_phys().
So make flush_dcache_icache_phys() dependent on CONFIG_HIGHMEM and
call it only when it is a HIGHMEM page.
We could make flush_dcache_icache_phys() available at all time,
but as it is declared NOKPROBE_SYMBOL(), GCC doesn't optimise
it out when it is not used.
So define a stub for !CONFIG_HIGHMEM in order to remove the #ifdef in
flush_dcache_icache_page() and use IS_ENABLED() instead.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/79ed5d7914f497cd5fcd681ca2f4d50a91719455.1617895813.git.christophe.leroy@csgroup.eu
flush_dcache_icache_hugepage() is a static function, with
only one caller. That caller calls it when PageCompound() is true,
so bugging on !PageCompound() is useless if we can trust the
compiler a little. Remove the BUG_ON(!PageCompound()).
The number of elements of a page won't change over time, but
GCC doesn't know about it, so it gets the value at every iteration.
To avoid that, call compound_nr() outside the loop and save it in
a local variable.
Whether the page is a HIGHMEM page or not doesn't change over time.
But GCC doesn't know it so it does the test on every iteration.
Do the test outside the loop.
When the page is not a HIGHMEM page, page_address() will fallback on
lowmem_page_address(), so call lowmem_page_address() directly and
don't suffer the call to page_address() on every iteration.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ab03712b70105fccfceef095aa03007de9295a40.1617895813.git.christophe.leroy@csgroup.eu
While removing large number of mappings from hash page tables for
large memory systems as soft-lockup is reported because of the time
spent inside htap_remove_mapping() like one below:
watchdog: BUG: soft lockup - CPU#8 stuck for 23s!
<snip>
NIP plpar_hcall+0x38/0x58
LR pSeries_lpar_hpte_invalidate+0x68/0xb0
Call Trace:
0x1fffffffffff000 (unreliable)
pSeries_lpar_hpte_removebolted+0x9c/0x230
hash__remove_section_mapping+0xec/0x1c0
remove_section_mapping+0x28/0x3c
arch_remove_memory+0xfc/0x150
devm_memremap_pages_release+0x180/0x2f0
devm_action_release+0x30/0x50
release_nodes+0x28c/0x300
device_release_driver_internal+0x16c/0x280
unbind_store+0x124/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd4/0x270
ksys_write+0xdc/0x130
system_call+0x5c/0x70
Fix this by adding a cond_resched() to the loop in
htap_remove_mapping() that issues hcall to remove hpte mapping. The
call to cond_resched() is issued every HZ jiffies which should prevent
the soft-lockup from being reported.
Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210404163148.321346-1-vaibhav@linux.ibm.com
When we enabled STRICT_KERNEL_RWX we received some reports of boot
failures when using the Hash MMU and running under phyp. The crashes
are intermittent, and often exhibit as a completely unresponsive
system, or possibly an oops.
One example, which was caught in xmon:
[ 14.068327][ T1] devtmpfs: mounted
[ 14.069302][ T1] Freeing unused kernel memory: 5568K
[ 14.142060][ T347] BUG: Unable to handle kernel instruction fetch
[ 14.142063][ T1] Run /sbin/init as init process
[ 14.142074][ T347] Faulting instruction address: 0xc000000000004400
cpu 0x2: Vector: 400 (Instruction Access) at [c00000000c7475e0]
pc: c000000000004400: exc_virt_0x4400_instruction_access+0x0/0x80
lr: c0000000001862d4: update_rq_clock+0x44/0x110
sp: c00000000c747880
msr: 8000000040001031
current = 0xc00000000c60d380
paca = 0xc00000001ec9de80 irqmask: 0x03 irq_happened: 0x01
pid = 347, comm = kworker/2:1
...
enter ? for help
[c00000000c747880] c0000000001862d4 update_rq_clock+0x44/0x110 (unreliable)
[c00000000c7478f0] c000000000198794 update_blocked_averages+0xb4/0x6d0
[c00000000c7479f0] c000000000198e40 update_nohz_stats+0x90/0xd0
[c00000000c747a20] c0000000001a13b4 _nohz_idle_balance+0x164/0x390
[c00000000c747b10] c0000000001a1af8 newidle_balance+0x478/0x610
[c00000000c747be0] c0000000001a1d48 pick_next_task_fair+0x58/0x480
[c00000000c747c40] c000000000eaab5c __schedule+0x12c/0x950
[c00000000c747cd0] c000000000eab3e8 schedule+0x68/0x120
[c00000000c747d00] c00000000016b730 worker_thread+0x130/0x640
[c00000000c747da0] c000000000174d50 kthread+0x1a0/0x1b0
[c00000000c747e10] c00000000000e0f0 ret_from_kernel_thread+0x5c/0x6c
This shows that CPU 2, which was idle, woke up and then appears to
randomly take an instruction fault on a completely valid area of
kernel text.
The cause turns out to be the call to hash__mark_rodata_ro(), late in
boot. Due to the way we layout text and rodata, that function actually
changes the permissions for all of text and rodata to read-only plus
execute.
To do the permission change we use a hypervisor call, H_PROTECT. On
phyp that appears to be implemented by briefly removing the mapping of
the kernel text, before putting it back with the updated permissions.
If any other CPU is executing during that window, it will see spurious
faults on the kernel text and/or data, leading to crashes.
To fix it we use stop machine to collect all other CPUs, and then have
them drop into real mode (MMU off), while we change the mapping. That
way they are unaffected by the mapping temporarily disappearing.
We don't see this bug on KVM because KVM always use VPM=1, where
faults are directed to the hypervisor, and the fault will be
serialised vs the h_protect() by HPTE_V_HVLOCK.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210331003845.216246-5-mpe@ellerman.id.au
In hash__mark_rodata_ro() we pass the raw PP_RXXX value to
hash__change_memory_range(). That has the effect of setting the key to
zero, because PP_RXXX contains no key value.
Fix it by using htab_convert_pte_flags(), which knows how to convert a
pgprot into a pp value, including the key.
Fixes: d94b827e89 ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Link: https://lore.kernel.org/r/20210331003845.216246-3-mpe@ellerman.id.au
When adding a PTE a ptesync is needed to order the update of the PTE
with subsequent accesses otherwise a spurious fault may be raised.
radix__set_pte_at() does not do this for performance gains. For
non-kernel memory this is not an issue as any faults of this kind are
corrected by the page fault handler. For kernel memory these faults
are not handled. The current solution is that there is a ptesync in
flush_cache_vmap() which should be called when mapping from the
vmalloc region.
However, map_kernel_page() does not call flush_cache_vmap(). This is
troublesome in particular for code patching with Strict RWX on radix.
In do_patch_instruction() the page frame that contains the instruction
to be patched is mapped and then immediately patched. With no ordering
or synchronization between setting up the PTE and writing to the page
it is possible for faults.
As the code patching is done using __put_user_asm_goto() the resulting
fault is obscured - but using a normal store instead it can be seen:
BUG: Unable to handle kernel data access on write at 0xc008000008f24a3c
Faulting instruction address: 0xc00000000008bd74
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: nop_module(PO+) [last unloaded: nop_module]
CPU: 4 PID: 757 Comm: sh Tainted: P O 5.10.0-rc5-01361-ge3c1b78c8440-dirty #43
NIP: c00000000008bd74 LR: c00000000008bd50 CTR: c000000000025810
REGS: c000000016f634a0 TRAP: 0300 Tainted: P O (5.10.0-rc5-01361-ge3c1b78c8440-dirty)
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 44002884 XER: 00000000
CFAR: c00000000007c68c DAR: c008000008f24a3c DSISR: 42000000 IRQMASK: 1
This results in the kind of issue reported here:
https://lore.kernel.org/linuxppc-dev/15AC5B0E-A221-4B8C-9039-FA96B8EF7C88@lca.pw/
Chris Riedl suggested a reliable way to reproduce the issue:
$ mount -t debugfs none /sys/kernel/debug
$ (while true; do echo function > /sys/kernel/debug/tracing/current_tracer ; echo nop > /sys/kernel/debug/tracing/current_tracer ; done) &
Turning ftrace on and off does a large amount of code patching which
in usually less then 5min will crash giving a trace like:
ftrace-powerpc: (____ptrval____): replaced (4b473b11) != old (60000000)
------------[ ftrace bug ]------------
ftrace failed to modify
[<c000000000bf8e5c>] napi_busy_loop+0xc/0x390
actual: 11:3b:47:4b
Setting ftrace call site to call ftrace function
ftrace record flags: 80000001
(1)
expected tramp: c00000000006c96c
------------[ cut here ]------------
WARNING: CPU: 4 PID: 809 at kernel/trace/ftrace.c:2065 ftrace_bug+0x28c/0x2e8
Modules linked in: nop_module(PO-) [last unloaded: nop_module]
CPU: 4 PID: 809 Comm: sh Tainted: P O 5.10.0-rc5-01360-gf878ccaf250a #1
NIP: c00000000024f334 LR: c00000000024f330 CTR: c0000000001a5af0
REGS: c000000004c8b760 TRAP: 0700 Tainted: P O (5.10.0-rc5-01360-gf878ccaf250a)
MSR: 900000000282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28008848 XER: 20040000
CFAR: c0000000001a9c98 IRQMASK: 0
GPR00: c00000000024f330 c000000004c8b9f0 c000000002770600 0000000000000022
GPR04: 00000000ffff7fff c000000004c8b6d0 0000000000000027 c0000007fe9bcdd8
GPR08: 0000000000000023 ffffffffffffffd8 0000000000000027 c000000002613118
GPR12: 0000000000008000 c0000007fffdca00 0000000000000000 0000000000000000
GPR16: 0000000023ec37c5 0000000000000000 0000000000000000 0000000000000008
GPR20: c000000004c8bc90 c0000000027a2d20 c000000004c8bcd0 c000000002612fe8
GPR24: 0000000000000038 0000000000000030 0000000000000028 0000000000000020
GPR28: c000000000ff1b68 c000000000bf8e5c c00000000312f700 c000000000fbb9b0
NIP ftrace_bug+0x28c/0x2e8
LR ftrace_bug+0x288/0x2e8
Call Trace:
ftrace_bug+0x288/0x2e8 (unreliable)
ftrace_modify_all_code+0x168/0x210
arch_ftrace_update_code+0x18/0x30
ftrace_run_update_code+0x44/0xc0
ftrace_startup+0xf8/0x1c0
register_ftrace_function+0x4c/0xc0
function_trace_init+0x80/0xb0
tracing_set_tracer+0x2a4/0x4f0
tracing_set_trace_write+0xd4/0x130
vfs_write+0xf0/0x330
ksys_write+0x84/0x140
system_call_exception+0x14c/0x230
system_call_common+0xf0/0x27c
To fix this when updating kernel memory PTEs using ptesync.
Fixes: f1cb8f9beb ("powerpc/64s/radix: avoid ptesync after set_pte and ptep_set_access_flags")
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Tidy up change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210208032957.1232102-1-jniethe5@gmail.com
