Pull locking updates from Info Molnar:
"Futex improvements:
- Add the 'futex2' syscall ABI, which is an attempt to get away from
the multiplex syscall and adds a little room for extentions, while
lifting some limitations.
- Fix futex PI recursive rt_mutex waiter state bug
- Fix inter-process shared futexes on no-MMU systems
- Use folios instead of pages
Micro-optimizations of locking primitives:
- Improve arch_spin_value_unlocked() on asm-generic ticket spinlock
architectures, to improve lockref code generation
- Improve the x86-32 lockref_get_not_zero() main loop by adding
build-time CMPXCHG8B support detection for the relevant lockref
code, and by better interfacing the CMPXCHG8B assembly code with
the compiler
- Introduce arch_sync_try_cmpxchg() on x86 to improve
sync_try_cmpxchg() code generation. Convert some sync_cmpxchg()
users to sync_try_cmpxchg().
- Micro-optimize rcuref_put_slowpath()
Locking debuggability improvements:
- Improve CONFIG_DEBUG_RT_MUTEXES=y to have a fast-path as well
- Enforce atomicity of sched_submit_work(), which is de-facto atomic
but was un-enforced previously.
- Extend <linux/cleanup.h>'s no_free_ptr() with __must_check
semantics
- Fix ww_mutex self-tests
- Clean up const-propagation in <linux/seqlock.h> and simplify the
API-instantiation macros a bit
RT locking improvements:
- Provide the rt_mutex_*_schedule() primitives/helpers and use them
in the rtmutex code to avoid recursion vs. rtlock on the PI state.
- Add nested blocking lockdep asserts to rt_mutex_lock(),
rtlock_lock() and rwbase_read_lock()
.. plus misc fixes & cleanups"
* tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
futex: Don't include process MM in futex key on no-MMU
locking/seqlock: Fix grammar in comment
alpha: Fix up new futex syscall numbers
locking/seqlock: Propagate 'const' pointers within read-only methods, remove forced type casts
locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
locking/seqlock: Change __seqprop() to return the function pointer
locking/seqlock: Simplify SEQCOUNT_LOCKNAME()
locking/atomics: Use atomic_try_cmpxchg_release() to micro-optimize rcuref_put_slowpath()
locking/atomic, xen: Use sync_try_cmpxchg() instead of sync_cmpxchg()
locking/atomic/x86: Introduce arch_sync_try_cmpxchg()
locking/atomic: Add generic support for sync_try_cmpxchg() and its fallback
locking/seqlock: Fix typo in comment
futex/requeue: Remove unnecessary ‘NULL’ initialization from futex_proxy_trylock_atomic()
locking/local, arch: Rewrite local_add_unless() as a static inline function
locking/debug: Fix debugfs API return value checks to use IS_ERR()
locking/ww_mutex/test: Make sure we bail out instead of livelock
locking/ww_mutex/test: Fix potential workqueue corruption
locking/ww_mutex/test: Use prng instead of rng to avoid hangs at bootup
futex: Add sys_futex_requeue()
futex: Add flags2 argument to futex_requeue()
...
Erhard reported that his G5 was crashing with v6.6-rc kernels:
mpic: Setting up HT PICs workarounds for U3/U4
BUG: Unable to handle kernel data access at 0xfeffbb62ffec65fe
Faulting instruction address: 0xc00000000005dc40
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G T 6.6.0-rc3-PMacGS #1
Hardware name: PowerMac11,2 PPC970MP 0x440101 PowerMac
NIP: c00000000005dc40 LR: c000000000066660 CTR: c000000000007730
REGS: c0000000022bf510 TRAP: 0380 Tainted: G T (6.6.0-rc3-PMacGS)
MSR: 9000000000001032 <SF,HV,ME,IR,DR,RI> CR: 44004242 XER: 00000000
IRQMASK: 3
GPR00: 0000000000000000 c0000000022bf7b0 c0000000010c0b00 00000000000001ac
GPR04: 0000000003c80000 0000000000000300 c0000000f20001ae 0000000000000300
GPR08: 0000000000000006 feffbb62ffec65ff 0000000000000001 0000000000000000
GPR12: 9000000000001032 c000000002362000 c000000000f76b80 000000000349ecd8
GPR16: 0000000002367ba8 0000000002367f08 0000000000000006 0000000000000000
GPR20: 00000000000001ac c000000000f6f920 c0000000022cd985 000000000000000c
GPR24: 0000000000000300 00000003b0a3691d c0003e008030000e 0000000000000000
GPR28: c00000000000000c c0000000f20001ee feffbb62ffec65fe 00000000000001ac
NIP hash_page_do_lazy_icache+0x50/0x100
LR __hash_page_4K+0x420/0x590
Call Trace:
hash_page_mm+0x364/0x6f0
do_hash_fault+0x114/0x2b0
data_access_common_virt+0x198/0x1f0
--- interrupt: 300 at mpic_init+0x4bc/0x10c4
NIP: c000000002020a5c LR: c000000002020a04 CTR: 0000000000000000
REGS: c0000000022bf9f0 TRAP: 0300 Tainted: G T (6.6.0-rc3-PMacGS)
MSR: 9000000000001032 <SF,HV,ME,IR,DR,RI> CR: 24004248 XER: 00000000
DAR: c0003e008030000e DSISR: 40000000 IRQMASK: 1
...
NIP mpic_init+0x4bc/0x10c4
LR mpic_init+0x464/0x10c4
--- interrupt: 300
pmac_setup_one_mpic+0x258/0x2dc
pmac_pic_init+0x28c/0x3d8
init_IRQ+0x90/0x140
start_kernel+0x57c/0x78c
start_here_common+0x1c/0x20
A bisect pointed to the breakage beginning with commit 9fee28baa6 ("powerpc:
implement the new page table range API").
Analysis of the oops pointed to a struct page with a corrupted
compound_head being loaded via page_folio() -> _compound_head() in
hash_page_do_lazy_icache().
The access by the mpic code is to an MMIO address, so the expectation
is that the struct page for that address would be initialised by
init_unavailable_range(), as pointed out by Aneesh.
Instrumentation showed that was not the case, which eventually lead to
the realisation that pfn_valid() was returning false for that address,
causing the struct page to not be initialised.
Because the system is using FLATMEM, the version of pfn_valid() in
memory_model.h is used:
static inline int pfn_valid(unsigned long pfn)
{
...
return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
}
Which relies on max_mapnr being initialised. Early in boot max_mapnr is
zero meaning no PFNs are valid.
max_mapnr is initialised in mem_init() called via:
start_kernel()
mm_core_init() # init/main.c:928
mem_init()
But that is too late for the usage in init_unavailable_range() called via:
start_kernel()
setup_arch() # init/main.c:893
paging_init()
free_area_init()
init_unavailable_range()
Although max_mapnr is currently set in mem_init(), the value is actually
already available much earlier, as soon as mem_topology_setup() has
completed, which is also before paging_init() is called. So move the
initialisation there, which causes paging_init() to correctly initialise
the struct page and fixes the bug.
This bug seems to have been lurking for years, but went unnoticed
because the pre-folio code was inspecting the uninitialised page->flags
but not dereferencing it.
Thanks to Erhard and Aneesh for help debugging.
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/20230929132750.3cd98452@yea/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231023112500.1550208-1-mpe@ellerman.id.au
A thread started via eg. user_mode_thread() runs in the kernel to begin
with and then may later return to userspace. While it's running in the
kernel it has a pt_regs at the base of its kernel stack, but that
pt_regs is all zeroes.
If the thread oopses in that state, it leads to an ugly stack trace with
a big block of zero GPRs, as reported by Joel:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc7-00004-gf7757129e3de-dirty #3
Hardware name: IBM PowerNV (emulated by qemu) POWER9 0x4e1200 opal:v7.0 PowerNV
Call Trace:
[c0000000036afb00] [c0000000010dd058] dump_stack_lvl+0x6c/0x9c (unreliable)
[c0000000036afb30] [c00000000013c524] panic+0x178/0x424
[c0000000036afbd0] [c000000002005100] mount_root_generic+0x250/0x324
[c0000000036afca0] [c0000000020057d0] prepare_namespace+0x2d4/0x344
[c0000000036afd20] [c0000000020049c0] kernel_init_freeable+0x358/0x3ac
[c0000000036afdf0] [c0000000000111b0] kernel_init+0x30/0x1a0
[c0000000036afe50] [c00000000000debc] ret_from_kernel_user_thread+0x14/0x1c
--- interrupt: 0 at 0x0
NIP: 0000000000000000 LR: 0000000000000000 CTR: 0000000000000000
REGS: c0000000036afe80 TRAP: 0000 Not tainted (6.5.0-rc7-00004-gf7757129e3de-dirty)
MSR: 0000000000000000 <> CR: 00000000 XER: 00000000
CFAR: 0000000000000000 IRQMASK: 0
GPR00: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR12: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR28: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
NIP [0000000000000000] 0x0
LR [0000000000000000] 0x0
--- interrupt: 0
The all-zero pt_regs looks ugly and conveys no useful information, other
than its presence. So detect that case and just show the presence of the
frame by printing the interrupt marker, eg:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc3-00126-g18e9506562a0-dirty #301
Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
Call Trace:
[c000000003aabb00] [c000000001143db8] dump_stack_lvl+0x6c/0x9c (unreliable)
[c000000003aabb30] [c00000000014c624] panic+0x178/0x424
[c000000003aabbd0] [c0000000020050fc] mount_root_generic+0x250/0x324
[c000000003aabca0] [c0000000020057cc] prepare_namespace+0x2d4/0x344
[c000000003aabd20] [c0000000020049bc] kernel_init_freeable+0x358/0x3ac
[c000000003aabdf0] [c0000000000111b0] kernel_init+0x30/0x1a0
[c000000003aabe50] [c00000000000debc] ret_from_kernel_user_thread+0x14/0x1c
--- interrupt: 0 at 0x0
To avoid ever suppressing a valid pt_regs make sure the pt_regs has a
zero MSR and TRAP value, and is located at the very base of the stack.
Fixes: 6895dfc047 ("powerpc: copy_thread fill in interrupt frame marker and back chain")
Reported-by: Joel Stanley <joel@jms.id.au>
Reported-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230824064210.907266-1-mpe@ellerman.id.au
Sparse reports several endianness warnings on variables and functions
that are consistently treated as big endian. There are no
multi-endianness shenanigans going on here so fix these low hanging
fruit up in one patch.
All changes are just type annotations; no endianness switching
operations are introduced by this patch.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231011053711.93427-7-bgray@linux.ibm.com
On 603 MMU, TLB missed are handled by SW and there are separated
DTLB and ITLB. It is therefore possible to implement execute-only
protection by not loading DTLB when read access is not permitted.
To do that, _PAGE_READ flag is needed but there is no bit available
for it in PTE. On the other hand the only real use of _PAGE_USER is
to implement PAGE_NONE by clearing _PAGE_USER.
As _PAGE_NONE can also be implemented by clearing _PAGE_READ, remove
_PAGE_USER and add _PAGE_READ. Then use the virtual address to know
whether user rights or kernel rights are to be used.
With that change, 603 MMU now honors execute-only protection.
For hash (604) MMU it is more tricky because hash table is common to
load/store and execute. Nevertheless it is still possible to check
whether _PAGE_READ is set before loading hash table for a load/store
access. At least it can't be read unless it is executed first.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b7702dd5a041ec59055ed2880f4952e94c087a2e.1695659959.git.christophe.leroy@csgroup.eu
_PAGE_USER is used to select the zone. Today zone 0 is kernel
and zone 1 is user.
To implement _PAGE_NONE, _PAGE_USER is cleared, leading to no access
for user but kernel still has access to the page so it's possible for
a user application to write in that page by using a kernel function
as trampoline.
What is really wanted is to have user rights on pages below TASK_SIZE
and no user rights on pages above TASK_SIZE. Use zones for that.
There are 16 zones so lets use the 4 upper address bits to set the
zone and declare zone rights based on TASK_SIZE.
Then drop _PAGE_USER and reuse it as _PAGE_READ that will be checked
in Data TLB miss handler. That will properly handle PAGE_NONE for
both kernel and user.
In addition, it partially implements execute-only right. The
implementation won't be complete because once a TLB has been loaded
via the Instruction TLB miss handler, it will be possible to read
the page. But at least it can't be read unless it is executed first.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2a13e3ba8a5dec43143cc1f9a91ec71ea1529f3c.1695659959.git.christophe.leroy@csgroup.eu
44x MMU has 6 page protection bits:
- R, W, X for supervisor
- R, W, X for user
It means that it can support X without R.
To do that, _PAGE_READ flag is needed but there is no bit available
for it in PTE. On the other hand the only real use of _PAGE_USER is
to implement PAGE_NONE by clearing _PAGE_USER.
As _PAGE_NONE can also be implemented by clearing _PAGE_READ,
remove _PAGE_USER and add _PAGE_READ. In order to insert bits in
one go during TLB miss, move _PAGE_ACCESSED and put _PAGE_READ
just after _PAGE_DIRTY so that _PAGE_DIRTY is copied into SW and
_PAGE_READ into SR at once.
With that change, 44x now also honors execute-only protection.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/043e17987b260b99b45094138c6cb2e89e63d499.1695659959.git.christophe.leroy@csgroup.eu
e500 MMU has 6 page protection bits:
- R, W, X for supervisor
- R, W, X for user
It means that it can support X without R.
To do that, _PAGE_READ flag is needed.
With 32 bits PTE there is no bit available for it in PTE. On the
other hand the only real use of _PAGE_USER is to implement PAGE_NONE
by clearing _PAGE_USER. As _PAGE_NONE can also be implemented by
clearing _PAGE_READ, remove _PAGE_USER and add _PAGE_READ. Move
_PAGE_PRESENT into bit 30 so that _PAGE_READ can match SR bit.
With 64 bits PTE _PAGE_USER is already the combination of SR and UR
so all we need to do is to rename it _PAGE_READ.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/0849ab6bf7ae2af23f94b0457fa40d0ea3983fe4.1695659959.git.christophe.leroy@csgroup.eu
I noticed that commit 0db5b61e0d ("fbdev/vga16fb: Create
EGA/VGA devices in sysfb code") broke vga16fb on non-x86 platforms,
because the sysfb code never creates a vga-framebuffer device when
screen_info.orig_video_isVGA is set to '1' instead of VIDEO_TYPE_VGAC.
However, it turns out that the only architecture that has allowed
building vga16fb in the past 20 years is powerpc, and this only worked
on two 32-bit platforms and never on 64-bit powerpc. The last machine
that actually used this was removed in linux-3.10, so this is all dead
code and can be removed.
The big-endian support in vga16fb.c could also be removed, but I'd just
leave this in place.
Fixes: 933ee7119f ("powerpc: remove PReP platform")
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20231009211845.3136536-8-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Eddie reported that newer kernels were crashing during boot on his 476
FSP2 system:
kernel tried to execute user page (b7ee2000) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel instruction fetch
Faulting instruction address: 0xb7ee2000
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K FSP-2
Modules linked in:
CPU: 0 PID: 61 Comm: mount Not tainted 6.1.55-d23900f.ppcnf-fsp2 #1
Hardware name: ibm,fsp2 476fpe 0x7ff520c0 FSP-2
NIP: b7ee2000 LR: 8c008000 CTR: 00000000
REGS: bffebd83 TRAP: 0400 Not tainted (6.1.55-d23900f.ppcnf-fs p2)
MSR: 00000030 <IR,DR> CR: 00001000 XER: 20000000
GPR00: c00110ac bffebe63 bffebe7e bffebe88 8c008000 00001000 00000d12 b7ee2000
GPR08: 00000033 00000000 00000000 c139df10 48224824 1016c314 10160000 00000000
GPR16: 10160000 10160000 00000008 00000000 10160000 00000000 10160000 1017f5b0
GPR24: 1017fa50 1017f4f0 1017fa50 1017f740 1017f630 00000000 00000000 1017f4f0
NIP [b7ee2000] 0xb7ee2000
LR [8c008000] 0x8c008000
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 0000000000000000 ]---
The problem is in ret_from_syscall where the check for
icache_44x_need_flush is done. When the flush is needed the code jumps
out-of-line to do the flush, and then intends to jump back to continue
the syscall return.
However the branch back to label 1b doesn't return to the correct
location, instead branching back just prior to the return to userspace,
causing bogus register values to be used by the rfi.
The breakage was introduced by commit 6f76a01173
("powerpc/syscall: implement system call entry/exit logic in C for PPC32") which
inadvertently removed the "1" label and reused it elsewhere.
Fix it by adding named local labels in the correct locations. Note that
the return label needs to be outside the ifdef so that CONFIG_PPC_47x=n
compiles.
Fixes: 6f76a01173 ("powerpc/syscall: implement system call entry/exit logic in C for PPC32")
Cc: stable@vger.kernel.org # v5.12+
Reported-by: Eddie James <eajames@linux.ibm.com>
Tested-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/linuxppc-dev/fdaadc46-7476-9237-e104-1d2168526e72@linux.ibm.com/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://msgid.link/20231010114750.847794-1-mpe@ellerman.id.au
This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
Remove sentinel from powersave_nap_ctl_table and nmi_wd_lpm_factor_ctl_table.
This removal is safe because register_sysctl implicitly uses ARRAY_SIZE()
in addition to checking for the sentinel.
Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
commit c35559f94e ("x86/shstk: Introduce map_shadow_stack syscall")
recently added support for map_shadow_stack() but it is limited to x86
only for now. There is a possibility that other architectures (namely,
arm64 and RISC-V), that are implementing equivalent support for shadow
stacks, might need to add support for it.
Independent of that, reserving arch-specific syscall numbers in the
syscall tables of all architectures is good practice and would help
avoid future conflicts. map_shadow_stack() is marked as a conditional
syscall in sys_ni.c. Adding it to the syscall tables of other
architectures is harmless and would return ENOSYS when exercised.
Note, map_shadow_stack() was assigned #453 during the merge process
since #452 was taken by fchmodat2().
For Powerpc, map it to sys_ni_syscall() as is the norm for Powerpc
syscall tables.
For Alpha, map_shadow_stack() takes up #563 as Alpha still diverges from
the common syscall numbering system in the other architectures.
Link: https://lore.kernel.org/lkml/20230515212255.GA562920@debug.ba.rivosinc.com/
Link: https://lore.kernel.org/lkml/b402b80b-a7c6-4ef0-b977-c0f5f582b78a@sirena.org.uk/
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
rcu_report_dead() and rcutree_migrate_callbacks() have their headers in
rcupdate.h while those are pure rcutree calls, like the other CPU-hotplug
functions.
Also rcu_cpu_starting() and rcu_report_dead() have different naming
conventions while they mirror each other's effects.
Fix the headers and propose a naming that relates both functions and
aligns with the prefix of other rcutree CPU-hotplug functions.
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
commit 'be65de6b03aa ("fs: Remove dcookies support")' removed the
syscall definition for lookup_dcookie. However, syscall tables still
point to the old sys_lookup_dcookie() definition. Update syscall tables
of all architectures to directly point to sys_ni_syscall() instead.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org> # for perf
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
PowerPC has a 'btext' font used for the console which is almost identical
to the shared font_sun8x16, so use it rather than duplicating the data.
They were actually identical until about a decade ago when
commit bcfbeecea1 ("drivers: console: font_: Change a glyph from
"broken bar" to "vertical line"")
which changed the | in the shared font to be a solid
bar rather than a broken bar. That's the only difference.
This was originally spotted by the PMF source code analyser, which
noticed that sparc does the same thing with the same data, and they
also share a bunch of functions to manipulate the data. I've previously
posted a near identical patch for sparc.
Tested very lightly with a boot without FS in qemu.
Signed-off-by: "Dr. David Alan Gilbert" <linux@treblig.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230825142754.1487900-1-linux@treblig.org
POWER is using the set_platform_dma_ops() callback to hook up its private
dma_ops, but this is buired under some indirection and is weirdly
happening for a BLOCKED domain as well.
For better documentation create a PLATFORM domain to manage the dma_ops,
since that is what it is for, and make the BLOCKED domain an alias for
it. BLOCKED is required for VFIO.
Also removes the leaky allocation of the BLOCKED domain by using a global
static.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v8-81230027b2fa+9d-iommu_all_defdom_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
The changes to copy_thread() made in commit eed7c420aa ("powerpc:
copy_thread differentiate kthreads and user mode threads") inadvertently
broke arch_stack_walk_reliable() because it has knowledge of the stack
layout.
Fix it by changing the condition to match the new logic in
copy_thread(). The changes make the comments about the stack layout
incorrect, rather than rephrasing them just refer the reader to
copy_thread().
Also the comment about the stack backchain is no longer true, since
commit edbd0387f3 ("powerpc: copy_thread add a back chain to the
switch stack frame"), so remove that as well.
Fixes: eed7c420aa ("powerpc: copy_thread differentiate kthreads and user mode threads")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230921232441.1181843-1-mpe@ellerman.id.au
Finish off the 'simple' futex2 syscall group by adding
sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are
too numerous to fit into a regular syscall. As such, use struct
futex_waitv to pass the 'source' and 'destination' futexes to the
syscall.
This syscall implements what was previously known as FUTEX_CMP_REQUEUE
and uses {val, uaddr, flags} for source and {uaddr, flags} for
destination.
This design explicitly allows requeueing between different types of
futex by having a different flags word per uaddr.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105248.511860556@noisy.programming.kicks-ass.net
To complement sys_futex_waitv()/wake(), add sys_futex_wait(). This
syscall implements what was previously known as FUTEX_WAIT_BITSET
except it uses 'unsigned long' for the value and bitmask arguments,
takes timespec and clockid_t arguments for the absolute timeout and
uses FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230921105248.164324363@noisy.programming.kicks-ass.net
Upstream Linux never had a "README.legal" file, but it was present
in early source releases of Linux/m68k. It contained a simple copyright
notice and a link to a version of the "COPYING" file that predated the
addition of the "only valid GPL version is v2" clause.
Get rid of the references to non-existent files by replacing the
boilerplate with SPDX license identifiers.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/d91725ff1ed5d4b6ba42474e2ebfeebe711cba23.1695031668.git.geert@linux-m68k.org
Syzkaller reported a sleep in atomic context bug relating to the HASHCHK
handler logic:
BUG: sleeping function called from invalid context at arch/powerpc/kernel/traps.c:1518
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 25040, name: syz-executor
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
no locks held by syz-executor/25040.
irq event stamp: 34
hardirqs last enabled at (33): [<c000000000048b38>] prep_irq_for_enabled_exit arch/powerpc/kernel/interrupt.c:56 [inline]
hardirqs last enabled at (33): [<c000000000048b38>] interrupt_exit_user_prepare_main+0x148/0x600 arch/powerpc/kernel/interrupt.c:230
hardirqs last disabled at (34): [<c00000000003e6a4>] interrupt_enter_prepare+0x144/0x4f0 arch/powerpc/include/asm/interrupt.h:176
softirqs last enabled at (0): [<c000000000281954>] copy_process+0x16e4/0x4750 kernel/fork.c:2436
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 15 PID: 25040 Comm: syz-executor Not tainted 6.5.0-rc5-00001-g3ccdff6bb06d #3
Hardware name: IBM,9105-22A POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1040.00 (NL1040_021) hv:phyp pSeries
Call Trace:
[c0000000a8247ce0] [c00000000032b0e4] __might_resched+0x3b4/0x400 kernel/sched/core.c:10189
[c0000000a8247d80] [c0000000008c7dc8] __might_fault+0xa8/0x170 mm/memory.c:5853
[c0000000a8247dc0] [c00000000004160c] do_program_check+0x32c/0xb20 arch/powerpc/kernel/traps.c:1518
[c0000000a8247e50] [c000000000009b2c] program_check_common_virt+0x3bc/0x3c0
To determine if a trap was caused by a HASHCHK instruction, we inspect
the user instruction that triggered the trap. However this may sleep
if the page needs to be faulted in (get_user_instr() reaches
__get_user(), which calls might_fault() and triggers the bug message).
Move the HASHCHK handler logic to after we allow IRQs, which is fine
because we are only interested in HASHCHK if it's a user space trap.
Fixes: 5bcba4e6c1 ("powerpc/dexcr: Handle hashchk exception")
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230915034604.45393-1-bgray@linux.ibm.com
This is called in an atomic context, so is not allowed to sleep if a
user page needs to be faulted in and has nowhere it can be deferred to.
The pagefault_disabled() function is documented as preventing user
access methods from sleeping.
In practice the page will be mapped in nearly always because we are
reading the instruction that just triggered the watchpoint trap.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230829063457.54157-3-bgray@linux.ibm.com
thread_change_pc() uses CPU local data, so must be protected from
swapping CPUs while it is reading the breakpoint struct.
The error is more noticeable after 1e60f3564b ("powerpc/watchpoints:
Track perf single step directly on the breakpoint"), which added an
unconditional __this_cpu_read() call in thread_change_pc(). However the
existing __this_cpu_read() that runs if a breakpoint does need to be
re-inserted has the same issue.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230829063457.54157-2-bgray@linux.ibm.com
Currently, is_kdump_kernel() returns true in crash dump capture kernel
for both kdump and fadump crash dump capturing methods, as both these
methods set elfcorehdr_addr. Some restrictions enforced for crash dump
capture kernel, based on is_kdump_kernel(), are specifically meant for
kdump case and not desirable for fadump - eg. IO queues restriction in
device drivers. So, define is_kdump_kernel() to return false when f/w
assisted dump is active.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230912082950.856977-2-hbathini@linux.ibm.com
Pull powerpc updates from Michael Ellerman:
- Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the
configured SMT state when hotplugging CPUs into the system
- Combine final TLB flush and lazy TLB mm shootdown IPIs when using the
Radix MMU to avoid a broadcast TLBIE flush on exit
- Drop the exclusion between ptrace/perf watchpoints, and drop the now
unused associated arch hooks
- Add support for the "nohlt" command line option to disable CPU idle
- Add support for -fpatchable-function-entry for ftrace, with GCC >=
13.1
- Rework memory block size determination, and support 256MB size on
systems with GPUs that have hotpluggable memory
- Various other small features and fixes
Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira
Rajeev, Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam
Menghani, Geoff Levand, Hari Bathini, Immad Mir, Jialin Zhang, Joel
Stanley, Jordan Niethe, Justin Stitt, Kajol Jain, Kees Cook, Krzysztof
Kozlowski, Laurent Dufour, Liang He, Linus Walleij, Mahesh Salgaonkar,
Masahiro Yamada, Michal Suchanek, Nageswara R Sastry, Nathan Chancellor,
Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick Desaulniers, Omar
Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell Currey, Sourabh
Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav Jain,
Xiongfeng Wang, Yuan Tan, Zhang Rui, and Zheng Zengkai.
* tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (135 commits)
macintosh/ams: linux/platform_device.h is needed
powerpc/xmon: Reapply "Relax frame size for clang"
powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached
powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled
powerpc/iommu: Fix notifiers being shared by PCI and VIO buses
powerpc/mpc5xxx: Add missing fwnode_handle_put()
powerpc/config: Disable SLAB_DEBUG_ON in skiroot
powerpc/pseries: Remove unused hcall tracing instruction
powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n
powerpc: dts: add missing space before {
powerpc/eeh: Use pci_dev_id() to simplify the code
powerpc/64s: Move CPU -mtune options into Kconfig
powerpc/powermac: Fix unused function warning
powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT
powerpc: Don't include lppaca.h in paca.h
powerpc/pseries: Move hcall_vphn() prototype into vphn.h
powerpc/pseries: Move VPHN constants into vphn.h
cxl: Drop unused detach_spa()
powerpc: Drop zalloc_maybe_bootmem()
powerpc/powernv: Use struct opal_prd_msg in more places
...
Pull integrity subsystem updates from Mimi Zohar:
- With commit 099f26f22f ("integrity: machine keyring CA
configuration") certificates may be loaded onto the IMA keyring,
directly or indirectly signed by keys on either the "builtin" or the
"machine" keyrings.
With the ability for the system/machine owner to sign the IMA policy
itself without needing to recompile the kernel, update the IMA
architecture specific policy rules to require the IMA policy itself
be signed.
[ As commit 099f26f22f was upstreamed in linux-6.4, updating the
IMA architecture specific policy now to require signed IMA policies
may break userspace expectations. ]
- IMA only checked the file data hash was not on the system blacklist
keyring for files with an appended signature (e.g. kernel modules,
Power kernel image).
Check all file data hashes regardless of how it was signed
- Code cleanup, and a kernel-doc update
* tag 'integrity-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
kexec_lock: Replace kexec_mutex() by kexec_lock() in two comments
ima: require signed IMA policy when UEFI secure boot is enabled
integrity: Always reference the blacklist keyring with appraisal
ima: Remove deprecated IMA_TRUSTED_KEYRING Kconfig
Pull dma-maping updates from Christoph Hellwig:
- allow dynamic sizing of the swiotlb buffer, to cater for secure
virtualization workloads that require all I/O to be bounce buffered
(Petr Tesarik)
- move a declaration to a header (Arnd Bergmann)
- check for memory region overlap in dma-contiguous (Binglei Wang)
- remove the somewhat dangerous runtime swiotlb-xen enablement and
unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross)
- per-node CMA improvements (Yajun Deng)
* tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: optimize get_max_slots()
swiotlb: move slot allocation explanation comment where it belongs
swiotlb: search the software IO TLB only if the device makes use of it
swiotlb: allocate a new memory pool when existing pools are full
swiotlb: determine potential physical address limit
swiotlb: if swiotlb is full, fall back to a transient memory pool
swiotlb: add a flag whether SWIOTLB is allowed to grow
swiotlb: separate memory pool data from other allocator data
swiotlb: add documentation and rename swiotlb_do_find_slots()
swiotlb: make io_tlb_default_mem local to swiotlb.c
swiotlb: bail out of swiotlb_init_late() if swiotlb is already allocated
dma-contiguous: check for memory region overlap
dma-contiguous: support numa CMA for specified node
dma-contiguous: support per-numa CMA for all architectures
dma-mapping: move arch_dma_set_mask() declaration to header
swiotlb: unexport is_swiotlb_active
x86: always initialize xen-swiotlb when xen-pcifront is enabling
xen/pci: add flag for PCI passthrough being possible
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder
("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
commands")
- vsprintf inclusion rationalization from Andy Shevchenko
("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel
handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
document while_each_thread(), change first_tid() to use for_each_thread()
drivers/char/mem.c: shrink character device's devlist[] array
x86/crash: optimize CPU changes
crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
crash: hotplug support for kexec_load()
x86/crash: add x86 crash hotplug support
crash: memory and CPU hotplug sysfs attributes
kexec: exclude elfcorehdr from the segment digest
crash: add generic infrastructure for crash hotplug support
crash: move a few code bits to setup support of crash hotplug
kstrtox: consistently use _tolower()
kill do_each_thread()
nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
scripts/bloat-o-meter: count weak symbol sizes
treewide: drop CONFIG_EMBEDDED
lockdep: fix static memory detection even more
lib/vsprintf: declare no_hash_pointers in sprintf.h
lib/vsprintf: split out sprintf() and friends
kernel/fork: stop playing lockless games for exe_file replacement
adfs: delete unused "union adfs_dirtail" definition
...
Pull fchmodat2 system call from Christian Brauner:
"This adds the fchmodat2() system call. It is a revised version of the
fchmodat() system call, adding a missing flag argument. Support for
both AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH are included.
Adding this system call revision has been a longstanding request but
so far has always fallen through the cracks. While the kernel
implementation of fchmodat() does not have a flag argument the libc
provided POSIX-compliant fchmodat(3) version does. Both glibc and musl
have to implement a workaround in order to support AT_SYMLINK_NOFOLLOW
(see [1] and [2]).
The workaround is brittle because it relies not just on O_PATH and
O_NOFOLLOW semantics and procfs magic links but also on our rather
inconsistent symlink semantics.
This gives userspace a proper fchmodat2() system call that libcs can
use to properly implement fchmodat(3) and allows them to get rid of
their hacks. In this case it will immediately benefit them as the
current workaround is already defunct because of aformentioned
inconsistencies.
In addition to AT_SYMLINK_NOFOLLOW, give userspace the ability to use
AT_EMPTY_PATH with fchmodat2(). This is already possible with
fchownat() so there's no reason to not also support it for
fchmodat2().
The implementation is simple and comes with selftests. Implementation
of the system call and wiring up the system call are done as separate
patches even though they could arguably be one patch. But in case
there are merge conflicts from other system call additions it can be
beneficial to have separate patches"
Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=17eca54051ee28ba1ec3f9aed170a62630959143;hb=a492b1e5ef7ab50c6fdd4e4e9879ea5569ab0a6c#l35 [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c?id=718f363bc2067b6487900eddc9180c84e7739f80#n28 [2]
* tag 'v6.6-vfs.fchmodat2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
selftests: fchmodat2: remove duplicate unneeded defines
fchmodat2: add support for AT_EMPTY_PATH
selftests: Add fchmodat2 selftest
arch: Register fchmodat2, usually as syscall 452
fs: Add fchmodat2()
Non-functional cleanup of a "__user * filename"
fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both
PCI and VIO buses. struct notifier_block is a linked list node, so this
causes any notifiers later registered to either bus type to also be
registered to the other since they share the same node.
This causes issues in (at least) the vgaarb code, which registers a
notifier for PCI buses. pci_notify() ends up being called on a vio
device, converted with to_pci_dev() even though it's not a PCI device,
and finally makes a bad access in vga_arbiter_add_pci_device() as
discovered with KASAN:
BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00
Read of size 4 at addr c000000264c26fdc by task swapper/0/1
Call Trace:
dump_stack_lvl+0x1bc/0x2b8 (unreliable)
print_report+0x3f4/0xc60
kasan_report+0x244/0x698
__asan_load4+0xe8/0x250
vga_arbiter_add_pci_device+0x60/0xe00
pci_notify+0x88/0x444
notifier_call_chain+0x104/0x320
blocking_notifier_call_chain+0xa0/0x140
device_add+0xac8/0x1d30
device_register+0x58/0x80
vio_register_device_node+0x9ac/0xce0
vio_bus_scan_register_devices+0xc4/0x13c
__machine_initcall_pseries_vio_device_init+0x94/0xf0
do_one_initcall+0x12c/0xaa8
kernel_init_freeable+0xa48/0xba8
kernel_init+0x64/0x400
ret_from_kernel_thread+0x5c/0x64
Fix this by creating separate notifier_block structs for each bus type.
Fixes: d6b9a81b2a ("powerpc: IOMMU fault injection")
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
[mpe: Add #ifdef to fix CONFIG_IBMVIO=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230322035322.328709-1-ruscur@russell.cc
