linux-stable.git/arch/powerpc/include/asm, branch linux-6.5.y

powerpc/40x: Remove stale PTE_ATOMIC_UPDATES macro

2023-11-20T10:57:16+00:00

[ Upstream commit cc8ee288f484a2a59c01ccd4d8a417d6ed3466e3 ]

40x TLB handlers were reworked by commit 2c74e2586bb9 ("powerpc/40x:
Rework 40x PTE access and TLB miss") to not require PTE_ATOMIC_UPDATES
anymore.

Then commit 4e1df545e2fa ("powerpc/pgtable: Drop PTE_ATOMIC_UPDATES")
removed all code related to PTE_ATOMIC_UPDATES.

Remove left over PTE_ATOMIC_UPDATES macro.

Fixes: 2c74e2586bb9 ("powerpc/40x: Rework 40x PTE access and TLB miss")
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/f061db5857fcd748f84a6707aad01754686ce97e.1695659959.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin

powerpc/64e: Fix wrong test in __ptep_test_and_clear_young()

2023-10-19T21:11:08+00:00

[ Upstream commit 5ea0bbaa32e8f54e9a57cfee4a3b8769b80be0d2 ]

Commit 45201c879469 ("powerpc/nohash: Remove hash related code from
nohash headers.") replaced:

  if ((pte_val(*ptep) & (_PAGE_ACCESSED | _PAGE_HASHPTE)) == 0)
	return 0;

By:

  if (pte_young(*ptep))
	return 0;

But it should be:

  if (!pte_young(*ptep))
	return 0;

Fix it.

Fixes: 45201c879469 ("powerpc/nohash: Remove hash related code from nohash headers.")
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/8bb7f06494e21adada724ede47a4c3d97e879d40.1695659959.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin

powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE

2023-10-19T21:11:08+00:00

[ Upstream commit 5d9cea8a552ee122e21fbd5a3c5d4eb85f648e06 ]

On 8xx, PAGE_NONE is handled by setting _PAGE_NA instead of clearing
_PAGE_USER.

But then pte_user() returns 1 also for PAGE_NONE.

As _PAGE_NA prevent reads, add a specific version of pte_read()
that returns 0 when _PAGE_NA is set instead of always returning 1.

Fixes: 351750331fc1 ("powerpc/mm: Introduce _PAGE_NA")
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/57bcfbe578e43123f9ed73e040229b80f1ad56ec.1695659959.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin

powerpc/ftrace: Fix dropping weak symbols with older toolchains

2023-09-13T07:53:52+00:00

commit f6834c8c59a8e977a6f6e4f96c5d28dfa5db8430 upstream.

The minimum level of gcc supported for building the kernel is v5.1.
v5.x releases of gcc emitted a three instruction sequence for
-mprofile-kernel:
	mflr	r0
	std	r0, 16(r1)
	bl	_mcount

It is only with the v6.x releases that gcc started emitting the two
instruction sequence for -mprofile-kernel, omitting the second store
instruction.

With the older three instruction sequence, the actual ftrace location
can be the 5th instruction into a function. Update the allowed offset
for ftrace location from 12 to 16 to accommodate the same.

Cc: stable@vger.kernel.org
Fixes: 7af82ff90a2b06 ("powerpc/ftrace: Ignore weak functions")
Signed-off-by: Naveen N Rao 
Reviewed-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/7b265908a9461e38fc756ef9b569703860a80621.1687166935.git.naveen@kernel.org
Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT

2023-09-13T07:53:32+00:00

[ Upstream commit eac030b22ea12cdfcbb2e941c21c03964403c63f ]

lppaca_shared_proc() takes a pointer to the lppaca which is typically
accessed through get_lppaca().  With DEBUG_PREEMPT enabled, this leads
to checking if preemption is enabled, for example:

  BUG: using smp_processor_id() in preemptible [00000000] code: grep/10693
  caller is lparcfg_data+0x408/0x19a0
  CPU: 4 PID: 10693 Comm: grep Not tainted 6.5.0-rc3 #2
  Call Trace:
    dump_stack_lvl+0x154/0x200 (unreliable)
    check_preemption_disabled+0x214/0x220
    lparcfg_data+0x408/0x19a0
    ...

This isn't actually a problem however, as it does not matter which
lppaca is accessed, the shared proc state will be the same.
vcpudispatch_stats_procfs_init() already works around this by disabling
preemption, but the lparcfg code does not, erroring any time
/proc/powerpc/lparcfg is accessed with DEBUG_PREEMPT enabled.

Instead of disabling preemption on the caller side, rework
lppaca_shared_proc() to not take a pointer and instead directly access
the lppaca, bypassing any potential preemption checks.

Fixes: f13c13a00512 ("powerpc: Stop using non-architected shared_proc field in lppaca")
Signed-off-by: Russell Currey 
[mpe: Rework to avoid needing a definition in paca.h and lppaca.h]
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230823055317.751786-4-mpe@ellerman.id.au
Signed-off-by: Sasha Levin

powerpc: Don't include lppaca.h in paca.h

2023-09-13T07:53:32+00:00

[ Upstream commit 1aa000667669fa855853decbb1c69e974d8ff716 ]

By adding a forward declaration for struct lppaca we can untangle paca.h
and lppaca.h. Also move get_lppaca() into lppaca.h for consistency.

Add includes of lppaca.h to some files that need it.

Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230823055317.751786-3-mpe@ellerman.id.au
Stable-dep-of: eac030b22ea1 ("powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT")
Signed-off-by: Sasha Levin

nmi_backtrace: allow excluding an arbitrary CPU

2023-09-13T07:53:08+00:00

[ Upstream commit 8d539b84f1e3478436f978ceaf55a0b6cab497b5 ]

The APIs that allow backtracing across CPUs have always had a way to
exclude the current CPU.  This convenience means callers didn't need to
find a place to allocate a CPU mask just to handle the common case.

Let's extend the API to take a CPU ID to exclude instead of just a
boolean.  This isn't any more complex for the API to handle and allows the
hardlockup detector to exclude a different CPU (the one it already did a
trace for) without needing to find space for a CPU mask.

Arguably, this new API also encourages safer behavior.  Specifically if
the caller wants to avoid tracing the current CPU (maybe because they
already traced the current CPU) this makes it more obvious to the caller
that they need to make sure that the current CPU ID can't change.

[akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub]
Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid
Signed-off-by: Douglas Anderson 
Acked-by: Michal Hocko 
Cc: kernel test robot 
Cc: Lecopzer Chen 
Cc: Petr Mladek 
Cc: Pingfan Liu 
Signed-off-by: Andrew Morton 
Stable-dep-of: 1f38c86bb29f ("watchdog/hardlockup: avoid large stack frames in watchdog_hardlockup_check()")
Signed-off-by: Sasha Levin

locking: remove spin_lock_prefetch

2023-08-12T16:18:47+00:00

The only remaining consumer is new_inode, where it showed up in 2001 as
commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1]
with a changelog which does not mention it.

Since then the line got only touched up to keep compiling.

While it may have been of benefit back in the day, it is guaranteed to
at best not get in the way in the multicore setting -- as the code
performs *a lot* of work between the prefetch and actual lock acquire,
any contention means the cacheline is already invalid by the time the
routine calls spin_lock().  It adds spurious traffic, for short.

On top of it prefetch is notoriously tricky to use for single-threaded
purposes, making it questionable from the get go.

As such, remove it.

I admit upfront I did not see value in benchmarking this change, but I
can do it if that is deemed appropriate.

Removal from new_inode and of the entire thing are in the same patch as
requested by Linus, so whatever weird looks can be directed at that guy.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/fs/inode.c?id=c37fa164f793735b32aa3f53154ff1a7659e6442 [1]
Signed-off-by: Mateusz Guzik 
Signed-off-by: Linus Torvalds

word-at-a-time: use the same return type for has_zero regardless of endianness

2023-08-02T17:23:36+00:00

Compiling big-endian targets with Clang produces the diagnostic:

  fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
	} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
	          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                               ||
  fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning

It appears that when has_zero was introduced, two definitions were
produced with different signatures (in particular different return
types).

Looking at the usage in hash_name() in fs/namei.c, I suspect that
has_zero() is meant to be invoked twice per while loop iteration; using
logical-or would not update `bdata` when `a` did not have zeros.  So I
think it's preferred to always return an unsigned long rather than a
bool than update the while loop in hash_name() to use a logical-or
rather than bitwise-or.

[ Also changed powerpc version to do the same  - Linus ]

Link: https://github.com/ClangBuiltLinux/linux/issues/1832
Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/
Fixes: 36126f8f2ed8 ("word-at-a-time: make the interfaces truly generic")
Debugged-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Acked-by: Heiko Carstens 
Cc: Arnd Bergmann 
Signed-off-by: Linus Torvalds

Revert "powerpc/64s: Remove support for ELFv1 little endian userspace"

2023-07-19T11:28:35+00:00

This reverts commit 606787fed7268feb256957872586370b56af697a.

ELFv1 with LE has never been a thing, and people who try to make ELFv1 LE
binaries are maniacs who need to be stopped, but unfortunately there are
ELFv1 LE binaries out there in the wild.

One such binary is the ppc64el (as Debian calls it) helper for
arch-test[0], a tool for detecting architectures that can be executed on a
given machine by means of attempting to execute helper binaries compiled
for each architecture and seeing which binaries succeed and fail. The
helpers are small snippets of assembly, and the ppc64el assembly doesn't
include the right directives to generate an ELFv2 binary.

This results in arch-test incorrectly determining that a ppc64el kernel
can't execute a ppc64el userspace, which in turn means that a number of
developer tools such as debootstrap will break (assuming arch-test is
installed).

[0] https://github.com/kilobyte/arch-test

Signed-off-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://msgid.link/20230719071821.320594-1-ajd@linux.ibm.com