linux.git/arch/alpha/include/asm, branch v6.12.80

alpha: fix user-space corruption during memory compaction

2026-03-04T12:20:55+00:00

[ Upstream commit dd5712f3379cfe760267cdd28ff957d9ab4e51c7 ]

Alpha systems can suffer sporadic user-space crashes and heap
corruption when memory compaction is enabled.

Symptoms include SIGSEGV, glibc allocator failures (e.g. "unaligned
tcache chunk"), and compiler internal errors. The failures disappear
when compaction is disabled or when using global TLB invalidation.

The root cause is insufficient TLB shootdown during page migration.
Alpha relies on ASN-based MM context rollover for instruction cache
coherency, but this alone is not sufficient to prevent stale data or
instruction translations from surviving migration.

Fix this by introducing a migration-specific helper that combines:
  - MM context invalidation (ASN rollover),
  - immediate per-CPU TLB invalidation (TBI),
  - synchronous cross-CPU shootdown when required.

The helper is used only by migration/compaction paths to avoid changing
global TLB semantics.

Additionally, update flush_tlb_other(), pte_clear(), to use
READ_ONCE()/WRITE_ONCE() for correct SMP memory ordering.

This fixes observed crashes on both UP and SMP Alpha systems.

Reviewed-by: Ivan Kokshaysky 
Tested-by: Matoro Mahri 
Tested-by: Michael Cree 
Signed-off-by: Magnus Lindholm 
Link: https://lore.kernel.org/r/20260102173603.18247-2-linmag7@gmail.com
Signed-off-by: Magnus Lindholm 
Signed-off-by: Sasha Levin

alpha/elf: Fix misc/setarch test of util-linux by removing 32bit support

2025-03-22T19:54:15+00:00

[ Upstream commit b029628be267cba3c7684ec684749fe3e4372398 ]

Richard Henderson  writes[1]:

> There was a Spec benchmark (I forget which) which was memory bound and ran
> twice as fast with 32-bit pointers.
>
> I copied the idea from DEC to the ELF abi, but never did all the other work
> to allow the toolchain to take advantage.
>
> Amusingly, a later Spec changed the benchmark data sets to not fit into a
> 32-bit address space, specifically because of this.
>
> I expect one could delete the ELF bit and personality and no one would
> notice. Not even the 10 remaining Alpha users.

In [2] it was pointed out that parts of setarch weren't working
properly on alpha because it has it's own SET_PERSONALITY
implementation.  In the discussion that followed Richard Henderson
pointed out that the 32bit pointer support for alpha was never
completed.

Fix this by removing alpha's 32bit pointer support.

As a bit of paranoia refuse to execute any alpha binaries that have
the EF_ALPHA_32BIT flag set.  Just in case someone somewhere has
binaries that try to use alpha's 32bit pointer support.

Link: https://lkml.kernel.org/r/CAFXwXrkgu=4Qn-v1PjnOR4SG0oUb9LSa0g6QXpBq4ttm52pJOQ@mail.gmail.com [1]
Link: https://lkml.kernel.org/r/20250103140148.370368-1-glaubitz@physik.fu-berlin.de [2]
Signed-off-by: Eric W. Biederman 
Reviewed-by: Richard Henderson 
Reviewed-by: Arnd Bergmann 
Reviewed-by: John Paul Adrian Glaubitz 
Tested-by: John Paul Adrian Glaubitz 
Link: https://lore.kernel.org/r/87y0zfs26i.fsf_-_@email.froward.int.ebiederm.org
Signed-off-by: Kees Cook 
Signed-off-by: Sasha Levin

alpha: no need to include asm/xchg.h twice

2024-08-19T07:45:27+00:00

We used to generate different helpers for local and full
{cmp,}xchg(); these days the barriers are in arch_{cmp,}xchg()
instead and generated helpers are identical for local and
full cases.  No need for those parametrized includes of
asm/xchg.h - we might as well insert its contents directly
in asm/cmpxchg.h and do it only once.

Signed-off-by: Al Viro

alpha: fix ioread64be()/iowrite64be() helpers

2024-08-01T13:48:03+00:00

Compile-testing the crypto/caam driver on alpha showed a pre-existing
problem on alpha with iowrite64be() missing:

ERROR: modpost: "iowrite64be" [drivers/crypto/caam/caam_jr.ko] undefined!

The prototypes were added a while ago when we started using asm-generic/io.h,
but the implementation was still missing. At some point the ioread64/iowrite64
helpers were added, but the big-endian versions are still missing, and
the generic version (using readq/writeq) is would not work here.

Change it to wrap ioread64()/iowrite64() instead.

Fixes: beba3771d9e0 ("crypto: caam: Make CRYPTO_DEV_FSL_CAAM dependent of COMPILE_TEST")
Fixes: e19d4ebc536d ("alpha: add full ioread64/iowrite64 implementation")
Fixes: 7e772dad9913 ("alpha: Use generic ")
Closes: https://lore.kernel.org/all/CAHk-=wgEyzSxTs467NDOVfBSzWvUS6ztcwhiy=M3xog==KBmTw@mail.gmail.com/
Tested-by: Guenter Roeck 
Reviewed-by: Linus Walleij 
Signed-off-by: Arnd Bergmann

alpha: drop pre-EV56 support

2024-05-06T10:05:00+00:00

All EV4 machines are already gone, and the remaining EV5 based machines
all support the slightly more modern EV56 generation as well.
Debian only supports EV56 and later.

Drop both of these and build kernels optimized for EV56 and higher
when the "generic" options is selected, tuning for an out-of-order
EV6 pipeline, same as Debian userspace.

Since this was the only supported architecture without 8-bit and
16-bit stores, common kernel code no longer has to worry about
aligning struct members, and existing workarounds from the block
and tty layers can be removed.

The alpha memory management code no longer needs an abstraction
for the differences between EV4 and EV5+.

Link: https://lists.debian.org/debian-alpha/2023/05/msg00009.html
Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann

alpha: cabriolet: remove EV5 CPU support

2024-05-03T20:10:03+00:00

The sys_cabriolet.c file includes support for multiple evaluation
boards. pc164 and lx164 are for ev56 CPUs, while the eb164 is
now the last supported machine that only supports ev5 but not
ev56.

Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann

alpha: remove LCA and APECS based machines

2024-05-03T20:09:59+00:00

APECS is the DECchip 21071x chipset for the EV4 and EV45 generation, while
LCA is the integrated I/O support on the corresponding low-cost alpha
machines of that generation.

All of these CPUs lack the BWX extension for byte and word access, so
drop the chipset support and all associated machines.

Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann

alpha: sable: remove early machine support

2024-05-03T20:09:55+00:00

The sable family (Alphaserver 2000 and 2100) comes in variants for
EV4, EV45, EV5 and EV56. Drop support for the earlier ones that
lack support for the BWX extension but keep the later 'gamma'
variant around since that works with EV56 CPUs.

Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann

alpha: remove DECpc AXP150 (Jensen) support

2024-05-03T20:09:50+00:00

This is one of the hackiest Alpha machines, and the only one without
PCI support. Removing this allows cleaning up code in eise and tty
drivers in addition to the architecture code.

Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann

alpha: sort scr_mem{cpy,move}w() out

2024-05-03T20:08:50+00:00

Take scr_memmove() out of line, make both it and scr_memcpyw()
conditional upon VGA_CONSOLE or MDA_CONSOLE (if neither is
selected, we are certain to be working with the kernel-allocated
buffer rather than VRAM and defaults will work just fine).

That allows to clean vt_buffer.h, but that's a separate story

Signed-off-by: Al Viro 
Acked-by: Paul E. McKenney 
Acked-by: Matt Turner 
Signed-off-by: Arnd Bergmann