kernel/linux.git/arch/alpha/include, 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: don't reference obsolete termio struct for TC* constants

2026-01-17T15:31:18+00:00

[ Upstream commit 9aeed9041929812a10a6d693af050846942a1d16 ] Similar in nature to ab107276607af90b13a5994997e19b7b9731e251. glibc-2.42 drops the legacy termio struct, but the ioctls.h header still defines some TC* constants in terms of termio (via sizeof). Hardcode the values instead. This fixes building Python for example, which falls over like: ./Modules/termios.c:1119:16: error: invalid application of 'sizeof' to incomplete type 'struct termio' Link: https://bugs.gentoo.org/961769 Link: https://bugs.gentoo.org/962600 Signed-off-by: Sam James Reviewed-by: Magnus Lindholm Link: https://lore.kernel.org/r/6ebd3451908785cad53b50ca6bc46cfe9d6bc03c.1764922497.git.sam@gentoo.org 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: make stack 16-byte aligned (most cases)

2025-02-21T13:01:33+00:00

commit 0a0f7362b0367634a2d5cb7c96226afc116f19c9 upstream. The problem is that GCC expects 16-byte alignment of the incoming stack since early 2004, as Maciej found out [1]: Having actually dug speculatively I can see that the psABI was changed in GCC 3.5 with commit e5e10fb4a350 ("re PR target/14539 (128-bit long double improperly aligned)") back in Mar 2004, when the stack pointer alignment was increased from 8 bytes to 16 bytes, and arch/alpha/kernel/entry.S has various suspicious stack pointer adjustments, starting with SP_OFF which is not a whole multiple of 16. Also, as Magnus noted, "ALPHA Calling Standard" [2] required the same: D.3.1 Stack Alignment This standard requires that stacks be octaword aligned at the time a new procedure is invoked. However: - the "normal" kernel stack is always misaligned by 8 bytes, thanks to the odd number of 64-bit words in 'struct pt_regs', which is the very first thing pushed onto the kernel thread stack; - syscall, fault, interrupt etc. handlers may, or may not, receive aligned stack depending on numerous factors. Somehow we got away with it until recently, when we ended up with a stack corruption in kernel/smp.c:smp_call_function_single() due to its use of 32-byte aligned local data and the compiler doing clever things allocating it on the stack. This adds padding between the PAL-saved and kernel-saved registers so that 'struct pt_regs' have an even number of 64-bit words. This makes the stack properly aligned for most of the kernel code, except two handlers which need special threatment. Note: struct pt_regs doesn't belong in uapi/asm; this should be fixed, but let's put this off until later. Link: https://lore.kernel.org/rcu/alpine.DEB.2.21.2501130248010.18889@angie.orcam.me.uk/ [1] Link: https://bitsavers.org/pdf/dec/alpha/Alpha_Calling_Standard_Rev_2.0_19900427.pdf [2] Cc: stable@vger.kernel.org Tested-by: Maciej W. Rozycki Tested-by: Magnus Lindholm Tested-by: Matt Turner Reviewed-by: Maciej W. Rozycki Signed-off-by: Ivan Kokshaysky Signed-off-by: Matt Turner Signed-off-by: Greg Kroah-Hartman

Merge tag 'asm-generic-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2024-09-26T18:54:40+00:00

Pull asm-generic updates from Arnd Bergmann: "These are only two small patches, one cleanup for arch/alpha and a preparation patch cleaning up the handling of runtime constants in the linker scripts" * tag 'asm-generic-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: runtime constants: move list of constants to vmlinux.lds.h alpha: no need to include asm/xchg.h twice

net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags

2024-09-12T03:44:32+00:00

Add an interface for the user to notify the kernel that it is done reading the devmem dmabuf frags returned as cmsg. The kernel will drop the reference on the frags to make them available for reuse. Signed-off-by: Willem de Bruijn Signed-off-by: Kaiyuan Zhang Signed-off-by: Mina Almasry Reviewed-by: Pavel Begunkov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20240910171458.219195-11-almasrymina@google.com Signed-off-by: Jakub Kicinski

tcp: RX path for devmem TCP

2024-09-12T03:44:32+00:00

In tcp_recvmsg_locked(), detect if the skb being received by the user is a devmem skb. In this case - if the user provided the MSG_SOCK_DEVMEM flag - pass it to tcp_recvmsg_devmem() for custom handling. tcp_recvmsg_devmem() copies any data in the skb header to the linear buffer, and returns a cmsg to the user indicating the number of bytes returned in the linear buffer. tcp_recvmsg_devmem() then loops over the unaccessible devmem skb frags, and returns to the user a cmsg_devmem indicating the location of the data in the dmabuf device memory. cmsg_devmem contains this information: 1. the offset into the dmabuf where the payload starts. 'frag_offset'. 2. the size of the frag. 'frag_size'. 3. an opaque token 'frag_token' to return to the kernel when the buffer is to be released. The pages awaiting freeing are stored in the newly added sk->sk_user_frags, and each page passed to userspace is get_page()'d. This reference is dropped once the userspace indicates that it is done reading this page. All pages are released when the socket is destroyed. Signed-off-by: Willem de Bruijn Signed-off-by: Kaiyuan Zhang Signed-off-by: Mina Almasry Reviewed-by: Pavel Begunkov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20240910171458.219195-10-almasrymina@google.com Signed-off-by: Jakub Kicinski

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