linux-toradex.git/arch/alpha/include/uapi/asm, branch master Linux kernel for Apalis and Colibri modules Merge tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 2026-06-14T22:29:45+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-06-14T22:29:45+00:00 7e0e7bd60d4a812b694c477716597fcb038b00cb Pull misc vfs updates from Christian Brauner: "Features: - Reduce pipe->mutex contention by pre-allocating pages outside the lock in anon_pipe_write(). anon_pipe_write() called alloc_page() once per page while holding pipe->mutex. The allocation can sleep doing direct reclaim and runs memcg charging, which extends the critical section and stalls any concurrent reader on the same mutex. Now up to 8 pages are pre-allocated before the mutex is taken, leftovers are recycled into the per-pipe tmp_page[] cache before unlock, and any remainder is released after unlock, keeping the allocator out of the critical section on both sides. On a writers x readers sweep with 64KB writes against a 1 MB pipe throughput improves 6-28% and average write latency drops 5-22%; under memory pressure - when the cost of holding the mutex across reclaim is highest - throughput improves 21-48% and latency drops 17-33%. The microbenchmark is added to selftests. - uaccess/sockptr: fix the ignored_trailing logic in copy_struct_to_user() to behave as documented and the usize check in copy_struct_from_sockptr() for user pointers, and add copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr() helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC). - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real inode backing a dentry via d_real_inode(). On overlayfs the inode attached to the dentry doesn't carry the underlying device information; this is used by the filesystem restriction BPF program that was merged into systemd. - docs: add guidelines for submitting new filesystems, motivated by the maintenance burden abandoned and untestable filesystems impose on VFS developers, blocking infrastructure work like folio conversions and iomap migration. Fixes: - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() and drop the now-redundant assignments in callers. This began as a one-line dma-buf fix for a path_noexec() warning; a pseudo filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo() callers were audited: the only visible effect is on dma-buf where SB_I_NOEXEC silences the warning. - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs, qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a device with a sector size > PAGE_SIZE crashed roughly half of them; the rest had the same missing error handling pattern. Plus a follow-up releasing the superblock buffer_head when setting the minix v3 block size fails. - mount: honour SB_NOUSER in the new mount API. - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by switching the process-group paths of send_sigio() and send_sigurg() from read_lock(&tasklist_lock) to RCU, matching the single-PID path. - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing delegated NFS mounts (fsopen() in a container with the mount performed by a privileged daemon) that broke when non-init s_user_ns was tied to FS_USERNS_MOUNT. - selftests/namespaces: fix a hang in nsid_test where an unreaped grandchild kept the TAP pipe write-end open, a waitpid(-1) race in listns_efault_test, and a false FAIL on kernels without listns() where the tests should SKIP. - filelock: fix the break_lease() stub signature for CONFIG_FILE_LOCKING=n. - init/initramfs_test: wait for the async initramfs unpacking before running; the test and do_populate_rootfs() share the parser state. - fs/coredump: reduce redundant log noise in validate_coredump_safety(). - iomap: pass the correct length to fserror_report_io() in __iomap_write_begin(). - backing-file: fix the backing_file_open() kerneldoc. Cleanups: - initramfs: refactor the cpio hex header parsing to use hex2bin() instead of the hand-rolled simple_strntoul() which is reverted, and extend the initramfs KUnit tests to cover header fields with 0x prefixes. - Replace __get_free_pages() and friends with kmalloc()/kzalloc() across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2, isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the do_mounts init code - part of the larger work of replacing page allocator calls with kmalloc(). - Use clear_and_wake_up_bit() in unlock_buffer() and journal_end_buffer_io_sync() instead of open-coding the sequence. - Drop unused VFS exports: unexport drop_super_exclusive(), remove start_removing_user_path_at(), and fold __start_removing_path() into start_removing_path(). - fs/read_write: narrow the __kernel_write() export with EXPORT_SYMBOL_FOR_MODULES(). - vfs: uapi: retire octal and hex constants in favor of (1 << n) for the O_ flags. Finding a free bit for a new flag across the architectures was needlessly hard with the mixed bases. - dcache: add extra sanity checks of dead dentries in dentry_free() via a new DENTRY_WARN_ONCE() that also prints d_flags. - iov_iter: use kmemdup_array() in dup_iter() to harden the allocation against multiplication overflow. - fs/pipe: write to ->poll_usage only once. - vfs: remove an always-taken if-branch in find_next_fd(). - dcache: use kmalloc_flex() for struct external_name in __d_alloc(). - namei: use QSTR() instead of QSTR_INIT() in path_pts(). - sync_file_range: delete dead S_ISLNK code. - Comment fixes: retire a stale comment in fget_task_next() and fix assorted spelling mistakes" * tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits) backing-file: fix backing_file_open() kerneldoc parameter iomap: pass the correct len to fserror_report_io in __iomap_write_begin vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags bpf: add bpf_real_inode() kfunc fs/read_write: Do not export __kernel_write() to the entire world libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() mount: honour SB_NOUSER in the new mount API fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling selftests/pipe: add pipe_bench microbenchmark fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write fs: retire stale comment in fget_task_next() fs: fix spelling mistakes in comment bfs: replace get_zeroed_page() with kzalloc() binfmt_misc: replace __get_free_page() with kmalloc() configfs: replace __get_free_pages() with kzalloc() fs/namespace: use __getname() to allocate mntpath buffer fs/select: replace __get_free_page() with kmalloc() ... 
Pull misc vfs updates from Christian Brauner:
 "Features:

   - Reduce pipe->mutex contention by pre-allocating pages outside the
     lock in anon_pipe_write().

     anon_pipe_write() called alloc_page() once per page while holding
     pipe->mutex. The allocation can sleep doing direct reclaim and runs
     memcg charging, which extends the critical section and stalls any
     concurrent reader on the same mutex. Now up to 8 pages are
     pre-allocated before the mutex is taken, leftovers are recycled
     into the per-pipe tmp_page[] cache before unlock, and any remainder
     is released after unlock, keeping the allocator out of the critical
     section on both sides. On a writers x readers sweep with 64KB
     writes against a 1 MB pipe throughput improves 6-28% and average
     write latency drops 5-22%; under memory pressure - when the cost of
     holding the mutex across reclaim is highest - throughput improves
     21-48% and latency drops 17-33%. The microbenchmark is added to
     selftests.

   - uaccess/sockptr: fix the ignored_trailing logic in
     copy_struct_to_user() to behave as documented and the usize check
     in copy_struct_from_sockptr() for user pointers, and add
     copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr()
     helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC).

   - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real
     inode backing a dentry via d_real_inode(). On overlayfs the inode
     attached to the dentry doesn't carry the underlying device
     information; this is used by the filesystem restriction BPF program
     that was merged into systemd.

   - docs: add guidelines for submitting new filesystems, motivated by
     the maintenance burden abandoned and untestable filesystems impose
     on VFS developers, blocking infrastructure work like folio
     conversions and iomap migration.

  Fixes:

   - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
     and drop the now-redundant assignments in callers. This began as a
     one-line dma-buf fix for a path_noexec() warning; a pseudo
     filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo()
     callers were audited: the only visible effect is on dma-buf where
     SB_I_NOEXEC silences the warning.

   - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs,
     qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a
     device with a sector size > PAGE_SIZE crashed roughly half of them;
     the rest had the same missing error handling pattern. Plus a
     follow-up releasing the superblock buffer_head when setting the
     minix v3 block size fails.

   - mount: honour SB_NOUSER in the new mount API.

   - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by
     switching the process-group paths of send_sigio() and send_sigurg()
     from read_lock(&tasklist_lock) to RCU, matching the single-PID
     path.

   - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing
     delegated NFS mounts (fsopen() in a container with the mount
     performed by a privileged daemon) that broke when non-init
     s_user_ns was tied to FS_USERNS_MOUNT.

   - selftests/namespaces: fix a hang in nsid_test where an unreaped
     grandchild kept the TAP pipe write-end open, a waitpid(-1) race in
     listns_efault_test, and a false FAIL on kernels without listns()
     where the tests should SKIP.

   - filelock: fix the break_lease() stub signature for
     CONFIG_FILE_LOCKING=n.

   - init/initramfs_test: wait for the async initramfs unpacking before
     running; the test and do_populate_rootfs() share the parser state.

   - fs/coredump: reduce redundant log noise in
     validate_coredump_safety().

   - iomap: pass the correct length to fserror_report_io() in
     __iomap_write_begin().

   - backing-file: fix the backing_file_open() kerneldoc.

  Cleanups:

   - initramfs: refactor the cpio hex header parsing to use hex2bin()
     instead of the hand-rolled simple_strntoul() which is reverted, and
     extend the initramfs KUnit tests to cover header fields with 0x
     prefixes.

   - Replace __get_free_pages() and friends with kmalloc()/kzalloc()
     across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2,
     isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the
     do_mounts init code - part of the larger work of replacing page
     allocator calls with kmalloc().

   - Use clear_and_wake_up_bit() in unlock_buffer() and
     journal_end_buffer_io_sync() instead of open-coding the sequence.

   - Drop unused VFS exports: unexport drop_super_exclusive(), remove
     start_removing_user_path_at(), and fold __start_removing_path()
     into start_removing_path().

   - fs/read_write: narrow the __kernel_write() export with
     EXPORT_SYMBOL_FOR_MODULES().

   - vfs: uapi: retire octal and hex constants in favor of (1 << n) for
     the O_ flags. Finding a free bit for a new flag across the
     architectures was needlessly hard with the mixed bases.

   - dcache: add extra sanity checks of dead dentries in dentry_free()
     via a new DENTRY_WARN_ONCE() that also prints d_flags.

   - iov_iter: use kmemdup_array() in dup_iter() to harden the
     allocation against multiplication overflow.

   - fs/pipe: write to ->poll_usage only once.

   - vfs: remove an always-taken if-branch in find_next_fd().

   - dcache: use kmalloc_flex() for struct external_name in __d_alloc().

   - namei: use QSTR() instead of QSTR_INIT() in path_pts().

   - sync_file_range: delete dead S_ISLNK code.

   - Comment fixes: retire a stale comment in fget_task_next() and fix
     assorted spelling mistakes"

* tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits)
  backing-file: fix backing_file_open() kerneldoc parameter
  iomap: pass the correct len to fserror_report_io in __iomap_write_begin
  vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS
  filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n
  vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags
  bpf: add bpf_real_inode() kfunc
  fs/read_write: Do not export __kernel_write() to the entire world
  libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
  libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
  mount: honour SB_NOUSER in the new mount API
  fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
  selftests/pipe: add pipe_bench microbenchmark
  fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write
  fs: retire stale comment in fget_task_next()
  fs: fix spelling mistakes in comment
  bfs: replace get_zeroed_page() with kzalloc()
  binfmt_misc: replace __get_free_page() with kmalloc()
  configfs: replace __get_free_pages() with kzalloc()
  fs/namespace: use __getname() to allocate mntpath buffer
  fs/select: replace __get_free_page() with kmalloc()
  ...
vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags 2026-06-06T13:34:03+00:00 Jori Koolstra jkoolstra@xs4all.nl 2026-06-04T22:24:05+00:00 0da79c259ad0554b36761a7135d4f92eb7c46263 A recent build failure[1] exposed the diffculty of working with the current octal and hex definitions of O_ flags when trying to find a gap for a new flag. This difficulty is compounded by the fact that O_ flags may have architectural specific values. Replace the hex/octal #defines, which are hard to parse when looking for free bits, with explicit bit shifts like (1 << 11). Also, add comments that identify which architectures redefine some of the seemingly free ("cursed") bits in uapi/asm-generic/fcntl.h. These should not be used to define new O_ flags (for now, at least). The translastion was done with Claude Opus 4.8, and verified with a (non-AI) gawk script. The accounting of which architectures claim which bit-gaps in uapi/asm-generic/fcntl.h is also done by hand. [1]: https://lore.kernel.org/all/agruPPybCx8q2XcJ@sirena.org.uk/ Assisted-by: Claude:Opus 4.8 Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl> Link: https://patch.msgid.link/20260604222405.5382-1-jkoolstra@xs4all.nl Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
A recent build failure[1] exposed the diffculty of working with the
current octal and hex definitions of O_ flags when trying to find a gap
for a new flag. This difficulty is compounded by the fact that O_ flags
may have architectural specific values.

Replace the hex/octal #defines, which are hard to parse when looking for
free bits, with explicit bit shifts like (1 << 11). Also, add comments
that identify which architectures redefine some of the seemingly free
("cursed") bits in uapi/asm-generic/fcntl.h. These should not be used to
define new O_ flags (for now, at least).

The translastion was done with Claude Opus 4.8, and verified with a
(non-AI) gawk script. The accounting of which architectures claim
which bit-gaps in uapi/asm-generic/fcntl.h is also done by hand.

[1]: https://lore.kernel.org/all/agruPPybCx8q2XcJ@sirena.org.uk/

Assisted-by: Claude:Opus 4.8
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260604222405.5382-1-jkoolstra@xs4all.nl
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
openat2: introduce EFTYPE error code 2026-05-21T08:53:41+00:00 Dorjoy Chowdhury dorjoychy111@gmail.com 2026-03-28T17:22:22+00:00 cf1b04aaef8b83f668fac10bfc4d4d76ba6e6fa1 Introduce a new error code EFTYPE for wrong file type operations. EFTYPE is already used in BSD systems like FreeBSD and macOS. This will be used by the upcoming OPENAT2_REGULAR flag support to return a specific error when a path doesn't refer to a regular file. Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com> Link: https://patch.msgid.link/20260328172314.45807-2-dorjoychy111@gmail.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Aleksa Sarai <aleksa@amutable.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
Introduce a new error code EFTYPE for wrong file type operations.
EFTYPE is already used in BSD systems like FreeBSD and macOS.

This will be used by the upcoming OPENAT2_REGULAR flag support to
return a specific error when a path doesn't refer to a regular file.

Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Link: https://patch.msgid.link/20260328172314.45807-2-dorjoychy111@gmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
uapi: promote EFSCORRUPTED and EUCLEAN to errno.h 2026-01-13T08:58:01+00:00 Darrick J. Wong djwong@kernel.org 2026-01-13T00:31:09+00:00 602544773763da411ffa67567fa1d146f3a40231 Stop definining these privately and instead move them to the uapi errno.h so that they become canonical instead of copy pasta. Cc: linux-api@vger.kernel.org Signed-off-by: Darrick J. Wong <djwong@kernel.org> Link: https://patch.msgid.link/176826402587.3490369.17659117524205214600.stgit@frogsfrogsfrogs Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> 
Stop definining these privately and instead move them to the uapi
errno.h so that they become canonical instead of copy pasta.

Cc: linux-api@vger.kernel.org
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://patch.msgid.link/176826402587.3490369.17659117524205214600.stgit@frogsfrogsfrogs
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
alpha: don't reference obsolete termio struct for TC* constants 2025-12-08T22:10:54+00:00 Sam James sam@gentoo.org 2025-12-05T08:14:57+00:00 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 <sam@gentoo.org> Reviewed-by: Magnus Lindholm <linmag7@gmail.com> Link: https://lore.kernel.org/r/6ebd3451908785cad53b50ca6bc46cfe9d6bc03c.1764922497.git.sam@gentoo.org Signed-off-by: Magnus Lindholm <linmag7@gmail.com> 
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 <sam@gentoo.org>
Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
Link: https://lore.kernel.org/r/6ebd3451908785cad53b50ca6bc46cfe9d6bc03c.1764922497.git.sam@gentoo.org
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
Merge tag 'net-next-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2025-07-30T15:58:55+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-07-30T15:58:55+00:00 8be4d31cb8aaeea27bde4b7ddb26e28a89062ebf Pull networking updates from Jakub Kicinski: "Core & protocols: - Wrap datapath globals into net_aligned_data, to avoid false sharing - Preserve MSG_ZEROCOPY in forwarding (e.g. out of a container) - Add SO_INQ and SCM_INQ support to AF_UNIX - Add SIOCINQ support to AF_VSOCK - Add TCP_MAXSEG sockopt to MPTCP - Add IPv6 force_forwarding sysctl to enable forwarding per interface - Make TCP validation of whether packet fully fits in the receive window and the rcv_buf more strict. With increased use of HW aggregation a single "packet" can be multiple 100s of kB - Add MSG_MORE flag to optimize large TCP transmissions via sockmap, improves latency up to 33% for sockmap users - Convert TCP send queue handling from tasklet to BH workque - Improve BPF iteration over TCP sockets to see each socket exactly once - Remove obsolete and unused TCP RFC3517/RFC6675 loss recovery code - Support enabling kernel threads for NAPI processing on per-NAPI instance basis rather than a whole device. Fully stop the kernel NAPI thread when threaded NAPI gets disabled. Previously thread would stick around until ifdown due to tricky synchronization - Allow multicast routing to take effect on locally-generated packets - Add output interface argument for End.X in segment routing - MCTP: add support for gateway routing, improve bind() handling - Don't require rtnl_lock when fetching an IPv6 neighbor over Netlink - Add a new neighbor flag ("extern_valid"), which cedes refresh responsibilities to userspace. This is needed for EVPN multi-homing where a neighbor entry for a multi-homed host needs to be synced across all the VTEPs among which the host is multi-homed - Support NUD_PERMANENT for proxy neighbor entries - Add a new queuing discipline for IETF RFC9332 DualQ Coupled AQM - Add sequence numbers to netconsole messages. Unregister netconsole's console when all net targets are removed. Code refactoring. Add a number of selftests - Align IPSec inbound SA lookup to RFC 4301. Only SPI and protocol should be used for an inbound SA lookup - Support inspecting ref_tracker state via DebugFS - Don't force bonding advertisement frames tx to ~333 ms boundaries. Add broadcast_neighbor option to send ARP/ND on all bonded links - Allow providing upcall pid for the 'execute' command in openvswitch - Remove DCCP support from Netfilter's conntrack - Disallow multiple packet duplications in the queuing layer - Prevent use of deprecated iptables code on PREEMPT_RT Driver API: - Support RSS and hashing configuration over ethtool Netlink - Add dedicated ethtool callbacks for getting and setting hashing fields - Add support for power budget evaluation strategy in PSE / Power-over-Ethernet. Generate Netlink events for overcurrent etc - Support DPLL phase offset monitoring across all device inputs. Support providing clock reference and SYNC over separate DPLL inputs - Support traffic classes in devlink rate API for bandwidth management - Remove rtnl_lock dependency from UDP tunnel port configuration Device drivers: - Add a new Broadcom driver for 800G Ethernet (bnge) - Add a standalone driver for Microchip ZL3073x DPLL - Remove IBM's NETIUCV device driver - Ethernet high-speed NICs: - Broadcom (bnxt): - support zero-copy Tx of DMABUF memory - take page size into account for page pool recycling rings - Intel (100G, ice, idpf): - idpf: XDP and AF_XDP support preparations - idpf: add flow steering - add link_down_events statistic - clean up the TSPLL code - preparations for live VM migration - nVidia/Mellanox: - support zero-copy Rx/Tx interfaces (DMABUF and io_uring) - optimize context memory usage for matchers - expose serial numbers in devlink info - support PCIe congestion metrics - Meta (fbnic): - add 25G, 50G, and 100G link modes to phylink - support dumping FW logs - Marvell/Cavium: - support for CN20K generation of the Octeon chips - Amazon: - add HW clock (without timestamping, just hypervisor time access) - Ethernet virtual: - VirtIO net: - support segmentation of UDP-tunnel-encapsulated packets - Google (gve): - support packet timestamping and clock synchronization - Microsoft vNIC: - add handler for device-originated servicing events - allow dynamic MSI-X vector allocation - support Tx bandwidth clamping - Ethernet NICs consumer, and embedded: - AMD: - amd-xgbe: hardware timestamping and PTP clock support - Broadcom integrated MACs (bcmgenet, bcmasp): - use napi_complete_done() return value to support NAPI polling - add support for re-starting auto-negotiation - Broadcom switches (b53): - support BCM5325 switches - add bcm63xx EPHY power control - Synopsys (stmmac): - lots of code refactoring and cleanups - TI: - icssg-prueth: read firmware-names from device tree - icssg: PRP offload support - Microchip: - lan78xx: convert to PHYLINK for improved PHY and MAC management - ksz: add KSZ8463 switch support - Intel: - support similar queue priority scheme in multi-queue and time-sensitive networking (taprio) - support packet pre-emption in both - RealTek (r8169): - enable EEE at 5Gbps on RTL8126 - Airoha: - add PPPoE offload support - MDIO bus controller for Airoha AN7583 - Ethernet PHYs: - support for the IPQ5018 internal GE PHY - micrel KSZ9477 switch-integrated PHYs: - add MDI/MDI-X control support - add RX error counters - add cable test support - add Signal Quality Indicator (SQI) reporting - dp83tg720: improve reset handling and reduce link recovery time - support bcm54811 (and its MII-Lite interface type) - air_en8811h: support resume/suspend - support PHY counters for QCA807x and QCA808x - support WoL for QCA807x - CAN drivers: - rcar_canfd: support for Transceiver Delay Compensation - kvaser: report FW versions via devlink dev info - WiFi: - extended regulatory info support (6 GHz) - add statistics and beacon monitor for Multi-Link Operation (MLO) - support S1G aggregation, improve S1G support - add Radio Measurement action fields - support per-radio RTS threshold - some work around how FIPS affects wifi, which was wrong (RC4 is used by TKIP, not only WEP) - improvements for unsolicited probe response handling - WiFi drivers: - RealTek (rtw88): - IBSS mode for SDIO devices - RealTek (rtw89): - BT coexistence for MLO/WiFi7 - concurrent station + P2P support - support for USB devices RTL8851BU/RTL8852BU - Intel (iwlwifi): - use embedded PNVM in (to be released) FW images to fix compatibility issues - many cleanups (unused FW APIs, PCIe code, WoWLAN) - some FIPS interoperability - MediaTek (mt76): - firmware recovery improvements - more MLO work - Qualcomm/Atheros (ath12k): - fix scan on multi-radio devices - more EHT/Wi-Fi 7 features - encapsulation/decapsulation offload - Broadcom (brcm80211): - support SDIO 43751 device - Bluetooth: - hci_event: add support for handling LE BIG Sync Lost event - ISO: add socket option to report packet seqnum via CMSG - ISO: support SCM_TIMESTAMPING for ISO TS - Bluetooth drivers: - intel_pcie: support Function Level Reset - nxpuart: add support for 4M baudrate - nxpuart: implement powerup sequence, reset, FW dump, and FW loading" * tag 'net-next-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1742 commits) dpll: zl3073x: Fix build failure selftests: bpf: fix legacy netfilter options ipv6: annotate data-races around rt->fib6_nsiblings ipv6: fix possible infinite loop in fib6_info_uses_dev() ipv6: prevent infinite loop in rt6_nlmsg_size() ipv6: add a retry logic in net6_rt_notify() vrf: Drop existing dst reference in vrf_ip6_input_dst net/sched: taprio: align entry index attr validation with mqprio net: fsl_pq_mdio: use dev_err_probe selftests: rtnetlink.sh: remove esp4_offload after test vsock: remove unnecessary null check in vsock_getname() igb: xsk: solve negative overflow of nb_pkts in zerocopy mode stmmac: xsk: fix negative overflow of budget in zerocopy mode dt-bindings: ieee802154: Convert at86rf230.txt yaml format net: dsa: microchip: Disable PTP function of KSZ8463 net: dsa: microchip: Setup fiber ports for KSZ8463 net: dsa: microchip: Write switch MAC address differently for KSZ8463 net: dsa: microchip: Use different registers for KSZ8463 net: dsa: microchip: Add KSZ8463 switch support to KSZ DSA driver dt-bindings: net: dsa: microchip: Add KSZ8463 switch support ... 
Pull networking updates from Jakub Kicinski:
 "Core & protocols:

   - Wrap datapath globals into net_aligned_data, to avoid false sharing

   - Preserve MSG_ZEROCOPY in forwarding (e.g. out of a container)

   - Add SO_INQ and SCM_INQ support to AF_UNIX

   - Add SIOCINQ support to AF_VSOCK

   - Add TCP_MAXSEG sockopt to MPTCP

   - Add IPv6 force_forwarding sysctl to enable forwarding per interface

   - Make TCP validation of whether packet fully fits in the receive
     window and the rcv_buf more strict. With increased use of HW
     aggregation a single "packet" can be multiple 100s of kB

   - Add MSG_MORE flag to optimize large TCP transmissions via sockmap,
     improves latency up to 33% for sockmap users

   - Convert TCP send queue handling from tasklet to BH workque

   - Improve BPF iteration over TCP sockets to see each socket exactly
     once

   - Remove obsolete and unused TCP RFC3517/RFC6675 loss recovery code

   - Support enabling kernel threads for NAPI processing on per-NAPI
     instance basis rather than a whole device. Fully stop the kernel
     NAPI thread when threaded NAPI gets disabled. Previously thread
     would stick around until ifdown due to tricky synchronization

   - Allow multicast routing to take effect on locally-generated packets

   - Add output interface argument for End.X in segment routing

   - MCTP: add support for gateway routing, improve bind() handling

   - Don't require rtnl_lock when fetching an IPv6 neighbor over Netlink

   - Add a new neighbor flag ("extern_valid"), which cedes refresh
     responsibilities to userspace. This is needed for EVPN multi-homing
     where a neighbor entry for a multi-homed host needs to be synced
     across all the VTEPs among which the host is multi-homed

   - Support NUD_PERMANENT for proxy neighbor entries

   - Add a new queuing discipline for IETF RFC9332 DualQ Coupled AQM

   - Add sequence numbers to netconsole messages. Unregister
     netconsole's console when all net targets are removed. Code
     refactoring. Add a number of selftests

   - Align IPSec inbound SA lookup to RFC 4301. Only SPI and protocol
     should be used for an inbound SA lookup

   - Support inspecting ref_tracker state via DebugFS

   - Don't force bonding advertisement frames tx to ~333 ms boundaries.
     Add broadcast_neighbor option to send ARP/ND on all bonded links

   - Allow providing upcall pid for the 'execute' command in openvswitch

   - Remove DCCP support from Netfilter's conntrack

   - Disallow multiple packet duplications in the queuing layer

   - Prevent use of deprecated iptables code on PREEMPT_RT

  Driver API:

   - Support RSS and hashing configuration over ethtool Netlink

   - Add dedicated ethtool callbacks for getting and setting hashing
     fields

   - Add support for power budget evaluation strategy in PSE /
     Power-over-Ethernet. Generate Netlink events for overcurrent etc

   - Support DPLL phase offset monitoring across all device inputs.
     Support providing clock reference and SYNC over separate DPLL
     inputs

   - Support traffic classes in devlink rate API for bandwidth
     management

   - Remove rtnl_lock dependency from UDP tunnel port configuration

  Device drivers:

   - Add a new Broadcom driver for 800G Ethernet (bnge)

   - Add a standalone driver for Microchip ZL3073x DPLL

   - Remove IBM's NETIUCV device driver

   - Ethernet high-speed NICs:
      - Broadcom (bnxt):
         - support zero-copy Tx of DMABUF memory
         - take page size into account for page pool recycling rings
      - Intel (100G, ice, idpf):
         - idpf: XDP and AF_XDP support preparations
         - idpf: add flow steering
         - add link_down_events statistic
         - clean up the TSPLL code
         - preparations for live VM migration
      - nVidia/Mellanox:
         - support zero-copy Rx/Tx interfaces (DMABUF and io_uring)
         - optimize context memory usage for matchers
         - expose serial numbers in devlink info
         - support PCIe congestion metrics
      - Meta (fbnic):
         - add 25G, 50G, and 100G link modes to phylink
         - support dumping FW logs
      - Marvell/Cavium:
         - support for CN20K generation of the Octeon chips
      - Amazon:
         - add HW clock (without timestamping, just hypervisor time access)

   - Ethernet virtual:
      - VirtIO net:
         - support segmentation of UDP-tunnel-encapsulated packets
      - Google (gve):
         - support packet timestamping and clock synchronization
      - Microsoft vNIC:
         - add handler for device-originated servicing events
         - allow dynamic MSI-X vector allocation
         - support Tx bandwidth clamping

   - Ethernet NICs consumer, and embedded:
      - AMD:
         - amd-xgbe: hardware timestamping and PTP clock support
      - Broadcom integrated MACs (bcmgenet, bcmasp):
         - use napi_complete_done() return value to support NAPI polling
         - add support for re-starting auto-negotiation
      - Broadcom switches (b53):
         - support BCM5325 switches
         - add bcm63xx EPHY power control
      - Synopsys (stmmac):
         - lots of code refactoring and cleanups
      - TI:
         - icssg-prueth: read firmware-names from device tree
         - icssg: PRP offload support
      - Microchip:
         - lan78xx: convert to PHYLINK for improved PHY and MAC management
         - ksz: add KSZ8463 switch support
      - Intel:
         - support similar queue priority scheme in multi-queue and
           time-sensitive networking (taprio)
         - support packet pre-emption in both
      - RealTek (r8169):
         - enable EEE at 5Gbps on RTL8126
      - Airoha:
         - add PPPoE offload support
         - MDIO bus controller for Airoha AN7583

   - Ethernet PHYs:
      - support for the IPQ5018 internal GE PHY
      - micrel KSZ9477 switch-integrated PHYs:
         - add MDI/MDI-X control support
         - add RX error counters
         - add cable test support
         - add Signal Quality Indicator (SQI) reporting
      - dp83tg720: improve reset handling and reduce link recovery time
      - support bcm54811 (and its MII-Lite interface type)
      - air_en8811h: support resume/suspend
      - support PHY counters for QCA807x and QCA808x
      - support WoL for QCA807x

   - CAN drivers:
      - rcar_canfd: support for Transceiver Delay Compensation
      - kvaser: report FW versions via devlink dev info

   - WiFi:
      - extended regulatory info support (6 GHz)
      - add statistics and beacon monitor for Multi-Link Operation (MLO)
      - support S1G aggregation, improve S1G support
      - add Radio Measurement action fields
      - support per-radio RTS threshold
      - some work around how FIPS affects wifi, which was wrong (RC4 is
        used by TKIP, not only WEP)
      - improvements for unsolicited probe response handling

   - WiFi drivers:
      - RealTek (rtw88):
         - IBSS mode for SDIO devices
      - RealTek (rtw89):
         - BT coexistence for MLO/WiFi7
         - concurrent station + P2P support
         - support for USB devices RTL8851BU/RTL8852BU
      - Intel (iwlwifi):
         - use embedded PNVM in (to be released) FW images to fix
           compatibility issues
         - many cleanups (unused FW APIs, PCIe code, WoWLAN)
         - some FIPS interoperability
      - MediaTek (mt76):
         - firmware recovery improvements
         - more MLO work
      - Qualcomm/Atheros (ath12k):
         - fix scan on multi-radio devices
         - more EHT/Wi-Fi 7 features
         - encapsulation/decapsulation offload
      - Broadcom (brcm80211):
         - support SDIO 43751 device

   - Bluetooth:
      - hci_event: add support for handling LE BIG Sync Lost event
      - ISO: add socket option to report packet seqnum via CMSG
      - ISO: support SCM_TIMESTAMPING for ISO TS

   - Bluetooth drivers:
      - intel_pcie: support Function Level Reset
      - nxpuart: add support for 4M baudrate
      - nxpuart: implement powerup sequence, reset, FW dump, and FW loading"

* tag 'net-next-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1742 commits)
  dpll: zl3073x: Fix build failure
  selftests: bpf: fix legacy netfilter options
  ipv6: annotate data-races around rt->fib6_nsiblings
  ipv6: fix possible infinite loop in fib6_info_uses_dev()
  ipv6: prevent infinite loop in rt6_nlmsg_size()
  ipv6: add a retry logic in net6_rt_notify()
  vrf: Drop existing dst reference in vrf_ip6_input_dst
  net/sched: taprio: align entry index attr validation with mqprio
  net: fsl_pq_mdio: use dev_err_probe
  selftests: rtnetlink.sh: remove esp4_offload after test
  vsock: remove unnecessary null check in vsock_getname()
  igb: xsk: solve negative overflow of nb_pkts in zerocopy mode
  stmmac: xsk: fix negative overflow of budget in zerocopy mode
  dt-bindings: ieee802154: Convert at86rf230.txt yaml format
  net: dsa: microchip: Disable PTP function of KSZ8463
  net: dsa: microchip: Setup fiber ports for KSZ8463
  net: dsa: microchip: Write switch MAC address differently for KSZ8463
  net: dsa: microchip: Use different registers for KSZ8463
  net: dsa: microchip: Add KSZ8463 switch support to KSZ DSA driver
  dt-bindings: net: dsa: microchip: Add KSZ8463 switch support
  ...
af_unix: Introduce SO_INQ. 2025-07-09T01:05:25+00:00 Kuniyuki Iwashima kuniyu@google.com 2025-07-02T22:35:18+00:00 df30285b3670bf52e1e5512e4d4482bec5e93c16 We have an application that uses almost the same code for TCP and AF_UNIX (SOCK_STREAM). TCP can use TCP_INQ, but AF_UNIX doesn't have it and requires an extra syscall, ioctl(SIOCINQ) or getsockopt(SO_MEMINFO) as an alternative. Let's introduce the generic version of TCP_INQ. If SO_INQ is enabled, recvmsg() will put a cmsg of SCM_INQ that contains the exact value of ioctl(SIOCINQ). The cmsg is also included when msg->msg_get_inq is non-zero to make sockets io_uring-friendly. Note that SOCK_CUSTOM_SOCKOPT is flagged only for SOCK_STREAM to override setsockopt() for SOL_SOCKET. By having the flag in struct unix_sock, instead of struct sock, we can later add SO_INQ support for TCP and reuse tcp_sk(sk)->recvmsg_inq. Note also that supporting custom getsockopt() for SOL_SOCKET will need preparation for other SOCK_CUSTOM_SOCKOPT users (UDP, vsock, MPTCP). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250702223606.1054680-7-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
We have an application that uses almost the same code for TCP and
AF_UNIX (SOCK_STREAM).

TCP can use TCP_INQ, but AF_UNIX doesn't have it and requires an
extra syscall, ioctl(SIOCINQ) or getsockopt(SO_MEMINFO) as an
alternative.

Let's introduce the generic version of TCP_INQ.

If SO_INQ is enabled, recvmsg() will put a cmsg of SCM_INQ that
contains the exact value of ioctl(SIOCINQ).  The cmsg is also
included when msg->msg_get_inq is non-zero to make sockets
io_uring-friendly.

Note that SOCK_CUSTOM_SOCKOPT is flagged only for SOCK_STREAM to
override setsockopt() for SOL_SOCKET.

By having the flag in struct unix_sock, instead of struct sock, we
can later add SO_INQ support for TCP and reuse tcp_sk(sk)->recvmsg_inq.

Note also that supporting custom getsockopt() for SOL_SOCKET will need
preparation for other SOCK_CUSTOM_SOCKOPT users (UDP, vsock, MPTCP).

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250702223606.1054680-7-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
alpha: regularize the situation with asm/param.h 2025-06-25T02:02:05+00:00 Al Viro viro@zeniv.linux.org.uk 2024-12-02T00:28:34+00:00 f65bbf05392b44714ccdcc4b5b1bebfd471d2665 The only reason why alpha can't do what sparc et.al. are doing is that include/asm-generic/param.h relies upon the value of HZ set for userland header in uapi/asm/param.h being 100. We need that value to define USER_HZ and we need that definition to outlive the redefinition of HZ kernel-side. And alpha needs it to be 1024, not 100 like everybody else. So let's add __USER_HZ to uapi/asm-generic/param.h, defaulting to 100 and used to define HZ. That way include/asm-generic/param.h can use that thing instead of open-coding it - it won't be affected by undefining and redefining HZ. That done, alpha asm/param.h can be removed and uapi/asm/param.h switched to defining __USER_HZ and EXEC_PAGESIZE and then including <asm-generic/param.h> - asm/param.h will resolve to uapi/asm/param.h, which pulls <asm-generic/param.h>, which will do the right thing both in the kernel and userland contexts. Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
The only reason why alpha can't do what sparc et.al. are doing
is that include/asm-generic/param.h relies upon the value of HZ
set for userland header in uapi/asm/param.h being 100.

We need that value to define USER_HZ and we need that definition
to outlive the redefinition of HZ kernel-side.  And alpha needs
it to be 1024, not 100 like everybody else.

So let's add __USER_HZ to uapi/asm-generic/param.h, defaulting to
100 and used to define HZ.  That way include/asm-generic/param.h
can use that thing instead of open-coding it - it won't be affected
by undefining and redefining HZ.

That done, alpha asm/param.h can be removed and uapi/asm/param.h
switched to defining __USER_HZ and EXEC_PAGESIZE and then including
<asm-generic/param.h> - asm/param.h will resolve to uapi/asm/param.h,
which pulls <asm-generic/param.h>, which will do the right thing
both in the kernel and userland contexts.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
af_unix: Introduce SO_PASSRIGHTS. 2025-05-23T09:24:18+00:00 Kuniyuki Iwashima kuniyu@amazon.com 2025-05-19T20:57:59+00:00 77cbe1a6d8730a07f99f9263c2d5f2304cf5e830 As long as recvmsg() or recvmmsg() is used with cmsg, it is not possible to avoid receiving file descriptors via SCM_RIGHTS. This behaviour has occasionally been flagged as problematic, as it can be (ab)used to trigger DoS during close(), for example, by passing a FUSE-controlled fd or a hung NFS fd. For instance, as noted on the uAPI Group page [0], an untrusted peer could send a file descriptor pointing to a hung NFS mount and then close it. Once the receiver calls recvmsg() with msg_control, the descriptor is automatically installed, and then the responsibility for the final close() now falls on the receiver, which may result in blocking the process for a long time. Regarding this, systemd calls cmsg_close_all() [1] after each recvmsg() to close() unwanted file descriptors sent via SCM_RIGHTS. However, this cannot work around the issue at all, because the final fput() may still occur on the receiver's side once sendmsg() with SCM_RIGHTS succeeds. Also, even filtering by LSM at recvmsg() does not work for the same reason. Thus, we need a better way to refuse SCM_RIGHTS at sendmsg(). Let's introduce SO_PASSRIGHTS to disable SCM_RIGHTS. Note that this option is enabled by default for backward compatibility. Link: https://uapi-group.org/kernel-features/#disabling-reception-of-scm_rights-for-af_unix-sockets #[0] Link: https://github.com/systemd/systemd/blob/v257.5/src/basic/fd-util.c#L612-L628 #[1] Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
As long as recvmsg() or recvmmsg() is used with cmsg, it is not
possible to avoid receiving file descriptors via SCM_RIGHTS.

This behaviour has occasionally been flagged as problematic, as
it can be (ab)used to trigger DoS during close(), for example, by
passing a FUSE-controlled fd or a hung NFS fd.

For instance, as noted on the uAPI Group page [0], an untrusted peer
could send a file descriptor pointing to a hung NFS mount and then
close it.  Once the receiver calls recvmsg() with msg_control, the
descriptor is automatically installed, and then the responsibility
for the final close() now falls on the receiver, which may result
in blocking the process for a long time.

Regarding this, systemd calls cmsg_close_all() [1] after each
recvmsg() to close() unwanted file descriptors sent via SCM_RIGHTS.

However, this cannot work around the issue at all, because the final
fput() may still occur on the receiver's side once sendmsg() with
SCM_RIGHTS succeeds.  Also, even filtering by LSM at recvmsg() does
not work for the same reason.

Thus, we need a better way to refuse SCM_RIGHTS at sendmsg().

Let's introduce SO_PASSRIGHTS to disable SCM_RIGHTS.

Note that this option is enabled by default for backward
compatibility.

Link: https://uapi-group.org/kernel-features/#disabling-reception-of-scm_rights-for-af_unix-sockets #[0]
Link: https://github.com/systemd/systemd/blob/v257.5/src/basic/fd-util.c#L612-L628 #[1]
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
alpha: make stack 16-byte aligned (most cases) 2025-02-14T19:05:47+00:00 Ivan Kokshaysky ink@unseen.parts 2025-02-04T22:35:23+00:00 0a0f7362b0367634a2d5cb7c96226afc116f19c9 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 <macro@orcam.me.uk> Tested-by: Magnus Lindholm <linmag7@gmail.com> Tested-by: Matt Turner <mattst88@gmail.com> Reviewed-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Ivan Kokshaysky <ink@unseen.parts> Signed-off-by: Matt Turner <mattst88@gmail.com> 
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 <macro@orcam.me.uk>
Tested-by: Magnus Lindholm <linmag7@gmail.com>
Tested-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Ivan Kokshaysky <ink@unseen.parts>
Signed-off-by: Matt Turner <mattst88@gmail.com>