[PATCH v6 00/14] sparc64: vdso: Switch to the generic vDSO library

[Nathaniel Roach]

No (new) issues seen on SPARC T5-2.

On 4/3/26 15:48, Thomas Weißschuh wrote:
> The generic vDSO provides a lot common functionality shared between
> different architectures. SPARC is the last architecture not using it,
> preventing some necessary code cleanup.
>
> Make use of the generic infrastructure.
>
> Follow-up to and replacement for Arnd's SPARC vDSO removal patches:
> https://lore.kernel.org/lkml/20250707144726.4008707-1-arnd@kernel.org/
>
> SPARC64 can not map .bss into userspace, so the vDSO datapages are
> switched over to be allocated dynamically.
>
> Tested on a Niagara T4 and QEMU.
>
> This has emantic conflicts with
> * "vdso: Reject absolute relocations during build" [0]
> * "vDSO: Respect COMPAT_32BIT_TIME" [1]
>
> But I expect both other serieses to need more discussions.
>
> [0] https://lore.kernel.org/lkml/20250812-vdso-absolute-reloc-v4-0-61a8b615e5ec@linutronix.de/
> [1] https://lore.kernel.org/lkml/20260227-vdso-compat_32bit_time-v1-0-3f0286a7bac3@linutronix.de/
>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
Tested-by: Nathaniel Roach <nroach44 at nroach44.id.au> # SPARC T5-2
> ---
> Changes in v6:
> - Provide statically allocated during early boot to avoid canges to the rng core
> - Use non-compound data pages
> - Reword commit messages
> - Rebase on v7.0-rc1
> - Link to v5: https://lore.kernel.org/r/20251106-vdso-sparc64-generic-2-v5-0-97ff2b6542f7@linutronix.de
>
> Changes in v5:
> - Merge the patches for 'struct page' mapping and dynamic allocation
> - Zero out newly-allocated data pages
> - Pick up review tags
> - Link to v4: https://lore.kernel.org/r/20251014-vdso-sparc64-generic-2-v4-0-e0607bf49dea@linutronix.de
>
> Changes in v4:
> - Rebase on v6.18-rc1.
> - Keep inclusion of asm/clocksource.h from linux/clocksource.h
> - Reword description of "s390/time: Set up vDSO datapage later"
> - Link to v3: https://lore.kernel.org/r/20250917-vdso-sparc64-generic-2-v3-0-3679b1bc8ee8@linutronix.de
>
> Changes in v3:
> - Allocate vDSO data pages dynamically (and lots of preparations for that)
> - Drop clock_getres()
> - Fix 32bit clock_gettime() syscall fallback
> - Link to v2: https://lore.kernel.org/r/20250815-vdso-sparc64-generic-2-v2-0-b5ff80672347@linutronix.de
>
> Changes in v2:
> - Rebase on v6.17-rc1
> - Drop RFC state
> - Fix typo in commit message
> - Drop duplicate 'select GENERIC_TIME_VSYSCALL'
> - Merge "sparc64: time: Remove architecture-specific clocksource data" into the
>    main conversion patch. It violated the check in __clocksource_register_scale()
> - Link to v1: https://lore.kernel.org/r/20250724-vdso-sparc64-generic-2-v1-0-e376a3bd24d1@linutronix.de
>
> ---
> Arnd Bergmann (1):
>        clocksource: remove ARCH_CLOCKSOURCE_DATA
>
> Thomas Weißschuh (13):
>        vdso/datastore: Reduce scope of some variables in vvar_fault()
>        vdso/datastore: Drop inclusion of linux/mmap_lock.h
>        vdso/datastore: Allocate data pages dynamically
>        sparc64: vdso: Link with -z noexecstack
>        sparc64: vdso: Remove obsolete "fake section table" reservation
>        sparc64: vdso: Replace code patching with runtime conditional
>        sparc64: vdso: Move hardware counter read into header
>        sparc64: vdso: Move syscall fallbacks into header
>        sparc64: vdso: Introduce vdso/processor.h
>        sparc64: vdso: Switch to the generic vDSO library
>        sparc64: vdso2c: Drop sym_vvar_start handling
>        sparc64: vdso2c: Remove symbol handling
>        sparc64: vdso: Implement clock_gettime64()
>
>   arch/sparc/Kconfig                         |   3 +-
>   arch/sparc/include/asm/clocksource.h       |   9 -
>   arch/sparc/include/asm/processor.h         |   3 +
>   arch/sparc/include/asm/processor_32.h      |   2 -
>   arch/sparc/include/asm/processor_64.h      |  25 --
>   arch/sparc/include/asm/vdso.h              |   2 -
>   arch/sparc/include/asm/vdso/clocksource.h  |  10 +
>   arch/sparc/include/asm/vdso/gettimeofday.h | 184 ++++++++++++++
>   arch/sparc/include/asm/vdso/processor.h    |  41 ++++
>   arch/sparc/include/asm/vdso/vsyscall.h     |  10 +
>   arch/sparc/include/asm/vvar.h              |  75 ------
>   arch/sparc/kernel/Makefile                 |   1 -
>   arch/sparc/kernel/time_64.c                |   6 +-
>   arch/sparc/kernel/vdso.c                   |  69 ------
>   arch/sparc/vdso/Makefile                   |   8 +-
>   arch/sparc/vdso/vclock_gettime.c           | 380 ++---------------------------
>   arch/sparc/vdso/vdso-layout.lds.S          |  26 +-
>   arch/sparc/vdso/vdso.lds.S                 |   2 -
>   arch/sparc/vdso/vdso2c.c                   |  24 --
>   arch/sparc/vdso/vdso2c.h                   |  45 +---
>   arch/sparc/vdso/vdso32/vdso32.lds.S        |   4 +-
>   arch/sparc/vdso/vma.c                      | 274 ++-------------------
>   include/linux/clocksource.h                |   6 +-
>   include/linux/vdso_datastore.h             |   6 +
>   init/main.c                                |   2 +
>   kernel/time/Kconfig                        |   4 -
>   lib/vdso/datastore.c                       |  97 +++++---
>   27 files changed, 375 insertions(+), 943 deletions(-)
> ---
> base-commit: f02e02079ac56b44ff89d4c2189cf7185ab794f3
> change-id: 20250722-vdso-sparc64-generic-2-25f2e058e92c
>
> Best regards,