Re: [PATCH v5 0/6] sparc32: replace sp_banks with memblock

[Andreas Larsson]

On 2026-10-07 19:41, Magnus Lindholm wrote:
> Replace the sparc32-private sp_banks memory description with memblock.
> 
> The first two patches convert the SRMMU consumers that already run after
> bootmem_init() has populated memblock. The third patch moves memblock
> population to prom_meminit() and applies the mem= limit there. Patch 4
> removes an unused address bitmap before patch 5 moves the early memory
> setup into setup_32.c. Patch 6 removes the now-unused sp_banks array.
> 
> This work is based on an earlier eight-patch series by Sam Ravnborg.
> Patch 2 directly carries over Sam's memblock sizing conversion. The series
> has otherwise been substantially reorganized and reworked for the current
> kernel. It retains the sparc32 mem= command-line option by using
> memblock_enforce_memory_limit() and uses memblock's exclusive range-end
> semantics throughout.
> 
> The series applies on top of Andreas Larsson's for-next branch at
> 22a749706e3b (sparc64: decide the TSB huge-page window fixup before the
> bank switch), which includes the sparc32 relocation and Viking fixes.
> setup_memory() preserves the sun4m/sun4d PAGE_OFFSET probe and diagnostics
> from that branch, removing RAM below the mapped physical address using
> memblock instead of trimming sp_banks.
> 
> Link: https://lore.kernel.org/sparclinux/20260816075141.3489194-1-linmag7@xxxxxxxxx/T/#t
> 
> The v1 series was boot tested on a Sun SPARCstation 20 with dual
> SuperSPARC-II CPUs (SM71).
> The v2 series was boot tested on a Sun SPARCstation 20 with dual
> ROSS HyperSPARC (RT626) CPUs.
> The v3 series was cross-compiled with the SPARCstation 20 and LEON
> configurations as well as boot tested on a Sun SPARCstation 20
> with dual ROSS HyperSPARC (RT626) CPUs.
> The v4 series was cross-compiled with the SPARCstation 20 SMP configuration
> and a sparc32_defconfig-derived LEON configuration, both with HIGHMEM
> enabled. Boot tested on a SPARCstation 20 SMP (ROSS).
> The v5 series was cross-compiled with the SPARCstation 20 SMP and LEON
> configurations, both with HIGHMEM enabled. Boot tested on a SPARCstation 20
> SMP (ROSS).
> 
> Changes in v5:
> - Rebase onto Andreas Larsson's for-next branch, resolving the patch 5
>   conflict and preserving the updated phys_base handling, including the
>   sun4m/sun4d probe restriction and diagnostics, from the relocation fixes.
> - Retain Sam's Reviewed-by tags on all six patches.
> 
> Changes in v4:
> - Use max_pfn in LEON's _pfn_valid() check, preserving the bounds of
>   last_valid_pfn instead of restricting the check to lowmem, as requested
>   by Andreas Larsson.
> - Correct the description: LEON systems can use highmem.
> - Carry Sam's Reviewed-by tag on patch 5; all six patches now retain his
>   review tags.
> - Rebase onto Linux 7.3-rc1 plus the three prerequisite patches; adjust
>   patch 6's context without changing its code changes.
> 
> Changes in v3:
> - Add Sam's Reviewed-by tag to patch 4.
> - Initialize max_pfn in patch 5 and use it as the highmem zone limit.
> - Use PHYS_PFN() instead of open-coded PAGE_SHIFT conversions in patch 5.
> - Remove the obsolete highstart_pfn and highend_pfn declarations.
> - Use the generic PFN limit declarations from linux/memblock.h.
> - Document removal of the duplicate private HIGHMEM summary.
> 
> Changes in v2:
> - Add Sam's Reviewed-by tags to patches 1-3 and 6. Patch 6 is the
>   unchanged source change from patch 5 in v1, renumbered by the new patch.
> - Drop the unused sparc_valid_addr_bitmap in a preparation patch.
> - Use for_each_mem_pfn_range() and the standard max_low_pfn variable in
>   the early memory setup. The change to LEON's PFN check made in v2 is
>   corrected in v4 to preserve its original bounds.
> 
> Suggested-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20260817153237.GA702187@xxxxxxxxxxxx
> Link: https://lore.kernel.org/r/20260901214611.60560-1-linmag7@xxxxxxxxx
> 
> Magnus Lindholm (6):
>   sparc32: use memblock when mapping the kernel
>   sparc32: use memblock to find available system memory
>   sparc32: populate memblock from the PROM memory map
>   sparc32: drop unused valid address bitmap
>   sparc32: move early memory setup to setup_arch
>   sparc32: drop sp_banks
> 
>  arch/sparc/include/asm/highmem.h    |   3 -
>  arch/sparc/include/asm/leon.h       |   2 +-
>  arch/sparc/include/asm/page_32.h    |  16 ---
>  arch/sparc/include/asm/pgtable_32.h |   3 +-
>  arch/sparc/include/asm/pgtsrmmu.h   |   1 -
>  arch/sparc/kernel/setup_32.c        | 117 ++++++++++---------
>  arch/sparc/mm/init_32.c             | 167 +---------------------------
>  arch/sparc/mm/leon_mm.c             |   1 +
>  arch/sparc/mm/srmmu.c               |  69 ++++--------
>  arch/sparc/prom/memory.c            |  51 ++-------
>  10 files changed, 103 insertions(+), 327 deletions(-)
> 
> 
> base-commit: 22a749706e3b0f857d5169a61f2f86a160eb9abd

Reviewed-by: Andreas Larsson <andreas@xxxxxxxxxxx>
Tested-by: Andreas Larsson <andreas@xxxxxxxxxxx>

Picking this up to my for-next.

Thanks,
Andreas