linux-toradex.git/arch/m68k/Kconfig, branch master

m68k: Enable dead code elimination

2025-07-06T10:50:50+00:00

Allow the experimental dead code elimination config to be enabled.

For my 68000 nommu config this frees up a few hundred K of memory
so seems worth while.

Boot and build tested on nommu and mmu enabled configs.

Before:
Memory: 5388K/8192K available (1986K kernel code, 114K rwdata,
244K rodata, 92K init, 41K bss, 2624K reserved, 0K cma-reserved)

After
Memory: 5684K/8192K available (1714K kernel code, 112K rwdata,
228K rodata, 92K init, 37K bss, 2328K reserved, 0K cma-reserved)

Signed-off-by: Daniel Palmer 
Acked-by: Greg Ungerer 
Tested-by: Finn Thain 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/20250416114240.2929832-1-daniel@0x0f.com
Signed-off-by: Geert Uytterhoeven

m68k: coldfire: select PCI_IOMAP for PCI

2025-03-24T14:41:07+00:00

After I dropped CONFIG_GENERIC_IOMAP, some PCI drivers started failing
to link when CONFIG_MMU is disabled:

ERROR: modpost: "pci_iounmap" [drivers/video/fbdev/i740fb.ko] undefined!
ERROR: modpost: "pci_iounmap" [drivers/video/fbdev/vt8623fb.ko] undefined!
ERROR: modpost: "pci_iomap_wc" [drivers/video/fbdev/vt8623fb.ko] undefined!
ERROR: modpost: "pci_iomap" [drivers/video/fbdev/vt8623fb.ko] undefined!
ERROR: modpost: "pci_iounmap" [drivers/video/fbdev/s3fb.ko] undefined!
...

It turns out that there were two mistakes in my patch: on !MMU I forgot
to enable CONFIG_GENERIC_PCI_IOMAP, and for Coldfire with MMU enabled,
teh GENERIC_IOMAP was left in place but incorrectly configured.

Fixes: 9d48cc07d0d7 ("m68k/nommu: stop using GENERIC_IOMAP")
Reported-by: Greg Ungerer 
Acked-by: Greg Ungerer 
Signed-off-by: Arnd Bergmann

m68k/nommu: stop using GENERIC_IOMAP

2025-03-15T10:07:07+00:00

There is no need to go through the GENERIC_IOMAP wrapper for PIO on
nommu platforms, since these always come from PCI I/O space that is
itself memory mapped.

Instead, the generic ioport_map() can just return the MMIO location
of the ports directly by applying the PCI_IO_PA offset, while
ioread32/iowrite32 trivially turn into readl/writel as they do
on most other architectures.

Signed-off-by: Arnd Bergmann

m68k: Use kernel's generic muldi3 libgcc function

2024-12-09T12:29:17+00:00

Use the kernels own generic lib/muldi3.c implementation of muldi3 for
68K machines. Some 68K CPUs support 64bit multiplies so move the arch
specific umul_ppmm() macro into a header file that is included by
lib/muldi3.c. That way it can take advantage of the single instruction
when available.

There does not appear to be any existing mechanism for the generic
lib/muldi3.c code to pick up an external arch definition of umul_ppmm().
Create an arch specific libgcc.h that can optionally be included by
the system include/linux/libgcc.h to allow for this.

Somewhat oddly there is also a similar definition of umul_ppmm() in
the non-architecture code in lib/crypto/mpi/longlong.h for a wide range
or machines. Its presence ends up complicating the include setup and
means not being able to use something like compiler.h instead. Actually
there is a few other defines of umul_ppmm() macros spread around in
various architectures, but not directly usable for the m68k case.

Signed-off-by: Greg Ungerer 
Link: https://lore.kernel.org/20231113133209.1367286-1-gerg@linux-m68k.org
Reviewed-by: Geert Uytterhoeven 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Geert Uytterhoeven

m68k: Move Sun 3 into a top-level platform option

2024-11-06T14:10:14+00:00

It is possible to select an m68k MMU build but not actually enable any
of the three MMU options, which then results in a build failure:

    arch/m68k/include/asm/page.h:10:25: error: 'CONFIG_PAGE_SHIFT' undeclared here (not in a function); did you mean 'CONFIG_LOG_BUF_SHIFT'?

Change the Kconfig selection to ensure that exactly one of the three
options is always enabled whenever an MMU-enabled kernel is built, but
moving CONFIG_SUN3 into a top-level option next to M68KCLASSIC and
COLDFIRE.

All defconfig files should keep working without changes, but
alldefconfig now builds support for the classic MMU.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202408032138.P7sBvIns-lkp@intel.com/
Signed-off-by: Arnd Bergmann 
Acked-by: Greg Ungerer 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/20241030195638.22542-1-arnd@kernel.org
Signed-off-by: Geert Uytterhoeven

m68k: Move ARCH_HAS_CPU_CACHE_ALIASING

2024-05-08T15:43:22+00:00

Move the recently added ARCH_HAS_CPU_CACHE_ALIASING to restore
alphabetical sort order.

Fixes: 8690bbcf3b7010b3 ("Introduce cpu_dcache_is_aliasing() across all architectures")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Mathieu Desnoyers 
Link: https://lore.kernel.org/r/4574ad6cc1117e4b5d29812c165bf7f6e5b60773.1714978406.git.geert@linux-m68k.org

m68k: Let GENERIC_IOMAP depend on HAS_IOPORT

2024-05-08T15:43:22+00:00

In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at
compile time. With that choosing dynamically between I/O port and MMIO
access via GNERIC_IOMAP will not work. So only select GENERIC_IOMAP when
HAS_IOPORT is selected.

Co-developed-by: Arnd Bergmann 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Niklas Schnelle 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20240403122851.38808-2-schnelle@linux.ibm.com
Signed-off-by: Geert Uytterhoeven

Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-03-15T00:43:30+00:00

Pull MM updates from Andrew Morton:

- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
from hotplugged memory rather than only from main memory. Series
"implement "memmap on memory" feature on s390".

- More folio conversions from Matthew Wilcox in the series

"Convert memcontrol charge moving to use folios"
"mm: convert mm counter to take a folio"

- Chengming Zhou has optimized zswap's rbtree locking, providing
significant reductions in system time and modest but measurable
reductions in overall runtimes. The series is "mm/zswap: optimize the
scalability of zswap rb-tree".

- Chengming Zhou has also provided the series "mm/zswap: optimize zswap
lru list" which provides measurable runtime benefits in some
swap-intensive situations.

- And Chengming Zhou further optimizes zswap in the series "mm/zswap:
optimize for dynamic zswap_pools". Measured improvements are modest.

- zswap cleanups and simplifications from Yosry Ahmed in the series
"mm: zswap: simplify zswap_swapoff()".

- In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
contributed several DAX cleanups as well as adding a sysfs tunable to
control the memmap_on_memory setting when the dax device is
hotplugged as system memory.

- Johannes Weiner has added the large series "mm: zswap: cleanups",
which does that.

- More DAMON work from SeongJae Park in the series

"mm/damon: make DAMON debugfs interface deprecation unignorable"
"selftests/damon: add more tests for core functionalities and corner cases"
"Docs/mm/damon: misc readability improvements"
"mm/damon: let DAMOS feeds and tame/auto-tune itself"

- In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension" Rakie Kim has developed a new mempolicy interleaving
policy wherein we allocate memory across nodes in a weighted fashion
rather than uniformly. This is beneficial in heterogeneous memory
environments appearing with CXL.

- Christophe Leroy has contributed some cleanup and consolidation work
against the ARM pagetable dumping code in the series "mm: ptdump:
Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".

- Luis Chamberlain has added some additional xarray selftesting in the
series "test_xarray: advanced API multi-index tests".

- Muhammad Usama Anjum has reworked the selftest code to make its
human-readable output conform to the TAP ("Test Anything Protocol")
format. Amongst other things, this opens up the use of third-party
tools to parse and process out selftesting results.

- Ryan Roberts has added fork()-time PTE batching of THP ptes in the
series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
targeted at arm64, this significantly speeds up fork() when the
process has a large number of pte-mapped folios.

- David Hildenbrand also gets in on the THP pte batching game in his
series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
implements batching during munmap() and other pte teardown
situations. The microbenchmark improvements are nice.

- And in the series "Transparent Contiguous PTEs for User Mappings"
Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte
mappings"). Kernel build times on arm64 improved nicely. Ryan's
series "Address some contpte nits" provides some followup work.

- In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
fixed an obscure hugetlb race which was causing unnecessary page
faults. He has also added a reproducer under the selftest code.

- In the series "selftests/mm: Output cleanups for the compaction
test", Mark Brown did what the title claims.

- Kinsey Ho has added the series "mm/mglru: code cleanup and
refactoring".

- Even more zswap material from Nhat Pham. The series "fix and extend
zswap kselftests" does as claimed.

- In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
regression" Mathieu Desnoyers has cleaned up and fixed rather a mess
in our handling of DAX on archiecctures which have virtually aliasing
data caches. The arm architecture is the main beneficiary.

- Lokesh Gidra's series "per-vma locks in userfaultfd" provides
dramatic improvements in worst-case mmap_lock hold times during
certain userfaultfd operations.

- Some page_owner enhancements and maintenance work from Oscar Salvador
in his series

"page_owner: print stacks and their outstanding allocations"
"page_owner: Fixup and cleanup"

- Uladzislau Rezki has contributed some vmalloc scalability
improvements in his series "Mitigate a vmap lock contention". It
realizes a 12x improvement for a certain microbenchmark.

- Some kexec/crash cleanup work from Baoquan He in the series "Split
crash out from kexec and clean up related config items".

- Some zsmalloc maintenance work from Chengming Zhou in the series

"mm/zsmalloc: fix and optimize objects/page migration"
"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"

- Zi Yan has taught the MM to perform compaction on folios larger than
order=0. This a step along the path to implementaton of the merging
of large anonymous folios. The series is named "Enable >0 order folio
memory compaction".

- Christoph Hellwig has done quite a lot of cleanup work in the
pagecache writeback code in his series "convert write_cache_pages()
to an iterator".

- Some modest hugetlb cleanups and speedups in Vishal Moola's series
"Handle hugetlb faults under the VMA lock".

- Zi Yan has changed the page splitting code so we can split huge pages
into sizes other than order-0 to better utilize large folios. The
series is named "Split a folio to any lower order folios".

- David Hildenbrand has contributed the series "mm: remove
total_mapcount()", a cleanup.

- Matthew Wilcox has sought to improve the performance of bulk memory
freeing in his series "Rearrange batched folio freeing".

- Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
provides large improvements in bootup times on large machines which
are configured to use large numbers of hugetlb pages.

- Matthew Wilcox's series "PageFlags cleanups" does that.

- Qi Zheng's series "minor fixes and supplement for ptdesc" does that
also. S390 is affected.

- Cleanups to our pagemap utility functions from Peter Xu in his series
"mm/treewide: Replace pXd_large() with pXd_leaf()".

- Nico Pache has fixed a few things with our hugepage selftests in his
series "selftests/mm: Improve Hugepage Test Handling in MM
Selftests".

- Also, of course, many singleton patches to many things. Please see
the individual changelogs for details.

* tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits)
mm/zswap: remove the memcpy if acomp is not sleepable
crypto: introduce: acomp_is_async to expose if comp drivers might sleep
memtest: use {READ,WRITE}_ONCE in memory scanning
mm: prohibit the last subpage from reusing the entire large folio
mm: recover pud_leaf() definitions in nopmd case
selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements
selftests/mm: skip uffd hugetlb tests with insufficient hugepages
selftests/mm: dont fail testsuite due to a lack of hugepages
mm/huge_memory: skip invalid debugfs new_order input for folio split
mm/huge_memory: check new folio order when split a folio
mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
mm: add an explicit smp_wmb() to UFFDIO_CONTINUE
mm: fix list corruption in put_pages_list
mm: remove folio from deferred split list before uncharging it
filemap: avoid unnecessary major faults in filemap_fault()
mm,page_owner: drop unnecessary check
mm,page_owner: check for null stack_record before bumping its refcount
mm: swap: fix race between free_swap_and_cache() and swapoff()
mm/treewide: align up pXd_leaf() retval across archs
mm/treewide: drop pXd_large()
...

arch: define CONFIG_PAGE_SIZE_*KB on all architectures

2024-03-06T18:29:09+00:00

Most architectures only support a single hardcoded page size. In order
to ensure that each one of these sets the corresponding Kconfig symbols,
change over the PAGE_SHIFT definition to the common one and allow
only the hardware page size to be selected.

Acked-by: Guo Ren 
Acked-by: Heiko Carstens 
Acked-by: Stafford Horne 
Acked-by: Johannes Berg 
Acked-by: Geert Uytterhoeven 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Arnd Bergmann

Introduce cpu_dcache_is_aliasing() across all architectures

2024-02-22T23:27:19+00:00

Introduce a generic way to query whether the data cache is virtually
aliased on all architectures. Its purpose is to ensure that subsystems
which are incompatible with virtually aliased data caches (e.g. FS_DAX)
can reliably query this.

For data cache aliasing, there are three scenarios dependending on the
architecture. Here is a breakdown based on my understanding:

A) The data cache is always aliasing:

* arc
* csky
* m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.)
* sh
* parisc

B) The data cache aliasing is statically known or depends on querying CPU
   state at runtime:

* arm (cache_is_vivt() || cache_is_vipt_aliasing())
* mips (cpu_has_dc_aliases)
* nios2 (NIOS2_DCACHE_SIZE > PAGE_SIZE)
* sparc32 (vac_cache_size > PAGE_SIZE)
* sparc64 (L1DCACHE_SIZE > PAGE_SIZE)
* xtensa (DCACHE_WAY_SIZE > PAGE_SIZE)

C) The data cache is never aliasing:

* alpha
* arm64 (aarch64)
* hexagon
* loongarch (but with incoherent write buffers, which are disabled since
             commit d23b7795 ("LoongArch: Change SHMLBA from SZ_64K to PAGE_SIZE"))
* microblaze
* openrisc
* powerpc
* riscv
* s390
* um
* x86

Require architectures in A) and B) to select ARCH_HAS_CPU_CACHE_ALIASING and
implement "cpu_dcache_is_aliasing()".

Architectures in C) don't select ARCH_HAS_CPU_CACHE_ALIASING, and thus
cpu_dcache_is_aliasing() simply evaluates to "false".

Note that this leaves "cpu_icache_is_aliasing()" to be implemented as future
work. This would be useful to gate features like XIP on architectures
which have aliasing CPU dcache-icache but not CPU dcache-dcache.

Use "cpu_dcache" and "cpu_cache" rather than just "dcache" and "cache"
to clarify that we really mean "CPU data cache" and "CPU cache" to
eliminate any possible confusion with VFS "dentry cache" and "page
cache".

Link: https://lore.kernel.org/lkml/20030910210416.GA24258@mail.jlokier.co.uk/
Link: https://lkml.kernel.org/r/20240215144633.96437-9-mathieu.desnoyers@efficios.com
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers 
Cc: Dan Williams 
Cc: Vishal Verma 
Cc: Dave Jiang 
Cc: Matthew Wilcox 
Cc: Arnd Bergmann 
Cc: Russell King 
Cc: Alasdair Kergon 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Heiko Carstens 
Cc: kernel test robot 
Cc: Michael Sclafani 
Cc: Mike Snitzer 
Cc: Mikulas Patocka 
Signed-off-by: Andrew Morton