kernel/linux.git/arch/arm/Kconfig, branch v6.12.91

ARM: 9461/1: Disable HIGHPTE on PREEMPT_RT kernels

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

[ Upstream commit fedadc4137234c3d00c4785eeed3e747fe9036ae ] gup_pgd_range() is invoked with disabled interrupts and invokes __kmap_local_page_prot() via pte_offset_map(), gup_p4d_range(). With HIGHPTE enabled, __kmap_local_page_prot() invokes kmap_high_get() which uses a spinlock_t via lock_kmap_any(). This leads to an sleeping-while-atomic error on PREEMPT_RT because spinlock_t becomes a sleeping lock and must not be acquired in atomic context. The loop in map_new_virtual() uses wait_queue_head_t for wake up which also is using a spinlock_t. Since HIGHPTE is rarely needed at all, turn it off for PREEMPT_RT to allow the use of get_user_pages_fast(). [arnd: rework patch to turn off HIGHPTE instead of HAVE_PAST_GUP] Co-developed-by: Arnd Bergmann Acked-by: Linus Walleij Reviewed-by: Arnd Bergmann Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin

ARM: 9450/1: Fix allowing linker DCE with binutils < 2.36

2025-08-01T08:48:42+00:00

commit 53e7e1fb81cc8ba2da1cb31f8917ef397caafe91 upstream. Commit e7607f7d6d81 ("ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE") accidentally broke the binutils version restriction that was added in commit 0d437918fb64 ("ARM: 9414/1: Fix build issue with LD_DEAD_CODE_DATA_ELIMINATION"), reintroducing the segmentation fault addressed by that workaround. Restore the binutils version dependency by using CONFIG_LD_CAN_USE_KEEP_IN_OVERLAY as an additional condition to ensure that CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION is only enabled with binutils >= 2.36 and ld.lld >= 21.0.0. Closes: https://lore.kernel.org/6739da7d-e555-407a-b5cb-e5681da71056@landley.net/ Closes: https://lore.kernel.org/CAFERDQ0zPoya5ZQfpbeuKVZEo_fKsonLf6tJbp32QnSGAtbi+Q@mail.gmail.com/ Cc: stable@vger.kernel.org Fixes: e7607f7d6d81 ("ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE") Reported-by: Rob Landley Tested-by: Rob Landley Reported-by: Martin Wetterwald Signed-off-by: Nathan Chancellor Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman

ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE

2025-04-10T12:39:40+00:00

commit e7607f7d6d81af71dcc5171278aadccc94d277cd upstream. ld.lld prior to 21.0.0 does not support using the KEEP keyword within an overlay description, which may be needed to avoid discarding necessary sections within an overlay with '--gc-sections', which can be enabled for the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEP within OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used to conditionally add KEEP when it is properly supported to avoid breaking old versions of ld.lld. Cc: stable@vger.kernel.org Link: https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8c Reviewed-by: Linus Walleij Signed-off-by: Nathan Chancellor Signed-off-by: Russell King (Oracle) [nathan: Fix conflict in init/Kconfig due to lack of RUSTC symbols] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32

2024-11-15T06:43:48+00:00

Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using Open Firmware. On these machines, the kernel refuses to boot from non-zero PHYSICAL_START, which occurs when CRASH_DUMP is on. Since most PPC_BOOK3S_32 machines boot via Open Firmware, it should default to off for them. Users booting via some other mechanism can still turn it on explicitly. Does not change the default on any other architectures for the time being. Link: https://lkml.kernel.org/r/20240917163720.1644584-1-dave@vasilevsky.ca Fixes: 75bc255a7444 ("crash: clean up kdump related config items") Signed-off-by: Dave Vasilevsky Reported-by: Reimar Döffinger Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html Acked-by: Michael Ellerman [powerpc] Acked-by: Baoquan He Cc: "Eric W. Biederman" Cc: John Paul Adrian Glaubitz Cc: Reimar Döffinger Cc: Signed-off-by: Andrew Morton

Merge tag 'dma-mapping-6.12-2024-09-19' of git://git.infradead.org/users/hch/dma-mapping

2024-09-19T09:12:49+00:00

Pull dma-mapping updates from Christoph Hellwig: - support DMA zones for arm64 systems where memory starts at > 4GB (Baruch Siach, Catalin Marinas) - support direct calls into dma-iommu and thus obsolete dma_map_ops for many common configurations (Leon Romanovsky) - add DMA-API tracing (Sean Anderson) - remove the not very useful return value from various dma_set_* APIs (Christoph Hellwig) - misc cleanups and minor optimizations (Chen Y, Yosry Ahmed, Christoph Hellwig) * tag 'dma-mapping-6.12-2024-09-19' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: reflow dma_supported dma-mapping: reliably inform about DMA support for IOMMU dma-mapping: add tracing for dma-mapping API calls dma-mapping: use IOMMU DMA calls for common alloc/free page calls dma-direct: optimize page freeing when it is not addressable dma-mapping: clearly mark DMA ops as an architecture feature vdpa_sim: don't select DMA_OPS arm64: mm: keep low RAM dma zone dma-mapping: don't return errors from dma_set_max_seg_size dma-mapping: don't return errors from dma_set_seg_boundary dma-mapping: don't return errors from dma_set_min_align_mask scsi: check that busses support the DMA API before setting dma parameters arm64: mm: fix DMA zone when dma-ranges is missing dma-mapping: direct calls for dma-iommu dma-mapping: call ->unmap_page and ->unmap_sg unconditionally arm64: support DMA zone above 4GB dma-mapping: replace zone_dma_bits by zone_dma_limit dma-mapping: use bit masking to check VM_DMA_COHERENT

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux

2024-09-16T04:32:08+00:00

Pull ARM updates from Russell King: - clean up TTBCR magic numbers and use u32 for this register - fix clang issue in VFP code leading to kernel oops, caused by compiler instruction scheduling. - switch 32-bit Arm to use GENERIC_CPU_DEVICES and use the arch_cpu_is_hotpluggable() hook. - pass struct device to arm_iommu_create_mapping() and move over to use iommu_paging_domain_alloc() rather than iommu_domain_alloc() - make amba_bustype constant * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux: ARM: 9418/1: dma-mapping: Use iommu_paging_domain_alloc() ARM: 9417/1: dma-mapping: Pass device to arm_iommu_create_mapping() ARM: 9416/1: amba: make amba_bustype constant ARM: 9412/1: Convert to arch_cpu_is_hotpluggable() ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu() ARM: 9410/1: vfp: Use asm volatile in fmrx/fmxr macros ARM: 9409/1: mmu: Do not use magic number for TTBCR settings

ARM: 9414/1: Fix build issue with LD_DEAD_CODE_DATA_ELIMINATION

2024-09-04T13:47:42+00:00

There is a build issue with LD segmentation fault, while CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is not enabled, as bellow. scripts/link-vmlinux.sh: line 49: 3796 Segmentation fault (core dumped) ${ld} ${ldflags} -o ${output} ${wl}--whole-archive ${objs} ${wl}--no-whole-archive ${wl}--start-group ${libs} ${wl}--end-group ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs} The error occurs in older versions of the GNU ld with version earlier than 2.36. It makes most sense to have a minimum LD version as a dependency for HAVE_LD_DEAD_CODE_DATA_ELIMINATION and eliminate the impact of ".reloc .text, R_ARM_NONE, ." when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is not enabled. Fixes: ed0f94102251 ("ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION") Reported-by: Harith George Tested-by: Harith George Suggested-by: Arnd Bergmann Acked-by: Arnd Bergmann Signed-off-by: Yuntao Liu Link: https://lore.kernel.org/all/14e9aefb-88d1-4eee-8288-ef15d4a9b059@gmail.com/ Signed-off-by: Russell King (Oracle)

dma-mapping: clearly mark DMA ops as an architecture feature

2024-09-04T04:08:51+00:00

DMA ops are a helper for architectures and not for drivers to override the DMA implementation. Unfortunately driver authors keep ignoring this. Make the fact more clear by renaming the symbol to ARCH_HAS_DMA_OPS and having the two drivers overriding their dma_ops depend on that. These drivers should probably be marked broken, but we can give them a bit of a grace period for that. Signed-off-by: Christoph Hellwig Reviewed-by: Thomas Gleixner Acked-by: Sakari Ailus # for IPU6 Acked-by: Robin Murphy

ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()

2024-08-20T10:18:49+00:00

Currently, almost all architectures have switched to GENERIC_CPU_DEVICES, except for arm32. Also switch over to GENERIC_CPU_DEVICES, and provide an arch_register_cpu() that populates the hotpluggable flag for arm32. The struct cpu in struct cpuinfo_arm is never used directly, remove it to use the one GENERIC_CPU_DEVICES provides. This also has the effect of moving the registration of CPUs from subsys to driver core initialisation, prior to any initcalls running. Signed-off-by: Jinjie Ruan Signed-off-by: Russell King (Oracle)

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux

2024-07-29T17:33:51+00:00

Pull ARM updates from Russell King: - ftrace: don't assume stack frames are contiguous in memory - remove unused mod_inwind_map structure - spelling fixes - allow use of LD dead code/data elimination - fix callchain_trace() return value - add support for stackleak gcc plugin - correct some reset asm function prototypes for CFI [ Missed the merge window because Russell forgot to push out ] * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux: ARM: 9408/1: mm: CFI: Fix some erroneous reset prototypes ARM: 9407/1: Add support for STACKLEAK gcc plugin ARM: 9406/1: Fix callchain_trace() return value ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION ARM: 9403/1: Alpine: Spelling s/initialiing/initializing/ ARM: 9402/1: Kconfig: Spelling s/Cortex A-/Cortex-A/ ARM: 9400/1: Remove unused struct 'mod_unwind_map'