Changes in Kconfig

e7607f7d - ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE

Thu, 20 Mar 2025 21:33:49 +0000

ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCEld.lld prior to 21.0.0 does not support using the KEEP keyword within anoverlay description, which may be needed to avoid discarding necessarysections within an overlay with '--gc-sections', which can be enabledfor the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEPwithin OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used toconditionally add KEEP when it is properly supported to avoid breakingold versions of ld.lld.Cc: stable@vger.kernel.orgLink: https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8cReviewed-by: Linus Walleij Signed-off-by: Nathan Chancellor Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

ccb8ce52 - ARM: 9441/1: rust: Enable Rust support for ARMv7

Thu, 30 Jan 2025 23:03:45 +0000

ARM: 9441/1: rust: Enable Rust support for ARMv7This commit allows building ARMv7 kernels with Rust support.The rust core library expects some __eabi_... functionsthat are not implemented in the kernel.Those functions are some float operations and __aeabi_uldivmod.For now those are implemented with define_panicking_intrinsics!.This is based on the code by Sven Van Asbroeck from the originalrust branch and inspired by the AArch version by Jamie Cunliffe.I have tested the rust samples and a custom simple MMIO moduleon hardware (De1SoC FPGA + Arm A9 CPU).Tested-by: Rudraksha Gupta Reviewed-by: Alice Ryhl Acked-by: Miguel Ojeda Tested-by: Miguel Ojeda Acked-by: Ard Biesheuvel Signed-off-by: Christian Schrefl Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

a9ff9447 - ARM: 9433/2: implement cacheinfo support

Tue, 14 Jan 2025 11:54:52 +0000

ARM: 9433/2: implement cacheinfo supportOn ARMv7 / v7m machines read CTR and CLIDR registers to provideinformation regarding the cache topology. Earlier machines shoulddescribe full cache topology in the device tree.Note, this follows the ARM64 cacheinfo support and provides only minimalsupport required to bootstrap cache info. All useful properties shouldbe decribed in Device Tree.Reviewed-by: Linus Walleij Signed-off-by: Dmitry Baryshkov Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

50867db0 - ARM: 9438/1: assembler: Drop obsolete VFP accessor fallback

Thu, 05 Dec 2024 13:30:52 +0000

ARM: 9438/1: assembler: Drop obsolete VFP accessor fallbackNow that the minimum supported binutils version is 2.25, we no longerneed a workaround for binutils older than 2.24 for accessing VFP controlregisters from assembler.Reviewed-by: Linus Walleij Reviewed-by: Nathan Chancellor Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

1684e829 - arm/crc-t10dif: expose CRC-T10DIF function through lib

Mon, 02 Dec 2024 01:20:49 +0000

arm/crc-t10dif: expose CRC-T10DIF function through libMove the arm CRC-T10DIF assembly code into the lib directory and wire itup to the library interface. This allows it to be used without goingthrough the crypto API. It remains usable via the crypto API too viathe shash algorithms that use the library interface. Thus all thearch-specific "shash" code becomes unnecessary and is removed.Note: to see the diff from arch/arm/crypto/crct10dif-ce-glue.c toarch/arm/lib/crc-t10dif-glue.c, view this commit with 'git show -M10'.Reviewed-by: Ard Biesheuvel Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20241202012056.209768-6-ebiggers@kernel.orgSigned-off-by: Eric Biggers List of files: /linux-6.15/arch/arm/Kconfig

1e1b6dbc - arm/crc32: expose CRC32 functions through lib

Mon, 02 Dec 2024 01:08:30 +0000

arm/crc32: expose CRC32 functions through libMove the arm CRC32 assembly code into the lib directory and wire it upto the library interface. This allows it to be used without goingthrough the crypto API. It remains usable via the crypto API too viathe shash algorithms that use the library interface. Thus all thearch-specific "shash" code becomes unnecessary and is removed.Note: to see the diff from arch/arm/crypto/crc32-ce-glue.c toarch/arm/lib/crc32-glue.c, view this commit with 'git show -M10'.Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20241202010844.144356-6-ebiggers@kernel.orgSigned-off-by: Eric Biggers List of files: /linux-6.15/arch/arm/Kconfig

31daa343 - crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32

Tue, 17 Sep 2024 16:37:20 +0000

crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using Open Firmware. On these machines, the kernel refuses to boot from non-zeroPHYSICAL_START, which occurs when CRASH_DUMP is on.Since most PPC_BOOK3S_32 machines boot via Open Firmware, it shoulddefault to off for them. Users booting via some other mechanism can stillturn it on explicitly.Does not change the default on any other architectures for thetime being.Link: https://lkml.kernel.org/r/20240917163720.1644584-1-dave@vasilevsky.caFixes: 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.htmlAcked-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 List of files: /linux-6.15/arch/arm/Kconfig

0d437918 - ARM: 9414/1: Fix build issue with LD_DEAD_CODE_DATA_ELIMINATION

Wed, 21 Aug 2024 06:34:41 +0000

ARM: 9414/1: Fix build issue with LD_DEAD_CODE_DATA_ELIMINATIONThere is a build issue with LD segmentation fault, whileCONFIG_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 earlierthan 2.36. It makes most sense to have a minimum LD version asa dependency for HAVE_LD_DEAD_CODE_DATA_ELIMINATION and eliminatethe impact of ".reloc .text, R_ARM_NONE, ." whenCONFIG_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) List of files: /linux-6.15/arch/arm/Kconfig

de6c85bf - dma-mapping: clearly mark DMA ops as an architecture feature

Wed, 28 Aug 2024 06:02:47 +0000

dma-mapping: clearly mark DMA ops as an architecture featureDMA ops are a helper for architectures and not for drivers to overridethe DMA implementation.Unfortunately driver authors keep ignoring this. Make the fact moreclear by renaming the symbol to ARCH_HAS_DMA_OPS and having the two driversoverriding their dma_ops depend on that. These drivers should probably bemarked 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 IPU6Acked-by: Robin Murphy List of files: /linux-6.15/arch/arm/Kconfig

609face0 - ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()

Wed, 31 Jul 2024 09:17:55 +0000

ARM: 9411/1: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu()Currently, almost all architectures have switched to GENERIC_CPU_DEVICES,except for arm32. Also switch over to GENERIC_CPU_DEVICES, and provide anarch_register_cpu() that populates the hotpluggable flag for arm32.The struct cpu in struct cpuinfo_arm is never used directly, removeit to use the one GENERIC_CPU_DEVICES provides.This also has the effect of moving the registration of CPUs from subsys todriver core initialisation, prior to any initcalls running.Signed-off-by: Jinjie Ruan Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

b9d73218 - treewide: change conditional prompt for choices to 'depends on'

Wed, 26 Jun 2024 18:22:00 +0000

treewide: change conditional prompt for choices to 'depends on'While Documentation/kbuild/kconfig-language.rst provides a briefexplanation, there are recurring confusions regarding the usage of aprompt followed by 'if '. This conditional controls _only_ theprompt.A typical usage is as follows: menuconfig BLOCK bool "Enable the block layer" if EXPERT default yWhen EXPERT=n, the prompt is hidden, but this config entry is stillactive, and BLOCK is set to its default value 'y'. This is reasonablebecause you are likely want to enable the block device support. WhenEXPERT=y, the prompt is shown, allowing you to toggle BLOCK.Please note that it is different from 'depends on EXPERT', which wouldenable and disable the entire config entry.However, this conditional prompt has never worked in a choice block.The following two work in the same way: when EXPERT is disabled, thechoice block is entirely disabled.[Test Code 1] choice prompt "choose" if EXPERT config A bool "A" config B bool "B" endchoice[Test Code 2] choice prompt "choose" depends on EXPERT config A bool "A" config B bool "B" endchoiceI believe the first case should hide only the prompt, producing thedefault: CONFIG_A=y # CONFIG_B is not setThe next commit will change (fix) the behavior of the conditional promptin choice blocks.I see several choice blocks wrongly using a conditional prompt, where'depends on' makes more sense.To preserve the current behavior, this commit converts such misuses.I did not touch the following entry in arch/x86/Kconfig: choice prompt "Memory split" if EXPERT default VMSPLIT_3GThis is truly the correct use of the conditional prompt; when EXPERT=n,this choice block should silently select the reasonable VMSPLIT_3G,although the resulting PAGE_OFFSET will not be affected anyway.Presumably, the one in fs/jffs2/Kconfig is also correct, but I convertedit to 'depends on' to avoid any potential behavioral change.Signed-off-by: Masahiro Yamada List of files: /linux-6.15/arch/arm/Kconfig

f1b56448 - ARM: Emulate one-byte cmpxchg

Thu, 30 May 2024 17:11:31 +0000

ARM: Emulate one-byte cmpxchgUse the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on ARM systemswith ARCH == ARMv6K.[ paulmck: Apply Arnd Bergmann and Nathan Chancellor feedback. ][ paulmck: Apply Linus Walleij feedback. ]Reported-by: Mark Brown Closes: https://lore.kernel.org/all/54798f68-48f7-4c65-9cba-47c0bf175143@sirena.org.uk/Reported-by: Naresh Kamboju Closes: https://lore.kernel.org/all/CA+G9fYuZ+pf6p8AXMZWtdFtX-gbG8HMaBKp=XbxcdzA_QeLkxQ@mail.gmail.com/Signed-off-by: Paul E. McKenney Tested-by: Nathan Chancellor Reviewed-by: Linus Walleij Cc: "Russell King (Oracle)" Cc: Arnd Bergmann Cc: Andrew Davis Cc: Andrew Morton Cc: Eric DeVolder Cc: Rob Herring Cc: List of files: /linux-6.15/arch/arm/Kconfig

2335c9cb - ARM: 9407/1: Add support for STACKLEAK gcc plugin

Thu, 27 Jun 2024 07:38:44 +0000

ARM: 9407/1: Add support for STACKLEAK gcc pluginAdd the STACKLEAK gcc plugin to arm32 by adding the helper used bystackleak common code: on_thread_stack(). It initialize the stack with thepoison value before returning from system calls which improves the kernelsecurity. Additionally, this disables the plugin in EFI stub code anddecompress code, which are out of scope for the protection.Before the test on Qemu versatilepb board: # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT lkdtm: Performing direct entry STACKLEAK_ERASING lkdtm: XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)After: # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT lkdtm: Performing direct entry STACKLEAK_ERASING lkdtm: stackleak stack usage: high offset: 80 bytes current: 280 bytes lowest: 696 bytes tracked: 696 bytes untracked: 192 bytes poisoned: 7220 bytes low offset: 4 bytes lkdtm: OK: the rest of the thread stack is properly erasedSigned-off-by: Jinjie Ruan Acked-by: Ard Biesheuvel Reviewed-by: Linus Walleij Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

ed0f9410 - ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION

Mon, 03 Jun 2024 15:37:50 +0000

ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATIONThe current arm32 architecture does not yet support theHAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used inembedded scenarios, and enabling this feature would be beneficial forreducing the size of the kernel image.In order to make this work, we keep the necessary tables by annotatingthem with KEEP, also it requires further changes to linker script to KEEPsome tables and wildcard compiler generated sections into the right place.When using ld.lld for linking, KEEP is not recognized within the OVERLAYcommand, and Ard proposed a concise method to solve this problem.It boots normally with defconfig, vexpress_defconfig and tinyconfig.The size comparison of zImage is as follows:defconfig vexpress_defconfig tinyconfig5137712 5138024 424192 no dce5032560 4997824 298384 dce2.0% 2.7% 29.7% shrinkWhen using smaller config file, there is a significant reduction in thesize of the zImage.We also tested this patch on a commercially available single-boardcomputer, and the comparison is as follows:a15eb_config2161384 no dce2092240 dce3.2% shrinkThe zImage size has been reduced by approximately 3.2%, which is 70KB on2.1M.Signed-off-by: Yuntao Liu Tested-by: Arnd Bergmann Reviewed-by: Arnd Bergmann Reviewed-by: Linus Walleij Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

8ede71e1 - ARM: 9402/1: Kconfig: Spelling s/Cortex A-/Cortex-A/

Wed, 29 May 2024 12:07:42 +0000

ARM: 9402/1: Kconfig: Spelling s/Cortex A-/Cortex-A/Fix a misspelling of "Cortex-A9", to make it easier to find which errataare applicable to Cortex-A9 CPU cores.Signed-off-by: Geert Uytterhoeven Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

1a4fec49 - ARM: 9392/2: Support CLANG CFI

Tue, 23 Apr 2024 07:54:45 +0000

ARM: 9392/2: Support CLANG CFISupport Control Flow Integrity (CFI) when compiling withCLANG.In the as-of-writing LLVM CLANG implementation (v17)the 32-bit ARM platform is supported by the generic CFIimplementation, which isn't tailored specifically for ARM32but works well enough to enable the feature.Tested-by: Kees Cook Reviewed-by: Sami Tolvanen Signed-off-by: Linus Walleij Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

25176ad0 - mm/treewide: rename CONFIG_HAVE_FAST_GUP to CONFIG_HAVE_GUP_FAST

Tue, 02 Apr 2024 12:55:15 +0000

mm/treewide: rename CONFIG_HAVE_FAST_GUP to CONFIG_HAVE_GUP_FASTNowadays, we call it "GUP-fast", the external interface includes functionslike "get_user_pages_fast()", and we renamed all internal functions toreflect that as well.Let's make the config option reflect that.Link: https://lkml.kernel.org/r/20240402125516.223131-3-david@redhat.comSigned-off-by: David Hildenbrand Reviewed-by: Mike Rapoport (IBM) Reviewed-by: Jason Gunthorpe Reviewed-by: John Hubbard Cc: Peter Xu Signed-off-by: Andrew Morton List of files: /linux-6.15/arch/arm/Kconfig

7af5b901 - ARM: 9358/2: Implement PAN for LPAE by TTBR0 page table walks disablement

Mon, 25 Mar 2024 07:31:13 +0000

ARM: 9358/2: Implement PAN for LPAE by TTBR0 page table walks disablementWith LPAE enabled, privileged no-access cannot be enforced using CPUdomains as such feature is not available. This patch implements PANby disabling TTBR0 page table walks while in kernel mode.The ARM architecture allows page table walks to be split between TTBR0and TTBR1. With LPAE enabled, the split is defined by a combination ofTTBCR T0SZ and T1SZ bits. Currently, an LPAE-enabled kernel uses TTBR0for user addresses and TTBR1 for kernel addresses with the VMSPLIT_2Gand VMSPLIT_3G configurations. The main advantage for the 3:1 split isthat TTBR1 is reduced to 2 levels, so potentially faster TLB refill(though usually the first level entries are already cached in the TLB).The PAN support on LPAE-enabled kernels uses TTBR0 when running in userspace or in kernel space during user access routines (TTBCR T0SZ andT1SZ are both 0). When running user accesses are disabled in kernelmode, TTBR0 page table walks are disabled by setting TTBCR.EPD0. TTBR1is used for kernel accesses (including loadable modules; anythingcovered by swapper_pg_dir) by reducing the TTBCR.T0SZ to the minimum(2^(32-7) = 32MB). To avoid user accesses potentially hitting stale TLBentries, the ASID is switched to 0 (reserved) by setting TTBCR.A1 andusing the ASID value in TTBR1. The difference from a non-PAN kernel isthat with the 3:1 memory split, TTBR1 always uses 3 levels of pagetables.As part of the change we are using preprocessor elif definied() clausesso balance these clauses by converting relevant precedingt ifdefclauses to if defined() clauses.Signed-off-by: Catalin Marinas Reviewed-by: Kees Cook Tested-by: Florian Fainelli Signed-off-by: Linus Walleij Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig

5394f1e9 - arch: define CONFIG_PAGE_SIZE_*KB on all architectures

Mon, 26 Feb 2024 16:14:13 +0000

arch: define CONFIG_PAGE_SIZE_*KB on all architecturesMost architectures only support a single hardcoded page size. In orderto ensure that each one of these sets the corresponding Kconfig symbols,change over the PAGE_SHIFT definition to the common one and allowonly 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 List of files: /linux-6.15/arch/arm/Kconfig

b9920fdd - ARM: 9352/1: iwmmxt: Remove support for PJ4/PJ4B cores

Wed, 14 Feb 2024 07:03:24 +0000

ARM: 9352/1: iwmmxt: Remove support for PJ4/PJ4B coresPJ4 is a v7 core that incorporates a iWMMXt coprocessor. However, GCCdoes not support this combination (its iWMMXt configuration alwaysimplies v5te), and so there is no v6/v7 user space that actually makesuse of this, beyond generic support for things like setjmp() thatpreserve/restore the iWMMXt register file using generic LDC/STCinstructions emitted in assembler. As [0] appears to imply, this logicis triggered for the init process at boot, and so most user threads willhave a iWMMXt register context associated with it, even though it isnever used.At this point, it is highly unlikely that such GCC support will evermaterialize (and Clang does not implement support for iWMMXt to beginwith).This means that advertising iWMMXt support on these cores results incontext switch overhead without any associated benefit, and so it isbetter to simply ignore the iWMMXt unit on these systems. So rip out thesupport. Doing so also fixes the issue reported in [0] related to UNDEFhandling of co-processor #0/#1 instructions issued from user spacerunning in Thumb2 mode.The PJ4 cores are used in four platforms: Armada 370/xp, Dove (Cubox,d2plug), MMP2 (xo-1.75) and Berlin (Google TV). Out of these, only thefirst is still widely used, but that one actually doesn't have iWMMXtbut instead has only VFPV3-D16, and so it is not impacted by thischange.Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218427 [0]Fixes: 8bcba70cb5c22 ("ARM: entry: Disregard Thumb undef exception ...")Acked-by: Linus Walleij Acked-by: Arnd Bergmann Acked-by: Nicolas Pitre Reviewed-by: Jisheng Zhang Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King (Oracle) List of files: /linux-6.15/arch/arm/Kconfig