kernel.git/arch/arm/mm/cache-v6.S, branch master

kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI

2025-09-24T21:29:14Z

The kernel's CFI implementation uses the KCFI ABI specifically, and is not strictly tied to a particular compiler. In preparation for GCC supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with associated options). Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will enable CONFIG_CFI during olddefconfig. Reviewed-by: Linus Walleij Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org Signed-off-by: Kees Cook

ARM: 9393/1: mm: Use conditionals for CFI branches

2024-05-07T09:30:24Z

Commit 9385/2 introduced a few branches inside function prototypes when using CFI in order to deal with the situation where CFI inserts a few bytes of function information in front of the symbol. This is not good for older CPUs where every cycle counts. Commit 9386/2 alleviated the situation a bit by using aliases for the cache functions with identical signatures. This leaves the coherent cache flush functions *_coherent_kern_range() with these branches to the corresponing *_coherent_user_range() around, since their return type differ and they therefore cannot be aliased. Solve this by a simple ifdef so at least we can use fallthroughs when compiling without CFI enabled. Link: https://lore.kernel.org/linux-arm-kernel/Zi+e9M%2Ff5b%2FSto9H@shell.armlinux.org.uk/ Suggested-by: Ard Biesheuvel Signed-off-by: Linus Walleij Signed-off-by: Russell King (Oracle)

ARM: 9387/2: mm: Rewrite cacheflush vtables in CFI safe C

2024-04-29T13:14:18Z

Instead of defining all cache flush operations with an assembly macro in proc-macros.S, provide an explicit struct cpu_cache_fns for each CPU cache type in mm/cache.c. As a side effect from rewriting the vtables in C, we can avoid the aliasing for the "louis" cache callback, instead we can just assign the NN_flush_kern_cache_all() function to the louis callback in the C vtable. As the louis cache callback is called explicitly (not through the vtable) if we only have one type of cache support compiled in, we need an ifdef quirk for this in the !MULTI_CACHE case. Feroceon and XScale have some dma mapping quirk, in this case we can just define two structs and assign all but one callback to the main implementation; since each of them invoked define_cache_functions twice they require MULTI_CACHE by definition so the compiled-in shortcut is not used on these variants. Tested-by: Kees Cook Reviewed-by: Sami Tolvanen Signed-off-by: Linus Walleij Signed-off-by: Russell King (Oracle)

ARM: 9385/2: mm: Type-annotate all cache assembly routines

2024-04-29T13:14:16Z

Tag all references to assembly functions with SYM_TYPED_FUNC_START() and SYM_FUNC_END() so they also become CFI-safe. When we add SYM_TYPED_FUNC_START() to assembly calls, a function prototype signature will be emitted into the object file at (pc-4) at the call site, so that the KCFI runtime check can compare this to the expected call. Example: 8011ae38: a540670c .word 0xa540670c 8011ae3c : 8011ae3c: e3a00000 mov r0, #0 8011ae40: ee070f11 mcr 15, 0, r0, cr7, cr1, {0} 8011ae44: e12fff1e bx lr This means no "fallthrough" code can enter a SYM_TYPED_FUNC_START() call from above it: there will be a function prototype signature there, so those are consistently converted to a branch or ret lr depending on context. Tested-by: Kees Cook Reviewed-by: Sami Tolvanen Signed-off-by: Linus Walleij Signed-off-by: Russell King (Oracle)

ARM: Delete ARM11MPCore (ARM11 ARMv6K SMP) support

2023-12-22T11:43:16Z

This ARM11 SMP configuration was one of the first SMP configurations the ARM kernel supported, but it has the downside of odd DMA handling, odd cache tagging, and often (as of recent) completely broken cache handling on the ARM RealView PB11MPCore test chips. To boot the platform it was necessary to completely disable the cache. When it comes to the EB 11MPCore it is unclear if this ever worked. These reference designs are now the only ARMv6K SMP platforms. As only reference designs of purely academic interest remain, and since the special-cased DMA and PMU code is hard to maintain and doesn't really work, it is not really worth our time. Delete the ARM11MPCore support along with: - The special DMA quirk CONFIG_DMA_CACHE_RWFO that is only used on ARMv6K SMP, and we are the last ARMV6K system leaving the building and the cache handling is awkward, so good-bye. - The special PMU handling that was only used by ARM11MPCore. The following is left behind: - TIMER_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", ...) in arch/arm/kernel/smp_twd.c, this is still in use by Marvell MMP3 arch/arm/boot/dts/marvell/mmp3.dtsi - IRQCHIP_DECLARE(arm11mp_gic, "arm,arm11mp-gic", ...) in drivers/irqchip/irq-gic.c, this is still in use by Marvell MMP3 arch/arm/boot/dts/marvell/mmp3.dtsi - A compatible for the arm11mpcore SCU, since this was mistakedly used for the Cortex-A9 version of RealView EB. These are unfortunate but will need to be kept around for compatibility. New Marvell-specific compatibles should however probably be added. Acked-by: Mark Rutland Reviewed-by: Arnd Bergmann Signed-off-by: Linus Walleij Acked-by: Liviu Dudau Link: https://lore.kernel.org/r/20231207-drop-11mpcore-v2-1-560b396f3bf5@linaro.org Signed-off-by: Arnd Bergmann

ARM: 9263/1: use .arch directives instead of assembler command line flags

2022-11-08T18:36:17Z

Similar to commit a6c30873ee4a ("ARM: 8989/1: use .fpu assembler directives instead of assembler arguments"). GCC and GNU binutils support setting the "sub arch" via -march=, -Wa,-march, target function attribute, and .arch assembler directive. Clang was missing support for -Wa,-march=, but this was implemented in clang-13. The behavior of both GCC and Clang is to prefer -Wa,-march= over -march= for assembler and assembler-with-cpp sources, but Clang will warn about the -march= being unused. clang: warning: argument unused during compilation: '-march=armv6k' [-Wunused-command-line-argument] Since most assembler is non-conditionally assembled with one sub arch (modulo arch/arm/delay-loop.S which conditionally is assembled as armv4 based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the .arch assembler directive. Add a few more instances found in compile testing as found by Arnd and Nathan. Link: https://github.com/llvm/llvm-project/commit/1d51c699b9e2ebc5bcfdbe85c74cc871426333d4 Link: https://bugs.llvm.org/show_bug.cgi?id=48894 Link: https://github.com/ClangBuiltLinux/linux/issues/1195 Link: https://github.com/ClangBuiltLinux/linux/issues/1315 Suggested-by: Arnd Bergmann Suggested-by: Nathan Chancellor Signed-off-by: Arnd Bergmann Tested-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Signed-off-by: Russell King (Oracle)

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

ARM: 8844/1: use unified assembler in assembly files

2019-02-26T11:26:07Z

Use unified assembler syntax (UAL) in assembly files. Divided syntax is considered deprecated. This will also allow to build the kernel using LLVM's integrated assembler. Signed-off-by: Stefan Agner Acked-by: Nicolas Pitre Signed-off-by: Russell King

ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+

2014-07-18T11:29:04Z

ARMv6 and greater introduced a new instruction ("bx") which can be used to return from function calls. Recent CPUs perform better when the "bx lr" instruction is used rather than the "mov pc, lr" instruction, and this sequence is strongly recommended to be used by the ARM architecture manual (section A.4.1.1). We provide a new macro "ret" with all its variants for the condition code which will resolve to the appropriate instruction. Rather than doing this piecemeal, and miss some instances, change all the "mov pc" instances to use the new macro, with the exception of the "movs" instruction and the kprobes code. This allows us to detect the "mov pc, lr" case and fix it up - and also gives us the possibility of deploying this for other registers depending on the CPU selection. Reported-by: Will Deacon Tested-by: Stephen Warren # Tegra Jetson TK1 Tested-by: Robert Jarzmik # mioa701_bootresume.S Tested-by: Andrew Lunn # Kirkwood Tested-by: Shawn Guo Tested-by: Tony Lindgren # OMAPs Tested-by: Gregory CLEMENT # Armada XP, 375, 385 Acked-by: Sekhar Nori # DaVinci Acked-by: Christoffer Dall # kvm/hyp Acked-by: Haojian Zhuang # PXA3xx Acked-by: Stefano Stabellini # Xen Tested-by: Uwe Kleine-König # ARMv7M Tested-by: Simon Horman # Shmobile Signed-off-by: Russell King

ARM: mm: implement LoUIS API for cache maintenance ops

2012-09-25T10:20:25Z

ARM v7 architecture introduced the concept of cache levels and related control registers. New processors like A7 and A15 embed an L2 unified cache controller that becomes part of the cache level hierarchy. Some operations in the kernel like cpu_suspend and __cpu_disable do not require a flush of the entire cache hierarchy to DRAM but just the cache levels belonging to the Level of Unification Inner Shareable (LoUIS), which in most of ARM v7 systems correspond to L1. The current cache flushing API used in cpu_suspend and __cpu_disable, flush_cache_all(), ends up flushing the whole cache hierarchy since for v7 it cleans and invalidates all cache levels up to Level of Coherency (LoC) which cripples system performance when used in hot paths like hotplug and cpuidle. Therefore a new kernel cache maintenance API must be added to cope with latest ARM system requirements. This patch adds flush_cache_louis() to the ARM kernel cache maintenance API. This function cleans and invalidates all data cache levels up to the Level of Unification Inner Shareable (LoUIS) and invalidates the instruction cache for processors that support it (> v7). This patch also creates an alias of the cache LoUIS function to flush_kern_all for all processor versions prior to v7, so that the current cache flushing behaviour is unchanged for those processors. v7 cache maintenance code implements a cache LoUIS function that cleans and invalidates the D-cache up to LoUIS and invalidates the I-cache, according to the new API. Reviewed-by: Santosh Shilimkar Reviewed-by: Nicolas Pitre Signed-off-by: Lorenzo Pieralisi Tested-by: Shawn Guo