kernel.git/arch/arm64/mm/cache.S, branch linux-5.10.y

arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer

2022-06-25T13:16:09Z

commit c50f11c6196f45c92ca48b16a5071615d4ae0572 upstream. Invalidating the buffer memory in arch_sync_dma_for_device() for FROM_DEVICE transfers When using the streaming DMA API to map a buffer prior to inbound non-coherent DMA (i.e. DMA_FROM_DEVICE), we invalidate any dirty CPU cachelines so that they will not be written back during the transfer and corrupt the buffer contents written by the DMA. This, however, poses two potential problems: (1) If the DMA transfer does not write to every byte in the buffer, then the unwritten bytes will contain stale data once the transfer has completed. (2) If the buffer has a virtual alias in userspace, then stale data may be visible via this alias during the period between performing the cache invalidation and the DMA writes landing in memory. Address both of these issues by cleaning (aka writing-back) the dirty lines in arch_sync_dma_for_device(DMA_FROM_DEVICE) instead of discarding them using invalidation. Cc: Ard Biesheuvel Cc: Christoph Hellwig Cc: Robin Murphy Cc: Russell King Cc: Link: https://lore.kernel.org/r/20220606152150.GA31568@willie-the-truck Signed-off-by: Will Deacon Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20220610151228.4562-2-will@kernel.org Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman

arm64: mm: Use modern annotations for assembly functions

2020-01-08T12:23:38Z

In an effort to clarify and simplify the annotation of assembly functions in the kernel new macros have been introduced. These replace ENTRY and ENDPROC and also add a new annotation for static functions which previously had no ENTRY equivalent. Update the annotations in the mm code to the new macros. Even the functions called from non-standard environments like idmap have no special requirements on their environments so can be treated like regular functions. Signed-off-by: Mark Brown Signed-off-by: Will Deacon

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

2019-06-19T15:09:07Z

Based on 1 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 distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Reviewed-by: Enrico Weigelt Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman

arm64: Fix minor issues with the dcache_by_line_op macro

2018-12-10T15:03:51Z

The dcache_by_line_op macro suffers from a couple of small problems: First, the GAS directives that are currently being used rely on assembler behavior that is not documented, and probably not guaranteed to produce the correct behavior going forward. As a result, we end up with some undefined symbols in cache.o: $ nm arch/arm64/mm/cache.o ... U civac ... U cvac U cvap U cvau This is due to the fact that the comparisons used to select the operation type in the dcache_by_line_op macro are comparing symbols not strings, and even though it seems that GAS is doing the right thing here (undefined symbols by the same name are equal to each other), it seems unwise to rely on this. Second, when patching in a DC CVAP instruction on CPUs that support it, the fallback path consists of a DC CVAU instruction which may be affected by CPU errata that require ARM64_WORKAROUND_CLEAN_CACHE. Solve these issues by unrolling the various maintenance routines and using the conditional directives that are documented as operating on strings. To avoid the complexity of nested alternatives, we move the DC CVAP patching to __clean_dcache_area_pop, falling back to a branch to __clean_dcache_area_poc if DCPOP is not supported by the CPU. Reported-by: Ard Biesheuvel Suggested-by: Robin Murphy Signed-off-by: Will Deacon

arm64: IPI each CPU after invalidating the I-cache for kernel mappings

2018-07-05T16:24:36Z

When invalidating the instruction cache for a kernel mapping via flush_icache_range(), it is also necessary to flush the pipeline for other CPUs so that instructions fetched into the pipeline before the I-cache invalidation are discarded. For example, if module 'foo' is unloaded and then module 'bar' is loaded into the same area of memory, a CPU could end up executing instructions from 'foo' when branching into 'bar' if these instructions were fetched into the pipeline before 'foo' was unloaded. Whilst this is highly unlikely to occur in practice, particularly as any exception acts as a context-synchronizing operation, following the letter of the architecture requires us to execute an ISB on each CPU in order for the new instruction stream to be visible. Acked-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: Add support for new control bits CTR_EL0.DIC and CTR_EL0.IDC

2018-03-09T13:57:57Z

The DCache clean & ICache invalidation requirements for instructions to be data coherence are discoverable through new fields in CTR_EL0. The following two control bits DIC and IDC were defined for this purpose. No need to perform point of unification cache maintenance operations from software on systems where CPU caches are transparent. This patch optimize the three functions __flush_cache_user_range(), clean_dcache_area_pou() and invalidate_icache_range() if the hardware reports CTR_EL0.IDC and/or CTR_EL0.IDC. Basically it skips the two instructions 'DC CVAU' and 'IC IVAU', and the associated loop logic in order to avoid the unnecessary overhead. CTR_EL0.DIC: Instruction cache invalidation requirements for instruction to data coherence. The meaning of this bit[29]. 0: Instruction cache invalidation to the point of unification is required for instruction to data coherence. 1: Instruction cache cleaning to the point of unification is not required for instruction to data coherence. CTR_EL0.IDC: Data cache clean requirements for instruction to data coherence. The meaning of this bit[28]. 0: Data cache clean to the point of unification is required for instruction to data coherence, unless CLIDR_EL1.LoC == 0b000 or (CLIDR_EL1.LoUIS == 0b000 && CLIDR_EL1.LoUU == 0b000). 1: Data cache clean to the point of unification is not required for instruction to data coherence. Co-authored-by: Philip Elcan Reviewed-by: Mark Rutland Signed-off-by: Shanker Donthineni Signed-off-by: Will Deacon

arm64: mm: Add additional parameter to uaccess_ttbr0_disable

2018-01-17T12:57:49Z

Add an extra temporary register parameter to uaccess_ttbr0_disable which is about to be required for arm64 PAN support. This patch doesn't introduce any functional change but ensures that the kernel compiles once the KVM/ARM tree is merged with the arm64 tree by ensuring a trivially mergable conflict with commit 6b88a32c7af68895134872cdec3b6bfdb532d94e ("arm64: kpti: Fix the interaction between ASID switching and software PAN"). Cc: Will Deacon Acked-by: Catalin Marinas Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall

arm64: mm: Add additional parameter to uaccess_ttbr0_enable

2018-01-09T20:08:52Z

Add an extra temporary register parameter to uaccess_ttbr0_enable which is about to be required for arm64 PAN support. This patch doesn't introduce any functional change but ensures that the kernel compiles once the KVM/ARM tree is merged with the arm64 tree by ensuring a trivially mergable conflict with commit 27a921e75711d924617269e0ba4adb8bae9fd0d1 ("arm64: mm: Fix and re-enable ARM64_SW_TTBR0_PAN"). Cc: Will Deacon Cc: Catalin Marinas Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall

arm64: KVM: Add invalidate_icache_range helper

2018-01-08T14:20:43Z

We currently tightly couple dcache clean with icache invalidation, but KVM could do without the initial flush to PoU, as we've already flushed things to PoC. Let's introduce invalidate_icache_range which is limited to invalidating the icache from the linear mapping (and thus has none of the userspace fault handling complexity), and wire it in KVM instead of flush_icache_range. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall

arm64: Implement pmem API support

2017-08-09T11:15:45Z

Add a clean-to-point-of-persistence cache maintenance helper, and wire up the basic architectural support for the pmem driver based on it. Reviewed-by: Will Deacon Signed-off-by: Robin Murphy [catalin.marinas@arm.com: move arch_*_pmem() functions to arch/arm64/mm/flush.c] [catalin.marinas@arm.com: change dmb(sy) to dmb(osh)] Signed-off-by: Catalin Marinas