linux/arch/mips/kernel/unaligned.c, branch v6.3

MIPS: Handle address errors for accesses above CPU max virtual user address

2022-02-25T08:36:05Z

Address errors have always been treated as unaliged accesses and handled as such. But address errors are also issued for illegal accesses like user to kernel space or accesses outside of implemented spaces. This change implements Linux exception handling for accesses to the illegal space above the CPU implemented maximum virtual user address and the MIPS 64bit architecture maximum. With this we can now use a fixed value for the maximum task size on every MIPS CPU and get a more optimized access_ok(). Signed-off-by: Thomas Bogendoerfer Signed-off-by: Arnd Bergmann

MIPS: Fix new sparse warnings

2021-04-07T14:11:05Z

Commit 45deb5faeb9e ("MIPS: uaccess: Remove get_fs/set_fs call sites") caused a few new sparse warnings, fix them. Signed-off-by: Thomas Bogendoerfer

MIPS: uaccess: Remove get_fs/set_fs call sites

2021-04-06T12:36:56Z

Use new helpers to access user/kernel for functions, which are used with user/kernel pointers. Instead of dealing with get_fs/set_fs select user/kernel access via parameter. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

uaccess: add force_uaccess_{begin,end} helpers

2020-08-12T17:57:59Z

Add helpers to wrap the get_fs/set_fs magic for undoing any damange done by set_fs(KERNEL_DS). There is no real functional benefit, but this documents the intent of these calls better, and will allow stubbing the functions out easily for kernels builds that do not allow address space overrides in the future. [hch@lst.de: drop two incorrect hunks, fix a commit log typo] Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Acked-by: Linus Torvalds Acked-by: Mark Rutland Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven Cc: Nick Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de Signed-off-by: Linus Torvalds

MIPS: Fix build warning about "PTR_STR" redefinition

2020-05-30T08:58:30Z

PTR_STR is redefined when CONFIG_TEST_PRINTF is set. This causes the following build warning: CC lib/test_printf.o lib/test_printf.c:214:0: warning: "PTR_STR" redefined #define PTR_STR "ffff0123456789ab" ^ In file included from ./arch/mips/include/asm/dsemul.h:11:0, from ./arch/mips/include/asm/processor.h:22, from ./arch/mips/include/asm/thread_info.h:16, from ./include/linux/thread_info.h:38, from ./include/asm-generic/preempt.h:5, from ./arch/mips/include/generated/asm/preempt.h:1, from ./include/linux/preempt.h:78, from ./include/linux/spinlock.h:51, from ./include/linux/seqlock.h:36, from ./include/linux/time.h:6, from ./include/linux/stat.h:19, from ./include/linux/module.h:13, from lib/test_printf.c:10: ./arch/mips/include/asm/inst.h:20:0: note: this is the location of the previous definition #define PTR_STR ".dword" ^ Instead of renaming PTR_STR we move the unaligned macros to a new file, which is only included inside MIPS code. This way we can safely include asm.h and can use STR(PTR) again. Fixes: e701656ec4db ("MIPS: inst.h: Stop including asm.h to avoid various build failures") Cc: Maciej W. Rozycki" Reported-by: Tiezhu Yang Co-developed-by: Huacai Chen Signed-off-by: Huacai Chen Signed-off-by: Thomas Bogendoerfer

MIPS: Move unaligned load/store helpers to inst.h

2020-04-24T16:18:06Z

Move unaligned load/store helpers from unaligned.c to inst.h, then other parts of the kernel can use these helpers. Use __ASSEMBLY__ to guard the definition of "LONG" in asm.h to avoid build error on IPxx platforms. Signed-off-by: Huacai Chen Signed-off-by: Pei Huang Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer

MIPS: make CPU_HAS_LOAD_STORE_LR opt-out

2020-01-22T18:16:47Z

CPU_HAS_LOAD_STORE_LR was introduced in 932afdeec18b ("MIPS: Add Kconfig variable for CPUs with unaligned load/store instructions") to make code in kernel/unaligned.c and lib/mem{cpy,set}.S more intuitive and give a possibility to easily add new CPUs without these instruction sets in future. Hovewer, this variant is not optimal for mainly two reasons: * For now, we have 20+ CPUs with such instructions and only two (MIPS R6) without. It will obviously be more effective and straightforward to have an option for these two rather than for the rest. * You can easily miss the fact that you need to select this option when adding a new CPU, while all processors lacking these sets are well-known, so the probability of missing something is way much lower. We can address both points by turning CPU_HAS_LOAD_STORE_LR into opt-out CPU_NO_LOAD_STORE_LR. This also makes MIPS root Kconfig more clear and understandable. Signed-off-by: Alexander Lobakin Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: Alexandre Belloni Cc: Microchip Linux Driver Support Cc: Will Deacon Cc: Greg Kroah-Hartman Cc: Masahiro Yamada Cc: Paul Walmsley Cc: Michal Simek Cc: Allison Randal Cc: Thomas Gleixner Cc: Eric W. Biederman Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

signal: Remove task parameter from force_sig

2019-05-27T14:36:28Z

All of the remaining callers pass current into force_sig so remove the task parameter to make this obvious and to make misuse more difficult in the future. This also makes it clear force_sig passes current into force_sig_info. Signed-off-by: "Eric W. Biederman"

MIPS: MemoryMapID (MMID) Support

2019-02-04T18:56:41Z

Introduce support for using MemoryMapIDs (MMIDs) as an alternative to Address Space IDs (ASIDs). The major difference between the two is that MMIDs are global - ie. an MMID uniquely identifies an address space across all coherent CPUs. In contrast ASIDs are non-global per-CPU IDs, wherein each address space is allocated a separate ASID for each CPU upon which it is used. This global namespace allows a new GINVT instruction be used to globally invalidate TLB entries associated with a particular MMID across all coherent CPUs in the system, removing the need for IPIs to invalidate entries with separate ASIDs on each CPU. The allocation scheme used here is largely borrowed from arm64 (see arch/arm64/mm/context.c). In essence we maintain a bitmap to track available MMIDs, and MMIDs in active use at the time of a rollover to a new MMID version are preserved in the new version. The allocation scheme requires efficient 64 bit atomics in order to perform reasonably, so this support depends upon CONFIG_GENERIC_ATOMIC64=n (ie. currently it will only be included in MIPS64 kernels). The first, and currently only, available CPU with support for MMIDs is the MIPS I6500. This CPU supports 16 bit MMIDs, and so for now we cap our MMIDs to 16 bits wide in order to prevent the bitmap growing to absurd sizes if any future CPU does implement 32 bit MMIDs as the architecture manuals suggest is recommended. When MMIDs are in use we also make use of GINVT instruction which is available due to the global nature of MMIDs. By executing a sequence of GINVT & SYNC 0x14 instructions we can avoid the overhead of an IPI to each remote CPU in many cases. One complication is that GINVT will invalidate wired entries (in all cases apart from type 0, which targets the entire TLB). In order to avoid GINVT invalidating any wired TLB entries we set up, we make sure to create those entries using a reserved MMID (0) that we never associate with any address space. Also of note is that KVM will require further work in order to support MMIDs & GINVT, since KVM is involved in allocating IDs for guests & in configuring the MMU. That work is not part of this patch, so for now when MMIDs are in use KVM is disabled. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org

mips: kernel: no need to check return value of debugfs_create functions

2019-01-22T19:17:20Z

When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Cc: Ralf Baechle Cc: Paul Burton Cc: James Hogan Cc: Yangtao Li Cc: Andrew Morton Cc: Mike Rapoport Cc: Mathieu Malaterre Cc: Huacai Chen Cc: Marcin Nowakowski Cc: Yasha Cherikovsky Cc: linux-mips@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Paul Burton