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path: root/arch/loongarch/include/asm/cmpxchg.h
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2023-04-29locking/arch: Rename all internal __xchg() names to __arch_xchg()Andrzej Hajda1-2/+2
Decrease the probability of this internal facility to be used by driver code. Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Palmer Dabbelt <palmer@rivosinc.com> [riscv] Link: https://lore.kernel.org/r/20230118154450.73842-1-andrzej.hajda@intel.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
2022-10-12LoongArch: Mark __xchg() and __cmpxchg() as __always_inlineHuacai Chen1-4/+4
Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") allows compiler to uninline functions marked as 'inline'. In case of __xchg()/__cmpxchg() this would cause to reference BUILD_BUG(), which is an error case for catching bugs and will not happen for correct code, if __xchg()/__cmpxchg() is inlined. This bug can be produced with CONFIG_DEBUG_SECTION_MISMATCH enabled, and the solution is similar to below commits: 46f1619500d0225 ("MIPS: include: Mark __xchg as __always_inline"), 88356d09904bc60 ("MIPS: include: Mark __cmpxchg as __always_inline"). Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-08-25LoongArch: Add subword xchg/cmpxchg emulationHuacai Chen1-1/+97
LoongArch only support 32-bit/64-bit xchg/cmpxchg in native. But percpu operation, qspinlock and some drivers need 8-bit/16-bit xchg/cmpxchg. We add subword xchg/cmpxchg emulation in this patch because the emulation has better performance than the generic implementation (on NUMA system), and it can fix some build errors meanwhile [1]. LoongArch's guarantee for forward progress (avoid many ll/sc happening at the same time and no one succeeds): We have the "exclusive access (with timeout) of ll" feature to avoid simultaneous ll (which also blocks other memory load/store on the same address), and the "random delay of sc" feature to avoid simultaneous sc. It is a mandatory requirement for multi-core LoongArch processors to implement such features, only except those single-core and dual-core processors (they also don't support multi-chip interconnection). Feature bits are introduced in CPUCFG3, bit 3 and bit 4 [2]. [1] https://lore.kernel.org/loongarch/CAAhV-H6vvkuOzy8OemWdYK3taj5Jn3bFX0ZTwE=twM8ywpBUYA@mail.gmail.com/T/#t [2] https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_cpucfg Reported-by: Sudip Mukherjee (Codethink) <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rui Wang <wangrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-07-29LoongArch: Simplify "BEQ/BNE foo, zero" with BEQZ/BNEZWANG Xuerui1-1/+1
While B{EQ,NE}Z and B{EQ,NE} are different instructions, and the vastly expanded range for branch destination does not really matter in the few cases touched, use the B{EQ,NE}Z where possible for shorter lines and better consistency (e.g. some places used "BEQ foo, zero", while some used "BEQ zero, foo"). Signed-off-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-07-29LoongArch: Use the "move" pseudo-instruction where applicableWANG Xuerui1-1/+1
Some of the assembly code in the LoongArch port likely originated from a time when the assembler did not support pseudo-instructions like "move" or "jr", so the desugared form was used and readability suffers (to a minor degree) as a result. As the upstream toolchain supports these pseudo-instructions from the beginning, migrate the existing few usages to them for better readability. Signed-off-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03LoongArch: Add multi-processor (SMP) supportHuacai Chen1-0/+1
LoongArch-based procesors have 4, 8 or 16 cores per package. This patch adds multi-processor (SMP) support for LoongArch. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03LoongArch: Add atomic/locking headersHuacai Chen1-0/+122
Add common headers (atomic, bitops, barrier and locking) for basic LoongArch support. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>