[PATCH V6 0/2] riscv: Support qspinlock with generic headers

Waiman Long longman at redhat.com
Tue Jun 21 08:08:21 PDT 2022


On 6/21/22 10:49, guoren at kernel.org wrote:
> From: Guo Ren <guoren at linux.alibaba.com>
>
> Enable qspinlock and meet the requirements mentioned in a8ad07e5240c9
> ("asm-generic: qspinlock: Indicate the use of mixed-size atomics").
>
> RISC-V LR/SC pairs could provide a strong/weak forward guarantee that
> depends on micro-architecture. And RISC-V ISA spec has given out
> several limitations to let hardware support strict forward guarantee
> (RISC-V User ISA - 8.3 Eventual Success of Store-Conditional
> Instructions):
> We restricted the length of LR/SC loops to fit within 64 contiguous
> instruction bytes in the base ISA to avoid undue restrictions on
> instruction cache and TLB size and associativity. Similarly, we

Does the 64 contiguous bytes need to be cacheline aligned?

Regards,
Longman




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