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path: root/lib/sbi/riscv_locks.c
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2026-03-10lib: Use proper add opcode on RV32 with ZalrscMarti Alonso
The addw opcode is only defined in RV64, which produces 32-bit results. On RV32, the default add opcode already produces 32-bit results. Fixes: 995f226f3f33 ("lib: Emit lr and sc instructions based on -march flags") Signed-off-by: Marti Alonso <[email protected]> Reviewed-by: Anup Patel <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Anup Patel <[email protected]>
2025-12-28lib: atomics: fix AMO test macrosVladimir Kondratiev
The "RISC-V C API" [1] defines architecture extension test macros says naming rule for the test macros is __riscv_<ext_name>, where <ext_name> is all lower-case. Three extensions dealing with atomics implementation are: "zaamo" consists of AMO instructions, "zalrsc" - LR/SC, "a" extension means both "zaamo" and "zalrsc" Built-in test macros are __riscv_a, __riscv_zaamo and __riscv_zalrsc. Alternative to the __riscv_a macro name, __riscv_atomic, is deprecated. Use correct test macro __riscv_zaamo for the AMO variant of atomics. It used to be __riscv_atomic that is both deprecated and incorrect because it tests for the "a" extension; i.e. both "zaamo" and "zalrsc" If ISA enables only zaamo but not zalrsc, code as it was would not compile. Older toolchains may have neither __riscv_zaamo nor __riscv_zalrsc, so query __riscv_atomic - it should be treated as both __riscv_zaamo and __riscv_zalrsc, in all present cases __riscv_zaamo is more favorable so take is as alternative for __riscv_zaamo [1] https://github.com/riscv-non-isa/riscv-c-api-doc Signed-off-by: Vladimir Kondratiev <[email protected]> Reviewed-by: Anup Patel <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Anup Patel <[email protected]>
2025-03-28lib: Emit lr and sc instructions based on -march flagsChao-ying Fu
When -march=rv64im_zalrsc_zicsr is used, provide atomic operations and locks using lr and sc instructions only. Signed-off-by: Chao-ying Fu <[email protected]> Reviewed-by: Anup Patel <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Anup Patel <[email protected]>
2021-05-14lib: sbi: Have spinlock checks return boolDaniel Schaefer
spin_lock_check already returned bool in the source file but not in the header. With some toolchains that causes an error, as it should. Because it and related functions all essentially return a bool, we can use this opportunity to change them. Signed-off-by: Daniel Schaefer <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2021-04-09lib: sbi: Replace test-and-set locks by ticket locksChristoph Muellner
Replace the test-and-set spinlock implementation with ticket locks in order to get fairness (in form of FIFO order). The implementation uses a 32-bit wide struct, which consists of two 16-bit counters (owner and next). This is inspired by similar spinlock implementations on other architectures. This allows that the code works for both, RV32 and RV64. Signed-off-by: Christoph Muellner <[email protected]> Reviewed-by: Anup Patel <[email protected]> Reviewed-by: Xiang W <[email protected]>
2019-06-19lib: Move sbi core library to lib/sbiAtish Patra
Signed-off-by: Atish Patra <[email protected]> Acked-by: Anup Patel <[email protected]>