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 <vladimir.kondratiev@mobileye.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20251228073321.1533844-1-vladimir.kondratiev@mobileye.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Simplify atomic-related bit operations through __atomic intrinsics.
Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
The original code returns the value of the word before modification.
When modifying the upper 32 bits under RV64, the value returned via
int return will have no meaning. Corrected to return the value of the
bit. And modify the function description.
Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
lr/sc is part of the A extension. If the A extension is not supported,
lr/sc cannot be used. So remove xchg/cmpxchg.
Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
The unsigned length may be 4 bytes or 8 bytes, amoadd.w only applies
to 4 bytes hence this patch.
Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
We should remove the "arch_" prefix from atomic xchg() and cmpxchg()
function names to have consistent naming of all atomic functions.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This fixes various coding style issues found in the SBI codes.
No functional changes.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
The right location for all bits related defines and macros is
sbi_bitops.h hence this patch. With this patch, the sbi_bits.h
is redundant so we remove it.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
There is a typo in atomic operations code which prevents the
usage of riscv atomic instructions even if it is supported.
Fix the typo.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
If compiler supports riscv atomic instructions, we should
use them instead of legacy gcc built-in macros
__sync_lock_test_and_set in atomic exchange functions.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
