diff options
| author | Yao Zi <ziyao@disroot.org> | 2025-09-02 08:19:32 +0000 |
|---|---|---|
| committer | Leo Yu-Chi Liang <ycliang@andestech.com> | 2025-09-19 19:22:29 +0800 |
| commit | a681cfecb4346107212f377e2075f6eb1bdc6a2b (patch) | |
| tree | 8b0ab52b167fbe04b90fe22d0e37c1969f2c0fec | |
| parent | 06b22f38af96ba9d347f2f70bc5ab8d41dd79312 (diff) | |
riscv: Add a Zalrsc-only alternative for synchronization in start.S
Add an alternative implementation that use Zalrsc extension only for
HART lottery and SMP locking to support SMP on cores without "Zaamo"
extension available. The Zaamo implementation is still prioritized if
both of them are available, since it takes fewer instructions.
Signed-off-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
| -rw-r--r-- | arch/riscv/cpu/start.S | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index 7bafdfd390a..6324ff585d4 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -151,9 +151,16 @@ call_harts_early_init: */ la t0, hart_lottery li t1, 1 +#if CONFIG_IS_ENABLED(RISCV_ISA_ZAAMO) amoswap.w s2, t1, 0(t0) bnez s2, wait_for_gd_init #else + lr.w s2, (t0) + bnez s2, wait_for_gd_init + sc.w s2, t1, (t0) + bnez s2, wait_for_gd_init +#endif +#else /* * FIXME: gp is set before it is initialized. If an XIP U-Boot ever * encounters a pending IPI on boot it is liable to jump to whatever @@ -177,7 +184,12 @@ call_harts_early_init: #if !CONFIG_IS_ENABLED(XIP) #ifdef CONFIG_AVAILABLE_HARTS la t0, available_harts_lock +#if CONFIG_IS_ENABLED(RISCV_ISA_ZAAMO) amoswap.w.rl zero, zero, 0(t0) +#else + fence rw, w + sw zero, 0(t0) +#endif #endif wait_for_gd_init: @@ -190,7 +202,14 @@ wait_for_gd_init: #ifdef CONFIG_AVAILABLE_HARTS la t0, available_harts_lock li t1, 1 -1: amoswap.w.aq t1, t1, 0(t0) +1: +#if CONFIG_IS_ENABLED(RISCV_ISA_ZAAMO) + amoswap.w.aq t1, t1, 0(t0) +#else + lr.w.aq t1, 0(t0) + bnez t1, 1b + sc.w.rl t1, t1, 0(t0) +#endif bnez t1, 1b /* register available harts in the available_harts mask */ @@ -200,7 +219,12 @@ wait_for_gd_init: or t2, t2, t1 SREG t2, GD_AVAILABLE_HARTS(gp) +#if CONFIG_IS_ENABLED(RISCV_ISA_ZAAMO) amoswap.w.rl zero, zero, 0(t0) +#else + fence rw, w + sw zero, 0(t0) +#endif #endif /* |