diff options
| author | Rick Chen <rick@andestech.com> | 2022-09-21 14:34:54 +0800 |
|---|---|---|
| committer | Leo Yu-Chi Liang <ycliang@andestech.com> | 2022-09-26 14:29:13 +0800 |
| commit | e0465f80bd33f239612ee9f0ee7b6cf13d2f5b4d (patch) | |
| tree | ddd81b0d82d1c0e8abf0b80853fdde07407bd5e6 /arch/riscv/cpu/start.S | |
| parent | c2bdf02c9d40da7154fea46b7d10343fe9f14209 (diff) | |
riscv: Introduce AVAILABLE_HARTS
In SMP all harts will register themself in available_hart
during start up. Then main hart will send IPI to other harts
according to this variables. But this mechanism may not
guarantee that all other harts can jump to next stage.
When main hart is sending IPI to other hart according to
available_harts, but other harts maybe still not finish the
registration. Then the SMP booting will miss some harts finally.
So let it become an option and it will be enabled by default.
Please refer to the discussion:
https://www.mail-archive.com/u-boot@lists.denx.de/msg449997.html
Signed-off-by: Rick Chen <rick@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Diffstat (limited to 'arch/riscv/cpu/start.S')
| -rw-r--r-- | arch/riscv/cpu/start.S | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index de9d078da1..4687bca3c9 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -153,21 +153,23 @@ call_harts_early_init: SREG tp, GD_BOOT_HART(gp) #if !CONFIG_IS_ENABLED(XIP) +#ifdef CONFIG_AVAILABLE_HARTS la t0, available_harts_lock amoswap.w.rl zero, zero, 0(t0) +#endif wait_for_gd_init: - la t0, available_harts_lock - li t1, 1 -1: amoswap.w.aq t1, t1, 0(t0) - bnez t1, 1b - /* * Set the global data pointer only when gd_t has been initialized. * This was already set by arch_setup_gd on the boot hart, but all other * harts' global data pointers gets set here. */ mv gp, s0 +#ifdef CONFIG_AVAILABLE_HARTS + la t0, available_harts_lock + li t1, 1 +1: amoswap.w.aq t1, t1, 0(t0) + bnez t1, 1b /* register available harts in the available_harts mask */ li t1, 1 @@ -177,6 +179,7 @@ wait_for_gd_init: SREG t2, GD_AVAILABLE_HARTS(gp) amoswap.w.rl zero, zero, 0(t0) +#endif /* * Continue on hart lottery winner, others branch to |