From: Rick Chen rick@andestech.com
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 --- arch/riscv/Kconfig | 7 +++++++ arch/riscv/cpu/cpu.c | 2 ++ arch/riscv/cpu/start.S | 13 ++++++++----- arch/riscv/include/asm/global_data.h | 2 ++ arch/riscv/lib/asm-offsets.c | 2 ++ arch/riscv/lib/smp.c | 2 ++ 6 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index c042506a64..32a90b83b5 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -276,6 +276,13 @@ config SPL_XIP rely on lock variables (for example hart_lottery and available_harts_lock), this affects only SPL, other stages should proceed as non-XIP.
+config AVAILABLE_HARTS + bool "Send IPI by available harts" + default y + help + By default, IPI sending mechanism will depend on available_harts. + If disable this, it will send IPI by CPUs node numbers of device tree. + config SHOW_REGS bool "Show registers on unhandled exception"
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index 0f323b26b3..52ab02519f 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -22,12 +22,14 @@ #if !CONFIG_IS_ENABLED(XIP) u32 hart_lottery __section(".data") = 0;
+#ifdef CONFIG_AVAILABLE_HARTS /* * The main hart running U-Boot has acquired available_harts_lock until it has * finished initialization of global data. */ u32 available_harts_lock = 1; #endif +#endif
static inline bool supports_extension(char ext) { 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 diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h index b3c79e1760..858594a191 100644 --- a/arch/riscv/include/asm/global_data.h +++ b/arch/riscv/include/asm/global_data.h @@ -28,8 +28,10 @@ struct arch_global_data { struct ipi_data ipi[CONFIG_NR_CPUS]; #endif #if !CONFIG_IS_ENABLED(XIP) +#ifdef CONFIG_AVAILABLE_HARTS ulong available_harts; #endif +#endif };
#include <asm-generic/global_data.h> diff --git a/arch/riscv/lib/asm-offsets.c b/arch/riscv/lib/asm-offsets.c index c4f48c8373..452dfcea97 100644 --- a/arch/riscv/lib/asm-offsets.c +++ b/arch/riscv/lib/asm-offsets.c @@ -17,7 +17,9 @@ int main(void) DEFINE(GD_BOOT_HART, offsetof(gd_t, arch.boot_hart)); DEFINE(GD_FIRMWARE_FDT_ADDR, offsetof(gd_t, arch.firmware_fdt_addr)); #if !CONFIG_IS_ENABLED(XIP) +#ifdef CONFIG_AVAILABLE_HARTS DEFINE(GD_AVAILABLE_HARTS, offsetof(gd_t, arch.available_harts)); +#endif #endif
return 0; diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index f8b756291f..c0f65af191 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -46,9 +46,11 @@ static int send_ipi_many(struct ipi_data *ipi, int wait) }
#if !CONFIG_IS_ENABLED(XIP) +#ifdef CONFIG_AVAILABLE_HARTS /* skip if hart is not available */ if (!(gd->arch.available_harts & (1 << reg))) continue; +#endif #endif
gd->arch.ipi[reg].addr = ipi->addr;