diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 86553d8c6b07b3ae666e5241162b5bf5bc3cfdf7..fd60ab94260b45e4bb72f81601cfa0ca037d5259 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -374,6 +374,20 @@ config RISCV_SBI_V01 This config allows kernel to use SBI v0.1 APIs. This will be deprecated in future once legacy M-mode software are no longer in use. +config RISCV_BOOT_SPINWAIT + bool "Spinwait booting method" + depends on SMP + default y + help + This enables support for booting Linux via spinwait method. In the + spinwait method, all cores randomly jump to Linux. One of the cores + gets chosen via lottery and all other keep spinning on a percpu + variable. This method cannot support CPU hotplug and sparse hartid + scheme. It should be only enabled for M-mode Linux or platforms relying + on older firmware without SBI HSM extension. All other platforms should + rely on ordered booting via SBI HSM extension which gets chosen + dynamically at runtime if the firmware supports it. + config KEXEC bool "Kexec system call" select KEXEC_CORE diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 3397ddac1a30caeab19cc7ee7fc99ff58a52fd7a..612556faa527f583cf6fc3bc9a737adcaa18a105 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -43,7 +43,8 @@ obj-$(CONFIG_FPU) += fpu.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_SMP) += cpu_ops.o -obj-$(CONFIG_SMP) += cpu_ops_spinwait.o + +obj-$(CONFIG_RISCV_BOOT_SPINWAIT) += cpu_ops_spinwait.o obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_MODULE_SECTIONS) += module-sections.o diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c index c1e30f403c3b463a7fbaf615aa14bdebabefa0fe..170d07e577215b2c40c23da0332b2a2c28a322a0 100644 --- a/arch/riscv/kernel/cpu_ops.c +++ b/arch/riscv/kernel/cpu_ops.c @@ -15,7 +15,15 @@ const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init; extern const struct cpu_operations cpu_ops_sbi; +#ifdef CONFIG_RISCV_BOOT_SPINWAIT extern const struct cpu_operations cpu_ops_spinwait; +#else +const struct cpu_operations cpu_ops_spinwait = { + .name = "", + .cpu_prepare = NULL, + .cpu_start = NULL, +}; +#endif void __init cpu_set_ops(int cpuid) { diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index b0766f62bd730aee6ae8db38fd7331c5eeb98027..2363b43312fc6490cb7327c420631fbe5ea58163 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -259,7 +259,7 @@ pmp_done: li t0, SR_FS csrc CSR_STATUS, t0 -#ifdef CONFIG_SMP +#ifdef CONFIG_RISCV_BOOT_SPINWAIT li t0, CONFIG_NR_CPUS blt a0, t0, .Lgood_cores tail .Lsecondary_park @@ -285,7 +285,7 @@ pmp_done: beq t0, t1, .Lsecondary_start #endif /* CONFIG_XIP */ -#endif /* CONFIG_SMP */ +#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ #ifdef CONFIG_XIP_KERNEL la sp, _end + THREAD_SIZE @@ -344,7 +344,7 @@ clear_bss_done: call soc_early_init tail start_kernel -#ifdef CONFIG_SMP +#if CONFIG_RISCV_BOOT_SPINWAIT .Lsecondary_start: /* Set trap vector to spin forever to help debug */ la a3, .Lsecondary_park @@ -371,7 +371,7 @@ clear_bss_done: fence tail .Lsecondary_start_common -#endif +#endif /* CONFIG_RISCV_BOOT_SPINWAIT */ END(_start_kernel) diff --git a/arch/riscv/kernel/head.h b/arch/riscv/kernel/head.h index 5393cca777901e37ae071f93c147bc9c278031a7..726731ada5349c3e5cc58765ce5d94dae0edfb58 100644 --- a/arch/riscv/kernel/head.h +++ b/arch/riscv/kernel/head.h @@ -16,7 +16,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa); asmlinkage void __init __copy_data(void); #endif +#ifdef CONFIG_RISCV_BOOT_SPINWAIT extern void *__cpu_spinwait_stack_pointer[]; extern void *__cpu_spinwait_task_pointer[]; +#endif #endif /* __ASM_HEAD_H */