diff options
Diffstat (limited to 'arch/riscv/kernel/cpu_ops_spinwait.c')
| -rw-r--r-- | arch/riscv/kernel/cpu_ops_spinwait.c | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/arch/riscv/kernel/cpu_ops_spinwait.c b/arch/riscv/kernel/cpu_ops_spinwait.c index b2c957bb68c1..24869eb88908 100644 --- a/arch/riscv/kernel/cpu_ops_spinwait.c +++ b/arch/riscv/kernel/cpu_ops_spinwait.c @@ -6,19 +6,36 @@ #include <linux/errno.h> #include <linux/of.h> #include <linux/string.h> +#include <linux/sched/task_stack.h> #include <asm/cpu_ops.h> #include <asm/sbi.h> #include <asm/smp.h> +#include "head.h" + const struct cpu_operations cpu_ops_spinwait; +void *__cpu_spinwait_stack_pointer[NR_CPUS] __section(".data"); +void *__cpu_spinwait_task_pointer[NR_CPUS] __section(".data"); -static int spinwait_cpu_prepare(unsigned int cpuid) +static void cpu_update_secondary_bootdata(unsigned int cpuid, + struct task_struct *tidle) { - if (!cpu_ops_spinwait.cpu_start) { - pr_err("cpu start method not defined for CPU [%d]\n", cpuid); - return -ENODEV; - } - return 0; + unsigned long hartid = cpuid_to_hartid_map(cpuid); + + /* + * The hartid must be less than NR_CPUS to avoid out-of-bound access + * errors for __cpu_spinwait_stack/task_pointer. That is not always possible + * for platforms with discontiguous hartid numbering scheme. That's why + * spinwait booting is not the recommended approach for any platforms + * booting Linux in S-mode and can be disabled in the future. + */ + if (hartid == INVALID_HARTID || hartid >= (unsigned long) NR_CPUS) + return; + + /* Make sure tidle is updated */ + smp_mb(); + WRITE_ONCE(__cpu_spinwait_stack_pointer[hartid], task_pt_regs(tidle)); + WRITE_ONCE(__cpu_spinwait_task_pointer[hartid], tidle); } static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle) @@ -28,7 +45,7 @@ static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle) * selects the first cpu to boot the kernel and causes the remainder * of the cpus to spin in a loop waiting for their stack pointer to be * setup by that main cpu. Writing to bootdata - * (i.e __cpu_up_stack_pointer) signals to the spinning cpus that they + * (i.e __cpu_spinwait_stack_pointer) signals to the spinning cpus that they * can continue the boot process. */ cpu_update_secondary_bootdata(cpuid, tidle); @@ -37,7 +54,5 @@ static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle) } const struct cpu_operations cpu_ops_spinwait = { - .name = "spinwait", - .cpu_prepare = spinwait_cpu_prepare, .cpu_start = spinwait_cpu_start, }; |