| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * SMP support for BPA machines. |
| * |
| * Dave Engebretsen, Peter Bergner, and |
| * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com |
| * |
| * Plus various changes from other IBM teams... |
| */ |
| |
| #undef DEBUG |
| |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/smp.h> |
| #include <linux/interrupt.h> |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| #include <linux/cache.h> |
| #include <linux/err.h> |
| #include <linux/device.h> |
| #include <linux/cpu.h> |
| |
| #include <asm/ptrace.h> |
| #include <linux/atomic.h> |
| #include <asm/irq.h> |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| #include <asm/io.h> |
| #include <asm/prom.h> |
| #include <asm/smp.h> |
| #include <asm/paca.h> |
| #include <asm/machdep.h> |
| #include <asm/cputable.h> |
| #include <asm/firmware.h> |
| #include <asm/rtas.h> |
| #include <asm/cputhreads.h> |
| #include <asm/code-patching.h> |
| |
| #include "interrupt.h" |
| #include <asm/udbg.h> |
| |
| #ifdef DEBUG |
| #define DBG(fmt...) udbg_printf(fmt) |
| #else |
| #define DBG(fmt...) |
| #endif |
| |
| /* |
| * The Primary thread of each non-boot processor was started from the OF client |
| * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. |
| */ |
| static cpumask_t of_spin_map; |
| |
| /** |
| * smp_startup_cpu() - start the given cpu |
| * |
| * At boot time, there is nothing to do for primary threads which were |
| * started from Open Firmware. For anything else, call RTAS with the |
| * appropriate start location. |
| * |
| * Returns: |
| * 0 - failure |
| * 1 - success |
| */ |
| static inline int smp_startup_cpu(unsigned int lcpu) |
| { |
| int status; |
| unsigned long start_here = |
| __pa(ppc_function_entry(generic_secondary_smp_init)); |
| unsigned int pcpu; |
| int start_cpu; |
| |
| if (cpumask_test_cpu(lcpu, &of_spin_map)) |
| /* Already started by OF and sitting in spin loop */ |
| return 1; |
| |
| pcpu = get_hard_smp_processor_id(lcpu); |
| |
| /* Fixup atomic count: it exited inside IRQ handler. */ |
| task_thread_info(paca_ptrs[lcpu]->__current)->preempt_count = 0; |
| |
| /* |
| * If the RTAS start-cpu token does not exist then presume the |
| * cpu is already spinning. |
| */ |
| start_cpu = rtas_token("start-cpu"); |
| if (start_cpu == RTAS_UNKNOWN_SERVICE) |
| return 1; |
| |
| status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu); |
| if (status != 0) { |
| printk(KERN_ERR "start-cpu failed: %i\n", status); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static void smp_cell_setup_cpu(int cpu) |
| { |
| if (cpu != boot_cpuid) |
| iic_setup_cpu(); |
| |
| /* |
| * change default DABRX to allow user watchpoints |
| */ |
| mtspr(SPRN_DABRX, DABRX_KERNEL | DABRX_USER); |
| } |
| |
| static int smp_cell_kick_cpu(int nr) |
| { |
| if (nr < 0 || nr >= nr_cpu_ids) |
| return -EINVAL; |
| |
| if (!smp_startup_cpu(nr)) |
| return -ENOENT; |
| |
| /* |
| * The processor is currently spinning, waiting for the |
| * cpu_start field to become non-zero After we set cpu_start, |
| * the processor will continue on to secondary_start |
| */ |
| paca_ptrs[nr]->cpu_start = 1; |
| |
| return 0; |
| } |
| |
| static struct smp_ops_t bpa_iic_smp_ops = { |
| .message_pass = iic_message_pass, |
| .probe = iic_request_IPIs, |
| .kick_cpu = smp_cell_kick_cpu, |
| .setup_cpu = smp_cell_setup_cpu, |
| .cpu_bootable = smp_generic_cpu_bootable, |
| }; |
| |
| /* This is called very early */ |
| void __init smp_init_cell(void) |
| { |
| int i; |
| |
| DBG(" -> smp_init_cell()\n"); |
| |
| smp_ops = &bpa_iic_smp_ops; |
| |
| /* Mark threads which are still spinning in hold loops. */ |
| if (cpu_has_feature(CPU_FTR_SMT)) { |
| for_each_present_cpu(i) { |
| if (cpu_thread_in_core(i) == 0) |
| cpumask_set_cpu(i, &of_spin_map); |
| } |
| } else |
| cpumask_copy(&of_spin_map, cpu_present_mask); |
| |
| cpumask_clear_cpu(boot_cpuid, &of_spin_map); |
| |
| /* Non-lpar has additional take/give timebase */ |
| if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { |
| smp_ops->give_timebase = rtas_give_timebase; |
| smp_ops->take_timebase = rtas_take_timebase; |
| } |
| |
| DBG(" <- smp_init_cell()\n"); |
| } |