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