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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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d2e60075a3
Change the paca array into an array of pointers to pacas. Allocate pacas individually. This allows flexibility in where the PACAs are allocated. Future work will allocate them node-local. Platforms that don't have address limits on PACAs would be able to defer PACA allocations until later in boot rather than allocate all possible ones up-front then freeing unused. This is slightly more overhead (one additional indirection) for cross CPU paca references, but those aren't too common. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
170 lines
3.9 KiB
C
170 lines
3.9 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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 <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/pgtable.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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/* Fixup atomic count: it exited inside IRQ handler. */
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task_thread_info(paca_ptrs[lcpu]->__current)->preempt_count = 0;
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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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