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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/cpumask.h>
- #include <linux/smp.h>
- #include <asm/io_apic.h>
- #include "local.h"
- DEFINE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
- #ifdef CONFIG_SMP
- static int apic_ipi_shorthand_off __ro_after_init;
- static __init int apic_ipi_shorthand(char *str)
- {
- get_option(&str, &apic_ipi_shorthand_off);
- return 1;
- }
- __setup("no_ipi_broadcast=", apic_ipi_shorthand);
- static int __init print_ipi_mode(void)
- {
- pr_info("IPI shorthand broadcast: %s\n",
- apic_ipi_shorthand_off ? "disabled" : "enabled");
- return 0;
- }
- late_initcall(print_ipi_mode);
- void apic_smt_update(void)
- {
- /*
- * Do not switch to broadcast mode if:
- * - Disabled on the command line
- * - Only a single CPU is online
- * - Not all present CPUs have been at least booted once
- *
- * The latter is important as the local APIC might be in some
- * random state and a broadcast might cause havoc. That's
- * especially true for NMI broadcasting.
- */
- if (apic_ipi_shorthand_off || num_online_cpus() == 1 ||
- !cpumask_equal(cpu_present_mask, &cpus_booted_once_mask)) {
- static_branch_disable(&apic_use_ipi_shorthand);
- } else {
- static_branch_enable(&apic_use_ipi_shorthand);
- }
- }
- void apic_send_IPI_allbutself(unsigned int vector)
- {
- if (num_online_cpus() < 2)
- return;
- if (static_branch_likely(&apic_use_ipi_shorthand))
- apic->send_IPI_allbutself(vector);
- else
- apic->send_IPI_mask_allbutself(cpu_online_mask, vector);
- }
- /*
- * Send a 'reschedule' IPI to another CPU. It goes straight through and
- * wastes no time serializing anything. Worst case is that we lose a
- * reschedule ...
- */
- void native_smp_send_reschedule(int cpu)
- {
- if (unlikely(cpu_is_offline(cpu))) {
- WARN(1, "sched: Unexpected reschedule of offline CPU#%d!\n", cpu);
- return;
- }
- apic->send_IPI(cpu, RESCHEDULE_VECTOR);
- }
- void native_send_call_func_single_ipi(int cpu)
- {
- apic->send_IPI(cpu, CALL_FUNCTION_SINGLE_VECTOR);
- }
- void native_send_call_func_ipi(const struct cpumask *mask)
- {
- if (static_branch_likely(&apic_use_ipi_shorthand)) {
- unsigned int cpu = smp_processor_id();
- if (!cpumask_or_equal(mask, cpumask_of(cpu), cpu_online_mask))
- goto sendmask;
- if (cpumask_test_cpu(cpu, mask))
- apic->send_IPI_all(CALL_FUNCTION_VECTOR);
- else if (num_online_cpus() > 1)
- apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR);
- return;
- }
- sendmask:
- apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
- }
- #endif /* CONFIG_SMP */
- static inline int __prepare_ICR2(unsigned int mask)
- {
- return SET_XAPIC_DEST_FIELD(mask);
- }
- static inline void __xapic_wait_icr_idle(void)
- {
- while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
- cpu_relax();
- }
- void __default_send_IPI_shortcut(unsigned int shortcut, int vector)
- {
- /*
- * Subtle. In the case of the 'never do double writes' workaround
- * we have to lock out interrupts to be safe. As we don't care
- * of the value read we use an atomic rmw access to avoid costly
- * cli/sti. Otherwise we use an even cheaper single atomic write
- * to the APIC.
- */
- unsigned int cfg;
- /*
- * Wait for idle.
- */
- if (unlikely(vector == NMI_VECTOR))
- safe_apic_wait_icr_idle();
- else
- __xapic_wait_icr_idle();
- /*
- * No need to touch the target chip field. Also the destination
- * mode is ignored when a shorthand is used.
- */
- cfg = __prepare_ICR(shortcut, vector, 0);
- /*
- * Send the IPI. The write to APIC_ICR fires this off.
- */
- native_apic_mem_write(APIC_ICR, cfg);
- }
- /*
- * This is used to send an IPI with no shorthand notation (the destination is
- * specified in bits 56 to 63 of the ICR).
- */
- void __default_send_IPI_dest_field(unsigned int mask, int vector, unsigned int dest)
- {
- unsigned long cfg;
- /*
- * Wait for idle.
- */
- if (unlikely(vector == NMI_VECTOR))
- safe_apic_wait_icr_idle();
- else
- __xapic_wait_icr_idle();
- /*
- * prepare target chip field
- */
- cfg = __prepare_ICR2(mask);
- native_apic_mem_write(APIC_ICR2, cfg);
- /*
- * program the ICR
- */
- cfg = __prepare_ICR(0, vector, dest);
- /*
- * Send the IPI. The write to APIC_ICR fires this off.
- */
- native_apic_mem_write(APIC_ICR, cfg);
- }
- void default_send_IPI_single_phys(int cpu, int vector)
- {
- unsigned long flags;
- local_irq_save(flags);
- __default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid, cpu),
- vector, APIC_DEST_PHYSICAL);
- local_irq_restore(flags);
- }
- void default_send_IPI_mask_sequence_phys(const struct cpumask *mask, int vector)
- {
- unsigned long query_cpu;
- unsigned long flags;
- /*
- * Hack. The clustered APIC addressing mode doesn't allow us to send
- * to an arbitrary mask, so I do a unicast to each CPU instead.
- * - mbligh
- */
- local_irq_save(flags);
- for_each_cpu(query_cpu, mask) {
- __default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid,
- query_cpu), vector, APIC_DEST_PHYSICAL);
- }
- local_irq_restore(flags);
- }
- void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask,
- int vector)
- {
- unsigned int this_cpu = smp_processor_id();
- unsigned int query_cpu;
- unsigned long flags;
- /* See Hack comment above */
- local_irq_save(flags);
- for_each_cpu(query_cpu, mask) {
- if (query_cpu == this_cpu)
- continue;
- __default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid,
- query_cpu), vector, APIC_DEST_PHYSICAL);
- }
- local_irq_restore(flags);
- }
- /*
- * Helper function for APICs which insist on cpumasks
- */
- void default_send_IPI_single(int cpu, int vector)
- {
- apic->send_IPI_mask(cpumask_of(cpu), vector);
- }
- void default_send_IPI_allbutself(int vector)
- {
- __default_send_IPI_shortcut(APIC_DEST_ALLBUT, vector);
- }
- void default_send_IPI_all(int vector)
- {
- __default_send_IPI_shortcut(APIC_DEST_ALLINC, vector);
- }
- void default_send_IPI_self(int vector)
- {
- __default_send_IPI_shortcut(APIC_DEST_SELF, vector);
- }
- #ifdef CONFIG_X86_32
- void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
- int vector)
- {
- unsigned long flags;
- unsigned int query_cpu;
- /*
- * Hack. The clustered APIC addressing mode doesn't allow us to send
- * to an arbitrary mask, so I do a unicasts to each CPU instead. This
- * should be modified to do 1 message per cluster ID - mbligh
- */
- local_irq_save(flags);
- for_each_cpu(query_cpu, mask)
- __default_send_IPI_dest_field(
- early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
- vector, APIC_DEST_LOGICAL);
- local_irq_restore(flags);
- }
- void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask,
- int vector)
- {
- unsigned long flags;
- unsigned int query_cpu;
- unsigned int this_cpu = smp_processor_id();
- /* See Hack comment above */
- local_irq_save(flags);
- for_each_cpu(query_cpu, mask) {
- if (query_cpu == this_cpu)
- continue;
- __default_send_IPI_dest_field(
- early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
- vector, APIC_DEST_LOGICAL);
- }
- local_irq_restore(flags);
- }
- /*
- * This is only used on smaller machines.
- */
- void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
- {
- unsigned long mask = cpumask_bits(cpumask)[0];
- unsigned long flags;
- if (!mask)
- return;
- local_irq_save(flags);
- WARN_ON(mask & ~cpumask_bits(cpu_online_mask)[0]);
- __default_send_IPI_dest_field(mask, vector, APIC_DEST_LOGICAL);
- local_irq_restore(flags);
- }
- /* must come after the send_IPI functions above for inlining */
- static int convert_apicid_to_cpu(int apic_id)
- {
- int i;
- for_each_possible_cpu(i) {
- if (per_cpu(x86_cpu_to_apicid, i) == apic_id)
- return i;
- }
- return -1;
- }
- int safe_smp_processor_id(void)
- {
- int apicid, cpuid;
- if (!boot_cpu_has(X86_FEATURE_APIC))
- return 0;
- apicid = hard_smp_processor_id();
- if (apicid == BAD_APICID)
- return 0;
- cpuid = convert_apicid_to_cpu(apicid);
- return cpuid >= 0 ? cpuid : 0;
- }
- #endif
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