Line data    Source code

       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * NOOP APIC driver.
       4             :  *
       5             :  * Does almost nothing and should be substituted by a real apic driver via
       6             :  * probe routine.
       7             :  *
       8             :  * Though in case if apic is disabled (for some reason) we try
       9             :  * to not uglify the caller's code and allow to call (some) apic routines
      10             :  * like self-ipi, etc...
      11             :  */
      12             : #include <linux/cpumask.h>
      13             : #include <linux/thread_info.h>
      14             : 
      15             : #include <asm/apic.h>
      16             : 
      17           0 : static void noop_init_apic_ldr(void) { }
      18           0 : static void noop_send_IPI(int cpu, int vector) { }
      19           0 : static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
      20           0 : static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
      21           0 : static void noop_send_IPI_allbutself(int vector) { }
      22           0 : static void noop_send_IPI_all(int vector) { }
      23           0 : static void noop_send_IPI_self(int vector) { }
      24           0 : static void noop_apic_wait_icr_idle(void) { }
      25           0 : static void noop_apic_icr_write(u32 low, u32 id) { }
      26             : 
      27           0 : static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
      28             : {
      29           0 :         return -1;
      30             : }
      31             : 
      32           0 : static u32 noop_safe_apic_wait_icr_idle(void)
      33             : {
      34           0 :         return 0;
      35             : }
      36             : 
      37           0 : static u64 noop_apic_icr_read(void)
      38             : {
      39           0 :         return 0;
      40             : }
      41             : 
      42           0 : static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
      43             : {
      44           0 :         return 0;
      45             : }
      46             : 
      47           0 : static unsigned int noop_get_apic_id(unsigned long x)
      48             : {
      49           0 :         return 0;
      50             : }
      51             : 
      52           0 : static int noop_probe(void)
      53             : {
      54             :         /*
      55             :          * NOOP apic should not ever be
      56             :          * enabled via probe routine
      57             :          */
      58           0 :         return 0;
      59             : }
      60             : 
      61           0 : static int noop_apic_id_registered(void)
      62             : {
      63             :         /*
      64             :          * if we would be really "pedantic"
      65             :          * we should pass read_apic_id() here
      66             :          * but since NOOP suppose APIC ID = 0
      67             :          * lets save a few cycles
      68             :          */
      69           0 :         return physid_isset(0, phys_cpu_present_map);
      70             : }
      71             : 
      72           0 : static u32 noop_apic_read(u32 reg)
      73             : {
      74           0 :         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
      75           0 :         return 0;
      76             : }
      77             : 
      78           0 : static void noop_apic_write(u32 reg, u32 v)
      79             : {
      80           0 :         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
      81           0 : }
      82             : 
      83             : #ifdef CONFIG_X86_32
      84             : static int noop_x86_32_early_logical_apicid(int cpu)
      85             : {
      86             :         return BAD_APICID;
      87             : }
      88             : #endif
      89             : 
      90             : struct apic apic_noop __ro_after_init = {
      91             :         .name                           = "noop",
      92             :         .probe                          = noop_probe,
      93             :         .acpi_madt_oem_check            = NULL,
      94             : 
      95             :         .apic_id_valid                  = default_apic_id_valid,
      96             :         .apic_id_registered             = noop_apic_id_registered,
      97             : 
      98             :         .delivery_mode                  = APIC_DELIVERY_MODE_FIXED,
      99             :         .dest_mode_logical              = true,
     100             : 
     101             :         .disable_esr                    = 0,
     102             : 
     103             :         .check_apicid_used              = default_check_apicid_used,
     104             :         .init_apic_ldr                  = noop_init_apic_ldr,
     105             :         .ioapic_phys_id_map             = default_ioapic_phys_id_map,
     106             :         .setup_apic_routing             = NULL,
     107             :         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
     108             :         .apicid_to_cpu_present          = physid_set_mask_of_physid,
     109             : 
     110             :         .check_phys_apicid_present      = default_check_phys_apicid_present,
     111             : 
     112             :         .phys_pkg_id                    = noop_phys_pkg_id,
     113             : 
     114             :         .get_apic_id                    = noop_get_apic_id,
     115             :         .set_apic_id                    = NULL,
     116             : 
     117             :         .calc_dest_apicid               = apic_flat_calc_apicid,
     118             : 
     119             :         .send_IPI                       = noop_send_IPI,
     120             :         .send_IPI_mask                  = noop_send_IPI_mask,
     121             :         .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
     122             :         .send_IPI_allbutself            = noop_send_IPI_allbutself,
     123             :         .send_IPI_all                   = noop_send_IPI_all,
     124             :         .send_IPI_self                  = noop_send_IPI_self,
     125             : 
     126             :         .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
     127             : 
     128             :         .inquire_remote_apic            = NULL,
     129             : 
     130             :         .read                           = noop_apic_read,
     131             :         .write                          = noop_apic_write,
     132             :         .eoi_write                      = noop_apic_write,
     133             :         .icr_read                       = noop_apic_icr_read,
     134             :         .icr_write                      = noop_apic_icr_write,
     135             :         .wait_icr_idle                  = noop_apic_wait_icr_idle,
     136             :         .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
     137             : 
     138             : #ifdef CONFIG_X86_32
     139             :         .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
     140             : #endif
     141             : };