apic_noop.c 3.4 KB

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  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. #include <asm/apic.h>
  15. static void noop_init_apic_ldr(void) { }
  16. static void noop_send_IPI(int cpu, int vector) { }
  17. static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
  18. static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
  19. static void noop_send_IPI_allbutself(int vector) { }
  20. static void noop_send_IPI_all(int vector) { }
  21. static void noop_send_IPI_self(int vector) { }
  22. static void noop_apic_wait_icr_idle(void) { }
  23. static void noop_apic_icr_write(u32 low, u32 id) { }
  24. static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
  25. {
  26. return -1;
  27. }
  28. static u32 noop_safe_apic_wait_icr_idle(void)
  29. {
  30. return 0;
  31. }
  32. static u64 noop_apic_icr_read(void)
  33. {
  34. return 0;
  35. }
  36. static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
  37. {
  38. return 0;
  39. }
  40. static unsigned int noop_get_apic_id(unsigned long x)
  41. {
  42. return 0;
  43. }
  44. static int noop_probe(void)
  45. {
  46. /*
  47. * NOOP apic should not ever be
  48. * enabled via probe routine
  49. */
  50. return 0;
  51. }
  52. static int noop_apic_id_registered(void)
  53. {
  54. /*
  55. * if we would be really "pedantic"
  56. * we should pass read_apic_id() here
  57. * but since NOOP suppose APIC ID = 0
  58. * lets save a few cycles
  59. */
  60. return physid_isset(0, phys_cpu_present_map);
  61. }
  62. static u32 noop_apic_read(u32 reg)
  63. {
  64. WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  65. return 0;
  66. }
  67. static void noop_apic_write(u32 reg, u32 v)
  68. {
  69. WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  70. }
  71. #ifdef CONFIG_X86_32
  72. static int noop_x86_32_early_logical_apicid(int cpu)
  73. {
  74. return BAD_APICID;
  75. }
  76. #endif
  77. struct apic apic_noop __ro_after_init = {
  78. .name = "noop",
  79. .probe = noop_probe,
  80. .acpi_madt_oem_check = NULL,
  81. .apic_id_valid = default_apic_id_valid,
  82. .apic_id_registered = noop_apic_id_registered,
  83. .delivery_mode = APIC_DELIVERY_MODE_FIXED,
  84. .dest_mode_logical = true,
  85. .disable_esr = 0,
  86. .check_apicid_used = default_check_apicid_used,
  87. .init_apic_ldr = noop_init_apic_ldr,
  88. .ioapic_phys_id_map = default_ioapic_phys_id_map,
  89. .setup_apic_routing = NULL,
  90. .cpu_present_to_apicid = default_cpu_present_to_apicid,
  91. .apicid_to_cpu_present = physid_set_mask_of_physid,
  92. .check_phys_apicid_present = default_check_phys_apicid_present,
  93. .phys_pkg_id = noop_phys_pkg_id,
  94. .get_apic_id = noop_get_apic_id,
  95. .set_apic_id = NULL,
  96. .calc_dest_apicid = apic_flat_calc_apicid,
  97. .send_IPI = noop_send_IPI,
  98. .send_IPI_mask = noop_send_IPI_mask,
  99. .send_IPI_mask_allbutself = noop_send_IPI_mask_allbutself,
  100. .send_IPI_allbutself = noop_send_IPI_allbutself,
  101. .send_IPI_all = noop_send_IPI_all,
  102. .send_IPI_self = noop_send_IPI_self,
  103. .wakeup_secondary_cpu = noop_wakeup_secondary_cpu,
  104. .inquire_remote_apic = NULL,
  105. .read = noop_apic_read,
  106. .write = noop_apic_write,
  107. .eoi_write = noop_apic_write,
  108. .icr_read = noop_apic_icr_read,
  109. .icr_write = noop_apic_icr_write,
  110. .wait_icr_idle = noop_apic_wait_icr_idle,
  111. .safe_wait_icr_idle = noop_safe_apic_wait_icr_idle,
  112. #ifdef CONFIG_X86_32
  113. .x86_32_early_logical_apicid = noop_x86_32_early_logical_apicid,
  114. #endif
  115. };