WIP x86 smp: start the framework for detecting and starting secondary cores

Author: travisg

arch/x86/mp.c

@@ -15,6 +15,8 @@
 #include <arch/arch_ops.h>
 #include <sys/types.h>
 
+#if WITH_SMP
+
 // the boot cpu's percpu struct
 static x86_percpu_t x86_boot_percpu;
 // pointer to an array of percpu structs for each of the secondary cpus
@@ -47,7 +49,6 @@ void x86_percpu_init_early(uint cpu_num, uint apic_id) {
     x86_set_gdt_descriptor(selector, percpu, sizeof(*percpu), 1, 0, 1, SEG_TYPE_DATA_RW, 0, 1);
     x86_set_gs(selector);
 #endif
-    __UNUSED volatile uint foo = x86_get_cpu_num();
 }
 
 status_t arch_mp_send_ipi(mp_cpu_mask_t target, mp_ipi_t ipi) {
@@ -56,3 +57,9 @@ status_t arch_mp_send_ipi(mp_cpu_mask_t target, mp_ipi_t ipi) {
 
 void arch_mp_init_percpu(void) {
 }
+
+#else
+
+void x86_percpu_init_early(uint cpu_num, uint apic_id) {}
+
+#endif

lib/acpi_lite/acpi_lite.cpp

@@ -407,7 +407,7 @@ void acpi_lite_dump_tables(bool full_dump) {
   }
 }
 
-status_t acpi_process_madt_entries_etc(const uint8_t search_type, const madt_entry_callback callback) {
+status_t acpi_process_madt_entries_etc(const uint8_t search_type, const madt_entry_callback callback, void *cookie) {
   const acpi_madt_table* madt =
       reinterpret_cast<const acpi_madt_table*>(acpi_get_table_by_sig(ACPI_MADT_SIG));
   if (!madt) {
@@ -417,14 +417,17 @@ status_t acpi_process_madt_entries_etc(const uint8_t search_type, const madt_ent
   // bytewise array of the same table
   const uint8_t* madt_array = reinterpret_cast<const uint8_t*>(madt);
 
+  LTRACEF("table at %p\n", madt_array);
+
   // walk the table off the end of the header, looking for the requested type
   size_t off = sizeof(*madt);
   while (off < madt->header.length) {
     uint8_t type = madt_array[off];
     uint8_t length = madt_array[off + 1];
 
+    LTRACEF("type %u, length %u\n", type, length);
     if (type == search_type) {
-      callback(static_cast<const void*>(&madt_array[off]), length);
+      callback(static_cast<const void*>(&madt_array[off]), length, cookie);
     }
 
     off += length;
@@ -433,4 +436,32 @@ status_t acpi_process_madt_entries_etc(const uint8_t search_type, const madt_ent
   return NO_ERROR;
 }
 
+void acpi_lite_dump_madt_table() {
+    auto local_apic_callback = [](const void *_entry, size_t entry_len, void *cookie) {
+        const auto *entry = reinterpret_cast<const struct acpi_madt_local_apic_entry *>(_entry);
+
+        printf("\tLOCAL APIC id %d, processor id %d, flags %#x\n",
+                entry->apic_id, entry->processor_id, entry->flags);
+    };
+
+    auto io_apic_callback = [](const void *_entry, size_t entry_len, void *cookie) {
+        const auto *entry = reinterpret_cast<const struct acpi_madt_io_apic_entry *>(_entry);
+
+        printf("\tIO APIC id %d, address %#x gsi base %u\n",
+                entry->io_apic_id, entry->io_apic_address, entry->global_system_interrupt_base);
+    };
+
+    auto int_source_override_callback = [](const void *_entry, size_t entry_len, void *cookie) {
+        const auto *entry = reinterpret_cast<const struct acpi_madt_int_source_override_entry *>(_entry);
+
+        printf("\tINT OVERRIDE bus %u, source %u, gsi %u, flags %#x\n",
+                entry->bus, entry->source, entry->global_sys_interrupt, entry->flags);
+    };
+    printf("MADT/APIC table:\n");
+    acpi_process_madt_entries_etc(ACPI_MADT_TYPE_LOCAL_APIC, local_apic_callback, nullptr);
+    acpi_process_madt_entries_etc(ACPI_MADT_TYPE_IO_APIC, io_apic_callback, nullptr);
+    acpi_process_madt_entries_etc(ACPI_MADT_TYPE_INT_SOURCE_OVERRIDE, int_source_override_callback, nullptr);
+}
+
+
 // vim: set ts=2 sw=2 expandtab:

lib/acpi_lite/include/lib/acpi_lite.h

@@ -17,12 +17,14 @@ __BEGIN_CDECLS
 
 status_t acpi_lite_init(paddr_t rsdt);
 void acpi_lite_dump_tables(bool full_dump);
+void acpi_lite_dump_madt_table(void);
 
 const struct acpi_sdt_header* acpi_get_table_by_sig(const char* sig);
 
 // A routine to iterate over all the MADT entries of a particular type via a callback
 //using MadtEntryCallback = fbl::Function<void(const void* entry, size_t entry_len)>;
-typedef void (*madt_entry_callback)(const void* entry, size_t entry_len);
-status_t acpi_process_madt_entries_etc(uint8_t search_type, const madt_entry_callback);
+typedef void (*madt_entry_callback)(const void* entry, size_t entry_len, void *cookie);
+status_t acpi_process_madt_entries_etc(uint8_t search_type, const madt_entry_callback, void *cookie);
+
 
 __END_CDECLS

lib/acpi_lite/include/lib/acpi_lite/structs.h

@@ -230,6 +230,7 @@ static_assert(sizeof(struct acpi_madt_int_source_override_entry) == 10, "");
 #define ACPI_MADT_FLAG_TRIGGER_MASK 0b1100
 
 // DBG2 table
+// From https://learn.microsoft.com/en-us/windows-hardware/drivers/bringup/acpi-debug-port-table
 #define ACPI_DBG2_SIG "DBG2"
 struct acpi_dbg2_table {
   struct acpi_sdt_header header;
@@ -263,7 +264,13 @@ static_assert(sizeof(struct acpi_dbg2_device) == 22, "");
 // debug port subtypes
 #define ACPI_DBG2_SUBTYPE_16550_COMPATIBLE 0x0000
 #define ACPI_DBG2_SUBTYPE_16550_SUBSET 0x0001
+#define ACPI_DBG2_SUBTYPE_PL011 0x0003
+#define ACPI_DBG2_SUBTYPE_ARM_SBSA 0x000e
+#define ACPI_DBG2_SUBTYPE_16550_DESCRIBED 0x0012
+#define ACPI_DBG2_SUBTYPE_RISCV_SBI 0x0015
+
 #define ACPI_DBG2_SUBTYPE_1394_STANDARD 0x0000
+
 #define ACPI_DBG2_SUBTYPE_USB_XHCI 0x0000
 #define ACPI_DBG2_SUBTYPE_USB_EHCI 0x0001
 

platform/pc/mp.c

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2024 Travis Geiselbrecht
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "platform_p.h"
+
+#include <lk/main.h>
+#include <lib/acpi_lite.h>
+#include <lk/trace.h>
+
+#define LOCAL_TRACE 1
+
+static void start_cpu(uint cpu_num, uint32_t apic_id) {
+    LTRACEF("cpu_num %u, apic_id %u\n", cpu_num, apic_id);
+
+    // XXX do work here
+}
+
+struct detected_cpus {
+    uint32_t num_detected;
+    uint32_t apic_ids[SMP_MAX_CPUS];
+};
+
+static void local_apic_callback(const void *_entry, size_t entry_len, void *cookie) {
+    const struct acpi_madt_local_apic_entry *entry = _entry;
+    struct detected_cpus *cpus = cookie;
+
+    if (entry->apic_id == 0) {
+        // skip the boot cpu
+        return;
+    }
+    if (cpus->num_detected < SMP_MAX_CPUS) {
+        cpus->apic_ids[cpus->num_detected++] = entry->apic_id;
+    }
+}
+
+void platform_start_secondary_cpus(void) {
+    struct detected_cpus cpus;
+    cpus.num_detected = 1;
+    cpus.apic_ids[0] = 0; // the boot cpu
+
+    acpi_process_madt_entries_etc(ACPI_MADT_TYPE_LOCAL_APIC, &local_apic_callback, &cpus);
+
+    // TODO: fall back to legacy methods if ACPI fails
+    // TODO: deal with cpu topology
+
+    // start up the secondary cpus
+    if (cpus.num_detected > 1) {
+        dprintf(INFO, "PC: detected %u cpus\n", cpus.num_detected);
+
+        lk_init_secondary_cpus(cpus.num_detected - 1);
+
+        for (uint i = 1; i < cpus.num_detected; i++) {
+            dprintf(INFO, "PC: starting cpu %u\n", cpus.apic_ids[i]);
+            start_cpu(i, cpus.apic_ids[i]);
+        }
+    }
+}
+

platform/pc/platform.c

@@ -13,7 +13,6 @@
 #include <lk/trace.h>
 #include <arch/x86/mmu.h>
 #include <platform.h>
-#include "platform_p.h"
 #include <platform/pc.h>
 #include <platform/console.h>
 #include <platform/keyboard.h>
@@ -22,12 +21,13 @@
 #include <arch/x86.h>
 #include <arch/mmu.h>
 #include <malloc.h>
-#include <string.h>
 #include <assert.h>
 #include <inttypes.h>
 #include <kernel/vm.h>
 #include <lib/acpi_lite.h>
 
+#include "platform_p.h"
+
 #if WITH_DEV_BUS_PCI
 #include <dev/bus/pci.h>
 #endif
@@ -218,44 +218,28 @@ void platform_early_init(void) {
     dprintf(INFO, "PC: total memory detected %" PRIu64 " bytes\n", total_mem);
 }
 
-void local_apic_callback(const void *_entry, size_t entry_len) {
-    const struct acpi_madt_local_apic_entry *entry = _entry;
-
-    printf("\tLOCAL APIC id %d, processor id %d, flags %#x\n",
-            entry->apic_id, entry->processor_id, entry->flags);
-}
-
-void io_apic_callback(const void *_entry, size_t entry_len) {
-    const struct acpi_madt_io_apic_entry *entry = _entry;
-
-    printf("\tIO APIC id %d, address %#x gsi base %u\n",
-            entry->io_apic_id, entry->io_apic_address, entry->global_system_interrupt_base);
-}
-
-void int_source_override_callback(const void *_entry, size_t entry_len) {
-    const struct acpi_madt_int_source_override_entry *entry = _entry;
-
-    printf("\tINT OVERRIDE bus %u, source %u, gsi %u, flags %#x\n",
-            entry->bus, entry->source, entry->global_sys_interrupt, entry->flags);
-}
-
 void platform_init(void) {
     platform_init_debug();
 
     platform_init_keyboard(&console_input_buf);
 
-#if WITH_DEV_BUS_PCI
-    bool pci_initted = false;
+    // Look for the root ACPI table
+    bool found_acpi = false;
     if (acpi_lite_init(0) == NO_ERROR) {
         if (LOCAL_TRACE) {
             acpi_lite_dump_tables(false);
         }
+        acpi_lite_dump_madt_table();
+        found_acpi = true;
+    }
+
+    // Look for secondary cpus
+    platform_start_secondary_cpus();
 
-        // dump the APIC table
-        printf("MADT/APIC table:\n");
-        acpi_process_madt_entries_etc(ACPI_MADT_TYPE_LOCAL_APIC, &local_apic_callback);
-        acpi_process_madt_entries_etc(ACPI_MADT_TYPE_IO_APIC, &io_apic_callback);
-        acpi_process_madt_entries_etc(ACPI_MADT_TYPE_INT_SOURCE_OVERRIDE, &int_source_override_callback);
+#if WITH_DEV_BUS_PCI
+    bool pci_initted = false;
+    if (found_acpi) {
+        // TODO: handle interrupt source overrides from the MADT table
 
         // try to find the mcfg table
         const struct acpi_mcfg_table *table = (const struct acpi_mcfg_table *)acpi_get_table_by_sig(ACPI_MCFG_SIG);

platform/pc/platform_p.h

@@ -26,3 +26,5 @@ void pic_mask_interrupts(void);
 void lapic_init(void);
 void lapic_eoi(unsigned int vector);
 
+// secondary cpus
+void platform_start_secondary_cpus(void);

platform/pc/rules.mk

@@ -23,6 +23,7 @@ MODULE_SRCS += \
     $(LOCAL_DIR)/interrupts.c \
     $(LOCAL_DIR)/keyboard.c \
     $(LOCAL_DIR)/lapic.c \
+    $(LOCAL_DIR)/mp.c \
     $(LOCAL_DIR)/pic.c \
     $(LOCAL_DIR)/platform.c \
     $(LOCAL_DIR)/timer.c \