3 files changed, 118 insertions, 0 deletions
diff --git a/sys/include/arch/amd64/cpu.h b/sys/include/arch/amd64/cpu.h
index 116661b..4586163 100644
--- a/sys/include/arch/amd64/cpu.h
+++ b/sys/include/arch/amd64/cpu.h
@@ -37,6 +37,7 @@
 #include <sys/spinlock.h>
 #include <machine/tss.h>
 #include <machine/cdefs.h>
+#include <machine/intr.h>
 
 #define CPU_IRQ(IRQ_N) (BIT((IRQ_N)) & 0xFF)
 
@@ -44,9 +45,14 @@
 #define CPU_FEAT_SMAP  BIT(0)
 #define CPU_FEAT_SMEP  BIT(1)
 
+typedef uint16_t ipi_pend_t;
+
 struct cpu_info {
     uint32_t apicid;
     uint32_t feat;
+    uint8_t ipi_dispatch : 1;   /* 1: IPIs being dispatched */
+    uint8_t ipi_id;
+    ipi_pend_t ipi_pending[N_IPIVEC];
     uint8_t id;                 /* MI Logical ID */
     uint8_t model : 4;          /* CPU model number */
     uint8_t family : 4;         /* CPU family ID */
diff --git a/sys/include/arch/amd64/intr.h b/sys/include/arch/amd64/intr.h
index 3870f18..6d9bb09 100644
--- a/sys/include/arch/amd64/intr.h
+++ b/sys/include/arch/amd64/intr.h
@@ -48,6 +48,9 @@
 #define IPL_CLOCK   2   /* Clock */
 #define IPL_HIGH    3   /* Defer everything */
 
+#define N_IPIVEC 4      /* Number of vectors reserved for IPIs */
+#define IPI_PER_VEC 16  /* Max IPIs per vector */
+
 struct intr_hand;
 
 /*
diff --git a/sys/include/arch/amd64/ipi.h b/sys/include/arch/amd64/ipi.h
new file mode 100644
index 0000000..1a3b51c
--- /dev/null
+++ b/sys/include/arch/amd64/ipi.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MACHINE_IPI_H_
+#define _MACHINE_IPI_H_
+
+#include <sys/types.h>
+#include <machine/cpu.h>
+#include <machine/lapic.h>
+
+/* Fixed IPI IDs */
+#define IPI_HALT   0
+#define IPI_TLB    1
+
+/*
+ * Represents an interprocessor interrupt
+ * handler.
+ *
+ * @cookie: Used to verifying an instance
+ * @id: IPI ID (identifies the IPI)
+ * @mask: If set, IPIs are ignored
+ * @handler: Handler routine
+ */
+struct cpu_ipi {
+    uint16_t cookie;
+    uint8_t id;
+    int(*handler)(struct cpu_ipi *ipi);
+};
+
+/*
+ * Represents an interrupt vector for a
+ * specific IPI
+ *
+ * @ipi: IPIs associated with this vector
+ * @cookie: Used to verify an instance
+ * @nipi: Number of IPIs associated
+ * @vec: System interrupt vector number
+ */
+struct ipi_vector {
+    struct cpu_ipi ipi[IPI_PER_VEC];
+    uint16_t cookie;
+    uint8_t nipi;
+    uint8_t vec;
+};
+
+int md_ipi_alloc(struct cpu_ipi **res);
+int md_ipi_send(struct cpu_info *ci);
+void md_ipi_init(void);
+
+/*
+ * Get the vector an IPI belongs to
+ *
+ * @ipi: IPI to check
+ */
+__always_inline static inline uint8_t
+ipi_vector(uint8_t ipi)
+{
+    return ipi / N_IPIVEC;
+}
+
+/*
+ * Get the handler index an IPI belongs
+ * to
+ *
+ * @ipi: IPI to check
+ */
+__always_inline static inline uint8_t
+ipi_index(uint8_t ipi)
+{
+    return ipi % (sizeof(ipi_pend_t) * 8);
+}
+
+__always_inline static inline int
+cpu_ipi_send(struct cpu_info *ci, uint8_t ipi)
+{
+    uint8_t vec = ipi_vector(ipi);
+    uint8_t idx = ipi_index(ipi);
+
+    ci->ipi_pending[vec] |= BIT(idx);
+    return md_ipi_send(ci);
+}
+
+#endif  /* !_MACHINE_IPI_H_ */