From c854bc705bb794582fc562d1e29cb3a194fba454 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 22 Dec 2025 14:41:10 -0500
Subject: mos: bpt: Add boot memory map interface

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 mos/sys/bpt/bpt_limine.c | 30 ++++++++++++++++++++++++++++++
 mos/sys/inc/kern/bpt.h   | 39 +++++++++++++++++++++++++++++++++++++++
 mos/sys/kern/kern_bpt.c  | 14 ++++++++++++++
 3 files changed, 83 insertions(+)

diff --git a/mos/sys/bpt/bpt_limine.c b/mos/sys/bpt/bpt_limine.c
index 0decc57..532ce6a 100644
--- a/mos/sys/bpt/bpt_limine.c
+++ b/mos/sys/bpt/bpt_limine.c
@@ -16,6 +16,13 @@ static volatile struct limine_hhdm_request hhdm_req = {
     .revision = 0
 };
 
+/* Memory map */
+static struct limine_memmap_response *mem_resp;
+static volatile struct limine_memmap_request mem_req = {
+    .id = LIMINE_MEMMAP_REQUEST,
+    .revision = 0
+};
+
 static MOS_STATUS
 limine_get_vars(BPT_VARS *res)
 {
@@ -27,6 +34,26 @@ limine_get_vars(BPT_VARS *res)
     return STATUS_SUCCESS;
 }
 
+static MOS_STATUS
+limine_get_mementry(USIZE index, BPT_MEMENTRY *res)
+{
+    struct limine_memmap_entry *entry;
+
+    if (res == NULL) {
+        return STATUS_INVALID_ARG;
+    }
+
+    if (index >= mem_resp->entry_count) {
+        return STATUS_INVALID_ARG;
+    }
+
+    entry = mem_resp->entries[index];
+    res->base = entry->base;
+    res->length = entry->length;
+    res->type = entry->type;    /* 1:1 */
+    return STATUS_SUCCESS;
+}
+
 MOS_STATUS
 bpt_limine_init(BPT_HOOKS *hooks_res)
 {
@@ -35,6 +62,9 @@ bpt_limine_init(BPT_HOOKS *hooks_res)
     }
 
     hhdm_resp = hhdm_req.response;
+    mem_resp = mem_req.response;
+
     hooks_res->get_vars = limine_get_vars;
+    hooks_res->get_mementry = limine_get_mementry;
     return STATUS_SUCCESS;
 }
diff --git a/mos/sys/inc/kern/bpt.h b/mos/sys/inc/kern/bpt.h
index 79d55f0..3e3c3f2 100644
--- a/mos/sys/inc/kern/bpt.h
+++ b/mos/sys/inc/kern/bpt.h
@@ -9,6 +9,20 @@
 #include <sdk/types.h>
 #include <sdk/status.h>
 
+/*
+ * Represents memory map entry types
+ */
+typedef enum {
+    BPT_MEM_USABLE,
+    BPT_MEM_RESERVED,
+    BPT_MEM_ACPI_RECLAIM,
+    BPT_MEM_ACPI_NVS,
+    BPT_MEM_BAD,
+    BPT_MEM_BOOTLOADER,
+    BPT_MEM_KERNEL,
+    BPT_MEM_FRAMEBUFFER
+} BPT_MEM_TYPE;
+
 /*
  * Represents boot protocol translation variables that
  * contain information provided by the bootloader
@@ -19,6 +33,19 @@ typedef struct {
     UPTR kernel_base;
 } BPT_VARS;
 
+/*
+ * Represents a memory map entry
+ *
+ * @base: Base address of memory area
+ * @length: Length of memory area in bytes
+ * @type: Memory entry type
+ */
+typedef struct {
+    UPTR base;
+    USIZE length;
+    BPT_MEM_TYPE type;
+} BPT_MEMENTRY;
+
 /*
  * Represents boot protocol translation hooks that can
  * be used to obtain state and variables from the underlying
@@ -26,6 +53,7 @@ typedef struct {
  */
 typedef struct {
     MOS_STATUS(*get_vars)(BPT_VARS *res);
+    MOS_STATUS(*get_mementry)(USIZE index, BPT_MEMENTRY *res);
 } BPT_HOOKS;
 
 /*
@@ -36,6 +64,17 @@ typedef struct {
  */
 MOS_STATUS bpt_get_vars(BPT_VARS *res);
 
+/*
+ * Obtain a memory map entry
+ *
+ * @index: Entry index
+ * @res: Entry result
+ *
+ * Returns STATUS_SUCCESS if the entry index is within
+ * proper range.
+ */
+MOS_STATUS bpt_get_mementry(USIZE index, BPT_MEMENTRY *res);
+
 /*
  * Initialize the boot protocol translation layer
  */
diff --git a/mos/sys/kern/kern_bpt.c b/mos/sys/kern/kern_bpt.c
index 21f1c04..7d3511e 100644
--- a/mos/sys/kern/kern_bpt.c
+++ b/mos/sys/kern/kern_bpt.c
@@ -34,6 +34,20 @@ bpt_get_vars(BPT_VARS *res)
     return global_hooks.get_vars(res);
 }
 
+MOS_STATUS
+bpt_get_mementry(USIZE index, BPT_MEMENTRY *res)
+{
+    if (res == NULL) {
+        return STATUS_INVALID_ARG;
+    }
+
+    if (global_hooks.get_mementry == NULL) {
+        return STATUS_IO_ERROR;
+    }
+
+    return global_hooks.get_mementry(index, res);
+}
+
 MOS_STATUS
 bpt_init(void)
 {
-- 
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