ptos: mm: Add physical memory groundwork

Signed-off-by: Chloe M <chloe@mensia.org>

service/ptos/head/mm/pm.h

@@ -24,4 +24,9 @@ typedef USIZE MM_PFN;
 #define ADDRESS_TO_PFN(ADDR) \
     ((ADDR) >> LOG2_PAGESIZE)
 
+/*
+ * Initialize the physical memory management
+ */
+VOID MmPmInit(VOID);
+
 #endif  /* !_MM_PM_H_ */

service/ptos/ke/Makefile

@@ -13,6 +13,7 @@ CFILES = $(shell find . -name "*.c")
 CFILES += $(shell find ../lib -name "*.c")
 CFILES += $(shell find ../xt -name "*.c")
 CFILES += $(shell find ../drivers -name "*.c")
+CFILES += $(shell find ../mm -name "*.c")
 DFILES = $(CFILES:.c=.d)
 OFILES = $(CFILES:.c=.o)
 

service/ptos/ke/init.c

@@ -9,6 +9,7 @@
 #include <ptdef.h>
 #include <ke/bpal.h>
 #include <ex/trace.h>
+#include <mm/pm.h>
 #include <hal/serial.h>
 #include <drivers/bootvid/fbio.h>
 #include <machine/pio.h>
@@ -45,4 +46,7 @@ KiKernelInit(VOID)
 
     /* Initialize the boot video console */
     BootVidInitCons(NULL);
+
+    /* Initialize physical memory */
+    MmPmInit();
 }

service/ptos/mm/pm.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Physical memory management
+ * Author:      Chloe M.
+ */
+
+#include <mm/pm.h>
+#include <ke/bpal.h>
+#include <ex/trace.h>
+
+#define DTRACE(Fmt, ...) \
+    TRACE("[ PM ]: " Fmt, ##__VA_ARGS__)
+
+/* Safe macro to get region string */
+#define PM_REGION(TYPE)                 \
+    ((TYPE) >= NELEM(PmRegionTable))    \
+        ? "bad type"                    \
+        : PmRegionTable[(TYPE)]
+
+/*
+ * Table of known memory regions
+ */
+static const CHAR *PmRegionTable[] = {
+    [MEMORY_USABLE]         = "available",
+    [MEMORY_RESERVED]       = "reserved",
+    [MEMORY_ACPI_RECLAIM]   = "acpi reclaimable",
+    [MEMORY_ACPI_NVS]       = "acpi nv-sleep",
+    [MEMORY_BAD]            = "bad",
+    [MEMORY_BOOTLOADER]     = "bootloader",
+    [MEMORY_KERNEL]         = "system",
+    [MEMORY_FRAMEBUFFER]    = "vram",
+    [MEMORY_ACPI_TABLES]    = "acpi tables"
+};
+
+/*
+ * Probe physical memory for usable regions and list
+ * installed memory.
+ */
+static VOID
+PmProbe(VOID)
+{
+    PT_STATUS Status;
+    BPAL_HANDLE BpalHandle;
+    MEMMAP_ENTRY Entry;
+    UPTR Start, End;
+    USIZE Index;
+
+    /*
+     * We obtain memory map entries from the BPAL layer as it is provided
+     * by the bootloader which got it from firmware.
+     */
+    KeBpalGetHandle(&BpalHandle);
+
+    /* Iterate each memory entry */
+    for (Index = 0;; ++Index) {
+        Status = BpalHandle.MemEntryIdx(Index, &Entry);
+
+        /* Are we out of entries to fetch? */
+        if (PT_ERROR(Status)) {
+            break;
+        }
+
+        Start = Entry.Base;
+        End = Start + Entry.Length;
+        DTRACE(
+            "%p - %p : %s\n",
+            Start,
+            End,
+            PM_REGION(Entry.Type)
+        );
+    }
+}
+
+VOID
+MmPmInit(VOID)
+{
+    DTRACE("probing physical memory...\n");
+    PmProbe();
+}