add paging test

Author: tas0dev

src/boot/config.inc

@@ -1,5 +1,5 @@
 KERNEL_OFFSET EQU 0x10000       ; カーネルをロードするアドレス
-SECTOR_COUNT  EQU 38            ; 読み込むセクタの数
+SECTOR_COUNT  EQU 39            ; 読み込むセクタの数
 START_SECTOR  EQU 2             ; 開始するセクタ番号
 CYLINDER_NUM  EQU 0             ; シリンダ番号
 HEAD_NUM      EQU 0             ; ヘッド番号

src/kernel/tests/paging_test.c

@@ -1,27 +1,61 @@
 #include <config.h>
 #include <console.h>
 #include <mem/paging.h>
+#include <mem/map.h>
 
 void paging_test(void) {
-    paging_init_identity(16);
-    printk("identity map set\n");
+    printk("[PAGING TEST] start\n");
 
+    /* Set up a small identity mapping for low memory so kernel stays accessible */
+    paging_init_identity(1); /* map first 1 MB */
+    printk("[PAGING TEST] identity map (1MB) set\n");
+
+    /* Allocate a physical frame to map */
+    void *frame = alloc_frame();
+    if (!frame) {
+        printk("[PAGING TEST] alloc_frame failed\n");
+        return;
+    }
+    uint32_t phys = (uint32_t)frame;
+    printk("[PAGING TEST] allocated phys frame=0x%x\n", (unsigned)phys);
+
+    /* choose a virtual address likely unmapped (above identity region) */
+    uint32_t virt = 0x4000000; /* 64MB */
+
+    /* map the page (present + rw) */
+    if (map_page(phys, virt, PAGING_PRESENT | PAGING_RW) != 0) {
+        printk("[PAGING TEST] map_page failed\n");
+        return;
+    }
+    printk("[PAGING TEST] mapped phys 0x%x -> virt 0x%x\n", (unsigned)phys, (unsigned)virt);
+
+    /* enable paging */
     paging_enable();
-    printk("paging enabled\n");
-
-    /* Access a low physical address (identity mapped) to ensure no PF */
-    volatile uint32_t *p = (uint32_t *)0x1000;
-    uint32_t val = *p; /* might be zero or garbage but should not fault */
-    (void)val;
-    printk("read from 0x1000 OK\n");
-
-    /* Touch a high unmapped address to trigger PF (optional) */
-#ifdef PAGING_TEST_TRIGGER_PF
-    volatile uint32_t *bad = (uint32_t *)0xC0000000; /* likely unmapped */
-    uint32_t badval = *bad; /* expect page fault handler */
-    (void)badval;
-    printk("unexpected: no page fault\n");
-#endif
-
-    printk("done\n");
+    printk("[PAGING TEST] paging enabled\n");
+
+    /* Access the newly mapped virtual address */
+    volatile uint32_t *p = (uint32_t *)virt;
+    *p = 0xdeadbeef;
+    uint32_t v = *p;
+    printk("[PAGING TEST] write/read virt 0x%x -> 0x%x\n", (unsigned)virt, (unsigned)v);
+
+    /* unmap the page (do not access after this to avoid page fault) */
+    if (unmap_page(virt) == 0) {
+        printk("[PAGING TEST] unmapped virt 0x%x\n", (unsigned)virt);
+    } else {
+        printk("[PAGING TEST] unmap_page failed for 0x%x\n", (unsigned)virt);
+    }
+
+    /* remap the same physical frame to a different virtual address and verify */
+    uint32_t virt2 = 0x4100000; /* 65MB */
+    if (map_page(phys, virt2, PAGING_PRESENT | PAGING_RW) != 0) {
+        printk("[PAGING TEST] remap failed\n");
+        return;
+    }
+    printk("[PAGING TEST] remapped phys 0x%x -> virt 0x%x\n", (unsigned)phys, (unsigned)virt2);
+    volatile uint32_t *p2 = (uint32_t *)virt2;
+    uint32_t v2 = *p2; /* should reflect previous write if caching coherent */
+    printk("[PAGING TEST] read virt2 0x%x -> 0x%x\n", (unsigned)virt2, (unsigned)v2);
+
+    printk("[PAGING TEST] done\n");
 }