feat: implement FDT-based memory discovery and add comprehensive debug logging to exec syscalls

2 files changed, 23 insertions, 4 deletions

diff --git a/src/kernel/mm/pmm.cc b/src/kernel/mm/pmm.cc
index 2d0c44f..d3d99ba 100644
--- a/src/kernel/mm/pmm.cc
+++ b/src/kernel/mm/pmm.cc
@@ -6,6 +6,7 @@
 #include "kernel/riscv.h"
 #include "kernel/pmm.h"
 #include "kernel/mm.h"
+#include "kernel/fdt.h"
 // #include "kernel/spinlock.h"
 #include "drivers/uart.h"
 #include "lib/string.h"
@@ -13,6 +14,9 @@
 extern "C" char kernel_end[];
 extern uint64 g_dtb_addr;
 
+// Default memory size 128MB, will be overwritten by FDT
+uint64 g_phys_size = 128 * 1024 * 1024;
+
 namespace PMM
 {
     // Global metadata array pointer
@@ -74,12 +78,20 @@ namespace PMM
 
     void init()
     {
+        // Use FDT memory size if available
+        if (g_devices.mem_size > 0)
+        {
+            g_phys_size = g_devices.mem_size;
+        }
+
         pmm_lock.init("pmm");
 
         uint64 kern_end_pa = PGROUNDUP((uint64)kernel_end);
         total_pages = (PHYSTOP - KERNBASE) / PGSIZE;
 
-        Drivers::uart_puts(ANSI_GREEN "[PMM] Total RAM size: 128MB\n" ANSI_RESET);
+        Drivers::uart_puts(ANSI_GREEN "[PMM] Total RAM size: ");
+        Drivers::uart_put_int(g_phys_size / (1024 * 1024));
+        Drivers::uart_puts(" MB\n" ANSI_RESET);
         // Place the mem_map array
         // mem_map is located immediately after kernel_end
         mem_map = (struct Page*)kern_end_pa;
diff --git a/src/kernel/mm/vm.cc b/src/kernel/mm/vm.cc
index 47b80e9..be2f2f2 100644
--- a/src/kernel/mm/vm.cc
+++ b/src/kernel/mm/vm.cc
@@ -8,6 +8,7 @@
 #include "common/types.h"
 #include "lib/string.h"
 #include "drivers/uart.h"
+#include "kernel/fdt.h"
 
 extern "C"
 {
@@ -421,9 +422,15 @@ namespace VM
     {
         kernel_pagetable = uvmcreate();
 
-        kvmmap(0x10000000, 0x10000000, 0x10000, PTE_R | PTE_W);
-        kvmmap(0x0c000000, 0x0c000000, 0x400000, PTE_R | PTE_W);
-        kvmmap(0x02000000, 0x02000000, 0x10000, PTE_R | PTE_W); // CLINT
+        // 1. Map all device MMIO regions discovered by FDT
+        for (int i = 0; i < g_devices.mmio_count; i++)
+        {
+            uint64 base = g_devices.mmio_regions[i].base;
+            uint64 size = g_devices.mmio_regions[i].size;
+            kvmmap(base, base, size, PTE_R | PTE_W);
+        }
+
+        // 2. Map Kernel Memory (PHYSTOP is now dynamic based on FDT)
         kvmmap(KERNBASE, KERNBASE, PHYSTOP - KERNBASE, PTE_R | PTE_W | PTE_X);
     }