dev(sell): add simple libc and implement shell

please see the log for detail.

2 files changed, 35 insertions, 6 deletions

diff --git a/src/kernel/mm/pmm.cc b/src/kernel/mm/pmm.cc
index 3474a49..e871d8a 100644
--- a/src/kernel/mm/pmm.cc
+++ b/src/kernel/mm/pmm.cc
@@ -75,7 +75,7 @@ namespace PMM
         uint64 kern_end_pa = PGROUNDUP((uint64)kernel_end);
         total_pages = (PHYSTOP - KERNBASE) / PGSIZE;
 
-        Drivers::uart_puts("PMM: Total RAM size: 128MB\n");
+        Drivers::uart_puts(ANSI_GREEN "[PMM] Total RAM size: 128MB\n" ANSI_RESET);
         // Place the mem_map array
         // mem_map is located immediately after kernel_end
         mem_map = (struct Page*)kern_end_pa;
@@ -83,17 +83,17 @@ namespace PMM
         uint64 mem_map_size = total_pages * sizeof(struct Page);
         uint64 free_mem_start = PGROUNDUP(kern_end_pa + mem_map_size);
 
-        Drivers::uart_puts("PMM: MemMap placed at: ");
+        Drivers::uart_puts(ANSI_GREEN "[PMM] MemMap placed at: " );
         Drivers::print_hex((uint64)mem_map);
-        Drivers::uart_putc('\n');
+        Drivers::uart_puts("\n" ANSI_RESET);
 
-        Drivers::uart_puts("PMM: Free memory starts at: ");
+        Drivers::uart_puts(ANSI_GREEN "[PMM] Free memory starts at: ");
         Drivers::print_hex(free_mem_start);
-        Drivers::uart_puts("\n");
+        Drivers::uart_puts("\n" ANSI_RESET);
 
         if (free_mem_start >= PHYSTOP)
         {
-            Drivers::uart_puts("PMM: Error - Kernel too large, no memory left!\n");
+            Drivers::uart_puts(ANSI_RED "[PMM] Error - Kernel too large, no memory left!\n" ANSI_RESET);
             while (1)
                 ;
         }
diff --git a/src/kernel/mm/vm.cc b/src/kernel/mm/vm.cc
index 29e9eb7..41d1aa1 100644
--- a/src/kernel/mm/vm.cc
+++ b/src/kernel/mm/vm.cc
@@ -261,6 +261,8 @@ namespace VM
         return 0;
     }
 
+    int handle_cow_fault(uint64 *pagetable, uint64 va);
+
     int copyout(uint64 *pagetable, uint64 dstva, char *src, uint64 len)
     {
         uint64 n, va0, pa0;
@@ -273,6 +275,17 @@ namespace VM
             if (pte == nullptr || (*pte & PTE_V) == 0 || (*pte & PTE_U) == 0)
                 return -1;
 
+            // Note: Maybe a bug
+            if (*pte & PTE_COW)
+            {
+                if (handle_cow_fault(pagetable, va0) < 0)
+                    return -1;
+                // Re-walk because handle_cow_fault replaced the page mapping
+                pte = walk(pagetable, va0, 0);
+                if (pte == nullptr || (*pte & PTE_V) == 0 || (*pte & PTE_U) == 0)
+                    return -1;
+            }
+
             pa0 = PTE2PA(*pte);
             n = PGSIZE - (dstva - va0);
             if (n > len)
@@ -419,4 +432,20 @@ namespace VM
         sfence_vma();
         Drivers::uart_puts("[Boot] MMU ENABLED! Using virtual addresses.\n");
     }
+
+    uint64 walkaddr(uint64 *pagetable, uint64 va)
+    {
+        uint64 *pte;
+        uint64 pa;
+
+        if (va >= MAXVA)
+            return 0;
+
+        pte = walk(pagetable, va, 0);
+        if (pte == 0 || (*pte & PTE_V) == 0 || (*pte & PTE_U) == 0)
+            return 0;
+
+        pa = PTE2PA(*pte);
+        return pa;
+    }
 }
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