refacto(kernel: memory: pmm): return pageframe address when allocating

kernel/arch/i686/src/memory/mmu.c

@@ -189,7 +189,7 @@ bool mmu_map(vaddr_t virtual, vaddr_t pageframe)
     return true;
 }
 
-void mmu_unmap(vaddr_t virtual)
+paddr_t mmu_unmap(vaddr_t virtual)
 {
     u16 pde_index = virtual >> 22;                     // bits 31-22
     u16 pte_index = (virtual >> 12) & ((1 << 10) - 1); // bits 21-12
@@ -198,14 +198,17 @@ void mmu_unmap(vaddr_t virtual)
     //       c.f. todo inside mmu_map
 
     if (!kernel_page_directory[pde_index].present)
-        return;
+        return 0;
 
     // Erase the content of the page table entry
     mmu_pte_entry *page_table =
         (mmu_pte_entry *)MMU_RECURSIVE_PAGE_TABLE_ADDRESS(pde_index);
+    paddr_t physical = page_table->page_frame << 12;
     *((volatile u32 *)&page_table[pte_index]) = 0x0;
 
     mmu_flush_tlb(virtual);
+
+    return physical;
 }
 
 static void mmu_offset_map(paddr_t start, paddr_t end, int64_t offset)

kernel/include/kernel/mmu.h

@@ -55,8 +55,10 @@ bool mmu_map(vaddr_t virt, paddr_t physical);
  * the CPU to raise an exception.
  *
  * @param virt The virtual address
+ *
+ * @return The physical pageframe associated with the unmapped address
  */
-void mmu_unmap(vaddr_t virt);
+paddr_t mmu_unmap(vaddr_t virt);
 
 /**
  * @brief Perform identity mapping inside a given virtual address range

kernel/include/kernel/pmm.h

@@ -1,14 +1,18 @@
 /**
  * @brief Physical Memory Manager
  *
+ * @file pmm.h
+ *
+ * @defgroup PMM Physical Memory Manager
+ *
  * The PMM is responsible for allocating and freeing new memory pages.
  * These pages are then used by the Virtual Memory Manager (e.g. UNIX's malloc)
  * to return (free) new mapped virtual addresses to the caller.
  *
  * The PMM should never interact with the virtual address space, this is the
  * responsabillity of the VMM only.
  *
- * @file pmm.h
+ * @{
  */
 
 #ifndef KERNEL_PMM_H
@@ -36,7 +40,7 @@
 // reference value (e.g. the physical memory manager's bit map size).
 #define TOTAL_PAGEFRAMES_COUNT (ADDRESS_SPACE_SIZE / PAGE_SIZE)
 
-/// \defgroup pmm_allocation_flags
+/// \defgroup Flags PMM Allocation Flags
 ///
 /// Flags used when allocating a page frame to specify that the allocation must
 /// respect certain constraints. Constraints can be specific addresses, rules,
@@ -45,8 +49,8 @@
 /// @{
 
 /// The pageframe should be located inside the kernel's physical address space.
-#define PMM_MAP_KERNEL_BIT 0x1
 #define PMM_MAP_KERNEL BIT(PMM_MAP_KERNEL_BIT)
+#define PMM_MAP_KERNEL_BIT 0x1
 
 /// @}
 
@@ -77,10 +81,12 @@ paddr_t pmm_allocate(int flags);
 /**
  * \brief Allocate a previously unused pageframe
  *
- * TODO: Take pagetable settings as parameter (writable, user, ...)
+ * @todo Take pagetable settings as parameter (writable, user, ...)
  *
  * @return The pageframe's **physical** address
  */
 void pmm_free(paddr_t pageframe);
 
 #endif /* KERNEL_PMM_H */
+
+/** @} */