🆕 内核堆内存调整函数

kernel/mm/mm.c

@@ -3,6 +3,7 @@
 #include "../common/printk.h"
 #include "../common/kprint.h"
 #include "../driver/multiboot2/multiboot2.h"
+#include <process/process.h>
 
 ul Total_Memory = 0;
 ul total_2M_pages = 0;
@@ -14,7 +15,8 @@ void mm_init()
     memory_management_struct.kernel_code_start = (ul)&_text;
     memory_management_struct.kernel_code_end = (ul)&_etext;
     memory_management_struct.kernel_data_end = (ul)&_edata;
-    memory_management_struct.kernel_end = (ul)&_end;
+    memory_management_struct.rodata_end = (ul)&_erodata;
+    memory_management_struct.start_brk = (ul)&_end;
 
     struct multiboot_mmap_entry_t mb2_mem_info[512];
     int count;
@@ -63,7 +65,7 @@ void mm_init()
     ul max_addr = memory_management_struct.e820[memory_management_struct.len_e820].BaseAddr + memory_management_struct.e820[memory_management_struct.len_e820].Length;
     // 初始化mms的bitmap
     // bmp的指针指向截止位置的4k对齐的上边界（防止修改了别的数据）
-    memory_management_struct.bmp = (unsigned long *)((memory_management_struct.kernel_end + PAGE_4K_SIZE - 1) & PAGE_4K_MASK);
+    memory_management_struct.bmp = (unsigned long *)((memory_management_struct.start_brk + PAGE_4K_SIZE - 1) & PAGE_4K_MASK);
     memory_management_struct.bits_size = max_addr >> PAGE_2M_SHIFT;                                                                                         // 物理地址空间的最大页面数
     memory_management_struct.bmp_len = (((unsigned long)(max_addr >> PAGE_2M_SHIFT) + sizeof(unsigned long) * 8 - 1) / 8) & (~(sizeof(unsigned long) - 1)); // bmp由多少个unsigned long变量组成
 
@@ -665,4 +667,26 @@ void mm_map_proc_page_table(ul proc_page_table_addr, bool is_phys, ul virt_addr_
     }
 
     flush_tlb();
+}
+
+/**
+ * @brief 调整堆区域的大小（暂时只能增加堆区域）
+ *
+ * @todo 缩小堆区域
+ * @param old_brk_end_addr 原本的堆内存区域的结束地址
+ * @param offset 新的地址相对于原地址的偏移量
+ * @return uint64_t
+ */
+uint64_t mm_do_brk(uint64_t old_brk_end_addr, int64_t offset)
+{
+    // 暂不支持缩小堆内存
+    if(offset <0)
+        return old_brk_end_addr;
+
+    uint64_t end_addr = old_brk_end_addr + offset;
+    for (uint64_t i = old_brk_end_addr; i < end_addr; i += PAGE_2M_SIZE)
+        mm_map_proc_page_table(current_pcb->mm->pgd, true, i, alloc_pages(ZONE_NORMAL, 1, PAGE_PGT_MAPPED), PAGE_2M_SIZE, PAGE_USER_PAGE, true);
+    
+    current_pcb->mm->brk_end = end_addr;
+    return end_addr;
 }

kernel/mm/mm.h

@@ -170,7 +170,8 @@ struct memory_desc
     ul zones_struct_len; // zones_struct列表的长度
 
     ul kernel_code_start, kernel_code_end; // 内核程序代码段起始地址、结束地址
-    ul kernel_data_end, kernel_end;        // 内核程序数据段结束地址、 内核程序结束地址
+    ul kernel_data_end, rodata_end;        // 内核程序数据段结束地址、 内核程序只读段结束地址
+    uint64_t start_brk; // 堆地址的起始位置
 
     ul end_of_struct; // 内存页管理结构的结束地址
 };
@@ -376,4 +377,14 @@ void mm_map_phys_addr(ul virt_addr_start, ul phys_addr_start, ul length, ul flag
 void mm_map_proc_page_table(ul proc_page_table_addr, bool is_phys, ul virt_addr_start, ul phys_addr_start, ul length, ul flags, bool user);
 
 
-void mm_map_phys_addr_user(ul virt_addr_start, ul phys_addr_start, ul length, ul flags);
+void mm_map_phys_addr_user(ul virt_addr_start, ul phys_addr_start, ul length, ul flags);
+
+/**
+ * @brief 调整堆区域的大小（暂时只能增加堆区域）
+ * 
+ * @todo 缩小堆区域
+ * @param old_brk_end_addr 原本的堆内存区域的结束地址
+ * @param offset 新的地址相对于原地址的偏移量
+ * @return uint64_t 
+ */
+uint64_t mm_do_brk(uint64_t old_brk_end_addr, int64_t offset);

kernel/process/process.c

@@ -400,6 +400,7 @@ ul do_execve(struct pt_regs *regs, char *path)
     // 映射1个2MB的物理页
     unsigned long code_start_addr = 0x800000;
     unsigned long stack_start_addr = 0xa00000;
+    uint64_t brk_start_addr = 0xc00000;
 
     mm_map_proc_page_table((uint64_t)current_pcb->mm->pgd, true, code_start_addr, alloc_pages(ZONE_NORMAL, 1, PAGE_PGT_MAPPED)->addr_phys, PAGE_2M_SIZE, PAGE_USER_PAGE, true);
 
@@ -417,8 +418,8 @@ ul do_execve(struct pt_regs *regs, char *path)
     current_pcb->mm->rodata_addr_end = 0;
     current_pcb->mm->bss_start = 0;
     current_pcb->mm->bss_end = 0;
-    current_pcb->mm->brk_start = 0;
+    current_pcb->mm->brk_start = brk_start_addr;
-    current_pcb->mm->brk_end = 0;
+    current_pcb->mm->brk_end = brk_start_addr;
     current_pcb->mm->stack_start = stack_start_addr;
 
     // 关闭之前的文件描述符
@@ -547,8 +548,8 @@ void process_init()
     initial_mm.bss_start = (uint64_t)&_bss;
     initial_mm.bss_end = (uint64_t)&_ebss;
 
-    initial_mm.brk_start = 0;
+    initial_mm.brk_start = memory_management_struct.start_brk;
-    initial_mm.brk_end = memory_management_struct.kernel_end;
+    initial_mm.brk_end = current_pcb->addr_limit;
 
     initial_mm.stack_start = _stack_start;
 

kernel/process/process.h

@@ -150,7 +150,7 @@ union proc_union
 		.flags = PF_KTHREAD,              \
 		.mm = &initial_mm,                \
 		.thread = &initial_thread,        \
-		.addr_limit = 0xffff800000000000, \
+		.addr_limit = 0xffffffffffffffff, \
 		.pid = 0,                         \
 		.virtual_runtime = 0,             \
 		.signal = 0,                      \

kernel/syscall/syscall.c

@@ -344,6 +344,33 @@ uint64_t sys_vfork(struct pt_regs *regs)
     return do_fork(regs, CLONE_VM | CLONE_FS | CLONE_SIGNAL, regs->rsp, 0);
 }
 
+/**
+ * @brief 堆内存调整
+ *
+ * @param arg0 新的堆区域的结束地址
+ * @return uint64_t 调整后的堆区域的结束地址
+ */
+uint64_t sys_brk(struct pt_regs *regs)
+{
+    uint64_t new_brk = PAGE_2M_ALIGN(regs->r8);
+
+    kdebug("sys_brk input= %#010lx bytes,  new_brk= %#010lx bytes current->end_brk=%#018lx", regs->r8, new_brk, current_pcb->mm->brk_end);
+
+    if (new_brk == 0)
+        return current_pcb->mm->brk_start;
+    
+    if(new_brk > current_pcb->addr_limit)   // 堆地址空间超过限制
+        return  -EADDRNOTAVAIL;
+        
+    if (new_brk < current_pcb->mm->brk_end) // todo: 释放堆内存空间
+        return 0;
+
+    new_brk = mm_do_brk(current_pcb->mm->brk_end, new_brk - current_pcb->mm->brk_end); // 扩展堆内存空间
+
+    current_pcb->mm->brk_end = new_brk;
+    return new_brk;
+}
+
 ul sys_ahci_end_req(struct pt_regs *regs)
 {
     ahci_end_request();