S-mode to access the memory of U-mode in the riscv

Ubiquitous/XiZi_AIoT/hardkernel/intr/riscv/rv64gc/trampoline.S

@@ -168,6 +168,12 @@ handle_syscall:
 
 /* Slow paths for ptrace. */
 handle_syscall_trace_enter:
+	csrr s0, satp
+	la a0, riscv_kernel_satp
+	ld a0, 0(a0)
+	csrw satp, a0
+	sfence.vma
+
 	move a0, sp
 	//call do_syscall_trace_enter
 	call syscall_arch_handler
@@ -185,6 +191,10 @@ handle_syscall_trace_enter:
 handle_syscall_trace_exit:
 	move a0, sp
 	//call do_syscall_trace_exit
+
+	csrw satp, s0
+	sfence.vma
+
 	j ret_from_exception
 
 

Ubiquitous/XiZi_AIoT/softkernel/memory/pagetable_riscv.c

@@ -127,6 +127,8 @@ static bool _unmap_pages(uintptr_t* pgdir, uintptr_t vaddr, int len)
 /// @return
 static bool _map_user_pages(struct MemSpace* pmemspace, uintptr_t vaddr, uintptr_t paddr, int len, bool is_dev)
 {
+    bool ret;
+
     if (len < 0) {
         return false;
     }
@@ -143,7 +145,26 @@ static bool _map_user_pages(struct MemSpace* pmemspace, uintptr_t vaddr, uintptr
         _p_pgtbl_mmu_access->MmuUsrDevPteAttr(&mem_attr);
     }
 
-    return _map_pages(pmemspace->pgdir.pd_addr, vaddr, paddr, (intptr_t)len, mem_attr);
+    ret = _map_pages(pmemspace->pgdir.pd_addr, vaddr, paddr, (intptr_t)len, mem_attr);
+    if (ret == false) {
+        ERROR("mapping _map_pages fail.\n");
+        return false;
+    }
+
+    // In order for the S-mode to access the memory of the U-mode, in the riscv architecture.
+    if (LIKELY(!is_dev)) {
+        _p_pgtbl_mmu_access->MmuKernPteAttr(&mem_attr);
+    } else {
+        _p_pgtbl_mmu_access->MmuDevPteAttr(&mem_attr);
+    }
+
+    ret = _map_pages(pmemspace->pgdir_riscv.pd_addr, vaddr, paddr, (intptr_t)len, mem_attr);
+    if (ret == false) {
+        ERROR("mapping _map_pages riscv fail.\n");
+        return false;
+    }
+
+    return true;
 }
 
 /// assume that a user pagedir is allocated from [0, size)

Ubiquitous/XiZi_AIoT/softkernel/task/memspace.c

@@ -120,6 +120,10 @@ uintptr_t* load_memspace(struct MemSpace* pmemspace, char* img_start)
     }
     /* copy kernel pagetable so that interrupt and syscall wont corrupt */
     memcpy(pmemspace->pgdir.pd_addr, kern_pgdir.pd_addr, TOPLEVLE_PAGEDIR_SIZE);
+#ifdef __riscv
+    xizi_pager.new_pgdir(&pmemspace->pgdir_riscv);
+    memcpy(pmemspace->pgdir_riscv.pd_addr, kern_pgdir.pd_addr, TOPLEVLE_PAGEDIR_SIZE);
+#endif
 
     // read elf file by (header, section)
     uintptr_t load_size = 0;

Ubiquitous/XiZi_AIoT/softkernel/task/task.c

@@ -288,6 +288,9 @@ static void task_state_set_running(struct Thread* task)
     doubleListAddOnHead(&task->node, &xizi_task_manager.task_running_list_head);
 }
 
+#ifdef __riscv
+uintptr_t riscv_kernel_satp = 0;
+#endif
 struct Thread* next_task_emergency = NULL;
 extern void context_switch(struct context**, struct context*);
 static void _scheduler(struct SchedulerRightGroup right_group)
@@ -318,8 +321,14 @@ static void _scheduler(struct SchedulerRightGroup right_group)
         /* run the chosen task */
         task_state_set_running(next_task);
         cpu->task = next_task;
+
+#ifdef __riscv
+        riscv_kernel_satp = PFN_DOWN((uintptr_t)V2P(next_task->memspace->pgdir_riscv.pd_addr)) | SATP_MODE;
+#endif
+
         assert(next_task->memspace->pgdir.pd_addr != NULL);
         p_mmu_driver->LoadPgdir((uintptr_t)V2P(next_task->memspace->pgdir.pd_addr));
+
         context_switch(&cpu->scheduler, next_task->thread_context.context);
         assert(next_task->state != RUNNING);
     }