5 files changed, 72 insertions, 6 deletions

diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index d663809..e11bdcd 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -302,7 +302,7 @@ extern long syscall_stub_data(struct mm_id * mm_idp,
 extern int map(struct mm_id * mm_idp, unsigned long virt,
 	       unsigned long len, int r, int w, int x, int phys_fd,
 	       unsigned long long offset, int done, void **data);
-extern int unmap(struct mm_id * mm_idp, void *addr, unsigned long len,
+extern int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
 		 int done, void **data);
 extern int protect(struct mm_id * mm_idp, unsigned long addr,
 		   unsigned long len, int r, int w, int x, int done,
diff --git a/arch/um/include/skas/mode_kern_skas.h b/arch/um/include/skas/mode_kern_skas.h
index 9cd9c6e..8ee6285 100644
--- a/arch/um/include/skas/mode_kern_skas.h
+++ b/arch/um/include/skas/mode_kern_skas.h
@@ -33,6 +33,8 @@ extern unsigned long set_task_sizes_skas(unsigned long *task_size_out);
 extern int start_uml_skas(void);
 extern int external_pid_skas(struct task_struct *task);
 extern int thread_pid_skas(struct task_struct *task);
+extern void flush_tlb_page_skas(struct vm_area_struct *vma,
+				unsigned long address);
 
 #define kmem_end_skas (host_task_size - 1024 * 1024)
 
diff --git a/arch/um/kernel/skas/tlb.c b/arch/um/kernel/skas/tlb.c
index 304a5b0..c43901a 100644
--- a/arch/um/kernel/skas/tlb.c
+++ b/arch/um/kernel/skas/tlb.c
@@ -32,8 +32,7 @@ static int do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
 				  op->u.mmap.offset, finished, flush);
 			break;
 		case MUNMAP:
-			ret = unmap(&mmu->skas.id,
-				    (void *) op->u.munmap.addr,
+			ret = unmap(&mmu->skas.id, op->u.munmap.addr,
 				    op->u.munmap.len, finished, flush);
 			break;
 		case MPROTECT:
@@ -94,3 +93,66 @@ void force_flush_all_skas(void)
 	unsigned long end = proc_mm ? task_size : CONFIG_STUB_START;
         fix_range(current->mm, 0, end, 1);
 }
+
+void flush_tlb_page_skas(struct vm_area_struct *vma, unsigned long address)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	struct mm_struct *mm = vma->vm_mm;
+	void *flush = NULL;
+	int r, w, x, err = 0;
+	struct mm_id *mm_id;
+
+	pgd = pgd_offset(vma->vm_mm, address);
+	if(!pgd_present(*pgd))
+		goto kill;
+
+	pud = pud_offset(pgd, address);
+	if(!pud_present(*pud))
+		goto kill;
+
+	pmd = pmd_offset(pud, address);
+	if(!pmd_present(*pmd))
+		goto kill;
+
+	pte = pte_offset_kernel(pmd, address);
+
+	r = pte_read(*pte);
+	w = pte_write(*pte);
+	x = pte_exec(*pte);
+	if (!pte_young(*pte)) {
+		r = 0;
+		w = 0;
+	} else if (!pte_dirty(*pte)) {
+		w = 0;
+	}
+
+	mm_id = &mm->context.skas.id;
+	if(pte_newpage(*pte)){
+		if(pte_present(*pte)){
+			unsigned long long offset;
+			int fd;
+
+			fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
+			err = map(mm_id, address, PAGE_SIZE, r, w, x, fd,
+				  offset, 1, &flush);
+		}
+		else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
+	}
+	else if(pte_newprot(*pte))
+		err = protect(mm_id, address, PAGE_SIZE, r, w, x, 1, &flush);
+
+	if(err)
+		goto kill;
+
+	*pte = pte_mkuptodate(*pte);
+
+	return;
+
+kill:
+	printk("Failed to flush page for address 0x%lx\n", address);
+	force_sig(SIGKILL, current);
+}
+
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index e201ccf..00de86e 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -381,7 +381,9 @@ pte_t *addr_pte(struct task_struct *task, unsigned long addr)
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
 {
 	address &= PAGE_MASK;
-	flush_tlb_range(vma, address, address + PAGE_SIZE);
+
+	CHOOSE_MODE(flush_tlb_range(vma, address, address + PAGE_SIZE),
+		    flush_tlb_page_skas(vma, address));
 }
 
 void flush_tlb_all(void)
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 6cdfda8..af07907 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -219,8 +219,8 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
 	return ret;
 }
 
-int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
-	  void **data)
+int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
+	  int done, void **data)
 {
 	int ret;