5 files changed, 72 insertions, 6 deletions

diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index d66380908703..e11bdcd8afc2 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 9cd9c6ec9a63..8ee6285dfacc 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 304a5b0695ab..c43901aa9368 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 e201ccf0ec89..00de86efccaa 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 6cdfda807b65..af0790719b77 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;