[PATCH] uml: skas0 stubs now check system call return values

Change syscall-stub's data to include a "expected retval".

Stub now checks syscalls retval and aborts execution of syscall list, if
retval != expected retval.

run_syscall_stub prints the data of the failed syscall, using the data pointer
and retval written by the stub to the beginning of the stack.

one_syscall_stub is removed, to simplify code, because only some instructions
are saved by one_syscall_stub, no host-syscall.

Using the stub with additional data (modify_ldt via stub)
is prepared also.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 11 deletions

diff --git a/arch/um/kernel/tt/tlb.c b/arch/um/kernel/tt/tlb.c
index 16fc6a28882d..f1d85dbb45b9 100644
--- a/arch/um/kernel/tt/tlb.c
+++ b/arch/um/kernel/tt/tlb.c
@@ -17,26 +17,31 @@
 #include "os.h"
 #include "tlb.h"
 
-static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
-                    int finished, void *flush)
+static int do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
+                    int finished, void **flush)
 {
         struct host_vm_op *op;
-        int i;
+        int i, ret=0;
 
-        for(i = 0; i <= last; i++){
+        for(i = 0; i <= last && !ret; i++){
                 op = &ops[i];
                 switch(op->type){
                 case MMAP:
-                        os_map_memory((void *) op->u.mmap.addr, op->u.mmap.fd,
-                                      op->u.mmap.offset, op->u.mmap.len,
-                                      op->u.mmap.r, op->u.mmap.w,
-                                      op->u.mmap.x);
+                        ret = os_map_memory((void *) op->u.mmap.addr,
+                                            op->u.mmap.fd, op->u.mmap.offset,
+                                            op->u.mmap.len, op->u.mmap.r,
+                                            op->u.mmap.w, op->u.mmap.x);
                         break;
                 case MUNMAP:
-                        os_unmap_memory((void *) op->u.munmap.addr,
-                                        op->u.munmap.len);
+                        ret = os_unmap_memory((void *) op->u.munmap.addr,
+                                              op->u.munmap.len);
                         break;
                 case MPROTECT:
+                        ret = protect_memory(op->u.mprotect.addr,
+                                             op->u.munmap.len,
+                                             op->u.mprotect.r,
+                                             op->u.mprotect.w,
+                                             op->u.mprotect.x, 1);
                         protect_memory(op->u.mprotect.addr, op->u.munmap.len,
                                        op->u.mprotect.r, op->u.mprotect.w,
                                        op->u.mprotect.x, 1);
@@ -47,7 +52,7 @@ static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
                 }
         }
 
-        return NULL;
+        return ret;
 }
 
 static void fix_range(struct mm_struct *mm, unsigned long start_addr,