[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>

arch/um/include/tlb.h

@@ -38,9 +38,9 @@ extern void mprotect_kernel_vm(int w);
 extern void force_flush_all(void);
 extern void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
                              unsigned long end_addr, int force,
-			     void *(*do_ops)(union mm_context *,
-					     struct host_vm_op *, int, int,
-					     void *));
+			     int (*do_ops)(union mm_context *,
+					   struct host_vm_op *, int, int,
+					   void **));
 extern int flush_tlb_kernel_range_common(unsigned long start,
 					 unsigned long end);
 

arch/um/kernel/skas/include/skas.h

@@ -24,31 +24,26 @@ extern void new_thread_proc(void *stack, void (*handler)(int sig));
 extern void remove_sigstack(void);
 extern void new_thread_handler(int sig);
 extern void handle_syscall(union uml_pt_regs *regs);
-extern void *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 void *unmap(struct mm_id * mm_idp, void *addr,
-		   unsigned long len, int done, void *data);
-extern void *protect(struct mm_id * mm_idp, unsigned long addr,
-		     unsigned long len, int r, int w, int x, int done,
-		     void *data);
+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,
+		 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,
+		   void **data);
 extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
 extern int new_mm(int from, unsigned long stack);
 extern int start_userspace(unsigned long stub_stack);
 extern int copy_context_skas0(unsigned long stack, int pid);
 extern void get_skas_faultinfo(int pid, struct faultinfo * fi);
 extern long execute_syscall_skas(void *r);
 extern unsigned long current_stub_stack(void);
+extern long run_syscall_stub(struct mm_id * mm_idp,
+                             int syscall, unsigned long *args, long expected,
+                             void **addr, int done);
+extern long syscall_stub_data(struct mm_id * mm_idp,
+                              unsigned long *data, int data_count,
+                              void **addr, void **stub_addr);
 
 #endif
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */