From: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>

Return an early error message when no TT support is compiled in and no SKAS
support is detected.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <[EMAIL PROTECTED]>
---

 linux-2.6.11-paolo/arch/um/kernel/process.c |   35 ++++++++++++++++++++--------
 linux-2.6.11-paolo/arch/um/kernel/um_arch.c |   10 +++++++-
 2 files changed, 35 insertions(+), 10 deletions(-)

diff -puN 
arch/um/kernel/um_arch.c~uml-refuse-to-run-without-skas-if-no-tt-mode-in 
arch/um/kernel/um_arch.c
--- 
linux-2.6.11/arch/um/kernel/um_arch.c~uml-refuse-to-run-without-skas-if-no-tt-mode-in
       2005-01-13 21:25:17.601847632 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/um_arch.c 2005-01-13 21:25:17.605847024 
+0100
@@ -198,7 +198,7 @@ __uml_setup("ncpus=", uml_ncpus_setup,
 );
 #endif
 
-int force_tt = 0;
+static int force_tt = 0;
 
 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 #define DEFAULT_TT 0
@@ -319,6 +319,14 @@ int linux_main(int argc, char **argv)
        if(have_root == 0) add_arg(saved_command_line, DEFAULT_COMMAND_LINE);
 
        mode_tt = force_tt ? 1 : !can_do_skas();
+#ifndef CONFIG_MODE_TT
+       if (mode_tt) {
+               /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
+                * can_do_skas() returned 0, and the message is correct. */
+               printf("Support for TT mode is disabled, and no SKAS support is 
present on the host.\n");
+               exit(1);
+       }
+#endif
        uml_start = CHOOSE_MODE_PROC(set_task_sizes_tt, set_task_sizes_skas, 0,
                                     &host_task_size, &task_size);
 
diff -puN 
arch/um/kernel/process.c~uml-refuse-to-run-without-skas-if-no-tt-mode-in 
arch/um/kernel/process.c
--- 
linux-2.6.11/arch/um/kernel/process.c~uml-refuse-to-run-without-skas-if-no-tt-mode-in
       2005-01-13 21:25:17.602847480 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/process.c 2005-01-13 21:25:17.605847024 
+0100
@@ -375,9 +375,9 @@ void forward_pending_sigio(int target)
                kill(target, SIGIO);
 }
 
-int can_do_skas(void)
-{
 #ifdef UML_CONFIG_MODE_SKAS
+static inline int check_skas3_ptrace_support(void)
+{
        struct ptrace_faultinfo fi;
        void *stack;
        int pid, n, ret = 1;
@@ -386,29 +386,46 @@ int can_do_skas(void)
        pid = start_ptraced_child(&stack);
 
        n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
-       if(n < 0){
+       if (n < 0) {
                if(errno == EIO)
                        printf("not found\n");
-               else printf("No (unexpected errno - %d)\n", errno);
+               else {
+                       perror("not found");
+               }
                ret = 0;
+       } else {
+               printf("found\n");
        }
-       else printf("found\n");
 
        init_registers(pid);
        stop_ptraced_child(pid, stack, 1, 1);
 
+       return(ret);
+}
+
+int can_do_skas(void)
+{
+       int ret = 1;
+
        printf("Checking for /proc/mm...");
-       if(os_access("/proc/mm", OS_ACC_W_OK) < 0){
+       if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
                printf("not found\n");
                ret = 0;
+               goto out;
+       } else {
+               printf("found\n");
        }
-       else printf("found\n");
 
-       return(ret);
+       ret = check_skas3_ptrace_support();
+out:
+       return ret;
+}
 #else
+int can_do_skas(void)
+{
        return(0);
-#endif
 }
+#endif
 
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
_


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