[PATCH] uml: add skas0 command-line option

This adds the "skas0" parameter to force skas0 operation on SKAS3 host and
shows which operating mode has been selected.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index c45a60e9c92d14237c86a7522efc8d0da0a48292..8b01a5584e805f6f0de9a8ab0b59f33e3f4ca9f6 100644 (file)
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -212,12 +212,26 @@ static int stop_ptraced_child(int pid, int exitcode, int mustexit)
 
 static int force_sysemu_disabled = 0;
 
+int ptrace_faultinfo = 1;
+int proc_mm = 1;
+
+static int __init skas0_cmd_param(char *str, int* add)
+{
+       ptrace_faultinfo = proc_mm = 0;
+       return 0;
+}
+
 static int __init nosysemu_cmd_param(char *str, int* add)
 {
        force_sysemu_disabled = 1;
        return 0;
 }
 
+__uml_setup("skas0", skas0_cmd_param,
+               "skas0\n"
+               "    Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
+               "    specify mode=tt.\n\n");
+
 __uml_setup("nosysemu", nosysemu_cmd_param,
                "nosysemu\n"
                "    Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
@@ -359,12 +373,10 @@ void forward_pending_sigio(int target)
                kill(target, SIGIO);
 }
 
-int ptrace_faultinfo = 0;
-int proc_mm = 1;
-
 extern void *__syscall_stub_start, __syscall_stub_end;
 
 #ifdef UML_CONFIG_MODE_SKAS
+
 static inline void check_skas3_ptrace_support(void)
 {
        struct ptrace_faultinfo fi;
@@ -375,6 +387,7 @@ static inline void check_skas3_ptrace_support(void)
 
        n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
        if (n < 0) {
+               ptrace_faultinfo = 0;
                if(errno == EIO)
                        printf("not found\n");
                else {
@@ -382,8 +395,10 @@ static inline void check_skas3_ptrace_support(void)
                }
        }
        else {
-               ptrace_faultinfo = 1;
-               printf("found\n");
+               if (!ptrace_faultinfo)
+                       printf("found but disabled on command line\n");
+               else
+                       printf("found\n");
        }
 
        init_registers(pid);
@@ -396,13 +411,13 @@ int can_do_skas(void)
        if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
                proc_mm = 0;
                printf("not found\n");
-               goto out;
-       }
-       else {
-               printf("found\n");
+       } else {
+               if (!proc_mm)
+                       printf("found but disabled on command line\n");
+               else
+                       printf("found\n");
        }
 
-out:
        check_skas3_ptrace_support();
        return 1;
 }

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 8736d098f0eed6ce704b137a455c5a0aa5f4660e..ca2bb6f09a7d4f5231f8910bb3df4ba2151ae478 100644 (file)
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -38,6 +38,9 @@
 #include "choose-mode.h"
 #include "mode_kern.h"
 #include "mode.h"
+#ifdef UML_CONFIG_MODE_SKAS
+#include "skas.h"
+#endif
 
 #define DEFAULT_COMMAND_LINE "root=98:0"
 
@@ -318,6 +321,7 @@ int linux_main(int argc, char **argv)
        unsigned long avail, diff;
        unsigned long virtmem_size, max_physmem;
        unsigned int i, add;
+       char * mode;
 
        for (i = 1; i < argc; i++){
                if((i == 1) && (argv[i][0] == ' ')) continue;
@@ -338,6 +342,21 @@ int linux_main(int argc, char **argv)
                exit(1);
        }
 #endif
+
+#ifndef CONFIG_MODE_SKAS
+       mode = "TT";
+#else
+       /* Show to the user the result of selection */
+       if (mode_tt)
+               mode = "TT";
+       else if (proc_mm && ptrace_faultinfo)
+               mode = "SKAS3";
+       else
+               mode = "SKAS0";
+#endif
+
+       printf("UML running in %s mode\n", mode);
+
        uml_start = CHOOSE_MODE_PROC(set_task_sizes_tt, set_task_sizes_skas, 0,
                                     &host_task_size, &task_size);