Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
[cascardo/linux.git] / kernel / debug / kdb / kdb_main.c
index 379650b..f191bdd 100644 (file)
@@ -12,6 +12,7 @@
  */
 
 #include <linux/ctype.h>
+#include <linux/types.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/kmsg_dump.h>
@@ -23,6 +24,7 @@
 #include <linux/vmalloc.h>
 #include <linux/atomic.h>
 #include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/kallsyms.h>
 #include <linux/slab.h>
 #include "kdb_private.h"
 
+#undef MODULE_PARAM_PREFIX
+#define        MODULE_PARAM_PREFIX "kdb."
+
+static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
+module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
+
 #define GREP_LEN 256
 char kdb_grep_string[GREP_LEN];
 int kdb_grepping_flag;
@@ -121,6 +129,7 @@ static kdbmsg_t kdbmsgs[] = {
        KDBMSG(BADLENGTH, "Invalid length field"),
        KDBMSG(NOBP, "No Breakpoint exists"),
        KDBMSG(BADADDR, "Invalid address"),
+       KDBMSG(NOPERM, "Permission denied"),
 };
 #undef KDBMSG
 
@@ -187,6 +196,26 @@ struct task_struct *kdb_curr_task(int cpu)
        return p;
 }
 
+/*
+ * Check whether the flags of the current command and the permissions
+ * of the kdb console has allow a command to be run.
+ */
+static inline bool kdb_check_flags(kdb_cmdflags_t flags, int permissions,
+                                  bool no_args)
+{
+       /* permissions comes from userspace so needs massaging slightly */
+       permissions &= KDB_ENABLE_MASK;
+       permissions |= KDB_ENABLE_ALWAYS_SAFE;
+
+       /* some commands change group when launched with no arguments */
+       if (no_args)
+               permissions |= permissions << KDB_ENABLE_NO_ARGS_SHIFT;
+
+       flags |= KDB_ENABLE_ALL;
+
+       return permissions & flags;
+}
+
 /*
  * kdbgetenv - This function will return the character string value of
  *     an environment variable.
@@ -475,6 +504,15 @@ int kdbgetaddrarg(int argc, const char **argv, int *nextarg,
        char *cp;
        kdb_symtab_t symtab;
 
+       /*
+        * If the enable flags prohibit both arbitrary memory access
+        * and flow control then there are no reasonable grounds to
+        * provide symbol lookup.
+        */
+       if (!kdb_check_flags(KDB_ENABLE_MEM_READ | KDB_ENABLE_FLOW_CTRL,
+                            kdb_cmd_enabled, false))
+               return KDB_NOPERM;
+
        /*
         * Process arguments which follow the following syntax:
         *
@@ -641,8 +679,13 @@ static int kdb_defcmd2(const char *cmdstr, const char *argv0)
                if (!s->count)
                        s->usable = 0;
                if (s->usable)
-                       kdb_register(s->name, kdb_exec_defcmd,
-                                    s->usage, s->help, 0);
+                       /* macros are always safe because when executed each
+                        * internal command re-enters kdb_parse() and is
+                        * safety checked individually.
+                        */
+                       kdb_register_flags(s->name, kdb_exec_defcmd, s->usage,
+                                          s->help, 0,
+                                          KDB_ENABLE_ALWAYS_SAFE);
                return 0;
        }
        if (!s->usable)
@@ -1003,25 +1046,22 @@ int kdb_parse(const char *cmdstr)
 
        if (i < kdb_max_commands) {
                int result;
+
+               if (!kdb_check_flags(tp->cmd_flags, kdb_cmd_enabled, argc <= 1))
+                       return KDB_NOPERM;
+
                KDB_STATE_SET(CMD);
                result = (*tp->cmd_func)(argc-1, (const char **)argv);
                if (result && ignore_errors && result > KDB_CMD_GO)
                        result = 0;
                KDB_STATE_CLEAR(CMD);
-               switch (tp->cmd_repeat) {
-               case KDB_REPEAT_NONE:
-                       argc = 0;
-                       if (argv[0])
-                               *(argv[0]) = '\0';
-                       break;
-               case KDB_REPEAT_NO_ARGS:
-                       argc = 1;
-                       if (argv[1])
-                               *(argv[1]) = '\0';
-                       break;
-               case KDB_REPEAT_WITH_ARGS:
-                       break;
-               }
+
+               if (tp->cmd_flags & KDB_REPEAT_WITH_ARGS)
+                       return result;
+
+               argc = tp->cmd_flags & KDB_REPEAT_NO_ARGS ? 1 : 0;
+               if (argv[argc])
+                       *(argv[argc]) = '\0';
                return result;
        }
 
@@ -1921,10 +1961,14 @@ static int kdb_rm(int argc, const char **argv)
  */
 static int kdb_sr(int argc, const char **argv)
 {
+       bool check_mask =
+           !kdb_check_flags(KDB_ENABLE_ALL, kdb_cmd_enabled, false);
+
        if (argc != 1)
                return KDB_ARGCOUNT;
+
        kdb_trap_printk++;
-       __handle_sysrq(*argv[1], false);
+       __handle_sysrq(*argv[1], check_mask);
        kdb_trap_printk--;
 
        return 0;
@@ -2157,6 +2201,8 @@ static void kdb_cpu_status(void)
        for (start_cpu = -1, i = 0; i < NR_CPUS; i++) {
                if (!cpu_online(i)) {
                        state = 'F';    /* cpu is offline */
+               } else if (!kgdb_info[i].enter_kgdb) {
+                       state = 'D';    /* cpu is online but unresponsive */
                } else {
                        state = ' ';    /* cpu is responding to kdb */
                        if (kdb_task_state_char(KDB_TSK(i)) == 'I')
@@ -2210,7 +2256,7 @@ static int kdb_cpu(int argc, const char **argv)
        /*
         * Validate cpunum
         */
-       if ((cpunum > NR_CPUS) || !cpu_online(cpunum))
+       if ((cpunum > NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
                return KDB_BADCPUNUM;
 
        dbg_switch_cpu = cpunum;
@@ -2375,6 +2421,8 @@ static int kdb_help(int argc, const char **argv)
                        return 0;
                if (!kt->cmd_name)
                        continue;
+               if (!kdb_check_flags(kt->cmd_flags, kdb_cmd_enabled, true))
+                       continue;
                if (strlen(kt->cmd_usage) > 20)
                        space = "\n                                    ";
                kdb_printf("%-15.15s %-20s%s%s\n", kt->cmd_name,
@@ -2629,7 +2677,7 @@ static int kdb_grep_help(int argc, const char **argv)
 }
 
 /*
- * kdb_register_repeat - This function is used to register a kernel
+ * kdb_register_flags - This function is used to register a kernel
  *     debugger command.
  * Inputs:
  *     cmd     Command name
@@ -2641,12 +2689,12 @@ static int kdb_grep_help(int argc, const char **argv)
  *     zero for success, one if a duplicate command.
  */
 #define kdb_command_extend 50  /* arbitrary */
-int kdb_register_repeat(char *cmd,
-                       kdb_func_t func,
-                       char *usage,
-                       char *help,
-                       short minlen,
-                       kdb_repeat_t repeat)
+int kdb_register_flags(char *cmd,
+                      kdb_func_t func,
+                      char *usage,
+                      char *help,
+                      short minlen,
+                      kdb_cmdflags_t flags)
 {
        int i;
        kdbtab_t *kp;
@@ -2694,19 +2742,18 @@ int kdb_register_repeat(char *cmd,
        kp->cmd_func   = func;
        kp->cmd_usage  = usage;
        kp->cmd_help   = help;
-       kp->cmd_flags  = 0;
        kp->cmd_minlen = minlen;
-       kp->cmd_repeat = repeat;
+       kp->cmd_flags  = flags;
 
        return 0;
 }
-EXPORT_SYMBOL_GPL(kdb_register_repeat);
+EXPORT_SYMBOL_GPL(kdb_register_flags);
 
 
 /*
  * kdb_register - Compatibility register function for commands that do
  *     not need to specify a repeat state.  Equivalent to
- *     kdb_register_repeat with KDB_REPEAT_NONE.
+ *     kdb_register_flags with flags set to 0.
  * Inputs:
  *     cmd     Command name
  *     func    Function to execute the command
@@ -2721,8 +2768,7 @@ int kdb_register(char *cmd,
             char *help,
             short minlen)
 {
-       return kdb_register_repeat(cmd, func, usage, help, minlen,
-                                  KDB_REPEAT_NONE);
+       return kdb_register_flags(cmd, func, usage, help, minlen, 0);
 }
 EXPORT_SYMBOL_GPL(kdb_register);
 
@@ -2764,80 +2810,109 @@ static void __init kdb_inittab(void)
        for_each_kdbcmd(kp, i)
                kp->cmd_name = NULL;
 
-       kdb_register_repeat("md", kdb_md, "<vaddr>",
+       kdb_register_flags("md", kdb_md, "<vaddr>",
          "Display Memory Contents, also mdWcN, e.g. md8c1", 1,
-                           KDB_REPEAT_NO_ARGS);
-       kdb_register_repeat("mdr", kdb_md, "<vaddr> <bytes>",
-         "Display Raw Memory", 0, KDB_REPEAT_NO_ARGS);
-       kdb_register_repeat("mdp", kdb_md, "<paddr> <bytes>",
-         "Display Physical Memory", 0, KDB_REPEAT_NO_ARGS);
-       kdb_register_repeat("mds", kdb_md, "<vaddr>",
-         "Display Memory Symbolically", 0, KDB_REPEAT_NO_ARGS);
-       kdb_register_repeat("mm", kdb_mm, "<vaddr> <contents>",
-         "Modify Memory Contents", 0, KDB_REPEAT_NO_ARGS);
-       kdb_register_repeat("go", kdb_go, "[<vaddr>]",
-         "Continue Execution", 1, KDB_REPEAT_NONE);
-       kdb_register_repeat("rd", kdb_rd, "",
-         "Display Registers", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("rm", kdb_rm, "<reg> <contents>",
-         "Modify Registers", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("ef", kdb_ef, "<vaddr>",
-         "Display exception frame", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("bt", kdb_bt, "[<vaddr>]",
-         "Stack traceback", 1, KDB_REPEAT_NONE);
-       kdb_register_repeat("btp", kdb_bt, "<pid>",
-         "Display stack for process <pid>", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("bta", kdb_bt, "[D|R|S|T|C|Z|E|U|I|M|A]",
-         "Backtrace all processes matching state flag", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("btc", kdb_bt, "",
-         "Backtrace current process on each cpu", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("btt", kdb_bt, "<vaddr>",
+         KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+       kdb_register_flags("mdr", kdb_md, "<vaddr> <bytes>",
+         "Display Raw Memory", 0,
+         KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+       kdb_register_flags("mdp", kdb_md, "<paddr> <bytes>",
+         "Display Physical Memory", 0,
+         KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+       kdb_register_flags("mds", kdb_md, "<vaddr>",
+         "Display Memory Symbolically", 0,
+         KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+       kdb_register_flags("mm", kdb_mm, "<vaddr> <contents>",
+         "Modify Memory Contents", 0,
+         KDB_ENABLE_MEM_WRITE | KDB_REPEAT_NO_ARGS);
+       kdb_register_flags("go", kdb_go, "[<vaddr>]",
+         "Continue Execution", 1,
+         KDB_ENABLE_REG_WRITE | KDB_ENABLE_ALWAYS_SAFE_NO_ARGS);
+       kdb_register_flags("rd", kdb_rd, "",
+         "Display Registers", 0,
+         KDB_ENABLE_REG_READ);
+       kdb_register_flags("rm", kdb_rm, "<reg> <contents>",
+         "Modify Registers", 0,
+         KDB_ENABLE_REG_WRITE);
+       kdb_register_flags("ef", kdb_ef, "<vaddr>",
+         "Display exception frame", 0,
+         KDB_ENABLE_MEM_READ);
+       kdb_register_flags("bt", kdb_bt, "[<vaddr>]",
+         "Stack traceback", 1,
+         KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS);
+       kdb_register_flags("btp", kdb_bt, "<pid>",
+         "Display stack for process <pid>", 0,
+         KDB_ENABLE_INSPECT);
+       kdb_register_flags("bta", kdb_bt, "[D|R|S|T|C|Z|E|U|I|M|A]",
+         "Backtrace all processes matching state flag", 0,
+         KDB_ENABLE_INSPECT);
+       kdb_register_flags("btc", kdb_bt, "",
+         "Backtrace current process on each cpu", 0,
+         KDB_ENABLE_INSPECT);
+       kdb_register_flags("btt", kdb_bt, "<vaddr>",
          "Backtrace process given its struct task address", 0,
-                           KDB_REPEAT_NONE);
-       kdb_register_repeat("env", kdb_env, "",
-         "Show environment variables", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("set", kdb_set, "",
-         "Set environment variables", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("help", kdb_help, "",
-         "Display Help Message", 1, KDB_REPEAT_NONE);
-       kdb_register_repeat("?", kdb_help, "",
-         "Display Help Message", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("cpu", kdb_cpu, "<cpunum>",
-         "Switch to new cpu", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("kgdb", kdb_kgdb, "",
-         "Enter kgdb mode", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("ps", kdb_ps, "[<flags>|A]",
-         "Display active task list", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("pid", kdb_pid, "<pidnum>",
-         "Switch to another task", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("reboot", kdb_reboot, "",
-         "Reboot the machine immediately", 0, KDB_REPEAT_NONE);
+         KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS);
+       kdb_register_flags("env", kdb_env, "",
+         "Show environment variables", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("set", kdb_set, "",
+         "Set environment variables", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("help", kdb_help, "",
+         "Display Help Message", 1,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("?", kdb_help, "",
+         "Display Help Message", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("cpu", kdb_cpu, "<cpunum>",
+         "Switch to new cpu", 0,
+         KDB_ENABLE_ALWAYS_SAFE_NO_ARGS);
+       kdb_register_flags("kgdb", kdb_kgdb, "",
+         "Enter kgdb mode", 0, 0);
+       kdb_register_flags("ps", kdb_ps, "[<flags>|A]",
+         "Display active task list", 0,
+         KDB_ENABLE_INSPECT);
+       kdb_register_flags("pid", kdb_pid, "<pidnum>",
+         "Switch to another task", 0,
+         KDB_ENABLE_INSPECT);
+       kdb_register_flags("reboot", kdb_reboot, "",
+         "Reboot the machine immediately", 0,
+         KDB_ENABLE_REBOOT);
 #if defined(CONFIG_MODULES)
-       kdb_register_repeat("lsmod", kdb_lsmod, "",
-         "List loaded kernel modules", 0, KDB_REPEAT_NONE);
+       kdb_register_flags("lsmod", kdb_lsmod, "",
+         "List loaded kernel modules", 0,
+         KDB_ENABLE_INSPECT);
 #endif
 #if defined(CONFIG_MAGIC_SYSRQ)
-       kdb_register_repeat("sr", kdb_sr, "<key>",
-         "Magic SysRq key", 0, KDB_REPEAT_NONE);
+       kdb_register_flags("sr", kdb_sr, "<key>",
+         "Magic SysRq key", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
 #endif
 #if defined(CONFIG_PRINTK)
-       kdb_register_repeat("dmesg", kdb_dmesg, "[lines]",
-         "Display syslog buffer", 0, KDB_REPEAT_NONE);
+       kdb_register_flags("dmesg", kdb_dmesg, "[lines]",
+         "Display syslog buffer", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
 #endif
        if (arch_kgdb_ops.enable_nmi) {
-               kdb_register_repeat("disable_nmi", kdb_disable_nmi, "",
-                 "Disable NMI entry to KDB", 0, KDB_REPEAT_NONE);
-       }
-       kdb_register_repeat("defcmd", kdb_defcmd, "name \"usage\" \"help\"",
-         "Define a set of commands, down to endefcmd", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("kill", kdb_kill, "<-signal> <pid>",
-         "Send a signal to a process", 0, KDB_REPEAT_NONE);
-       kdb_register_repeat("summary", kdb_summary, "",
-         "Summarize the system", 4, KDB_REPEAT_NONE);
-       kdb_register_repeat("per_cpu", kdb_per_cpu, "<sym> [<bytes>] [<cpu>]",
-         "Display per_cpu variables", 3, KDB_REPEAT_NONE);
-       kdb_register_repeat("grephelp", kdb_grep_help, "",
-         "Display help on | grep", 0, KDB_REPEAT_NONE);
+               kdb_register_flags("disable_nmi", kdb_disable_nmi, "",
+                 "Disable NMI entry to KDB", 0,
+                 KDB_ENABLE_ALWAYS_SAFE);
+       }
+       kdb_register_flags("defcmd", kdb_defcmd, "name \"usage\" \"help\"",
+         "Define a set of commands, down to endefcmd", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("kill", kdb_kill, "<-signal> <pid>",
+         "Send a signal to a process", 0,
+         KDB_ENABLE_SIGNAL);
+       kdb_register_flags("summary", kdb_summary, "",
+         "Summarize the system", 4,
+         KDB_ENABLE_ALWAYS_SAFE);
+       kdb_register_flags("per_cpu", kdb_per_cpu, "<sym> [<bytes>] [<cpu>]",
+         "Display per_cpu variables", 3,
+         KDB_ENABLE_MEM_READ);
+       kdb_register_flags("grephelp", kdb_grep_help, "",
+         "Display help on | grep", 0,
+         KDB_ENABLE_ALWAYS_SAFE);
 }
 
 /* Execute any commands defined in kdb_cmds.  */