This patch introduces several new flags to collect kdb commands into groups (later allowing them to be optionally disabled).
This follows similar prior art to enable/disable magic sysrq commands.
The commands have been categorized as follows:
Always on: go (w/o args), env, set, help, ?, cpu (w/o args), sr, dmesg, disable_nmi, defcmd, summary, grephelp Mem read: md, mdr, mdp, mds, ef, bt (with args), per_cpu Mem write: mm Reg read: rd Reg write: go (with args), rm Inspect: bt (w/o args), btp, bta, btc, btt, ps, pid, lsmod Flow ctrl: bp, bl, bph, bc, be, bd, ss Signal: kill Reboot: reboot All: cpu, kgdb, (and all of the above), nmi_console
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org --- include/linux/kdb.h | 68 +++++++++++++++++++++++++++++- kernel/debug/kdb/kdb_bp.c | 21 ++++++---- kernel/debug/kdb/kdb_main.c | 100 +++++++++++++++++++++++++++++--------------- kernel/trace/trace_kdb.c | 2 +- 4 files changed, 148 insertions(+), 43 deletions(-)
diff --git a/include/linux/kdb.h b/include/linux/kdb.h index 39b44b3..08f9875 100644 --- a/include/linux/kdb.h +++ b/include/linux/kdb.h @@ -13,11 +13,75 @@ * Copyright (C) 2009 Jason Wessel jason.wessel@windriver.com */
+/* Shifted versions of the command enable bits are be used if the command + * has no arguments (see kdb_check_flags). This allows commands, such as + * go, to have different permissions depending upon whether it is called + * with an argument. + */ +#define KDB_ENABLE_NO_ARGS_SHIFT 10 + typedef enum { - KDB_REPEAT_NO_ARGS = 0x1, /* Repeat the command w/o arguments */ - KDB_REPEAT_WITH_ARGS = 0x2, /* Repeat the command w/ its arguments */ + KDB_ENABLE_ALL = (1 << 0), /* Enable everything */ + KDB_ENABLE_MEM_READ = (1 << 1), + KDB_ENABLE_MEM_WRITE = (1 << 2), + KDB_ENABLE_REG_READ = (1 << 3), + KDB_ENABLE_REG_WRITE = (1 << 4), + KDB_ENABLE_INSPECT = (1 << 5), + KDB_ENABLE_FLOW_CTRL = (1 << 6), + KDB_ENABLE_SIGNAL = (1 << 7), + KDB_ENABLE_REBOOT = (1 << 8), + /* User exposed values stop here, all remaining flags are + * exclusively used to describe a commands behaviour. + */ + + KDB_ENABLE_ALWAYS_SAFE = (1 << 9), + KDB_ENABLE_MASK = (1 << KDB_ENABLE_NO_ARGS_SHIFT) - 1, + + KDB_ENABLE_ALL_NO_ARGS = KDB_ENABLE_ALL << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_MEM_READ_NO_ARGS = KDB_ENABLE_MEM_READ + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_MEM_WRITE_NO_ARGS = KDB_ENABLE_MEM_WRITE + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_REG_READ_NO_ARGS = KDB_ENABLE_REG_READ + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_REG_WRITE_NO_ARGS = KDB_ENABLE_REG_WRITE + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_INSPECT_NO_ARGS = KDB_ENABLE_INSPECT + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_FLOW_CTRL_NO_ARGS = KDB_ENABLE_FLOW_CTRL + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_SIGNAL_NO_ARGS = KDB_ENABLE_SIGNAL + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_REBOOT_NO_ARGS = KDB_ENABLE_REBOOT + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_ALWAYS_SAFE_NO_ARGS = KDB_ENABLE_ALWAYS_SAFE + << KDB_ENABLE_NO_ARGS_SHIFT, + KDB_ENABLE_MASK_NO_ARGS = KDB_ENABLE_MASK << KDB_ENABLE_NO_ARGS_SHIFT, + + KDB_REPEAT_NO_ARGS = 0x40000000, /* Repeat the command w/o arguments */ + KDB_REPEAT_WITH_ARGS = 0x80000000, /* Repeat the command with args */ } kdb_cmdflags_t;
+/* + * 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; +} + typedef int (*kdb_func_t)(int, const char **);
#ifdef CONFIG_KGDB_KDB diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c index 87343f0..f5b3d89 100644 --- a/kernel/debug/kdb/kdb_bp.c +++ b/kernel/debug/kdb/kdb_bp.c @@ -532,21 +532,28 @@ void __init kdb_initbptab(void) bp->bp_free = 1;
kdb_register_flags("bp", kdb_bp, "[<vaddr>]", - "Set/Display breakpoints", 0, KDB_REPEAT_NO_ARGS); + "Set/Display breakpoints", 0, + KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS); kdb_register_flags("bl", kdb_bp, "[<vaddr>]", - "Display breakpoints", 0, KDB_REPEAT_NO_ARGS); + "Display breakpoints", 0, + KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS); if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) kdb_register_flags("bph", kdb_bp, "[<vaddr>]", - "[datar [length]|dataw [length]] Set hw brk", 0, KDB_REPEAT_NO_ARGS); + "[datar [length]|dataw [length]] Set hw brk", 0, + KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS); kdb_register_flags("bc", kdb_bc, "<bpnum>", - "Clear Breakpoint", 0, 0); + "Clear Breakpoint", 0, + KDB_ENABLE_FLOW_CTRL); kdb_register_flags("be", kdb_bc, "<bpnum>", - "Enable Breakpoint", 0, 0); + "Enable Breakpoint", 0, + KDB_ENABLE_FLOW_CTRL); kdb_register_flags("bd", kdb_bc, "<bpnum>", - "Disable Breakpoint", 0, 0); + "Disable Breakpoint", 0, + KDB_ENABLE_FLOW_CTRL);
kdb_register_flags("ss", kdb_ss, "", - "Single Step", 1, KDB_REPEAT_NO_ARGS); + "Single Step", 1, + KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS); /* * Architecture dependent initialization. */ diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 41dac47..dcf45a9 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -641,8 +641,13 @@ 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) @@ -2764,78 +2769,107 @@ static void __init kdb_inittab(void)
kdb_register_flags("md", kdb_md, "<vaddr>", "Display Memory Contents, also mdWcN, e.g. md8c1", 1, - KDB_REPEAT_NO_ARGS); + KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS); kdb_register_flags("mdr", kdb_md, "<vaddr> <bytes>", - "Display Raw Memory", 0, KDB_REPEAT_NO_ARGS); + "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_REPEAT_NO_ARGS); + "Display Physical Memory", 0, + KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS); kdb_register_flags("mds", kdb_md, "<vaddr>", - "Display Memory Symbolically", 0, KDB_REPEAT_NO_ARGS); + "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_REPEAT_NO_ARGS); + "Modify Memory Contents", 0, + KDB_ENABLE_MEM_WRITE | KDB_REPEAT_NO_ARGS); kdb_register_flags("go", kdb_go, "[<vaddr>]", - "Continue Execution", 1, 0); + "Continue Execution", 1, + KDB_ENABLE_REG_WRITE | KDB_ENABLE_ALWAYS_SAFE_NO_ARGS); kdb_register_flags("rd", kdb_rd, "", - "Display Registers", 0, 0); + "Display Registers", 0, + KDB_ENABLE_REG_READ); kdb_register_flags("rm", kdb_rm, "<reg> <contents>", - "Modify Registers", 0, 0); + "Modify Registers", 0, + KDB_ENABLE_REG_WRITE); kdb_register_flags("ef", kdb_ef, "<vaddr>", - "Display exception frame", 0, 0); + "Display exception frame", 0, + KDB_ENABLE_MEM_READ); kdb_register_flags("bt", kdb_bt, "[<vaddr>]", - "Stack traceback", 1, 0); + "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, 0); + "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, 0); + "Backtrace all processes matching state flag", 0, + KDB_ENABLE_INSPECT); kdb_register_flags("btc", kdb_bt, "", - "Backtrace current process on each cpu", 0, 0); + "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, - 0); + KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS); kdb_register_flags("env", kdb_env, "", - "Show environment variables", 0, 0); + "Show environment variables", 0, + KDB_ENABLE_ALWAYS_SAFE); kdb_register_flags("set", kdb_set, "", - "Set environment variables", 0, 0); + "Set environment variables", 0, + KDB_ENABLE_ALWAYS_SAFE); kdb_register_flags("help", kdb_help, "", - "Display Help Message", 1, 0); + "Display Help Message", 1, + KDB_ENABLE_ALWAYS_SAFE); kdb_register_flags("?", kdb_help, "", - "Display Help Message", 0, 0); + "Display Help Message", 0, + KDB_ENABLE_ALWAYS_SAFE); kdb_register_flags("cpu", kdb_cpu, "<cpunum>", - "Switch to new cpu", 0, 0); + "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, 0); + "Display active task list", 0, + KDB_ENABLE_INSPECT); kdb_register_flags("pid", kdb_pid, "<pidnum>", - "Switch to another task", 0, 0); + "Switch to another task", 0, + KDB_ENABLE_INSPECT); kdb_register_flags("reboot", kdb_reboot, "", - "Reboot the machine immediately", 0, 0); + "Reboot the machine immediately", 0, + KDB_ENABLE_REBOOT); #if defined(CONFIG_MODULES) kdb_register_flags("lsmod", kdb_lsmod, "", - "List loaded kernel modules", 0, 0); + "List loaded kernel modules", 0, + KDB_ENABLE_INSPECT); #endif #if defined(CONFIG_MAGIC_SYSRQ) kdb_register_flags("sr", kdb_sr, "<key>", - "Magic SysRq key", 0, 0); + "Magic SysRq key", 0, + KDB_ENABLE_ALWAYS_SAFE); #endif #if defined(CONFIG_PRINTK) kdb_register_flags("dmesg", kdb_dmesg, "[lines]", - "Display syslog buffer", 0, 0); + "Display syslog buffer", 0, + KDB_ENABLE_ALWAYS_SAFE); #endif if (arch_kgdb_ops.enable_nmi) { kdb_register_flags("disable_nmi", kdb_disable_nmi, "", - "Disable NMI entry to KDB", 0, 0); + "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, 0); + "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, 0); + "Send a signal to a process", 0, + KDB_ENABLE_SIGNAL); kdb_register_flags("summary", kdb_summary, "", - "Summarize the system", 4, 0); + "Summarize the system", 4, + KDB_ENABLE_ALWAYS_SAFE); kdb_register_flags("per_cpu", kdb_per_cpu, "<sym> [<bytes>] [<cpu>]", - "Display per_cpu variables", 3, 0); + "Display per_cpu variables", 3, + KDB_ENABLE_MEM_READ); kdb_register_flags("grephelp", kdb_grep_help, "", - "Display help on | grep", 0, 0); + "Display help on | grep", 0, + KDB_ENABLE_ALWAYS_SAFE); }
/* Execute any commands defined in kdb_cmds. */ diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c index 3da7e30..1058f6b 100644 --- a/kernel/trace/trace_kdb.c +++ b/kernel/trace/trace_kdb.c @@ -128,7 +128,7 @@ static int kdb_ftdump(int argc, const char **argv) static __init int kdb_ftrace_register(void) { kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]", - "Dump ftrace log", 0, 0); + "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE); return 0; }