Combining the kdb seq_file infrastructure with its symbolic lookups allows a good sub-set of files held in pseudo filesystems to be displayed by kdb. The seq_file command does exactly this and allows a significant subset of pseudo files to be safely examined whilst debugging (and in the hands of a brave expert an even bigger subset can be unsafely examined).
Good arguments to try with this command include: cpuinfo_op, gpiolib_seq_ops and vmalloc_op.
Signed-off-by: Daniel Thompson daniel.thompson@linaro.org --- kernel/debug/kdb/kdb_main.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 379650b..f11db91 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -1734,6 +1734,32 @@ static int kdb_mm(int argc, const char **argv) }
/* + * kdb_seq_file - This function implements the 'seq_file' command. + * seq_file address-expression + */ +static int kdb_seq_file(int argc, const char **argv) +{ + int diag; + unsigned long addr; + int nextarg; + long offset; + char *name; + const struct seq_operations *ops; + + nextarg = 1; + diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, &name); + if (diag) + return diag; + + if (nextarg != argc+1) + return KDB_ARGCOUNT; + + ops = (const struct seq_operations *) (addr + offset); + kdb_printf("Using sequence_ops at 0x%p (%s)\n", ops, name); + return kdb_print_seq_file(ops); +} + +/* * kdb_go - This function implements the 'go' command. * go [address-expression] */ @@ -2838,6 +2864,8 @@ static void __init kdb_inittab(void) "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_repeat("seq_file", kdb_seq_file, "", + "Show a seq_file using struct seq_operations", 3, KDB_REPEAT_NONE); }
/* Execute any commands defined in kdb_cmds. */