From a648ec05bb950fae2f35d0490ddd6cf15010af72 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 6 Aug 2010 16:11:02 +0200 Subject: Dynamic Debug: Introduce ddebug_query= boot parameter Dynamic debug lacks the ability to enable debug messages at boot time. One could patch initramfs or service startup scripts to write to /sys/../dynamic_debug/control, but this sucks. This patch makes it possible to pass a query in the same format one can write to /sys/../dynamic_debug/control via boot param. When dynamic debug gets initialized, this query will automatically be applied. Signed-off-by: Thomas Renninger Acked-by: jbaron@redhat.com Acked-by: Pekka Enberg Signed-off-by: Greg Kroah-Hartman --- lib/dynamic_debug.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'lib/dynamic_debug.c') diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 84d103c474e..44ce66bdb21 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -450,6 +450,19 @@ static int ddebug_exec_query(char *query_string) return 0; } +static __initdata char ddebug_setup_string[1024]; +static __init int ddebug_setup_query(char *str) +{ + if (strlen(str) >= 1024) { + pr_warning("ddebug boot param string too large\n"); + return 0; + } + strcpy(ddebug_setup_string, str); + return 1; +} + +__setup("ddebug_query=", ddebug_setup_query); + /* * File_ops->write method for /dynamic_debug/conrol. Gathers the * command text from userspace, parses and executes it. @@ -769,6 +782,18 @@ static int __init dynamic_debug_init(void) } ret = ddebug_add_module(iter_start, n, modname); } + + /* ddebug_query boot param got passed -> set it up */ + if (ddebug_setup_string[0] != '\0') { + ret = ddebug_exec_query(ddebug_setup_string); + if (ret) + pr_warning("Invalid ddebug boot param %s", + ddebug_setup_string); + else + pr_info("ddebug initialized with string %s", + ddebug_setup_string); + } + out_free: if (ret) { ddebug_remove_all_tables(); -- cgit v1.2.3