Messages in this thread Patch in this message | | | From | Sumit Garg <> | Subject | [PATCH v4] kdb: Simplify kdb commands registration | Date | Thu, 18 Feb 2021 17:39:58 +0530 |
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Simplify kdb commands registration via using linked list instead of static array for commands storage.
Signed-off-by: Sumit Garg <sumit.garg@linaro.org> ---
Changes in v4: - Fix kdb commands memory allocation issue prior to slab being available with an array of statically allocated commands. Now it works fine with kgdbwait. - Fix a misc checkpatch warning. - I have dropped Doug's review tag as I think this version includes a major fix that should be reviewed again.
Changes in v3: - Remove redundant "if" check. - Pick up review tag from Doug.
Changes in v2: - Remove redundant NULL check for "cmd_name". - Incorporate misc. comment.
kernel/debug/kdb/kdb_main.c | 129 ++++++++++++++--------------------------- kernel/debug/kdb/kdb_private.h | 2 + 2 files changed, 47 insertions(+), 84 deletions(-)
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 930ac1b..5215e04 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -33,6 +33,7 @@ #include <linux/kallsyms.h> #include <linux/kgdb.h> #include <linux/kdb.h> +#include <linux/list.h> #include <linux/notifier.h> #include <linux/interrupt.h> #include <linux/delay.h> @@ -84,15 +85,12 @@ static unsigned int kdb_continue_catastrophic = static unsigned int kdb_continue_catastrophic; #endif -/* kdb_commands describes the available commands. */ -static kdbtab_t *kdb_commands; -#define KDB_BASE_CMD_MAX 50 -static int kdb_max_commands = KDB_BASE_CMD_MAX; -static kdbtab_t kdb_base_commands[KDB_BASE_CMD_MAX]; -#define for_each_kdbcmd(cmd, num) \ - for ((cmd) = kdb_base_commands, (num) = 0; \ - num < kdb_max_commands; \ - num++, num == KDB_BASE_CMD_MAX ? cmd = kdb_commands : cmd++) +/* kdb_cmds_head describes the available commands. */ +static LIST_HEAD(kdb_cmds_head); + +#define KDB_CMD_INIT_MAX 50 +static int kdb_cmd_init_idx; +static kdbtab_t kdb_commands_init[KDB_CMD_INIT_MAX]; typedef struct _kdbmsg { int km_diag; /* kdb diagnostic */ @@ -921,7 +919,7 @@ int kdb_parse(const char *cmdstr) char *cp; char *cpp, quoted; kdbtab_t *tp; - int i, escaped, ignore_errors = 0, check_grep = 0; + int escaped, ignore_errors = 0, check_grep = 0; /* * First tokenize the command string. @@ -1011,25 +1009,17 @@ int kdb_parse(const char *cmdstr) ++argv[0]; } - for_each_kdbcmd(tp, i) { - if (tp->cmd_name) { - /* - * If this command is allowed to be abbreviated, - * check to see if this is it. - */ - - if (tp->cmd_minlen - && (strlen(argv[0]) <= tp->cmd_minlen)) { - if (strncmp(argv[0], - tp->cmd_name, - tp->cmd_minlen) == 0) { - break; - } - } + list_for_each_entry(tp, &kdb_cmds_head, list_node) { + /* + * If this command is allowed to be abbreviated, + * check to see if this is it. + */ + if (tp->cmd_minlen && (strlen(argv[0]) <= tp->cmd_minlen) && + (strncmp(argv[0], tp->cmd_name, tp->cmd_minlen) == 0)) + break; - if (strcmp(argv[0], tp->cmd_name) == 0) - break; - } + if (strcmp(argv[0], tp->cmd_name) == 0) + break; } /* @@ -1037,19 +1027,15 @@ int kdb_parse(const char *cmdstr) * few characters of this match any of the known commands. * e.g., md1c20 should match md. */ - if (i == kdb_max_commands) { - for_each_kdbcmd(tp, i) { - if (tp->cmd_name) { - if (strncmp(argv[0], - tp->cmd_name, - strlen(tp->cmd_name)) == 0) { - break; - } - } + if (list_entry_is_head(tp, &kdb_cmds_head, list_node)) { + list_for_each_entry(tp, &kdb_cmds_head, list_node) { + if (strncmp(argv[0], tp->cmd_name, + strlen(tp->cmd_name)) == 0) + break; } } - if (i < kdb_max_commands) { + if (!list_entry_is_head(tp, &kdb_cmds_head, list_node)) { int result; if (!kdb_check_flags(tp->cmd_flags, kdb_cmd_enabled, argc <= 1)) @@ -2428,17 +2414,14 @@ static int kdb_kgdb(int argc, const char **argv) static int kdb_help(int argc, const char **argv) { kdbtab_t *kt; - int i; kdb_printf("%-15.15s %-20.20s %s\n", "Command", "Usage", "Description"); kdb_printf("-----------------------------" "-----------------------------\n"); - for_each_kdbcmd(kt, i) { + list_for_each_entry(kt, &kdb_cmds_head, list_node) { char *space = ""; if (KDB_FLAG(CMD_INTERRUPT)) 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) @@ -2667,49 +2650,30 @@ int kdb_register_flags(char *cmd, short minlen, kdb_cmdflags_t flags) { - int i; kdbtab_t *kp; - /* - * Brute force method to determine duplicates - */ - for_each_kdbcmd(kp, i) { - if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) { + list_for_each_entry(kp, &kdb_cmds_head, list_node) { + if (strcmp(kp->cmd_name, cmd) == 0) { kdb_printf("Duplicate kdb command registered: " "%s, func %px help %s\n", cmd, func, help); return 1; } } - /* - * Insert command into first available location in table - */ - for_each_kdbcmd(kp, i) { - if (kp->cmd_name == NULL) - break; - } - - if (i >= kdb_max_commands) { - kdbtab_t *new = kmalloc_array(kdb_max_commands - - KDB_BASE_CMD_MAX + - kdb_command_extend, - sizeof(*new), - GFP_KDB); - if (!new) { - kdb_printf("Could not allocate new kdb_command " - "table\n"); + if (slab_is_available()) { + kp = kmalloc(sizeof(*kp), GFP_KDB); + if (!kp) { + kdb_printf("Could not allocate new kdb_command table\n"); return 1; } - if (kdb_commands) { - memcpy(new, kdb_commands, - (kdb_max_commands - KDB_BASE_CMD_MAX) * sizeof(*new)); - kfree(kdb_commands); + kp->is_dynamic = true; + } else { + if (kdb_cmd_init_idx >= KDB_CMD_INIT_MAX) { + kdb_printf("Could not allocate init kdb_command table\n"); + return 1; } - memset(new + kdb_max_commands - KDB_BASE_CMD_MAX, 0, - kdb_command_extend * sizeof(*new)); - kdb_commands = new; - kp = kdb_commands + kdb_max_commands - KDB_BASE_CMD_MAX; - kdb_max_commands += kdb_command_extend; + kp = &kdb_commands_init[kdb_cmd_init_idx]; + kdb_cmd_init_idx++; } kp->cmd_name = cmd; @@ -2719,6 +2683,8 @@ int kdb_register_flags(char *cmd, kp->cmd_minlen = minlen; kp->cmd_flags = flags; + list_add_tail(&kp->list_node, &kdb_cmds_head); + return 0; } EXPORT_SYMBOL_GPL(kdb_register_flags); @@ -2757,15 +2723,16 @@ EXPORT_SYMBOL_GPL(kdb_register); */ int kdb_unregister(char *cmd) { - int i; kdbtab_t *kp; /* * find the command. */ - for_each_kdbcmd(kp, i) { - if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) { - kp->cmd_name = NULL; + list_for_each_entry(kp, &kdb_cmds_head, list_node) { + if (strcmp(kp->cmd_name, cmd) == 0) { + list_del(&kp->list_node); + if (kp->is_dynamic) + kfree(kp); return 0; } } @@ -2778,12 +2745,6 @@ EXPORT_SYMBOL_GPL(kdb_unregister); /* Initialize the kdb command table. */ static void __init kdb_inittab(void) { - int i; - kdbtab_t *kp; - - for_each_kdbcmd(kp, i) - kp->cmd_name = NULL; - kdb_register_flags("md", kdb_md, "<vaddr>", "Display Memory Contents, also mdWcN, e.g. md8c1", 1, KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS); diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index a4281fb..f969a6a 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -174,6 +174,8 @@ typedef struct _kdbtab { short cmd_minlen; /* Minimum legal # command * chars required */ kdb_cmdflags_t cmd_flags; /* Command behaviour flags */ + struct list_head list_node; /* Command list */ + bool is_dynamic; /* Command table allocation type */ } kdbtab_t; extern int kdb_bt(int, const char **); /* KDB display back trace */ -- 2.7.4
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