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Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Cc: Jinchao Wang Subject: [PATCH v7 05/23] mm/ksw: add ksw_config struct and parser Date: Thu, 9 Oct 2025 18:55:41 +0800 Message-ID: <20251009105650.168917-6-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251009105650.168917-1-wangjinchao600@gmail.com> References: <20251009105650.168917-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add struct ksw_config and ksw_parse_config() to parse user string. Signed-off-by: Jinchao Wang --- mm/kstackwatch/kernel.c | 112 +++++++++++++++++++++++++++++++++++ mm/kstackwatch/kstackwatch.h | 27 +++++++++ 2 files changed, 139 insertions(+) diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c index 78f1d019225f..3b7009033dd4 100644 --- a/mm/kstackwatch/kernel.c +++ b/mm/kstackwatch/kernel.c @@ -1,16 +1,128 @@ // SPDX-License-Identifier: GPL-2.0 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include +#include + +#include "kstackwatch.h" + +static struct ksw_config *ksw_config; + +struct param_map { + const char *name; /* long name */ + const char *short_name; /* short name (2 letters) */ + size_t offset; /* offsetof(struct ksw_config, field) */ + bool is_string; /* true for string */ +}; + +/* macro generates both long and short name automatically */ +#define PMAP(field, short, is_str) \ + { #field, #short, offsetof(struct ksw_config, field), is_str } + +static const struct param_map ksw_params[] = { + PMAP(func_name, fn, true), + PMAP(func_offset, fo, false), + PMAP(depth, dp, false), + PMAP(max_watch, mw, false), + PMAP(sp_offset, so, false), + PMAP(watch_len, wl, false), +}; + +static int ksw_parse_param(struct ksw_config *config, const char *key, + const char *val) +{ + const struct param_map *pm = NULL; + int ret; + + for (int i = 0; i < ARRAY_SIZE(ksw_params); i++) { + if (strcmp(key, ksw_params[i].name) == 0 || + strcmp(key, ksw_params[i].short_name) == 0) { + pm = &ksw_params[i]; + break; + } + } + + if (!pm) + return -EINVAL; + + if (pm->is_string) { + char **dst = (char **)((char *)config + pm->offset); + *dst = kstrdup(val, GFP_KERNEL); + if (!*dst) + return -ENOMEM; + } else { + ret = kstrtou16(val, 0, (u16 *)((char *)config + pm->offset)); + if (ret) + return ret; + } + + return 0; +} + +/* + * Configuration string format: + * param_name= [param_name= ...] + * + * Required parameters: + * - func_name |fn (str) : target function name + * - func_offset|fo (u16) : instruction pointer offset + * + * Optional parameters: + * - depth |dp (u16) : recursion depth + * - max_watch |mw (u16) : maximum number of watchpoints + * - sp_offset |so (u16) : offset from stack pointer at func_offset + * - watch_len |wl (u16) : watch length (1,2,4,8) + */ +static int __maybe_unused ksw_parse_config(char *buf, struct ksw_config *config) +{ + char *part, *key, *val; + int ret; + + kfree(config->func_name); + kfree(config->user_input); + memset(ksw_config, 0, sizeof(*ksw_config)); + + buf = strim(buf); + config->user_input = kstrdup(buf, GFP_KERNEL); + if (!config->user_input) + return -ENOMEM; + + while ((part = strsep(&buf, " \t\n")) != NULL) { + if (*part == '\0') + continue; + + key = strsep(&part, "="); + val = part; + if (!key || !val) + continue; + ret = ksw_parse_param(config, key, val); + if (ret) + pr_warn("unsupported param %s=%s", key, val); + } + + if (!config->func_name || !config->func_offset) { + pr_err("Missing required parameters: function or func_offset\n"); + return -EINVAL; + } + + return 0; +} static int __init kstackwatch_init(void) { + ksw_config = kzalloc(sizeof(*ksw_config), GFP_KERNEL); + if (!ksw_config) + return -ENOMEM; + pr_info("module loaded\n"); return 0; } static void __exit kstackwatch_exit(void) { + kfree(ksw_config); + pr_info("module unloaded\n"); } diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 0273ef478a26..a7bad207f863 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -2,4 +2,31 @@ #ifndef _KSTACKWATCH_H #define _KSTACKWATCH_H +#include + +#define MAX_CONFIG_STR_LEN 128 + +struct ksw_config { + char *func_name; + u16 depth; + + /* + * watched variable info: + * - func_offset : instruction offset in the function, typically the + * assignment of the watched variable, where ksw + * registers a kprobe post-handler. + * - sp_offset : offset from stack pointer at func_offset. Usually 0. + * - watch_len : size of the watched variable (1, 2, 4, or 8 bytes). + */ + u16 func_offset; + u16 sp_offset; + u16 watch_len; + + /* max number of hwbps that can be used */ + u16 max_watch; + + /* save to show */ + char *user_input; +}; + #endif /* _KSTACKWATCH_H */ -- 2.43.0