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Miller" , Dietmar Eggemann , Dmitry Vyukov , "H. Peter Anvin" , Ian Rogers , Ingo Molnar , James Clark , Jinchao Wang , Jinjie Ruan , Jiri Olsa , Jonathan Corbet , Juri Lelli , Justin Stitt , kasan-dev@googlegroups.com, Kees Cook , "Liam R. Howlett" , "Liang Kan" , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, llvm@lists.linux.dev, Lorenzo Stoakes , Mark Rutland , Masahiro Yamada , Mathieu Desnoyers , Mel Gorman , Michal Hocko , Miguel Ojeda , Nam Cao , Namhyung Kim , Nathan Chancellor , Naveen N Rao , Nick Desaulniers , Rong Xu , Sami Tolvanen , Steven Rostedt , Suren Baghdasaryan , Thomas Gleixner , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Valentin Schneider , Vincent Guittot , Vincenzo Frascino , Vlastimil Babka , Will Deacon , workflows@vger.kernel.org, x86@kernel.org Subject: [PATCH v8 20/27] mm/ksw: add self-debug helpers Date: Tue, 11 Nov 2025 00:36:15 +0800 Message-ID: <20251110163634.3686676-21-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251110163634.3686676-1-wangjinchao600@gmail.com> References: <20251110163634.3686676-1-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 Provide two debug helpers: - ksw_watch_show(): print the current watch target address and length. - ksw_watch_fire(): intentionally trigger the watchpoint immediately by writing to the watched address, useful for testing HWBP behavior. Signed-off-by: Jinchao Wang --- include/linux/kstackwatch.h | 2 ++ mm/kstackwatch/watch.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/include/linux/kstackwatch.h b/include/linux/kstackwatch.h index ce3882acc5dc..6daded932ba6 100644 --- a/include/linux/kstackwatch.h +++ b/include/linux/kstackwatch.h @@ -60,5 +60,7 @@ void ksw_watch_exit(void); int ksw_watch_get(struct ksw_watchpoint **out_wp); int ksw_watch_on(struct ksw_watchpoint *wp, ulong watch_addr, u16 watch_len); int ksw_watch_off(struct ksw_watchpoint *wp); +void ksw_watch_show(void); +void ksw_watch_fire(void); #endif /* _KSTACKWATCH_H */ diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index c2aa912bf4c4..a298c31848a2 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -273,3 +273,37 @@ void ksw_watch_exit(void) { ksw_watch_free(); } + +/* self debug function */ +void ksw_watch_show(void) +{ + struct ksw_watchpoint *wp = current->ksw_ctx.wp; + + if (!wp) { + pr_info("nothing to show\n"); + return; + } + + pr_info("watch target bp_addr: 0x%llx len:%llu\n", wp->attr.bp_addr, + wp->attr.bp_len); +} +EXPORT_SYMBOL_GPL(ksw_watch_show); + +/* self debug function */ +void ksw_watch_fire(void) +{ + struct ksw_watchpoint *wp; + char *ptr; + + wp = current->ksw_ctx.wp; + + if (!wp) { + pr_info("nothing to fire\n"); + return; + } + + ptr = (char *)wp->attr.bp_addr; + pr_warn("watch triggered immediately\n"); + *ptr = 0x42; // This should trigger immediately for any bp_len +} +EXPORT_SYMBOL_GPL(ksw_watch_fire); -- 2.43.0