[PATCH v4 3/8] x86/hw_breakpoint: Add arch_reinstall_hw_breakpoint
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2025-09-14 14:10:14
Also in:
linux-doc, linux-perf-users, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Jinchao Wang <redacted> The new arch_reinstall_hw_breakpoint() function can be used in an atomic context, unlike the more expensive free and re-allocation path. This allows callers to efficiently re-establish an existing breakpoint. Signed-off-by: Jinchao Wang <redacted> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- arch/x86/include/asm/hw_breakpoint.h | 2 ++ arch/x86/kernel/hw_breakpoint.c | 9 +++++++++ 2 files changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw_breakpoint.h
index aa6adac6c3a2..c22cc4e87fc5 100644
--- a/arch/x86/include/asm/hw_breakpoint.h
+++ b/arch/x86/include/asm/hw_breakpoint.h@@ -21,6 +21,7 @@ struct arch_hw_breakpoint { enum bp_slot_action { BP_SLOT_ACTION_INSTALL, + BP_SLOT_ACTION_REINSTALL, BP_SLOT_ACTION_UNINSTALL, };
@@ -65,6 +66,7 @@ extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused, int arch_install_hw_breakpoint(struct perf_event *bp); +int arch_reinstall_hw_breakpoint(struct perf_event *bp); void arch_uninstall_hw_breakpoint(struct perf_event *bp); void hw_breakpoint_pmu_read(struct perf_event *bp); void hw_breakpoint_pmu_unthrottle(struct perf_event *bp);
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index 3658ace4bd8d..29c9369264d4 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c@@ -99,6 +99,10 @@ static int manage_bp_slot(struct perf_event *bp, enum bp_slot_action action) old_bp = NULL; new_bp = bp; break; + case BP_SLOT_ACTION_REINSTALL: + old_bp = bp; + new_bp = bp; + break; case BP_SLOT_ACTION_UNINSTALL: old_bp = bp; new_bp = NULL;
@@ -187,6 +191,11 @@ int arch_install_hw_breakpoint(struct perf_event *bp) return arch_manage_bp(bp, BP_SLOT_ACTION_INSTALL); } +int arch_reinstall_hw_breakpoint(struct perf_event *bp) +{ + return arch_manage_bp(bp, BP_SLOT_ACTION_REINSTALL); +} + void arch_uninstall_hw_breakpoint(struct perf_event *bp) { arch_manage_bp(bp, BP_SLOT_ACTION_UNINSTALL);