[PATCH v8 18/27] arm64/hw_breakpoint: Add arch_reinstall_hw_breakpoint
From: Jinchao Wang <hidden>
Date: 2025-11-10 16:38:02
Also in:
linux-doc, linux-mm, linux-perf-users, lkml, llvm, workflows
Subsystem:
arm pmu profiling and debugging, arm64 port (aarch64 architecture), the rest · Maintainers:
Will Deacon, Mark Rutland, Catalin Marinas, Linus Torvalds
Add arch_reinstall_hw_breakpoint() to restore a hardware breakpoint in an atomic context. Unlike the full uninstall and reallocation path, this lightweight function re-establishes an existing breakpoint efficiently and safely. This aligns ARM64 with x86 support for atomic breakpoint reinstalls. --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/hw_breakpoint.h | 1 + arch/arm64/kernel/hw_breakpoint.c | 5 +++++ 3 files changed, 7 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6663ffd23f25..fa35dfa2f5cc 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -232,6 +232,7 @@ config ARM64 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \ HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI select HAVE_HW_BREAKPOINT if PERF_EVENTS + select HAVE_REINSTALL_HW_BREAKPOINT if PERF_EVENTS select HAVE_IOREMAP_PROT select HAVE_IRQ_TIME_ACCOUNTING select HAVE_LIVEPATCH
diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h
index bd81cf17744a..6c98bbbc6aa6 100644
--- a/arch/arm64/include/asm/hw_breakpoint.h
+++ b/arch/arm64/include/asm/hw_breakpoint.h@@ -119,6 +119,7 @@ extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused, unsigned long val, void *data); extern int arch_install_hw_breakpoint(struct perf_event *bp); +extern int arch_reinstall_hw_breakpoint(struct perf_event *bp); extern void arch_uninstall_hw_breakpoint(struct perf_event *bp); extern void hw_breakpoint_pmu_read(struct perf_event *bp); extern int hw_breakpoint_slots(int type);
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index ab76b36dce82..bd7d23d7893d 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c@@ -292,6 +292,11 @@ int arch_install_hw_breakpoint(struct perf_event *bp) return hw_breakpoint_control(bp, HW_BREAKPOINT_INSTALL); } +int arch_reinstall_hw_breakpoint(struct perf_event *bp) +{ + return hw_breakpoint_control(bp, HW_BREAKPOINT_RESTORE); +} + void arch_uninstall_hw_breakpoint(struct perf_event *bp) { hw_breakpoint_control(bp, HW_BREAKPOINT_UNINSTALL);
--
2.43.0