From 670f9dc65f8c7326dcb160111c930cc6d411eff6 Mon Sep 17 00:00:00 2001 From: Sumit Garg Date: Tue, 23 Feb 2021 20:39:12 +0800 Subject: [PATCH] kgdb: Expose default CPUs roundup fallback mechanism maillist inclusion category: feature bugzilla: 49593 CVE: NA Reference: https://www.spinics.net/lists/arm-kernel/msg851005.html ------------------------------------------------- Add a new API kgdb_smp_call_nmi_hook() to expose default CPUs roundup mechanism to a particular archichecture as a runtime fallback if it detects to not support NMI roundup. Currently such an architecture example is arm64 supporting pseudo NMIs feature which is only available on platforms which have support for GICv3 or later version. Signed-off-by: Sumit Garg Signed-off-by: Wei Li Reviewed-by: Xie XiuQi Signed-off-by: Zheng Zengkai --- include/linux/kgdb.h | 12 ++++++++++++ kernel/debug/debug_core.c | 8 +++++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 0d6cf64c8bb1..4190f13a6b8c 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -199,6 +199,18 @@ kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, extern void kgdb_call_nmi_hook(void *ignored); +/** + * kgdb_smp_call_nmi_hook - Provide default fallback mechanism to + * round-up CPUs + * + * If you're using the default implementation of kgdb_roundup_cpus() + * this function will be called. And if an arch detects at runtime to + * not support NMI based roundup then it can fallback to default + * mechanism using this API. + */ + +extern void kgdb_smp_call_nmi_hook(void); + /** * kgdb_roundup_cpus - Get other CPUs into a holding pattern * diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 1e75a8923a8d..ae785d8c3a10 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -241,7 +241,7 @@ void __weak kgdb_call_nmi_hook(void *ignored) } NOKPROBE_SYMBOL(kgdb_call_nmi_hook); -void __weak kgdb_roundup_cpus(void) +void kgdb_smp_call_nmi_hook(void) { call_single_data_t *csd; int this_cpu = raw_smp_processor_id(); @@ -273,6 +273,12 @@ void __weak kgdb_roundup_cpus(void) kgdb_info[cpu].rounding_up = false; } } +NOKPROBE_SYMBOL(kgdb_smp_call_nmi_hook); + +void __weak kgdb_roundup_cpus(void) +{ + kgdb_smp_call_nmi_hook(); +} NOKPROBE_SYMBOL(kgdb_roundup_cpus); #endif -- GitLab