Messages in this thread Patch in this message | | | From | Sumit Garg <> | Subject | [PATCH v6 6/7] kgdb: roundup: Allow runtime arch specific override | Date | Thu, 29 Oct 2020 20:26:26 +0530 |
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Add a new API kgdb_arch_roundup_cpus() for a particular archichecture to override default kgdb roundup and if it detects at runtime to not support NMI roundup then it can fallback to default implementation using async SMP cross-calls.
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 <sumit.garg@linaro.org> --- arch/powerpc/kernel/kgdb.c | 3 ++- arch/sparc/kernel/smp_64.c | 3 ++- arch/x86/kernel/kgdb.c | 6 ++++-- include/linux/kgdb.h | 5 +++-- kernel/debug/debug_core.c | 10 +++++++++- 5 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index 4090802..126575d 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -125,9 +125,10 @@ static int kgdb_debugger_ipi(struct pt_regs *regs) } #ifdef CONFIG_SMP -void kgdb_roundup_cpus(void) +bool kgdb_arch_roundup_cpus(void) { smp_send_debugger_break(); + return true; } #endif diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index e38d8bf..c459c83 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -1014,9 +1014,10 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page) } #ifdef CONFIG_KGDB -void kgdb_roundup_cpus(void) +bool kgdb_arch_roundup_cpus(void) { smp_cross_call(&xcall_kgdb_capture, 0, 0, 0); + return true; } #endif diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index ff7878d..1b756d9 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -404,7 +404,8 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs) #ifdef CONFIG_SMP /** - * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * kgdb_arch_roundup_cpus - Get other CPUs into a holding pattern + * in an architectural specific manner * * On SMP systems, we need to get the attention of the other CPUs * and get them be in a known state. This should do what is needed @@ -414,9 +415,10 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs) * * On non-SMP systems, this is not called. */ -void kgdb_roundup_cpus(void) +bool kgdb_arch_roundup_cpus(void) { apic_send_IPI_allbutself(NMI_VECTOR); + return true; } #endif diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 0d6cf64..f9db5b8 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -200,7 +200,8 @@ kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, extern void kgdb_call_nmi_hook(void *ignored); /** - * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * kgdb_arch_roundup_cpus - Get other CPUs into a holding pattern + * in an architectural specific manner * * On SMP systems, we need to get the attention of the other CPUs * and get them into a known state. This should do what is needed @@ -210,7 +211,7 @@ extern void kgdb_call_nmi_hook(void *ignored); * * On non-SMP systems, this is not called. */ -extern void kgdb_roundup_cpus(void); +extern bool kgdb_arch_roundup_cpus(void); /** * kgdb_arch_set_pc - Generic call back to the program counter diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 1e75a89..27e401c 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -241,13 +241,21 @@ void __weak kgdb_call_nmi_hook(void *ignored) } NOKPROBE_SYMBOL(kgdb_call_nmi_hook); -void __weak kgdb_roundup_cpus(void) +bool __weak kgdb_arch_roundup_cpus(void) +{ + return false; +} + +static void kgdb_roundup_cpus(void) { call_single_data_t *csd; int this_cpu = raw_smp_processor_id(); int cpu; int ret; + if (kgdb_arch_roundup_cpus()) + return; + for_each_online_cpu(cpu) { /* No need to roundup ourselves */ if (cpu == this_cpu) -- 2.7.4
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