Commit 900434c5 authored by Sumit Garg's avatar Sumit Garg Committed by Liao Chen
Browse files

kgdb: Expose default CPUs roundup fallback mechanism 

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8PLUM?from=project-issue
CVE: NA
Reference: https://lore.kernel.org/all/1604317487-14543-7-git-send-email-sumit.garg@linaro.org/



-------------------------------------------------

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: default avatarSumit Garg <sumit.garg@linaro.org>
Signed-off-by: default avatarWei Li <liwei391@huawei.com>
Reviewed-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: default avatarRuan Jinjie <ruanjinjie@huawei.com>
Signed-off-by: default avatarLiao Chen <liaochen4@huawei.com>
parent 6ab1c301

include/linux/kgdb.h

+12 −0
Original line number Diff line number Diff line
@@ -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

 *

kernel/debug/debug_core.c

+7 −1
Original line number Diff line number Diff line
@@ -238,7 +238,7 @@ NOKPROBE_SYMBOL(kgdb_call_nmi_hook); 
static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd) =

	CSD_INIT(kgdb_call_nmi_hook, NULL);



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();
@@ -269,6 +269,12 @@ 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