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-rw-r--r--arch/powerpc/include/asm/smp.h1
-rw-r--r--arch/powerpc/kernel/kgdb.c10
-rw-r--r--arch/powerpc/kernel/smp.c5
-rw-r--r--arch/x86/kernel/kgdb.c9
-rw-r--r--include/linux/console.h1
-rw-r--r--include/linux/kgdb.h3
-rw-r--r--include/linux/printk.h23
-rw-r--r--kernel/debug/debug_core.c45
-rw-r--r--kernel/printk/printk.c26
9 files changed, 100 insertions, 23 deletions
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 7ef1cd8168a0..f9e63cacd220 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -62,6 +62,7 @@ struct smp_ops_t {
extern int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us);
extern int smp_send_safe_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us);
+extern void smp_send_debugger_break_cpu(unsigned int cpu);
extern void smp_send_debugger_break(void);
extern void start_secondary_resume(void);
extern void smp_generic_give_timebase(void);
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index bdee7262c080..d57d37497862 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -120,11 +120,19 @@ int kgdb_skipexception(int exception, struct pt_regs *regs)
static int kgdb_debugger_ipi(struct pt_regs *regs)
{
- kgdb_nmicallback(raw_smp_processor_id(), regs);
+ int cpu = raw_smp_processor_id();
+
+ if (!kgdb_roundup_delay(cpu))
+ kgdb_nmicallback(cpu, regs);
return 0;
}
#ifdef CONFIG_SMP
+void kgdb_roundup_cpu(unsigned int cpu)
+{
+ smp_send_debugger_break_cpu(cpu);
+}
+
void kgdb_roundup_cpus(void)
{
smp_send_debugger_break();
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 605bab448f84..26c2179cf64a 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -589,6 +589,11 @@ static void debugger_ipi_callback(struct pt_regs *regs)
debugger_ipi(regs);
}
+void smp_send_debugger_break_cpu(unsigned int cpu)
+{
+ smp_send_nmi_ipi(cpu, debugger_ipi_callback, 1000000);
+}
+
void smp_send_debugger_break(void)
{
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, debugger_ipi_callback, 1000000);
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 3a43a2dee658..37bd37cdf2b6 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -502,9 +502,12 @@ static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
if (atomic_read(&kgdb_active) != -1) {
/* KGDB CPU roundup */
cpu = raw_smp_processor_id();
- kgdb_nmicallback(cpu, regs);
- set_bit(cpu, was_in_debug_nmi);
- touch_nmi_watchdog();
+
+ if (!kgdb_roundup_delay(cpu)) {
+ kgdb_nmicallback(cpu, regs);
+ set_bit(cpu, was_in_debug_nmi);
+ touch_nmi_watchdog();
+ }
return NMI_HANDLED;
}
diff --git a/include/linux/console.h b/include/linux/console.h
index 20874db50bc8..b0e783248b20 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -140,6 +140,7 @@ static inline int con_debug_leave(void)
struct console {
char name[16];
void (*write)(struct console *, const char *, unsigned);
+ void (*write_atomic)(struct console *co, const char *s, unsigned int count);
int (*read)(struct console *, char *, unsigned);
struct tty_driver *(*device)(struct console *, int *);
void (*unblank)(void);
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index 258cdde8d356..9bca0d98db5a 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -212,6 +212,8 @@ extern void kgdb_call_nmi_hook(void *ignored);
*/
extern void kgdb_roundup_cpus(void);
+extern void kgdb_roundup_cpu(unsigned int cpu);
+
/**
* kgdb_arch_set_pc - Generic call back to the program counter
* @regs: Current &struct pt_regs.
@@ -365,5 +367,6 @@ extern void kgdb_free_init_mem(void);
#define dbg_late_init()
static inline void kgdb_panic(const char *msg) {}
static inline void kgdb_free_init_mem(void) { }
+static inline void kgdb_roundup_cpu(unsigned int cpu) {}
#endif /* ! CONFIG_KGDB */
#endif /* _KGDB_H_ */
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 67aa497b9498..453458c722f5 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -280,10 +280,18 @@ static inline void dump_stack(void)
extern int __printk_cpu_trylock(void);
extern void __printk_wait_on_cpu_lock(void);
extern void __printk_cpu_unlock(void);
+extern bool kgdb_roundup_delay(unsigned int cpu);
+
#else
+
#define __printk_cpu_trylock() 1
#define __printk_wait_on_cpu_lock()
#define __printk_cpu_unlock()
+
+static inline bool kgdb_roundup_delay(unsigned int cpu)
+{
+ return false;
+}
#endif /* CONFIG_SMP */
/**
@@ -315,6 +323,21 @@ extern void __printk_cpu_unlock(void);
local_irq_restore(flags); \
} while (0)
+/*
+ * Used to synchronize atomic consoles.
+ *
+ * The same as raw_printk_cpu_lock_irqsave() except that hardware interrupts
+ * are _not_ restored while spinning.
+ */
+#define console_atomic_lock(flags) \
+ do { \
+ local_irq_save(flags); \
+ while (!__printk_cpu_trylock()) \
+ cpu_relax(); \
+ } while (0)
+
+#define console_atomic_unlock raw_printk_cpu_unlock_irqrestore
+
extern int kptr_restrict;
/**
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index da06a5553835..3e39636da842 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -238,35 +238,42 @@ 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 __weak kgdb_roundup_cpu(unsigned int cpu)
{
call_single_data_t *csd;
+ int ret;
+
+ csd = &per_cpu(kgdb_roundup_csd, cpu);
+
+ /*
+ * If it didn't round up last time, don't try again
+ * since smp_call_function_single_async() will block.
+ *
+ * If rounding_up is false then we know that the
+ * previous call must have at least started and that
+ * means smp_call_function_single_async() won't block.
+ */
+ if (kgdb_info[cpu].rounding_up)
+ return;
+ kgdb_info[cpu].rounding_up = true;
+
+ ret = smp_call_function_single_async(cpu, csd);
+ if (ret)
+ kgdb_info[cpu].rounding_up = false;
+}
+NOKPROBE_SYMBOL(kgdb_roundup_cpu);
+
+void __weak kgdb_roundup_cpus(void)
+{
int this_cpu = raw_smp_processor_id();
int cpu;
- int ret;
for_each_online_cpu(cpu) {
/* No need to roundup ourselves */
if (cpu == this_cpu)
continue;
- csd = &per_cpu(kgdb_roundup_csd, cpu);
-
- /*
- * If it didn't round up last time, don't try again
- * since smp_call_function_single_async() will block.
- *
- * If rounding_up is false then we know that the
- * previous call must have at least started and that
- * means smp_call_function_single_async() won't block.
- */
- if (kgdb_info[cpu].rounding_up)
- continue;
- kgdb_info[cpu].rounding_up = true;
-
- ret = smp_call_function_single_async(cpu, csd);
- if (ret)
- kgdb_info[cpu].rounding_up = false;
+ kgdb_roundup_cpu(cpu);
}
}
NOKPROBE_SYMBOL(kgdb_roundup_cpus);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a8d0a58deebc..c344072fc0d5 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -44,6 +44,7 @@
#include <linux/irq_work.h>
#include <linux/ctype.h>
#include <linux/uio.h>
+#include <linux/kgdb.h>
#include <linux/sched/clock.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
@@ -3582,6 +3583,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
#ifdef CONFIG_SMP
static atomic_t printk_cpulock_owner = ATOMIC_INIT(-1);
static atomic_t printk_cpulock_nested = ATOMIC_INIT(0);
+static unsigned int kgdb_cpu = -1;
/**
* __printk_wait_on_cpu_lock() - Busy wait until the printk cpu-reentrant
@@ -3661,6 +3663,9 @@ EXPORT_SYMBOL(__printk_cpu_trylock);
*/
void __printk_cpu_unlock(void)
{
+ bool trigger_kgdb = false;
+ unsigned int cpu;
+
if (atomic_read(&printk_cpulock_nested)) {
atomic_dec(&printk_cpulock_nested);
return;
@@ -3671,6 +3676,12 @@ void __printk_cpu_unlock(void)
* LMM(__printk_cpu_unlock:A)
*/
+ cpu = smp_processor_id();
+ if (kgdb_cpu == cpu) {
+ trigger_kgdb = true;
+ kgdb_cpu = -1;
+ }
+
/*
* Guarantee loads and stores from this CPU when it was the
* lock owner are visible to the next lock owner. This pairs
@@ -3691,6 +3702,21 @@ void __printk_cpu_unlock(void)
*/
atomic_set_release(&printk_cpulock_owner,
-1); /* LMM(__printk_cpu_unlock:B) */
+
+ if (trigger_kgdb) {
+ pr_warn("re-triggering kgdb roundup for CPU#%d\n", cpu);
+ kgdb_roundup_cpu(cpu);
+ }
}
EXPORT_SYMBOL(__printk_cpu_unlock);
+
+bool kgdb_roundup_delay(unsigned int cpu)
+{
+ if (cpu != atomic_read(&printk_cpulock_owner))
+ return false;
+
+ kgdb_cpu = cpu;
+ return true;
+}
+EXPORT_SYMBOL(kgdb_roundup_delay);
#endif /* CONFIG_SMP */
generated by cgit v1.2.3 (git 2.39.0) at 2025-09-02 05:42:51 +0300