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Subject[PATCH v7 4/7] nmi: backtrace: Allow runtime arch specific override
Date
Add a boolean return to arch_trigger_cpumask_backtrace() to support a
use-case where a particular architecture detects at runtime if it supports
NMI backtrace or it would like to fallback to default implementation using
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/arm/include/asm/irq.h | 2 +-
arch/arm/kernel/smp.c | 3 ++-
arch/mips/include/asm/irq.h | 2 +-
arch/mips/kernel/process.c | 3 ++-
arch/powerpc/include/asm/nmi.h | 2 +-
arch/powerpc/kernel/stacktrace.c | 3 ++-
arch/sparc/include/asm/irq_64.h | 2 +-
arch/sparc/kernel/process_64.c | 4 +++-
arch/x86/include/asm/irq.h | 2 +-
arch/x86/kernel/apic/hw_nmi.c | 3 ++-
include/linux/nmi.h | 12 ++++--------
11 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
index 46d4114..54b0180 100644
--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -31,7 +31,7 @@ void handle_IRQ(unsigned int, struct pt_regs *);
void init_IRQ(void);

#ifdef CONFIG_SMP
-extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
+extern bool arch_trigger_cpumask_backtrace(const cpumask_t *mask,
bool exclude_self);
#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
#endif
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 48099c6e..bb20a43 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -856,7 +856,8 @@ static void raise_nmi(cpumask_t *mask)
__ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
}

-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
+ return true;
}
diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index c5d3517..34f3b42 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -78,7 +78,7 @@ extern int cp0_fdc_irq;

extern int get_c0_fdc_int(void);

-void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
+bool arch_trigger_cpumask_backtrace(const struct cpumask *mask,
bool exclude_self);
#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 75ebd8d..d19e672 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -735,9 +735,10 @@ static void raise_backtrace(cpumask_t *mask)
}
}

-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
+ return true;
}

int mips_get_process_fp_mode(struct task_struct *task)
diff --git a/arch/powerpc/include/asm/nmi.h b/arch/powerpc/include/asm/nmi.h
index 84b4cfe..a5eb3e2 100644
--- a/arch/powerpc/include/asm/nmi.h
+++ b/arch/powerpc/include/asm/nmi.h
@@ -9,7 +9,7 @@ static inline void arch_touch_nmi_watchdog(void) {}
#endif

#if defined(CONFIG_NMI_IPI) && defined(CONFIG_STACKTRACE)
-extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
+extern bool arch_trigger_cpumask_backtrace(const cpumask_t *mask,
bool exclude_self);
#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
#endif
diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index b644065..22b112a 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -264,8 +264,9 @@ static void raise_backtrace_ipi(cpumask_t *mask)
}
}

-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace_ipi);
+ return true;
}
#endif /* defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI) */
diff --git a/arch/sparc/include/asm/irq_64.h b/arch/sparc/include/asm/irq_64.h
index 4d748e9..35c01ff 100644
--- a/arch/sparc/include/asm/irq_64.h
+++ b/arch/sparc/include/asm/irq_64.h
@@ -87,7 +87,7 @@ static inline unsigned long get_softint(void)
return retval;
}

-void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
+bool arch_trigger_cpumask_backtrace(const struct cpumask *mask,
bool exclude_self);
#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace

diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index a75093b..9182001 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -248,7 +248,7 @@ static void __global_reg_poll(struct global_reg_snapshot *gp)
}
}

-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
struct thread_info *tp = current_thread_info();
struct pt_regs *regs = get_irq_regs();
@@ -303,6 +303,8 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));

spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
+
+ return true;
}

#ifdef CONFIG_MAGIC_SYSRQ
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 528c8a7..b7668e0 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -47,7 +47,7 @@ extern void init_ISA_irqs(void);
extern void __init init_IRQ(void);

#ifdef CONFIG_X86_LOCAL_APIC
-void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
+bool arch_trigger_cpumask_backtrace(const struct cpumask *mask,
bool exclude_self);

#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 34a992e..e7dcd28 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -34,10 +34,11 @@ static void nmi_raise_cpu_backtrace(cpumask_t *mask)
apic->send_IPI_mask(mask, NMI_VECTOR);
}

-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self,
nmi_raise_cpu_backtrace);
+ return true;
}

static int nmi_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 750c7f3..cedbfc1 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -143,26 +143,22 @@ static inline void touch_nmi_watchdog(void)
#ifdef arch_trigger_cpumask_backtrace
static inline bool trigger_all_cpu_backtrace(void)
{
- arch_trigger_cpumask_backtrace(cpu_online_mask, false);
- return true;
+ return arch_trigger_cpumask_backtrace(cpu_online_mask, false);
}

static inline bool trigger_allbutself_cpu_backtrace(void)
{
- arch_trigger_cpumask_backtrace(cpu_online_mask, true);
- return true;
+ return arch_trigger_cpumask_backtrace(cpu_online_mask, true);
}

static inline bool trigger_cpumask_backtrace(struct cpumask *mask)
{
- arch_trigger_cpumask_backtrace(mask, false);
- return true;
+ return arch_trigger_cpumask_backtrace(mask, false);
}

static inline bool trigger_single_cpu_backtrace(int cpu)
{
- arch_trigger_cpumask_backtrace(cpumask_of(cpu), false);
- return true;
+ return arch_trigger_cpumask_backtrace(cpumask_of(cpu), false);
}

/* generic implementation */
--
2.7.4
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