[PATCHv2 1/5] arm64/entry-common: push the judgement of nmi ahead
Pingfan Liu
kernelfans at gmail.com
Fri Sep 24 06:28:33 PDT 2021
In enter_el1_irq_or_nmi(), it can be the case which NMI interrupts an
irq, which makes the condition !interrupts_enabled(regs) fail to detect
the NMI. This will cause a mistaken account for irq.
Introducing two interfaces: handle_arch_nmi and interrupt_is_nmi to
judge NMI at this stage.
Signed-off-by: Pingfan Liu <kernelfans at gmail.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Joey Gouly <joey.gouly at arm.com>
Cc: Sami Tolvanen <samitolvanen at google.com>
Cc: Julien Thierry <julien.thierry at arm.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Yuichi Ito <ito-yuichi at fujitsu.com>
Cc: linux-kernel at vger.kernel.org
To: linux-arm-kernel at lists.infradead.org
---
arch/arm64/include/asm/irq.h | 5 ++++
arch/arm64/kernel/entry-common.c | 45 ++++++++++++++++++++++----------
arch/arm64/kernel/irq.c | 29 ++++++++++++++++++++
3 files changed, 65 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
index fac08e18bcd5..a59b1745f458 100644
--- a/arch/arm64/include/asm/irq.h
+++ b/arch/arm64/include/asm/irq.h
@@ -12,6 +12,11 @@ int set_handle_irq(void (*handle_irq)(struct pt_regs *));
#define set_handle_irq set_handle_irq
int set_handle_fiq(void (*handle_fiq)(struct pt_regs *));
+extern void (*handle_arch_irq)(struct pt_regs *regs);
+extern void (*handle_arch_fiq)(struct pt_regs *regs);
+extern void (*handle_arch_nmi)(struct pt_regs *regs);
+extern bool (*interrupt_is_nmi)(void);
+
static inline int nr_legacy_irqs(void)
{
return 0;
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 32f9796c4ffe..69a8cc082712 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -24,6 +24,7 @@
#include <asm/stacktrace.h>
#include <asm/sysreg.h>
#include <asm/system_misc.h>
+#include <asm/irq.h>
/*
* Handle IRQ/context state management when entering from kernel mode.
@@ -219,17 +220,28 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs)
lockdep_hardirqs_on(CALLER_ADDR0);
}
-static void noinstr enter_el1_irq_or_nmi(struct pt_regs *regs)
+static inline bool arm64_in_nmi(struct pt_regs *regs)
{
- if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
+ if (!interrupts_enabled(regs) || (*interrupt_is_nmi)())
+ return true;
+ return false;
+}
+
+/* return true if in irq, otherwise in nmi */
+static bool noinstr enter_el1_irq_or_nmi(struct pt_regs *regs)
+{
+ if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && arm64_in_nmi(regs)) {
arm64_enter_nmi(regs);
- else
+ return false;
+ } else {
enter_from_kernel_mode(regs);
+ return true;
+ }
}
-static void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs)
+static void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs, bool in_irq)
{
- if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
+ if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !in_irq)
arm64_exit_nmi(regs);
else
exit_to_kernel_mode(regs);
@@ -269,9 +281,6 @@ static void do_interrupt_handler(struct pt_regs *regs,
handler(regs);
}
-extern void (*handle_arch_irq)(struct pt_regs *);
-extern void (*handle_arch_fiq)(struct pt_regs *);
-
static void noinstr __panic_unhandled(struct pt_regs *regs, const char *vector,
unsigned int esr)
{
@@ -433,12 +442,20 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs)
}
static void noinstr el1_interrupt(struct pt_regs *regs,
- void (*handler)(struct pt_regs *))
+ void (*handler)(struct pt_regs *),
+ void (*nmi_handler)(struct pt_regs *))
{
+ bool in_irq;
+ void (*h)(struct pt_regs *regs);
+
write_sysreg(DAIF_PROCCTX_NOIRQ, daif);
- enter_el1_irq_or_nmi(regs);
- do_interrupt_handler(regs, handler);
+ in_irq = enter_el1_irq_or_nmi(regs);
+ if (in_irq)
+ h = handler;
+ else
+ h = nmi_handler;
+ do_interrupt_handler(regs, h);
/*
* Note: thread_info::preempt_count includes both thread_info::count
@@ -449,17 +466,17 @@ static void noinstr el1_interrupt(struct pt_regs *regs,
READ_ONCE(current_thread_info()->preempt_count) == 0)
arm64_preempt_schedule_irq();
- exit_el1_irq_or_nmi(regs);
+ exit_el1_irq_or_nmi(regs, in_irq);
}
asmlinkage void noinstr el1h_64_irq_handler(struct pt_regs *regs)
{
- el1_interrupt(regs, handle_arch_irq);
+ el1_interrupt(regs, handle_arch_irq, handle_arch_nmi);
}
asmlinkage void noinstr el1h_64_fiq_handler(struct pt_regs *regs)
{
- el1_interrupt(regs, handle_arch_fiq);
+ el1_interrupt(regs, handle_arch_fiq, handle_arch_nmi);
}
asmlinkage void noinstr el1h_64_error_handler(struct pt_regs *regs)
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index bda49430c9ea..e67435eb4cba 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -81,8 +81,19 @@ static void default_handle_fiq(struct pt_regs *regs)
panic("FIQ taken without a root FIQ handler\n");
}
+static void default_handle_nmi(struct pt_regs *unused)
+{
+}
+
+static bool default_nmi_discriminator(void)
+{
+ return false;
+}
+
void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
+void (*handle_arch_nmi)(struct pt_regs *) __ro_after_init = default_handle_nmi;
+bool (*interrupt_is_nmi)(void) __ro_after_init = default_nmi_discriminator;
int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
{
@@ -104,6 +115,24 @@ int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
return 0;
}
+int __init set_handle_nmi(void (*handle_nmi)(struct pt_regs *))
+{
+ if (handle_arch_nmi != default_handle_nmi)
+ return -EBUSY;
+
+ handle_arch_nmi = handle_nmi;
+ return 0;
+}
+
+int __init set_nmi_discriminator(bool (*discriminator)(void))
+{
+ if (interrupt_is_nmi != default_nmi_discriminator)
+ return -EBUSY;
+
+ interrupt_is_nmi = discriminator;
+ return 0;
+}
+
void __init init_IRQ(void)
{
init_irq_stacks();
--
2.31.1
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