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From: Liao Chang <liaochang1@huawei.com>
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Subject: [PATCH v3 8/8] arm64: kprobe: Keep NMI maskabled while kprobe is stepping xol
Date: Mon, 15 Apr 2024 06:47:58 +0000
Message-ID: <20240415064758.3250209-9-liaochang1@huawei.com>
In-Reply-To: <20240415064758.3250209-1-liaochang1@huawei.com>
References: <20240415064758.3250209-1-liaochang1@huawei.com>
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Keeping NMI maskable while executing instruction out of line, otherwise,
add kprobe on the functions invoken while handling NMI will cause kprobe
reenter bug and kernel panic.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
 arch/arm64/include/asm/daifflags.h | 2 ++
 arch/arm64/kernel/probes/kprobes.c | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h
index 1196eb85aa8d..60fd3b25fd73 100644
--- a/arch/arm64/include/asm/daifflags.h
+++ b/arch/arm64/include/asm/daifflags.h
@@ -17,6 +17,8 @@
 #define DAIF_PROCCTX_NOIRQ	(PSR_I_BIT | PSR_F_BIT)
 #define DAIF_ERRCTX		(PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
 #define DAIF_MASK		(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
+#define DAIF_ALLINT_MASK	\
+	(system_uses_nmi() ? (ALLINT_ALLINT | DAIF_MASK) : (DAIF_MASK))
 
 /*
  * For Arm64 processor support Armv8.8 or later, kernel supports three types
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 327855a11df2..e8c2b993bbb8 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -187,13 +187,13 @@ static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb,
 						struct pt_regs *regs)
 {
 	kcb->saved_irqflag = regs->pstate & DAIF_MASK;
-	regs->pstate |= DAIF_MASK;
+	regs->pstate |= DAIF_ALLINT_MASK;
 }
 
 static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb,
 						struct pt_regs *regs)
 {
-	regs->pstate &= ~DAIF_MASK;
+	regs->pstate &= ~DAIF_ALLINT_MASK;
 	regs->pstate |= kcb->saved_irqflag;
 }
 
-- 
2.34.1