stop_machine: mask pseudo nmi before running the callback

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4JBQ8

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

Kprobes use 'stop_machine' to modify code which could be ran in the
pseudo nmi context at the same time. This patch mask pseudo nmi before
running the stop_machine callback to avoid this race condition.
Signed-off-by: NWei Li <liwei391@huawei.com>
Reviewed-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NCheng Jian <cj.chengjian@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/include/asm/arch_gicv3.h

@@ -184,5 +184,16 @@ static inline void gic_arch_enable_irqs(void)
 	asm volatile ("msr daifclr, #2" : : : "memory");
 }
 
+static inline void gic_arch_disable_irqs(void)
+{
+	asm volatile ("msr daifset, #2" : : : "memory");
+}
+
+static inline void gic_arch_restore_irqs(unsigned long flags)
+{
+	if (gic_supports_nmi())
+		asm volatile ("msr	daif, %0" : : "r" (flags >> 32)
+					: "memory");
+}
 #endif /* __ASSEMBLY__ */
 #endif /* __ASM_ARCH_GICV3_H */

kernel/stop_machine.c

@@ -25,6 +25,7 @@
 
 #ifdef CONFIG_ARM64
 #include <linux/arm_sdei.h>
+#include <asm/arch_gicv3.h>
 #endif
 
 /*
@@ -223,6 +224,7 @@ static int multi_cpu_stop(void *data)
 				local_irq_disable();
 				hard_irq_disable();
 #ifdef CONFIG_ARM64
+				gic_arch_disable_irqs();
 				sdei_mask_local_cpu();
 #endif
 				break;
@@ -247,6 +249,7 @@ static int multi_cpu_stop(void *data)
 
 #ifdef CONFIG_ARM64
 	sdei_unmask_local_cpu();
+	gic_arch_restore_irqs(flags);
 #endif
 	local_irq_restore(flags);
 	return err;