From: Zengruan Ye yezengruan@huawei.com
virt inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8WMFU CVE: NA
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This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the CPU as parameter and return true if the CPU is preempted. Then kernel can break the spin loops upon the retval of vcpu_is_preempted.
As kernel has used this interface, So lets support it.
Signed-off-by: Zengruan Ye yezengruan@huawei.com Signed-off-by: lishusen lishusen2@huawei.com --- arch/arm64/include/asm/paravirt.h | 8 ++++++++ arch/arm64/include/asm/spinlock.h | 10 ++++++++++ arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/paravirt-spinlocks.c | 16 ++++++++++++++++ 4 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/kernel/paravirt-spinlocks.c
diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h index 9aa193e0e8f2..53282dc429f8 100644 --- a/arch/arm64/include/asm/paravirt.h +++ b/arch/arm64/include/asm/paravirt.h @@ -20,6 +20,14 @@ static inline u64 paravirt_steal_clock(int cpu)
int __init pv_time_init(void);
+__visible bool __native_vcpu_is_preempted(int cpu); +DECLARE_STATIC_CALL(pv_vcpu_preempted, __native_vcpu_is_preempted); + +static inline bool pv_vcpu_is_preempted(int cpu) +{ + return static_call(pv_vcpu_preempted)(cpu); +} + #else
#define pv_time_init() do {} while (0) diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index 0525c0b089ed..3dcb1c903ba0 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -7,6 +7,7 @@
#include <asm/qspinlock.h> #include <asm/qrwlock.h> +#include <asm/paravirt.h>
/* See include/linux/spinlock.h */ #define smp_mb__after_spinlock() smp_mb() @@ -19,9 +20,18 @@ * https://lore.kernel.org/lkml/20200110100612.GC2827@hirez.programming.kicks-a... */ #define vcpu_is_preempted vcpu_is_preempted +#ifdef CONFIG_PARAVIRT +static inline bool vcpu_is_preempted(int cpu) +{ + return pv_vcpu_is_preempted(cpu); +} + +#else + static inline bool vcpu_is_preempted(int cpu) { return false; } +#endif /* CONFIG_PARAVIRT */
#endif /* __ASM_SPINLOCK_H */ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 31859e7741a5..235963ed87b1 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -60,7 +60,7 @@ obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o obj-$(CONFIG_ACPI) += acpi.o obj-$(CONFIG_ACPI_NUMA) += acpi_numa.o obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o -obj-$(CONFIG_PARAVIRT) += paravirt.o +obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt-spinlocks.o obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o pi/ obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o obj-$(CONFIG_ELF_CORE) += elfcore.o diff --git a/arch/arm64/kernel/paravirt-spinlocks.c b/arch/arm64/kernel/paravirt-spinlocks.c new file mode 100644 index 000000000000..3566897070d9 --- /dev/null +++ b/arch/arm64/kernel/paravirt-spinlocks.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright(c) 2019 Huawei Technologies Co., Ltd + * Author: Zengruan Ye yezengruan@huawei.com + */ + +#include <linux/static_call.h> +#include <linux/spinlock.h> +#include <asm/paravirt.h> + +__visible bool __native_vcpu_is_preempted(int cpu) +{ + return false; +} + +DEFINE_STATIC_CALL(pv_vcpu_preempted, __native_vcpu_is_preempted);