[PATCH v3 1/2] arm64: add an MTE support check to the top of mte_thread_switch()
From: Peter Collingbourne <hidden>
Date: 2021-09-15 19:06:14
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This lets us avoid doing unnecessary work on hardware that does not support MTE, and will allow us to freely use MTE instructions in the code called by mte_thread_switch(). Since this would mean that we do a redundant check in mte_check_tfsr_el1(), remove it and add two checks now required in its callers. Signed-off-by: Peter Collingbourne <redacted> Link: https://linux-review.googlesource.com/id/I02fd000d1ef2c86c7d2952a7f099b254ec227a5d --- v3: - remove check from mte_check_tfsr_el1() arch/arm64/include/asm/mte.h | 6 ++++++ arch/arm64/kernel/mte.c | 10 ++++------ 2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index 3f93b9e0b339..02511650cffe 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h@@ -99,11 +99,17 @@ void mte_check_tfsr_el1(void); static inline void mte_check_tfsr_entry(void) { + if (!system_supports_mte()) + return; + mte_check_tfsr_el1(); } static inline void mte_check_tfsr_exit(void) { + if (!system_supports_mte()) + return; + /* * The asynchronous faults are sync'ed automatically with * TFSR_EL1 on kernel entry but for exit an explicit dsb()
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 9d314a3bad3b..e5e801bc5312 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c@@ -142,12 +142,7 @@ void mte_enable_kernel_async(void) #ifdef CONFIG_KASAN_HW_TAGS void mte_check_tfsr_el1(void) { - u64 tfsr_el1; - - if (!system_supports_mte()) - return; - - tfsr_el1 = read_sysreg_s(SYS_TFSR_EL1); + u64 tfsr_el1 = read_sysreg_s(SYS_TFSR_EL1); if (unlikely(tfsr_el1 & SYS_TFSR_EL1_TF1)) { /*
@@ -199,6 +194,9 @@ void mte_thread_init_user(void) void mte_thread_switch(struct task_struct *next) { + if (!system_supports_mte()) + return; + mte_update_sctlr_user(next); /*
--
2.33.0.309.g3052b89438-goog
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