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| author | Peter Collingbourne <pcc@google.com> | 2021-09-15 21:03:35 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-09-21 13:17:30 +0200 |
| commit | 8c8a3b5bd960cd88f7655b5251dc28741e11f139 (patch) | |
| tree | bc716ac5b48029dcdb82f57361d50b35e417ae4d /arch/arm64/kernel/mte.c | |
| parent | arm64: Mark __stack_chk_guard as __ro_after_init (diff) | |
| download | linux-8c8a3b5bd960cd88f7655b5251dc28741e11f139.tar.xz linux-8c8a3b5bd960cd88f7655b5251dc28741e11f139.zip | |
arm64: add MTE supported check to thread switching and syscall entry/exit
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. This also avoids an unnecessary DSB+ISB sequence on the syscall
exit path for hardware not supporting MTE.
Fixes: 65812c6921cc ("arm64: mte: Enable async tag check fault")
Cc: <stable@vger.kernel.org> # 5.13.x
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I02fd000d1ef2c86c7d2952a7f099b254ec227a5d
Link: https://lore.kernel.org/r/20210915190336.398390-1-pcc@google.com
[catalin.marinas@arm.com: adjust the commit log slightly]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/mte.c')
| -rw-r--r-- | arch/arm64/kernel/mte.c | 10 |
1 files changed, 4 insertions, 6 deletions
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); /* |