Re: [PATCH v3 27/39] arm64: kasan: Enable in-kernel MTE

Catalin Marinas
2020-09-25T11:14:44Z

On Fri, Sep 25, 2020 at 12:50:34AM +0200, Andrey Konovalov wrote:
> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
> index 23c326a06b2d..12ba98bc3b3f 100644
> --- a/arch/arm64/mm/proc.S
> +++ b/arch/arm64/mm/proc.S
> @@ -427,6 +427,10 @@ SYM_FUNC_START(__cpu_setup)
> */
> mov_q x5, MAIR_EL1_SET
> #ifdef CONFIG_ARM64_MTE
> + mte_tcr .req x20
> +
> + mov mte_tcr, #0
> +
> /*
> * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
> * (ID_AA64PFR1_EL1[11:8] > 1).
> @@ -447,6 +451,9 @@ SYM_FUNC_START(__cpu_setup)
> /* clear any pending tag check faults in TFSR*_EL1 */
> msr_s SYS_TFSR_EL1, xzr
> msr_s SYS_TFSRE0_EL1, xzr
> +
> + /* set the TCR_EL1 bits */
> + orr mte_tcr, mte_tcr, #SYS_TCR_EL1_TCMA1
> 1:
> #endif
> msr mair_el1, x5
> @@ -457,6 +464,10 @@ SYM_FUNC_START(__cpu_setup)
> mov_q x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
> TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
> TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS
> +#ifdef CONFIG_ARM64_MTE
> + orr x10, x10, mte_tcr
> + .unreq mte_tcr
> +#endif
> tcr_clear_errata_bits x10, x9, x5

I had a slightly different preference (see the previous version) to
avoid the #ifdef altogether but this works as well.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>