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From: Peter Maydell <peter.maydell@linaro.org>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-arm <qemu-arm@nongnu.org>, QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PATCH v5 18/22] target/arm: Enable MTE
Date: Thu, 5 Dec 2019 18:23:01 +0000	[thread overview]
Message-ID: <CAFEAcA-N++JGRDfOLE7AUsMWVqchSNMvshRu9NJAkCSR1-N=Eg@mail.gmail.com> (raw)
In-Reply-To: <20191011134744.2477-19-richard.henderson@linaro.org>

On Fri, 11 Oct 2019 at 14:50, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> We now implement all of the components of MTE, without actually
> supporting any tagged memory.  All MTE instructions will work,
> trivially, so we can enable support.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/cpu.c   | 10 ++++++++++
>  target/arm/cpu64.c |  1 +
>  2 files changed, 11 insertions(+)
>
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 2399c14471..12fffa3ee4 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -209,6 +209,16 @@ static void arm_cpu_reset(CPUState *s)
>           * make no difference to the user-level emulation.
>           */
>          env->cp15.tcr_el[1].raw_tcr = (3ULL << 37);
> +        /* Enable MTE allocation tags.  */
> +        env->cp15.hcr_el2 |= HCR_ATA;
> +        env->cp15.scr_el3 |= SCR_ATA;
> +        env->cp15.sctlr_el[1] |= SCTLR_ATA0;
> +        /* Enable synchronous tag check failures.  */
> +        env->cp15.sctlr_el[1] |= 1ull << 38;

Isn't this making assumptions about the Linux ABI for
memtag (ie that it actually will expose it to userspace
and that it will make tag check failures synchronous)?

> +#ifdef TARGET_AARCH64
> +        /* Set MTE seed to non-zero value, otherwise RandomTag fails.  */
> +        env->cp15.rgsr_el1 = 0x123400;
> +#endif

Does anything go wrong if we don't bother with the #ifdef?

>  #else
>          /* Reset into the highest available EL */
>          if (arm_feature(env, ARM_FEATURE_EL3)) {
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index d7f5bf610a..ac1e2dc2c4 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -350,6 +350,7 @@ static void aarch64_max_initfn(Object *obj)
>
>          t = cpu->isar.id_aa64pfr1;
>          t = FIELD_DP64(t, ID_AA64PFR1, BT, 1);
> +        t = FIELD_DP64(t, ID_AA64PFR1, MTE, 2);
>          cpu->isar.id_aa64pfr1 = t;
>
>          t = cpu->isar.id_aa64mmfr1;
> --

thanks
-- PMM


  reply	other threads:[~2019-12-05 18:26 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11 13:47 [PATCH v5 00/22] target/arm: Implement ARMv8.5-MemTag, system mode Richard Henderson
2019-10-11 13:47 ` [PATCH v5 01/22] target/arm: Add MTE_ACTIVE to tb_flags Richard Henderson
2019-10-11 13:47 ` [PATCH v5 02/22] target/arm: Add regime_has_2_ranges Richard Henderson
2019-12-03 11:01   ` Peter Maydell
2019-12-03 15:09     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 03/22] target/arm: Add MTE system registers Richard Henderson
2019-12-03 11:48   ` Peter Maydell
2019-12-06 14:47     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 04/22] target/arm: Add helper_mte_check{1,2,3} Richard Henderson
2019-12-03 13:42   ` Peter Maydell
2019-12-03 16:06     ` Richard Henderson
2019-12-03 16:26       ` Peter Maydell
2019-12-03 16:14     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 05/22] target/arm: Suppress tag check for sp+offset Richard Henderson
2019-12-03 14:07   ` Peter Maydell
2020-02-17 21:32     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 06/22] target/arm: Implement the IRG instruction Richard Henderson
2019-12-03 14:26   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 07/22] target/arm: Implement ADDG, SUBG instructions Richard Henderson
2019-10-11 13:47 ` [PATCH v5 08/22] target/arm: Implement the GMI instruction Richard Henderson
2019-10-11 13:47 ` [PATCH v5 09/22] target/arm: Implement the SUBP instruction Richard Henderson
2019-10-11 13:47 ` [PATCH v5 10/22] target/arm: Define arm_cpu_do_unaligned_access for CONFIG_USER_ONLY Richard Henderson
2019-12-05 16:12   ` Peter Maydell
2020-02-17 22:56     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 11/22] target/arm: Implement LDG, STG, ST2G instructions Richard Henderson
2019-12-05 17:07   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 12/22] target/arm: Implement the STGP instruction Richard Henderson
2019-12-05 17:15   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 13/22] target/arm: Implement the LDGM and STGM instructions Richard Henderson
2019-12-05 17:42   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 14/22] target/arm: Implement the access tag cache flushes Richard Henderson
2019-12-05 17:49   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 15/22] target/arm: Clean address for DC ZVA Richard Henderson
2019-12-05 17:54   ` Peter Maydell
2019-12-05 18:58   ` Peter Maydell
2020-02-18  0:50     ` Richard Henderson
2020-02-18 11:10       ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 16/22] target/arm: Implement data cache set allocation tags Richard Henderson
2019-12-05 18:17   ` Peter Maydell
2020-02-18  1:19     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 17/22] target/arm: Set PSTATE.TCO on exception entry Richard Henderson
2019-10-11 13:47 ` [PATCH v5 18/22] target/arm: Enable MTE Richard Henderson
2019-12-05 18:23   ` Peter Maydell [this message]
2019-10-11 13:47 ` [PATCH v5 19/22] target/arm: Cache the Tagged bit for a page in MemTxAttrs Richard Henderson
2019-12-05 18:32   ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 20/22] target/arm: Create tagged ram when MTE is enabled Richard Henderson
2019-12-05 18:40   ` Peter Maydell
2019-12-05 19:24     ` Richard Henderson
2019-12-06  9:51       ` Peter Maydell
2019-10-11 13:47 ` [PATCH v5 21/22] target/arm: Add mmu indexes for tag memory Richard Henderson
2019-12-06 11:46   ` Peter Maydell
2019-12-06 14:03     ` Richard Henderson
2019-10-11 13:47 ` [PATCH v5 22/22] target/arm: Add allocation tag storage for system mode Richard Henderson
2019-12-06 13:02   ` Peter Maydell
2019-12-06 14:14     ` Richard Henderson
2019-10-11 19:32 ` [PATCH v5 00/22] target/arm: Implement ARMv8.5-MemTag, " no-reply
2019-10-15 20:39 ` Evgenii Stepanov
2019-10-15 22:04   ` Richard Henderson

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