Re: [PATCH v5 1/4] crypto: caam - Prevent crash on suspend with iMX8QM / iMX8ULP

[Frank Li <Frank.li@nxp.com>]

On Tue, Jun 10, 2025 at 08:51:17AM +0000, John Ernberg wrote:
> Since the CAAM on these SoCs is managed by another ARM core, called the
> SECO (Security Controller) on iMX8QM and Secure Enclave on iMX8ULP, which
> also reserves access to register page 0 suspend operations cannot touch
> this page.
>
> This is similar to when running OPTEE, where OPTEE will reserve page 0.
>
> Track this situation using a new state variable no_page0, reflecting if
> page 0 is reserved elsewhere, either by other management cores in SoC or
> by OPTEE.
>
> Replace the optee_en check in suspend/resume with the new check.
>
> optee_en cannot go away as it's needed elsewhere to gate OPTEE specific
> situations.
>
> Fixes the following splat at suspend:
>
>     Internal error: synchronous external abort: 0000000096000010 [#1] SMP
>     Hardware name: Freescale i.MX8QXP ACU6C (DT)
>     pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>     pc : readl+0x0/0x18
>     lr : rd_reg32+0x18/0x3c
>     sp : ffffffc08192ba20
>     x29: ffffffc08192ba20 x28: ffffff8025190000 x27: 0000000000000000
>     x26: ffffffc0808ae808 x25: ffffffc080922338 x24: ffffff8020e89090
>     x23: 0000000000000000 x22: ffffffc080922000 x21: ffffff8020e89010
>     x20: ffffffc080387ef8 x19: ffffff8020e89010 x18: 000000005d8000d5
>     x17: 0000000030f35963 x16: 000000008f785f3f x15: 000000003b8ef57c
>     x14: 00000000c418aef8 x13: 00000000f5fea526 x12: 0000000000000001
>     x11: 0000000000000002 x10: 0000000000000001 x9 : 0000000000000000
>     x8 : ffffff8025190870 x7 : ffffff8021726880 x6 : 0000000000000002
>     x5 : ffffff80217268f0 x4 : ffffff8021726880 x3 : ffffffc081200000
>     x2 : 0000000000000001 x1 : ffffff8020e89010 x0 : ffffffc081200004
>     Call trace:
>      readl+0x0/0x18
>      caam_ctrl_suspend+0x30/0xdc
>      dpm_run_callback.constprop.0+0x24/0x5c
>      device_suspend+0x170/0x2e8
>      dpm_suspend+0xa0/0x104
>      dpm_suspend_start+0x48/0x50
>      suspend_devices_and_enter+0x7c/0x45c
>      pm_suspend+0x148/0x160
>      state_store+0xb4/0xf8
>      kobj_attr_store+0x14/0x24
>      sysfs_kf_write+0x38/0x48
>      kernfs_fop_write_iter+0xb4/0x178
>      vfs_write+0x118/0x178
>      ksys_write+0x6c/0xd0
>      __arm64_sys_write+0x14/0x1c
>      invoke_syscall.constprop.0+0x64/0xb0
>      do_el0_svc+0x90/0xb0
>      el0_svc+0x18/0x44
>      el0t_64_sync_handler+0x88/0x124
>      el0t_64_sync+0x150/0x154
>     Code: 88dffc21 88dffc21 5ac00800 d65f03c0 (b9400000)
>
> Fixes: d2835701d93c ("crypto: caam - i.MX8ULP donot have CAAM page0 access")
> Cc: stable@kernel.org # v6.10+
> Signed-off-by: John Ernberg <john.ernberg@actia.se>
> Reviewed-by: Peng Fan <peng.fan@nxp.com>

Reviewed-by: Frank Li <Frank.Li@nxp.com>
>
> ---
>
> I noticed this when enabling the iMX8QXP support (next patch), hence the
> iMX8QXP backtrace, but the iMX8QM CAAM integration works exactly the same
> and according to the NXP tree [1] the iMX8ULP suffers the same issue.
>
> [1]: https://github.com/nxp-imx/linux-imx/commit/653712ffe52dd59f407af1b781ce318f3d9e17bb
>
> ---
>
> v5:
>  - Collect tags
>
> v4:
>  - Drop 2nd Fixes tag (Frank Li)
>
> v3:
>  - no changes
>
> v2:
>  - Adjust commit message to make it clearer what is happening around no_page0 (Frank Li)
> ---
>  drivers/crypto/caam/ctrl.c   | 5 +++--
>  drivers/crypto/caam/intern.h | 1 +
>  2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
> index 38ff931059b4..766c447c9cfb 100644
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -831,7 +831,7 @@ static int caam_ctrl_suspend(struct device *dev)
>  {
>  	const struct caam_drv_private *ctrlpriv = dev_get_drvdata(dev);
>
> -	if (ctrlpriv->caam_off_during_pm && !ctrlpriv->optee_en)
> +	if (ctrlpriv->caam_off_during_pm && !ctrlpriv->no_page0)
>  		caam_state_save(dev);
>
>  	return 0;
> @@ -842,7 +842,7 @@ static int caam_ctrl_resume(struct device *dev)
>  	struct caam_drv_private *ctrlpriv = dev_get_drvdata(dev);
>  	int ret = 0;
>
> -	if (ctrlpriv->caam_off_during_pm && !ctrlpriv->optee_en) {
> +	if (ctrlpriv->caam_off_during_pm && !ctrlpriv->no_page0) {
>  		caam_state_restore(dev);
>
>  		/* HW and rng will be reset so deinstantiation can be removed */
> @@ -908,6 +908,7 @@ static int caam_probe(struct platform_device *pdev)
>
>  		imx_soc_data = imx_soc_match->data;
>  		reg_access = reg_access && imx_soc_data->page0_access;
> +		ctrlpriv->no_page0 = !reg_access;
>  		/*
>  		 * CAAM clocks cannot be controlled from kernel.
>  		 */
> diff --git a/drivers/crypto/caam/intern.h b/drivers/crypto/caam/intern.h
> index e51320150872..51c90d17a40d 100644
> --- a/drivers/crypto/caam/intern.h
> +++ b/drivers/crypto/caam/intern.h
> @@ -115,6 +115,7 @@ struct caam_drv_private {
>  	u8 blob_present;	/* Nonzero if BLOB support present in device */
>  	u8 mc_en;		/* Nonzero if MC f/w is active */
>  	u8 optee_en;		/* Nonzero if OP-TEE f/w is active */
> +	u8 no_page0;		/* Nonzero if register page 0 is not controlled by Linux */
>  	bool pr_support;        /* RNG prediction resistance available */
>  	int secvio_irq;		/* Security violation interrupt number */
>  	int virt_en;		/* Virtualization enabled in CAAM */
> --
> 2.49.0