Message-ID: <CAAOTY__g3Fnwsoqx=x_tgdMii5K_L9TmF_9048XbAOSJwb-Cxg@mail.gmail.com>
Date:   Wed, 10 Jun 2020 00:01:44 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Neal Liu <neal.liu@...iatek.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        devicetree@...r.kernel.org, wsd_upstream@...iatek.com,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] soc: mediatek: devapc: add devapc-mt6873 driver

Hi, Neal:

Neal Liu <neal.liu@...iatek.com> 於 2020年6月9日 週二 下午6:25寫道：
>
> MT6873 bus frabric provides TrustZone security support and data
> protection to prevent slaves from being accessed by unexpected
> masters.
> The security violations are logged and sent to the processor for
> further analysis or countermeasures.
>
> Any occurrence of security violation would raise an interrupt, and
> it will be handled by devapc-mt6873 driver. The violation
> information is printed in order to find the murderer.
>
> Signed-off-by: Neal Liu <neal.liu@...iatek.com>
> ---
>  drivers/soc/mediatek/Kconfig                      |    6 +
>  drivers/soc/mediatek/Makefile                     |    1 +
>  drivers/soc/mediatek/devapc/Kconfig               |   25 +
>  drivers/soc/mediatek/devapc/Makefile              |   13 +
>  drivers/soc/mediatek/devapc/devapc-mt6873.c       | 1733 +++++++++++++++++++++
>  drivers/soc/mediatek/devapc/devapc-mt6873.h       |  130 ++
>  drivers/soc/mediatek/devapc/devapc-mtk-multi-ao.c | 1019 ++++++++++++
>  drivers/soc/mediatek/devapc/devapc-mtk-multi-ao.h |  183 +++
>  include/linux/soc/mediatek/devapc_public.h        |   41 +
>  9 files changed, 3151 insertions(+)
>  create mode 100644 drivers/soc/mediatek/devapc/Kconfig
>  create mode 100644 drivers/soc/mediatek/devapc/Makefile
>  create mode 100644 drivers/soc/mediatek/devapc/devapc-mt6873.c
>  create mode 100644 drivers/soc/mediatek/devapc/devapc-mt6873.h
>  create mode 100644 drivers/soc/mediatek/devapc/devapc-mtk-multi-ao.c
>  create mode 100644 drivers/soc/mediatek/devapc/devapc-mtk-multi-ao.h
>  create mode 100644 include/linux/soc/mediatek/devapc_public.h
>
> diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> index 2114b56..cc46f50 100644
> --- a/drivers/soc/mediatek/Kconfig
> +++ b/drivers/soc/mediatek/Kconfig
> @@ -44,4 +44,10 @@ config MTK_SCPSYS
>           Say yes here to add support for the MediaTek SCPSYS power domain
>           driver.
>
> +menu "Security"
> +
> +source "drivers/soc/mediatek/devapc/Kconfig"
> +
> +endmenu # Security
> +
>  endmenu
> diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
> index b017330..7154a2a 100644
> --- a/drivers/soc/mediatek/Makefile
> +++ b/drivers/soc/mediatek/Makefile
> @@ -3,3 +3,4 @@ obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
>  obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
>  obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
>  obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
> +obj-$(CONFIG_MTK_DEVAPC) += devapc/

alphabetic order.

> diff --git a/drivers/soc/mediatek/devapc/Kconfig b/drivers/soc/mediatek/devapc/Kconfig
> new file mode 100644
> index 0000000..9428360
> --- /dev/null
> +++ b/drivers/soc/mediatek/devapc/Kconfig
> @@ -0,0 +1,25 @@
> +config MTK_DEVAPC
> +       tristate "Mediatek Device APC Support"
> +       help
> +         Device APC is a kernel driver controlling internal device security.
> +         If someone tries to access a device, which is not allowed by the
> +         device, it cannot access the device and will get a violation
> +         interrupt. Device APC prevents malicious access to internal devices.
> +
> +config DEVAPC_ARCH_MULTI
> +       tristate "Mediatek Device APC driver architecture multi"
> +       help
> +         Say yes here to enable support Mediatek
> +         Device APC driver which is based on Infra
> +         architecture.
> +         This architecture supports multiple Infra AO.
> +
> +config DEVAPC_MT6873
> +       tristate "Mediatek MT6873 Device APC driver"
> +       select MTK_DEVAPC
> +       select DEVAPC_ARCH_MULTI
> +       help
> +         Say yes here to enable support Mediatek MT6873
> +         Device APC driver.
> +         This driver is combined with DEVAPC_ARCH_MULTI for
> +         common handle flow.

[snip]

> +static struct mtk_devapc_context {
> + struct clk *devapc_infra_clk;
> + u32 devapc_irq;
> +
> + /* HW reg mapped addr */
> + void __iomem *devapc_pd_base[4];
> + void __iomem *infracfg_base;
> +
> + struct mtk_devapc_soc *soc;
> +} mtk_devapc_ctx[1];
> +
> +static LIST_HEAD(viocb_list);
> +static DEFINE_SPINLOCK(devapc_lock);

Move global variable into struct mtk_devapc_context .

> +
> +/*
> + * mtk_devapc_pd_get - get devapc pd_types of register address.
> + *
> + * Returns the value of reg addr
> + */
> +static void __iomem *mtk_devapc_pd_get(int slave_type,
> +                                      enum DEVAPC_PD_REG_TYPE pd_reg_type,
> +                                      u32 index)
> +{
> +       struct mtk_devapc_vio_info *vio_info = mtk_devapc_ctx->soc->vio_info;
> +       u32 slave_type_num = mtk_devapc_ctx->soc->slave_type_num;
> +       const u32 *devapc_pds = mtk_devapc_ctx->soc->devapc_pds;
> +       void __iomem *reg;
> +
> +       if (!devapc_pds)
> +               return NULL;
> +
> +       if ((slave_type < slave_type_num &&
> +            index < vio_info->vio_mask_sta_num[slave_type]) &&
> +           pd_reg_type < PD_REG_TYPE_NUM) {
> +               reg = mtk_devapc_ctx->devapc_pd_base[slave_type] +
> +                       devapc_pds[pd_reg_type];
> +
> +               if (pd_reg_type == VIO_MASK || pd_reg_type == VIO_STA)
> +                       reg += 0x4 * index;
> +
> +       } else {
> +               pr_err(PFX "%s:0x%x or %s:0x%x or %s:0x%x is out of boundary\n",
> +                      "slave_type", slave_type,

Move "slave_type" into format string.

> +                      "pd_reg_type", pd_reg_type,
> +                      "index", index);
> +               return NULL;
> +       }
> +
> +       return reg;
> +}
> +

[snip]

> +
> +/*
> + * devapc_violation_irq - the devapc Interrupt Service Routine (ISR) will dump
> + *                       violation information including which master violates
> + *                       access slave.
> + */
> +static irqreturn_t devapc_violation_irq(int irq_number, void *dev_id)
> +{
> +       u32 slave_type_num = mtk_devapc_ctx->soc->slave_type_num;
> +       const struct mtk_device_info **device_info;
> +       struct mtk_devapc_vio_info *vio_info;
> +       int slave_type, vio_idx, index;
> +       const char *vio_master;
> +       unsigned long flags;
> +       bool normal;
> +       u8 perm;
> +
> +       spin_lock_irqsave(&devapc_lock, flags);
> +
> +       device_info = mtk_devapc_ctx->soc->device_info;
> +       vio_info = mtk_devapc_ctx->soc->vio_info;
> +       normal = false;
> +       vio_idx = -1;
> +       index = -1;
> +
> +       /* There are multiple DEVAPC_PD */
> +       for (slave_type = 0; slave_type < slave_type_num; slave_type++) {
> +               if (!check_type2_vio_status(slave_type, &vio_idx, &index))
> +                       if (!mtk_devapc_dump_vio_dbg(slave_type, &vio_idx,
> +                                                    &index))
> +                               continue;
> +
> +               /* Ensure that violation info are written before
> +                * further operations
> +                */
> +               smp_mb();
> +               normal = true;
> +
> +               mask_module_irq(slave_type, vio_idx, true);
> +
> +               if (clear_vio_status(slave_type, vio_idx))
> +                       pr_warn(PFX "%s, %s:0x%x, %s:0x%x\n",
> +                               "clear vio status failed",
> +                               "slave_type", slave_type,
> +                               "vio_index", vio_idx);
> +
> +               perm = get_permission(slave_type, index, vio_info->domain_id);
> +
> +               vio_master = mtk_devapc_ctx->soc->master_get
> +                       (vio_info->master_id,
> +                        vio_info->vio_addr,
> +                        slave_type,
> +                        vio_info->shift_sta_bit,
> +                        vio_info->domain_id);

Call mt6873_bus_id_to_master() directly. For first patch, make things
as simple as possible.

> +
> +               if (!vio_master) {
> +                       pr_warn(PFX "master_get failed\n");
> +                       vio_master = "UNKNOWN_MASTER";
> +               }
> +
> +               pr_info(PFX "%s - %s:0x%x, %s:0x%x, %s:0x%x, %s:0x%x\n",
> +                       "Violation", "slave_type", slave_type,
> +                       "sys_index",
> +                       device_info[slave_type][index].sys_index,
> +                       "ctrl_index",
> +                       device_info[slave_type][index].ctrl_index,
> +                       "vio_index",
> +                       device_info[slave_type][index].vio_index);
> +
> +               pr_info(PFX "%s %s %s %s\n",
> +                       "Violation - master:", vio_master,
> +                       "access violation slave:",
> +                       device_info[slave_type][index].device);
> +
> +               devapc_vio_reason(perm);
> +
> +               devapc_extra_handler(slave_type, vio_master, vio_idx,
> +                                    vio_info->vio_addr);
> +
> +               mask_module_irq(slave_type, vio_idx, false);
> +       }
> +
> +       if (normal) {
> +               spin_unlock_irqrestore(&devapc_lock, flags);
> +               return IRQ_HANDLED;
> +       }
> +
> +       spin_unlock_irqrestore(&devapc_lock, flags);
> +       return IRQ_HANDLED;
> +}
> +

[snip]

> +uint32_t devapc_vio_check(void);
> +void dump_dbg_info(void);
> +void register_devapc_vio_callback(struct devapc_vio_callbacks *viocb);
> +void devapc_catch_illegal_range(phys_addr_t phys_addr, size_t size);

devapc_catch_illegal_range() is useless, so remove it.

Regards,
Chun-Kuang.

> +
> +#endif  /* __DEVAPC_PUBLIC_H__ */
> +
> --
> 1.7.9.5
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> Linux-mediatek@...ts.infradead.org
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