Re: [PATCH v3 23/27] powerpc/powernv/pmem: Add debug IOCTLs

From: Alastair D'Silva
Date: Thu Mar 12 2020 - 00:59:35 EST

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In reply to: Alastair D'Silva: "Re: [PATCH v3 23/27] powerpc/powernv/pmem: Add debug IOCTLs"
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On Thu, 2020-03-05 at 14:11 +1100, Andrew Donnellan wrote:
> On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@xxxxxxxxxxx>
> >
> > These IOCTLs provide low level access to the card to aid in
> > debugging
> > controller/FPGA firmware.
> >
> > Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
> > ---
> > arch/powerpc/platforms/powernv/pmem/Kconfig | 6 +
> > arch/powerpc/platforms/powernv/pmem/ocxl.c | 249
> > ++++++++++++++++++++
> > include/uapi/nvdimm/ocxl-pmem.h | 32 +++
> > 3 files changed, 287 insertions(+)
> >
> > diff --git a/arch/powerpc/platforms/powernv/pmem/Kconfig
> > b/arch/powerpc/platforms/powernv/pmem/Kconfig
> > index c5d927520920..3f44429d70c9 100644
> > --- a/arch/powerpc/platforms/powernv/pmem/Kconfig
> > +++ b/arch/powerpc/platforms/powernv/pmem/Kconfig
> > @@ -12,4 +12,10 @@ config OCXL_PMEM
> >
> > Select N if unsure.
> >
> > +config OCXL_PMEM_DEBUG
> > + bool "OpenCAPI Persistent Memory debugging"
> > + depends on OCXL_PMEM
> > + help
> > + Enables low level IOCTLs for OpenCAPI Persistent Memory
> > firmware development
> > +
>
> How dangerous are these ioctls and does that need to be pointed out
> in
> this description?

Good point, I'll elaborate.

>
> > endif
> > diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c
> > b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> > index e01f6f9fc180..d4ce5e9e0521 100644
> > --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
> > +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> > @@ -1050,6 +1050,235 @@ int req_controller_health_perf(struct
> > ocxlpmem *ocxlpmem)
> > GLOBAL_MMIO_HCI_REQ_HEALTH_PERF);
> > }
> >
> > +#ifdef CONFIG_OCXL_PMEM_DEBUG
> > +/**
> > + * enable_fwdebug() - Enable FW debug on the controller
> > + * @ocxlpmem: the device metadata
> > + * Return: 0 on success, negative on failure
> > + */
> > +static int enable_fwdebug(const struct ocxlpmem *ocxlpmem)
> > +{
> > + return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu,
> > GLOBAL_MMIO_HCI,
> > + OCXL_LITTLE_ENDIAN,
> > + GLOBAL_MMIO_HCI_FW_DEBUG);
> > +}
> > +
> > +/**
> > + * disable_fwdebug() - Disable FW debug on the controller
> > + * @ocxlpmem: the device metadata
> > + * Return: 0 on success, negative on failure
> > + */
> > +static int disable_fwdebug(const struct ocxlpmem *ocxlpmem)
> > +{
> > + return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu,
> > GLOBAL_MMIO_HCIC,
> > + OCXL_LITTLE_ENDIAN,
> > + GLOBAL_MMIO_HCI_FW_DEBUG);
> > +}
> > +
> > +static int ioctl_fwdebug(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_fwdebug __user
> > *uarg)
> > +{
> > + struct ioctl_ocxl_pmem_fwdebug args;
> > + u64 val;
> > + int i;
> > + int rc;
> > +
> > + if (copy_from_user(&args, uarg, sizeof(args)))
> > + return -EFAULT;
> > +
> > + // Buffer size must be a multiple of 8
> > + if ((args.buf_size & 0x07))
> > + return -EINVAL;
> > +
> > + if (args.buf_size > ocxlpmem->admin_command.data_size)
> > + return -EINVAL;
> > +
> > + mutex_lock(&ocxlpmem->admin_command.lock);
> > +
> > + rc = enable_fwdebug(ocxlpmem);
> > + if (rc)
> > + goto out;
> > +
> > + rc = admin_command_request(ocxlpmem, ADMIN_COMMAND_FW_DEBUG);
> > + if (rc)
> > + goto out;
> > +
> > + // Write DebugAction & FunctionCode
> > + val = ((u64)args.debug_action << 56) | ((u64)args.function_code
> > << 40);
> > +
> > + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> > + ocxlpmem-
> > >admin_command.request_offset + 0x08,
> > + OCXL_LITTLE_ENDIAN, val);
> > + if (rc)
> > + goto out;
> > +
> > + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> > + ocxlpmem-
> > >admin_command.request_offset + 0x10,
> > + OCXL_LITTLE_ENDIAN,
> > args.debug_parameter_1);
> > + if (rc)
> > + goto out;
> > +
> > + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> > + ocxlpmem-
> > >admin_command.request_offset + 0x18,
> > + OCXL_LITTLE_ENDIAN,
> > args.debug_parameter_2);
> > + if (rc)
> > + goto out;
> > +
> > + for (i = 0x20; i < 0x38; i += 0x08)
>
> Comparison should be <=, the request block ends at 0x40.
>
> But in any case, scm_command_request() should I think already handle
> the
> clearing of the request block?
>
Correct.

> > + rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> > + ocxlpmem-
> > >admin_command.request_offset + i,
> > + OCXL_LITTLE_ENDIAN, 0);
> > + if (rc)
> > + goto out;
> > +
> > +
> > + // Populate admin command buffer
> > + if (args.buf_size) {
> > + for (i = 0; i < args.buf_size; i += sizeof(u64)) {
> > + u64 val;
> > +
> > + if (copy_from_user(&val, &args.buf[i],
> > sizeof(u64)))
> > + return -EFAULT;
> > +
> > + rc = ocxl_global_mmio_write64(ocxlpmem-
> > >ocxl_afu,
> > + ocxlpmem-
> > >admin_command.data_offset + i,
> > + OCXL_HOST_ENDIAN,
> > val);
> > + if (rc)
> > + goto out;
> > + }
> > + }
> > +
> > + rc = admin_command_execute(ocxlpmem);
> > + if (rc)
> > + goto out;
> > +
> > + rc = admin_command_complete_timeout(ocxlpmem,
> > + ocxlpmem-
> > >timeouts[ADMIN_COMMAND_FW_DEBUG]);
> > + if (rc < 0)
> > + goto out;
> > +
> > + rc = admin_response(ocxlpmem);
> > + if (rc < 0)
> > + goto out;
> > + if (rc != STATUS_SUCCESS) {
> > + warn_status(ocxlpmem, "Unexpected status from FW
> > Debug", rc);
> > + goto out;
> > + }
> > +
> > + if (args.buf_size) {
> > + for (i = 0; i < args.buf_size; i += sizeof(u64)) {
> > + u64 val;
> > +
> > + rc = ocxl_global_mmio_read64(ocxlpmem-
> > >ocxl_afu,
> > + ocxlpmem-
> > >admin_command.data_offset + i,
> > + OCXL_HOST_ENDIAN,
> > &val);
>
> No check of the data identifier?
>
There isn't one documented.

> It seems to me that there's no definition in the spec whatsoever for
> the
> format of the data, so just copying as much as fits in the buffer
> seems
> correct.
>

That's right, decisions about this data will be left to userspace.

> > + if (rc)
> > + goto out;
> > +
> > + if (copy_to_user(&args.buf[i], &val,
> > sizeof(u64))) {
> > + rc = -EFAULT;
> > + goto out;
> > + }
> > + }
> > + }
> > +
> > + rc = admin_response_handled(ocxlpmem);
> > + if (rc)
> > + goto out;
> > +
> > + rc = disable_fwdebug(ocxlpmem);
> > + if (rc)
> > + goto out;
> > +
> > +out:
> > + mutex_unlock(&ocxlpmem->admin_command.lock);
> > + return rc;
> > +}
> > +
> > +static int ioctl_shutdown(struct ocxlpmem *ocxlpmem)
> > +{
> > + int rc;
> > +
> > + mutex_lock(&ocxlpmem->admin_command.lock);
> > +
> > + rc = admin_command_request(ocxlpmem, ADMIN_COMMAND_SHUTDOWN);
> > + if (rc)
> > + goto out;
> > +
> > + rc = admin_command_execute(ocxlpmem);
> > + if (rc)
> > + goto out;
> > +
> > + rc = admin_command_complete_timeout(ocxlpmem,
> > ADMIN_COMMAND_SHUTDOWN);
> > + if (rc < 0) {
> > + dev_warn(&ocxlpmem->dev, "Shutdown timed out\n");
> > + goto out;
> > + }
> > +
> > + rc = 0;
> > + goto out;
> > +
> > +out:
> > + mutex_unlock(&ocxlpmem->admin_command.lock);
> > + return rc;
> > +}
> > +
> > +static int ioctl_mmio_write(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_mmio __user
> > *uarg)
> > +{
> > + struct scm_ioctl_mmio args;
> > +
> > + if (copy_from_user(&args, uarg, sizeof(args)))
> > + return -EFAULT;
> > +
> > + return ocxl_global_mmio_write64(ocxlpmem->ocxl_afu,
> > args.address,
> > + OCXL_LITTLE_ENDIAN, args.val);
> > +}
> > +
> > +static int ioctl_mmio_read(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_mmio __user
> > *uarg)
> > +{
> > + struct ioctl_ocxl_pmem_mmio args;
> > + int rc;
> > +
> > + if (copy_from_user(&args, uarg, sizeof(args)))
> > + return -EFAULT;
> > +
> > + rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, args.address,
> > + OCXL_LITTLE_ENDIAN, &args.val);
> > + if (rc)
> > + return rc;
> > +
> > + if (copy_to_user(uarg, &args, sizeof(args)))
> > + return -EFAULT;
> > +
> > + return 0;
> > +}
> > +#else /* CONFIG_OCXL_PMEM_DEBUG */
> > +static int ioctl_fwdebug(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_fwdebug __user
> > *uarg)
> > +{
> > + return -EPERM;
> > +}
> > +
> > +static int ioctl_shutdown(struct ocxlpmem *ocxlpmem)
> > +{
> > + return -EPERM;
> > +}
> > +
> > +static int ioctl_mmio_write(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_mmio __user
> > *uarg)
> > +{
> > + return -EPERM;
> > +}
> > +
> > +static int ioctl_mmio_read(struct ocxlpmem *ocxlpmem,
> > + struct ioctl_ocxl_pmem_mmio __user
> > *uarg)
> > +{
> > + return -EPERM;
> > +}
> > +#endif /* CONFIG_OCXL_PMEM_DEBUG */
> > +
> > static long file_ioctl(struct file *file, unsigned int cmd,
> > unsigned long args)
> > {
> > struct ocxlpmem *ocxlpmem = file->private_data;
> > @@ -1091,6 +1320,26 @@ static long file_ioctl(struct file *file,
> > unsigned int cmd, unsigned long args)
> > case IOCTL_OCXL_PMEM_REQUEST_HEALTH:
> > rc = req_controller_health_perf(ocxlpmem);
> > break;
> > +
> > + case IOCTL_OCXL_PMEM_FWDEBUG:
> > + rc = ioctl_fwdebug(ocxlpmem,
> > + (struct ioctl_ocxl_pmem_fwdebug
> > __user *)args);
> > + break;
> > +
> > + case IOCTL_OCXL_PMEM_SHUTDOWN:
> > + rc = ioctl_shutdown(ocxlpmem);
> > + break;
> > +
> > + case IOCTL_OCXL_PMEM_MMIO_WRITE:
> > + rc = ioctl_mmio_write(ocxlpmem,
> > + (struct ioctl_ocxl_pmem_mmio
> > __user *)args);
> > + break;
> > +
> > + case IOCTL_OCXL_PMEM_MMIO_READ:
> > + rc = ioctl_mmio_read(ocxlpmem,
> > + (struct ioctl_ocxl_pmem_mmio
> > __user *)args);
> > + break;
> > +
> > }
> >
> > return rc;
> > diff --git a/include/uapi/nvdimm/ocxl-pmem.h
> > b/include/uapi/nvdimm/ocxl-pmem.h
> > index 0d03abb44001..e20a4f8be82a 100644
> > --- a/include/uapi/nvdimm/ocxl-pmem.h
> > +++ b/include/uapi/nvdimm/ocxl-pmem.h
> > @@ -6,6 +6,28 @@
> > #include <linux/types.h>
> > #include <linux/ioctl.h>
> >
> > +enum ocxlpmem_fwdebug_action {
> > + OCXL_PMEM_FWDEBUG_READ_CONTROLLER_MEMORY = 0x01,
> > + OCXL_PMEM_FWDEBUG_WRITE_CONTROLLER_MEMORY = 0x02,
> > + OCXL_PMEM_FWDEBUG_ENABLE_FUNCTION = 0x03,
> > + OCXL_PMEM_FWDEBUG_DISABLE_FUNCTION = 0x04,
> > + OCXL_PMEM_FWDEBUG_GET_PEL = 0x05, // Retrieve Persistent Error
> > Log
> > +};
> > +
> > +struct ioctl_ocxl_pmem_buffer_info {
> > + __u32 admin_command_buffer_size; // out
> > + __u32 near_storage_buffer_size; // out
> > +};
>
> This struct seems unused.
>
Whoops

> > +
> > +struct ioctl_ocxl_pmem_fwdebug { // All args are inputs
> > + enum ocxlpmem_fwdebug_action debug_action;
> > + __u16 function_code;
> > + __u16 buf_size; // Size of optional data buffer
> > + __u64 debug_parameter_1;
> > + __u64 debug_parameter_2;
> > + __u8 *buf; // Pointer to optional in/out data buffer
> > +};
> > +
> > #define OCXL_PMEM_ERROR_LOG_ACTION_RESET (1 << (32-32))
> > #define OCXL_PMEM_ERROR_LOG_ACTION_CHKFW (1 << (53-32))
> > #define OCXL_PMEM_ERROR_LOG_ACTION_REPLACE (1 << (54-32))
> > @@ -66,6 +88,11 @@ struct ioctl_ocxl_pmem_controller_stats {
> > __u64 cache_write_latency; /* nanoseconds */
> > };
> >
> > +struct ioctl_ocxl_pmem_mmio {
> > + __u64 address; /* Offset in global MMIO space */
> > + __u64 val; /* value to write/was read */
> > +};
> > +
> > struct ioctl_ocxl_pmem_eventfd {
> > __s32 eventfd;
> > __u32 reserved;
> > @@ -92,4 +119,9 @@ struct ioctl_ocxl_pmem_eventfd {
> > #define IOCTL_OCXL_PMEM_EVENT_CHECK _IOR(OC
> > XL_PMEM_MAGIC, 0x07, __u64)
> > #define IOCTL_OCXL_PMEM_REQUEST_HEALTH _IO(OCX
> > L_PMEM_MAGIC, 0x08)
> >
> > +#define IOCTL_OCXL_PMEM_FWDEBUG _IOWR(OCXL_PMEM_MAGIC,
> > 0xf0, struct ioctl_ocxl_pmem_fwdebug)
> > +#define IOCTL_OCXL_PMEM_MMIO_WRITE _IOW(OCXL_PMEM_MAGIC, 0xf1,
> > struct ioctl_ocxl_pmem_mmio)
> > +#define IOCTL_OCXL_PMEM_MMIO_READ _IOWR(OCXL_PMEM_MAGIC, 0xf2,
> > struct ioctl_ocxl_pmem_mmio)
> > +#define IOCTL_OCXL_PMEM_SHUTDOWN _IO(OCXL_PMEM_MAGIC, 0xf3)
> > +
> > #endif /* _UAPI_OCXL_SCM_H */
> >
--
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819

Next message: Bjorn Andersson: "Re: [v1 2/6] arm64: dts: apq8016-sbc: Add CCI/Sensor nodes"
Previous message: Kees Cook: "Re: [PATCH 1/2] selftests/seccomp: Move test child waiting logic"
In reply to: Alastair D'Silva: "Re: [PATCH v3 23/27] powerpc/powernv/pmem: Add debug IOCTLs"
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