Re: [RFC PATCH v2 7/8] ACPI: APEI: EINJ: Enable EINJv2 error injections

[Ben Cheatham <benjamin.cheatham@amd.com>]

On 5/21/24 4:10 PM, Zaid Alali wrote:
> Enable the driver to inject EINJv2 type errors. The component
> array values are parsed from user_input and expected to contain
> hex values for component id and syndrome separated by space,
> and multiple components are separated by new line as follows:
> 
> component_id1 component_syndrome1
> component_id2 component_syndrome2
>  :
> component_id(n) component_syndrome(n)
> 
> for example:
> 
> $comp_arr="0x1 0x2
>> 0x1 0x4
>> 0x2 0x4"
> $cd /sys/kernel/debug/apei/einj/
> $echo "$comp_arr" > einjv2_component_array
> 

I think it would be good to change this from being newline-delimited to comma-delimited instead.
So instead of your first example above it would be:

component_id1 component_syndrome1, component_id2 component_syndrome2, ...

My reasoning here is that it's less error-prone. For example, if I run your example but forget to
quote the comp_arr variable in the last line, i.e.:

$ echo $comp_arr > einjv2_component_array

I would effectively be running (at least in my stock Ubuntu 22.04 terminal):

$ echo "0x1 0x2 0x1 0x4 0x2 0x4" > einjv2_component_array

Which would result in an error for something that isn't necessarily readily apparent.
I also think keeping the input on a single line is nicer on the eyes, but that's a subjective thing
and I'd understand if you think differently.

> Signed-off-by: Zaid Alali <zaidal@os.amperecomputing.com>
> ---
>  drivers/acpi/apei/einj-core.c | 81 ++++++++++++++++++++++++++++++++---
>  1 file changed, 75 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/apei/einj-core.c b/drivers/acpi/apei/einj-core.c
> index 2e30ebed079b..2e5c00b34a4b 100644
> --- a/drivers/acpi/apei/einj-core.c
> +++ b/drivers/acpi/apei/einj-core.c
> @@ -87,6 +87,13 @@ enum {
>  	SETWA_FLAGS_APICID = 1,
>  	SETWA_FLAGS_MEM = 2,
>  	SETWA_FLAGS_PCIE_SBDF = 4,
> +	SETWA_FLAGS_EINJV2 = 8,
> +};
> +
> +enum {
> +	EINJV2_PROCESSOR_ERROR = 0x1,
> +	EINJV2_MEMORY_ERROR = 0x2,
> +	EINJV2_PCIE_ERROR = 0x4,
>  };
>  
>  /*
> @@ -111,6 +118,7 @@ static char vendor_dev[64];
>  static struct debugfs_blob_wrapper einjv2_component_arr;
>  static u64 component_count;
>  static void *user_input;
> +static int nr_components;
>  static u32 available_error_type;
>  static u32 available_error_type_v2;
>  
> @@ -287,8 +295,18 @@ static void *einj_get_parameter_address(void)
>  
>  		v5param = acpi_os_map_iomem(pa_v5, sizeof(*v5param));
>  		if (v5param) {
> +			int offset, len;
> +
>  			acpi5 = 1;
>  			check_vendor_extension(pa_v5, v5param);
> +			if (available_error_type & ACPI65_EINJV2_SUPP) {
> +				len = v5param->einjv2_struct.length;
> +				offset = offsetof(struct einjv2_extension_struct, component_arr);
> +				nr_components = (len - offset) / 32;
> +				acpi_os_unmap_iomem(v5param, sizeof(*v5param));
> +				v5param = acpi_os_map_iomem(pa_v5, sizeof(*v5param) + (
> +					(nr_components) * sizeof(struct syndrome_array)));
> +			}
>  			return v5param;
>  		}
>  	}
> @@ -494,10 +512,52 @@ static int __einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
>  			v5param->flags = vendor_flags;
>  		} else if (flags) {
>  			v5param->flags = flags;
> -			v5param->memory_address = param1;
> -			v5param->memory_address_range = param2;
> -			v5param->apicid = param3;
> -			v5param->pcie_sbdf = param4;
> +			if (flags & SETWA_FLAGS_MEM) {
> +				v5param->memory_address = param1;
> +				v5param->memory_address_range = param2;
> +			}

I don't think you need this if statement since the values will be ignored
when the SETWA_FLAGS_MEM bit isn't set anyway as per the spec.

> +			if (flags & SETWA_FLAGS_EINJV2) {
> +				int count = 0, bytes_read, pos = 0;
> +				unsigned int comp, synd;
> +				struct syndrome_array *component_arr;
> +
> +				if (component_count > nr_components)
> +					goto err_out;
> +
> +				v5param->einjv2_struct.component_arr_count = component_count;
> +				component_arr = v5param->einjv2_struct.component_arr;
> +
> +				while (sscanf(user_input+pos, "%x %x\n%n", &comp, &synd,
> +							&bytes_read) == 2) {
> +					count++;
> +					pos += bytes_read;
> +					if (count > component_count)
> +						goto err_out;
> +
> +					switch (type) {
> +					case EINJV2_PROCESSOR_ERROR:
> +						component_arr[count-1].comp_id.acpi_id = comp;
> +						component_arr[count-1].comp_synd.proc_synd = synd;
> +						break;
> +					case EINJV2_MEMORY_ERROR:
> +						component_arr[count-1].comp_id.device_id = comp;
> +						component_arr[count-1].comp_synd.mem_synd = synd;
> +						break;
> +					case EINJV2_PCIE_ERROR:
> +						component_arr[count-1].comp_id.pcie_sbdf = comp;
> +						component_arr[count-1].comp_synd.pcie_synd = synd;
> +						break;
> +					}
> +				}
> +				if (count != component_count)
> +					goto err_out;

Nitpick here, but you could use count directly instead of count-1 when indexing component_arr[]
if you move the count++ to the bottom of the loop and change the above if to:

	if (count != component_count - 1)
		goto err_out;

or use count + 1 instead of component_count - 1.

> +
> +				/* clear buffer after user input for next injection */
> +				memset(user_input, 0, COMP_ARR_SIZE);
> +			} else {
> +				v5param->apicid = param3;
> +				v5param->pcie_sbdf = param4;
> +			}
>  		} else {
>  			switch (type) {
>  			case ACPI_EINJ_PROCESSOR_CORRECTABLE:
> @@ -570,6 +630,9 @@ static int __einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
>  	rc = apei_exec_run_optional(&ctx, ACPI_EINJ_END_OPERATION);
>  
>  	return rc;
> +err_out:
> +	memset(user_input, 0, COMP_ARR_SIZE);
> +	return -EINVAL;
>  }
>  
>  /* Inject the specified hardware error */
> @@ -581,9 +644,14 @@ int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, u64 param3,
>  
>  	/* If user manually set "flags", make sure it is legal */
>  	if (flags && (flags &
> -		~(SETWA_FLAGS_APICID|SETWA_FLAGS_MEM|SETWA_FLAGS_PCIE_SBDF)))
> +		~(SETWA_FLAGS_APICID|SETWA_FLAGS_MEM|SETWA_FLAGS_PCIE_SBDF|SETWA_FLAGS_EINJV2)))
>  		return -EINVAL;
>  
> +	/*check if type is a valid EINJv2 error type*/
> +	if (flags & SETWA_FLAGS_EINJV2) {
> +		if (!(type & available_error_type_v2))
> +			return -EINVAL;
> +	}
>  	/*
>  	 * We need extra sanity checks for memory errors.
>  	 * Other types leap directly to injection.
> @@ -915,7 +983,8 @@ static void __exit einj_remove(struct platform_device *pdev)
>  			sizeof(struct set_error_type_with_address) :
>  			sizeof(struct einj_parameter);
>  
> -		acpi_os_unmap_iomem(einj_param, size);
> +		acpi_os_unmap_iomem(einj_param,
> +				size + (nr_components * sizeof(struct syndrome_array)));
>  		if (vendor_errors.size)
>  			acpi_os_unmap_memory(vendor_errors.data, vendor_errors.size);
>  	}