Re: [PATCH ethtool] hns3: add support dump registers for hns3 driver

[Michal Kubecek]

On Fri, Aug 18, 2023 at 04:56:11PM +0800, Jijie Shao wrote:
> Add support pretty printer for the registers of hns3 driver.
> This printer supports PF and VF, and is compatible with hns3
> drivers of earlier versions.
> 
> Sample output:
> 
> $ ethtool -d eth1
> [cmdq_regs]
>   comm_nic_csq_baseaddr_l : 0x48168000
>   comm_nic_csq_baseaddr_h : 0x00000000
>   comm_nic_csq_depth      : 0x00000080
>   comm_nic_csq_tail       : 0x00000050
>   comm_nic_csq_head       : 0x00000050
>   comm_nic_crq_baseaddr_l : 0x48170000
>   comm_nic_crq_baseaddr_h : 0x00000000
>   comm_nic_crq_depth      : 0x00000080
>   comm_nic_crq_tail       : 0x00000000
>   comm_nic_crq_head       : 0x00000000
>   comm_vector0_cmdq_src   : 0x00000000
>   comm_cmdq_intr_sts      : 0x00000000
>   comm_cmdq_intr_en       : 0x00000002
>   comm_cmdq_intr_gen      : 0x00000000
> [common_regs]
>   misc_vector_base    : 0x00000001
>   pf_other_int        : 0x00000040
>   misc_reset_sts      : 0x00000000
>   misc_vector_int_sts : 0x00000000
>   global_reset        : 0x00000000
>   fun_rst_ing         : 0x00000000
>   gro_en              : 0x00000001
> ...
> 
> Signed-off-by: Jijie Shao <shaojijie@xxxxxxxxxx>
> ---
[...]
> --- /dev/null
> +++ b/hns3.c
[...]
> +#pragma pack(4)
> +struct hns3_reg_tlv {
> +	u16 tag;
> +	u16 len;
> +};
> +
> +struct hns3_reg_header {
> +	u64 magic_number;
> +	u8 is_vf;
> +	u8 rsv[7];
> +};
> +
> +#pragma pack()

Could we please avoid these #pragma directives? AFAIK this is a Microsoft
extension, which, while implemented in gcc for compatibility reasons, is
not very common in linux world. To be honest, I had to search the web to
see what exactly does it do - and even after that, only checking the object
file with gdb revealed that it does not really do anything except weakening
the alignment of struct hns3_reg_header (as a whole). Given how the
structure is used in this file, the only practical effect would be
header_len in hns3_dump_regs() being 12 rather than 16 (on 64-bit
architectures).

Michal

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