linux-kernel - Re: [Patch 3/3] firmware: dmi_scan: use full dmi version for SMBIOS3

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Message-ID: <CAKv+Gu-zxcbJRzNB-fMBgagCP-Ob=aFEjBYKFSbEVmG6150-PQ@mail.gmail.com>
Date:	Wed, 11 Feb 2015 17:55:23 +0800
From:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:	Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
Cc:	Matt Fleming <matt.fleming@...el.com>,
	Leif Lindholm <leif.lindholm@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [Patch 3/3] firmware: dmi_scan: use full dmi version for SMBIOS3

On 11 February 2015 at 17:46, Ivan Khoronzhuk
<ivan.khoronzhuk@...aro.org> wrote:
> New SMBIOS3 spec adds additional field for versioning - docrev.
> The docrev identifies the revision of a specification implemented in
> the table structures, so display SMBIOS version > 3 in format,
> like: 3.22.1
>
> It's not affect on other part of code because version number
> is analyzed using comparing, and it's obvious that 0x000208 is less
> than 0x030201 for example.
>

I don't think the spec forbids passing a 3.0+ table using the legacy
32-bit entry point, in which case the packing of the version could
potentially become a problem.

I don't care deeply about the docrev, so I think we could drop this
patch, but if others feel differently, could we at least pack the
version in a consistent manner (i.e., always account for docrev, and
set it to 0 if the 32-bit entry point is used?)

-- 
Ard.

> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
> ---
>  drivers/firmware/dmi_scan.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> index 952e95c..e4a2d25 100644
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -17,7 +17,7 @@
>   */
>  static const char dmi_empty_string[] = "        ";
>
> -static u16 __initdata dmi_ver;
> +static u32 dmi_ver __initdata;
>  static u32 dmi_len;
>  static u16 dmi_num;
>  /*
> @@ -534,7 +534,8 @@ static int __init dmi_smbios3_present(const u8 *buf)
>  {
>         if (memcmp(buf, "_SM3_", 5) == 0 &&
>             buf[6] < 32 && dmi_checksum(buf, buf[6])) {
> -               dmi_ver = get_unaligned_be16(buf + 7);
> +               dmi_ver = get_unaligned_be32(buf + 6);
> +               dmi_ver &= 0xFFFFFF;
>                 dmi_len = get_unaligned_le32(buf + 12);
>                 dmi_base = get_unaligned_le64(buf + 16);
>                 smbios_header_size = buf[6];
> @@ -553,8 +554,9 @@ static int __init dmi_smbios3_present(const u8 *buf)
>                 dmi_num = dmi_len / 4;
>
>                 if (dmi_walk_early(dmi_decode) == 0) {
> -                       pr_info("SMBIOS %d.%d present.\n",
> -                               dmi_ver >> 8, dmi_ver & 0xFF);
> +                       pr_info("SMBIOS %d.%d.%d present.\n",
> +                               dmi_ver >> 16, (dmi_ver >> 8) & 0xFF,
> +                               dmi_ver & 0xFF);
>                         dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
>                         pr_debug("DMI: %s\n", dmi_ids_string);
>                         return 0;
> --
> 1.9.1
>
--
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