[PATCH v5 08/12] smbios: Drop support for SMBIOS2 tables

[Peter Robinson]

On Sun, Dec 31, 2023 at 3:26 PM Simon Glass <sjg at chromium.org> wrote:
>
> These tables are a pain since there is no way to handle memory above
> 4GB. Use SMBIOS3 always.
>
> This should hopefully not create problems on x86 devices, since SMBIOS3
> was released seven years ago (2015).
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
Reviewed-by: Peter Robinson <pbrobinson at gmail.com>

It's also worth noting here the aarch64 Server Base Boot Requirements
(SBBR) has required SMBIOS v3 since version 1.0 of the spec [1].

[1] https://documentation-service.arm.com/static/5fb7e5adca04df4095c1d64d

> ---
>
> Changes in v5:
> - Add new patch to drop support for SMBIOS2 tables
>
>  lib/smbios.c | 76 ++++++++++++----------------------------------------
>  1 file changed, 17 insertions(+), 59 deletions(-)
>
> diff --git a/lib/smbios.c b/lib/smbios.c
> index cfd451e4088..d9d52bd58d7 100644
> --- a/lib/smbios.c
> +++ b/lib/smbios.c
> @@ -545,13 +545,12 @@ ulong write_smbios_table(ulong addr)
>  {
>         ofnode parent_node = ofnode_null();
>         ulong table_addr, start_addr;
> +       struct smbios3_entry *se;
>         struct smbios_ctx ctx;
>         ulong tables;
>         int len = 0;
>         int max_struct_size = 0;
>         int handle = 0;
> -       char *istart;
> -       int isize;
>         int i;
>
>         ctx.node = ofnode_null();
> @@ -565,12 +564,8 @@ ulong write_smbios_table(ulong addr)
>
>         start_addr = addr;
>
> -       /*
> -        * So far we don't know which struct will be used, but they both end
> -        * up using the same amount of 16-bit-aligned space
> -        */
> -       addr += max(sizeof(struct smbios_entry), sizeof(struct smbios3_entry));
> -       addr = ALIGN(addr, 16);
> +       /* move past the (so-far-unwritten) header to start writing structs */
> +       addr = ALIGN(addr + sizeof(struct smbios3_entry), 16);
>         tables = addr;
>
>         /* populate minimum required tables */
> @@ -592,59 +587,22 @@ ulong write_smbios_table(ulong addr)
>          * We must use a pointer here so things work correctly on sandbox. The
>          * user of this table is not aware of the mapping of addresses to
>          * sandbox's DRAM buffer.
> -        *
> -        * Check the address of the end of the tables. If it is above 4GB then
> -        * it is sensible to use SMBIOS3 even if the start of the table is below
> -        * 4GB (this case is very unlikely to happen in practice)
>          */
>         table_addr = (ulong)map_sysmem(tables, 0);
> -       if (sizeof(table_addr) > sizeof(u32) && addr >= (ulong)UINT_MAX) {
> -               struct smbios3_entry *se;
> -               /*
> -                * We need to put this >32-bit pointer into the table but the
> -                * field is only 32 bits wide.
> -                */
> -               log_debug("WARNING: Using SMBIOS3.0 due to table-address overflow %lx\n",
> -                         table_addr);
> -               se = map_sysmem(start_addr, sizeof(struct smbios_entry));
> -               memset(se, '\0', sizeof(struct smbios_entry));
> -               memcpy(se->anchor, "_SM3_", 5);
> -               se->length = sizeof(struct smbios3_entry);
> -               se->major_ver = SMBIOS_MAJOR_VER;
> -               se->minor_ver = SMBIOS_MINOR_VER;
> -               se->doc_rev = 0;
> -               se->entry_point_rev = 1;
> -               se->max_struct_size = len;
> -               se->struct_table_address = table_addr;
> -               se->checksum = table_compute_checksum(se,
> -                                               sizeof(struct smbios3_entry));
> -       } else {
> -               struct smbios_entry *se;
> -
> -               se = map_sysmem(start_addr, sizeof(struct smbios_entry));
> -               memset(se, '\0', sizeof(struct smbios_entry));
> -               memcpy(se->anchor, "_SM_", 4);
> -               se->length = sizeof(struct smbios_entry);
> -               se->major_ver = SMBIOS_MAJOR_VER;
> -               se->minor_ver = SMBIOS_MINOR_VER;
> -               se->max_struct_size = max_struct_size;
> -               memcpy(se->intermediate_anchor, "_DMI_", 5);
> -               se->struct_table_length = len;
> -
> -               se->struct_table_address = table_addr;
> -
> -               se->struct_count = handle;
> -
> -               /* calculate checksums */
> -               istart = (char *)se + SMBIOS_INTERMEDIATE_OFFSET;
> -               isize = sizeof(struct smbios_entry) -
> -                       SMBIOS_INTERMEDIATE_OFFSET;
> -               se->intermediate_checksum = table_compute_checksum(istart,
> -                                                                  isize);
> -               se->checksum = table_compute_checksum(se,
> -                                             sizeof(struct smbios_entry));
> -               unmap_sysmem(se);
> -       }
> +
> +       /* now go back and write the SMBIOS3 header */
> +       se = map_sysmem(start_addr, sizeof(struct smbios_entry));
> +       memset(se, '\0', sizeof(struct smbios_entry));
> +       memcpy(se->anchor, "_SM3_", 5);
> +       se->length = sizeof(struct smbios3_entry);
> +       se->major_ver = SMBIOS_MAJOR_VER;
> +       se->minor_ver = SMBIOS_MINOR_VER;
> +       se->doc_rev = 0;
> +       se->entry_point_rev = 1;
> +       se->max_struct_size = len;
> +       se->struct_table_address = table_addr;
> +       se->checksum = table_compute_checksum(se, sizeof(struct smbios3_entry));
> +       unmap_sysmem(se);
>
>         return addr;
>  }
> --
> 2.34.1
>