On Wednesday, October 14, 2015 03:26:24 PM Al Stone wrote:
> In some environments, the FADT revision number is always 2, independent
> of any other factors indicating that it may be a newer revision. So,
> we cannot rely on the FADT and MADT revisions being in proper sync. For
> those environments, relax the checking so we only enforce the size check,
> even if we do issue warnings on other problems.
>
> If we do not relax the rules, these systems will not boot as they have in
> the past.
>
> Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
> ---
> drivers/acpi/tables.c | 34 +++++++++++++++++++++++++++++-----
> 1 file changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index 3b5ddfb..790d4b0 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -416,7 +416,6 @@ static int __init bad_madt_entry(struct acpi_table_header *table,
> /* ... but relax it on legacy systems so they boot */
> pr_warn("undefined version for either FADT %d.%d or MADT %d\n",
> major, minor, madt->header.revision);
> - return 0;
> }
> }
>
> @@ -430,16 +429,41 @@ static int __init bad_madt_entry(struct acpi_table_header *table,
> /* ... but relax it on legacy systems so they boot */
> pr_warn("undefined MADT subtable type for FADT %d.%d: %d (length %d)\n",
> major, minor, entry->type, entry->length);
> - return 0;
> }
> }
>
> /* verify that the table is allowed for this version of the spec */
> len = ms->lengths[entry->type];
> if (!len) {
> - pr_err("MADT subtable %d not defined for FADT %d.%d\n",
> - entry->type, major, minor);
> - return 1;
> + if (IS_ENABLED(CONFIG_ARM64)) {
> + pr_err("MADT subtable %d not defined for FADT %d.%d\n",
> + entry->type, major, minor);
> + return 1;
> + } else {
> + pr_warn("MADT subtable %d not defined for FADT %d.%d\n",
> + entry->type, major, minor);
> + }
Same comment again.
> + }
> +
> + /*
> + * When we get this far, we may have issued warnings on either
> + * a mismatch in FADT/MADT revisions, or have noted that the subtable
> + * ID is not defined for the MADT revision we're using. On some
> + * architectures, this is an error, but for legacy systems, we need
> + * to push on with other checks of the subtable.
> + *
> + * In fact, there are environments where the *only* value the FADT
> + * revision will ever have is 2, regardless of anything else. So,
> + * for those systems to boot, we have to pretend the MADT is the
> + * latest version to allow all known subtables since we have no way
> + * to determine what revision it should be.
> + */
> + if (!IS_ENABLED(CONFIG_ARM64) && major == 2) {
Gosh. No sorry, this isn't going in. Please rethink the approach.
> + ms = spec_info;
> + while (ms->num_types != 0)
> + ms++;
> + ms--;
> + len = ms->lengths[entry->type];
> }
>
> /* verify that the length is what we expect */
>
Thanks,
Rafael
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