On Wednesday, October 14, 2015 03:26:22 PM Al Stone wrote:
> According to the ACPI specification, version 6.0, table 5-46, MADT
> subtable IDs in the range of 0x10-0x7f are reserved for possible
> future use by the specification. The function bad_madt_entry() tries
> to enforce the spec, but it turns out there are x86 machines that use
> 0x7f even though they should not.
>
> So, continue to enforce this rule for arm64, since we're starting out
> fresh, but relax it for systems already out there so we don't keep them
> from booting.
>
> Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
> ---
> drivers/acpi/tables.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index a2ed38a..e5cfd72 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -413,9 +413,17 @@ static int __init bad_madt_entry(struct acpi_table_header *table,
> }
>
> if (entry->type >= ms->num_types) {
> - pr_err("undefined MADT subtable type for FADT %d.%d: %d (length %d)\n",
> - major, minor, entry->type, entry->length);
> - return 1;
> + if (IS_ENABLED(CONFIG_ARM64)) {
> + /* Enforce this stricture on arm64... */
> + pr_err("undefined MADT subtable type for FADT %d.%d: %d (length %d)\n",
> + major, minor, entry->type, entry->length);
> + return 1;
> + } else {
> + /* ... 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;
I don't see much point in varying the log level of the message depending on
the architecture. It can stay pr_err() for all of them as far as I'm concerned
and then you only need to change the return line to something like:
return IS_ENABLED(CONFIG_ARM64);
That said, this is getting messy and we may be much better off by having
bad_madt_entry() defined per arch. Then, for x86 and ia64 it may just do
what was done before and you may use a more sophisticated one for ARM64.
Have you considered doing that?
> + }
> }
>
> /* verify that the table is allowed for this version of the spec */
Thanks,
Rafael
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