| Message ID | 7498607873ad7c9ff59d0a24d35391c0e4ba0a11.1269936879.git.eduard.munteanu@linux360.ro |
|---|---|
| State | New |
| Headers | show |
On 03/30/2010 01:20 AM, Eduard - Gabriel Munteanu wrote: > + /* Ignore preexisting garbage in checksum. */ > + acpi_hdr = (struct acpi_table_header *) data; > + sum -= acpi_hdr->checksum; > + > return (-sum) & 0xff; Wouldn't it be cleaner to adjust the acpi_checksum definition to take and acpi_table_header operand instead of uint8_t? And given it's only usage, perhaps update the checksum instead of returning it? E.g. - ((struct acpi_table_header*)p)->checksum = acpi_checksum((uint8_t*)p, off); + acpi_update_checksum((struct acpi_table_header *)p, off); r~
diff --git a/hw/acpi.c b/hw/acpi.c index f067f85..bb015f3 100644 --- a/hw/acpi.c +++ b/hw/acpi.c @@ -832,11 +832,16 @@ size_t acpi_tables_len, acpi_tables_prev_len; static int acpi_checksum(const uint8_t *data, int len) { int sum, i; + struct acpi_table_header *acpi_hdr; sum = 0; for(i = 0; i < len; i++) sum += data[i]; + /* Ignore preexisting garbage in checksum. */ + acpi_hdr = (struct acpi_table_header *) data; + sum -= acpi_hdr->checksum; + return (-sum) & 0xff; }
The whole table must sum to zero. We need to ignore garbage in the checksum field (i.e. consider it zero) when checksumming. It is legitimate to have garbage there, as the checksum makes sense only when the table has been filled. Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> --- hw/acpi.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)