diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2016-03-01 18:56:07 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2016-03-11 14:54:28 +0200 |
| commit | f20354910893310d5496ebb6edfc551d83d95343 (patch) | |
| tree | 8a9bcec19faf0b9d864dee9f9b569d538fe90809 | |
| parent | 3f3009c0983428f517b743c9de14858b1fdaacb7 (diff) | |
acpi: add build_append_named_dword, returning an offset in buffer
This is a very limited form of support for runtime patching -
similar in functionality to what we can do with ACPI_EXTRACT
macros in python, but implemented in C.
This is to allow ACPI code direct access to data tables -
which is exactly what DataTableRegion is there for, except
no known windows release so far implements DataTableRegion.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | hw/acpi/aml-build.c | 28 | ||||
| -rw-r--r-- | include/hw/acpi/aml-build.h | 3 |
2 files changed, 31 insertions, 0 deletions
diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index f26fa26802..ab89ca6380 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -258,6 +258,34 @@ static void build_append_int(GArray *table, uint64_t value) } } +/* + * Build NAME(XXXX, 0x00000000) where 0x00000000 is encoded as a dword, + * and return the offset to 0x00000000 for runtime patching. + * + * Warning: runtime patching is best avoided. Only use this as + * a replacement for DataTableRegion (for guests that don't + * support it). + */ +int +build_append_named_dword(GArray *array, const char *name_format, ...) +{ + int offset; + va_list ap; + + build_append_byte(array, 0x08); /* NameOp */ + va_start(ap, name_format); + build_append_namestringv(array, name_format, ap); + va_end(ap); + + build_append_byte(array, 0x0C); /* DWordPrefix */ + + offset = array->len; + build_append_int_noprefix(array, 0x00000000, 4); + assert(array->len == offset + 4); + + return offset; +} + static GPtrArray *alloc_list; static Aml *aml_alloc(void) diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h index b16017ed71..66f48ec04f 100644 --- a/include/hw/acpi/aml-build.h +++ b/include/hw/acpi/aml-build.h @@ -368,4 +368,7 @@ void build_rsdt(GArray *table_data, GArray *linker, GArray *table_offsets, const char *oem_id, const char *oem_table_id); +int +build_append_named_dword(GArray *array, const char *name_format, ...); + #endif |