Commit f2035491 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 3f3009c0

hw/acpi/aml-build.c

+28 −0
Original line number Diff line number Diff line
@@ -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)

include/hw/acpi/aml-build.h

+3 −0
Original line number Diff line number Diff line
@@ -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