[efi] Create a copy of the system flattened device tree, if present

EFI configuration tables may be freed at any time, and there is no way
to be notified when the table becomes invalidated.  Create a copy of
the system flattened device tree (if present), so that we do not risk
being left with an invalid pointer.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/core/fdt.c b/src/core/fdt.c
index 9c2880c843ef49bbd33fa2729731e3bc8ca00490..4fd2b76bfe4bbd026611ee2e67f96deabac19904 100644 (file)
--- a/src/core/fdt.c
+++ b/src/core/fdt.c
@@ -456,8 +456,7 @@ int fdt_mac ( struct fdt *fdt, unsigned int offset,
  * @v max_len          Maximum device tree length
  * @ret rc             Return status code
  */
-int fdt_parse ( struct fdt *fdt, const struct fdt_header *hdr,
-               size_t max_len ) {
+int fdt_parse ( struct fdt *fdt, struct fdt_header *hdr, size_t max_len ) {
        const uint8_t *end;
 
        /* Sanity check */

diff --git a/src/include/ipxe/fdt.h b/src/include/ipxe/fdt.h
index 70dc017909f9e733e1679c9154a55aca6fed33f7..2799e0d07f1eb766a4d595f93c4055896ea094ef 100644 (file)
--- a/src/include/ipxe/fdt.h
+++ b/src/include/ipxe/fdt.h
@@ -78,9 +78,9 @@ struct fdt {
        /** Tree data */
        union {
                /** Tree header */
-               const struct fdt_header *hdr;
+               struct fdt_header *hdr;
                /** Raw data */
-               const void *raw;
+               void *raw;
        };
        /** Length of tree */
        size_t len;
@@ -107,7 +107,7 @@ extern int fdt_u64 ( struct fdt *fdt, unsigned int offset, const char *name,
                     uint64_t *value );
 extern int fdt_mac ( struct fdt *fdt, unsigned int offset,
                     struct net_device *netdev );
-extern int fdt_parse ( struct fdt *fdt, const struct fdt_header *hdr,
+extern int fdt_parse ( struct fdt *fdt, struct fdt_header *hdr,
                       size_t max_len );
 
 #endif /* _IPXE_FDT_H */

diff --git a/src/interface/efi/efi_fdt.c b/src/interface/efi/efi_fdt.c
index e207f7e6d6930d67570d2bb9150dc1935a07d97b..71b788ae71ac24eb8e52e9f0da77e08499dfbd51 100644 (file)
--- a/src/interface/efi/efi_fdt.c
+++ b/src/interface/efi/efi_fdt.c
@@ -44,6 +44,8 @@ EFI_USE_TABLE ( FDT_TABLE, &efi_fdt, 0 );
  *
  */
 static void efi_fdt_init ( void ) {
+       EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+       EFI_STATUS efirc;
        int rc;
 
        /* Do nothing if no configuration table is present */
@@ -59,6 +61,15 @@ static void efi_fdt_init ( void ) {
                       strerror ( rc ) );
                return;
        }
+
+       /* Create copy, since table may be removed at any time */
+       if ( ( efirc = bs->AllocatePool ( EfiBootServicesData, sysfdt.len,
+                                         &sysfdt.raw ) ) != 0 ) {
+               DBGC ( &efi_fdt, "EFIFDT could not create copy\n" );
+               sysfdt.len = 0;
+               return;
+       }
+       memcpy ( sysfdt.raw, efi_fdt, sysfdt.len );
 }
 
 /** EFI Flattened Device Tree initialisation function */