bloblist: Support allocating the bloblist

Typically the bloblist is positioned at a fixed address in memory until
relocation. This is convenient when it is set up in SPL or before
relocation.

But for EFI we want to set it up only when U-Boot proper is running. Add
a way to allocate it using malloc() and update the documentation to cover
this aspect of bloblist.

Note there are no tests of this feature at present, nor any direct testing
of bloblist_init().

This can be added, e.g. by making this option controllable at runtime.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/Kconfig

@@ -727,6 +727,8 @@ config TPL_BLOBLIST
 	  This enables a bloblist in TPL. The bloblist is set up in TPL and
 	  passed to SPL and U-Boot proper.
 
+if BLOBLIST
+
 config BLOBLIST_SIZE
 	hex "Size of bloblist"
 	depends on BLOBLIST
@@ -737,17 +739,24 @@ config BLOBLIST_SIZE
 	  is set up in the first part of U-Boot to run (TPL, SPL or U-Boot
 	  proper), and this sane bloblist is used for subsequent stages.
 
+config BLOBLIST_ALLOC
+	bool "Allocate bloblist"
+	help
+	  Allocate the bloblist using malloc(). This avoids the need to
+	  specify a fixed address on systems where this is unknown or can
+	  change at runtime.
+
 config BLOBLIST_ADDR
 	hex "Address of bloblist"
-	depends on BLOBLIST
 	default 0xc000 if SANDBOX
 	help
 	  Sets the address of the bloblist, set up by the first part of U-Boot
 	  which runs. Subsequent U-Boot stages typically use the same address.
 
+	  This is not used if BLOBLIST_ALLOC is selected.
+
 config BLOBLIST_SIZE_RELOC
 	hex "Size of bloblist after relocation"
-	depends on BLOBLIST
 	default BLOBLIST_SIZE
 	help
 	  Sets the size of the bloblist in bytes after relocation. Since U-Boot
@@ -755,6 +764,8 @@ config BLOBLIST_SIZE_RELOC
 	  size than the one set up by SPL. This bloblist is set up during the
 	  relocation process.
 
+endif # BLOBLIST
+
 endmenu
 
 source "common/spl/Kconfig"

common/bloblist.c

@@ -7,6 +7,7 @@
 #include <common.h>
 #include <bloblist.h>
 #include <log.h>
+#include <malloc.h>
 #include <mapmem.h>
 #include <spl.h>
 #include <asm/global_data.h>
@@ -416,10 +417,21 @@ int bloblist_init(void)
 		ret = bloblist_check(CONFIG_BLOBLIST_ADDR,
 				     CONFIG_BLOBLIST_SIZE);
 	if (ret) {
+		ulong addr;
+
 		log(LOGC_BLOBLIST, expected ? LOGL_WARNING : LOGL_DEBUG,
 		    "Existing bloblist not found: creating new bloblist\n");
-		ret = bloblist_new(CONFIG_BLOBLIST_ADDR, CONFIG_BLOBLIST_SIZE,
-				   0);
+		if (IS_ENABLED(CONFIG_BLOBLIST_ALLOC)) {
+			void *ptr = memalign(BLOBLIST_ALIGN,
+					     CONFIG_BLOBLIST_SIZE);
+
+			if (!ptr)
+				return log_msg_ret("alloc", -ENOMEM);
+			addr = map_to_sysmem(ptr);
+		} else {
+			addr = CONFIG_BLOBLIST_ADDR;
+		}
+		ret = bloblist_new(addr, CONFIG_BLOBLIST_SIZE, 0);
 	} else {
 		log(LOGC_BLOBLIST, LOGL_DEBUG, "Found existing bloblist\n");
 	}

common/board_f.c

@@ -655,8 +655,14 @@ static int reloc_bootstage(void)
 static int reloc_bloblist(void)
 {
 #ifdef CONFIG_BLOBLIST
-	if (gd->flags & GD_FLG_SKIP_RELOC)
+	/*
+	 * Relocate only if we are supposed to send it
+	 */
+	if ((gd->flags & GD_FLG_SKIP_RELOC) &&
+	    CONFIG_BLOBLIST_SIZE == CONFIG_BLOBLIST_SIZE_RELOC) {
+		debug("Not relocating bloblist\n");
 		return 0;
+	}
 	if (gd->new_bloblist) {
 		int size = CONFIG_BLOBLIST_SIZE;
 

doc/develop/bloblist.rst

@@ -59,6 +59,22 @@ Bloblist provides a fairly simple API which allows blobs to be created and
 found. All access is via the blob's tag. Blob records are zeroed when added.
 
 
+Placing the bloblist
+--------------------
+
+The bloblist is typically positioned at a fixed address by TPL, or SPL. This
+is controlled by `CONFIG_BLOBLIST_ADDR`. But in some cases it is preferable to
+allocate the bloblist in the malloc() space. Use the `CONFIG_BLOBLIST_ALLOC`
+option to enable this.
+
+The bloblist is automatically relocated as part of U-Boot relocation. Sometimes
+it is useful to expand the bloblist in U-Boot proper, since it may want to add
+information for use by Linux. Note that this does not mean that Linux needs to
+know anything about the bloblist format, just that it is convenient to use
+bloblist to place things contiguously in memory. Set
+`CONFIG_BLOBLIST_SIZE_RELOC` to define the expanded size, if needed.
+
+
 Finishing the bloblist
 ----------------------