fdt: Check for overlapping data and FDT

If the FDT overlaps with the data region of the image, or with the stack,
it can become corrupted before relocation. Add a check for this, behind a
debug flag, as it can be very confusing and time-consuming to debug.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass
2022-12-21 16:08:21 -07:00
parent ec4f327145
commit 9557592edc

View File

@@ -1231,6 +1231,29 @@ static void *fdt_find_separate(void)
#else #else
/* FDT is at end of image */ /* FDT is at end of image */
fdt_blob = (ulong *)&_end; fdt_blob = (ulong *)&_end;
if (_DEBUG && !fdtdec_prepare_fdt(fdt_blob)) {
int stack_ptr;
const void *top = fdt_blob + fdt_totalsize(fdt_blob);
/*
* Perform a sanity check on the memory layout. If this fails,
* it indicates that the device tree is positioned above the
* global data pointer or the stack pointer. This should not
* happen.
*
* If this fails, check that SYS_INIT_SP_ADDR has enough space
* below it for SYS_MALLOC_F_LEN and global_data, as well as the
* stack, without overwriting the device tree or U-Boot itself.
* Since the device tree is sitting at _end (the start of the
* BSS region), we need the top of the device tree to be below
* any memory allocated by board_init_f_alloc_reserve().
*/
if (top > (void *)gd || top > (void *)&stack_ptr) {
printf("FDT %p gd %p\n", fdt_blob, gd);
panic("FDT overlap");
}
}
#endif #endif
return fdt_blob; return fdt_blob;