elfloader: fix EFI image size

The size calculation was incorrect, unfortunately. That lead to
an incorrect memory map provided by UEFI. When switching on EFI_DEBUG
one can see that the memory range occupied by the ELF-loader
("paddr=" line) is not fully marked as used by UEFI and the last
few pages of the ELF-loader are actually marked as being free.

Output before:

ELF-loader started on Image ranges:
  paddr=[7f9bc0000..7fcde1fff]
    text[7f9bc0000..7f9bd1e8f]
    data[7f9bd2000..7fcddd9ff]
     bss[7f9bd2850..7f9c0a4cf]
   edata[7fcddda00..7fcde1fff]
[...]
[paddr=0x180023000-0x7f9bbffff]
    [type = Conventional, attr: Normal  <- ok
[paddr=0x7f9bc0000-0x7fcdddfff]
    [type = Loader Code, attr: Normal   <- Not ok: end address too low
                                                Should be 0x4000 higher

[paddr=0x7fcdde000-0x7ffffffff]
    [type = Conventional, attr: Normal  <- Not ok: start address too low
                                                Should be 0x4000 higher

After:

ELF-loader started on Image ranges:
  paddr=[7f9bbc000..7fcdddfff]
    text[7f9bbc000..7f9bcde8f]
    data[7f9bce000..7fcdd99ff]
     bss[7f9bce850..7f9c064cf]
   edata[7fcdd9a00..7fcdddfff]
[...]
[paddr=0x180023000-0x7f9bbbfff]
    [type = Conventional, attr: Normal  <- ok
[paddr=0x7f9bbc000-0x7fcdddfff]
    [type = Loader Code, attr: Normal   <- ok (same as above)
[paddr=0x7fcdde000-0x7ffffffff]
    [type = Conventional, attr: Normal  <- ok (starts one after
                                               paddr end)

Note: You don't have that debug output (EFI_DEBUG) in your code,
that prints the UEFI memory map. So you have to believe me that
this is the actual output.

This fixes 030d83b ("elfloader: improve EFI support").

Signed-off-by: Matthias Rosenfelder <[email protected]>

elfloader-tool/src/binaries/efi/gnuefi/crt0-efi-aarch64.S

@@ -64,7 +64,7 @@ extra_header_fields:
 	.short	0				// MinorSubsystemVersion
 	.long	0				// Win32VersionValue
 
-	.long	_edata - ImageBase		// SizeOfImage
+	.long	_end - ImageBase		// SizeOfImage
 
 	// Everything before the kernel image is considered part of the header
 	.long	_gnuefi_start - ImageBase		// SizeOfHeaders