arm64/efi: efistub: cover entire static mem footprint in PE/COFF .text

The static memory footprint of a kernel Image at boot is larger than the
Image file itself. Things like .bss data and initial page tables are allocated
statically but populated dynamically so their content is not contained in the
Image file.

However, if EFI (or GRUB) has loaded the Image at precisely the desired offset
of base of DRAM + TEXT_OFFSET, the Image will be booted in place, and we have
to make sure that the allocation done by the PE/COFF loader is large enough.

Fix this by growing the PE/COFF .text section to cover the entire static
memory footprint. The part of the section that is not covered by the payload
will be zero initialised by the PE/COFF loader.

Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 8730690..0a6e4f9 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -151,7 +151,7 @@ optional_header:
        .short  0x20b                           // PE32+ format
        .byte   0x02                            // MajorLinkerVersion
        .byte   0x14                            // MinorLinkerVersion
-       .long   _edata - stext                  // SizeOfCode
+       .long   _end - stext                    // SizeOfCode
        .long   0                               // SizeOfInitializedData
        .long   0                               // SizeOfUninitializedData
        .long   efi_stub_entry - efi_head       // AddressOfEntryPoint
@@ -169,7 +169,7 @@ extra_header_fields:
        .short  0                               // MinorSubsystemVersion
        .long   0                               // Win32VersionValue
 
-       .long   _edata - efi_head               // SizeOfImage
+       .long   _end - efi_head                 // SizeOfImage
 
        // Everything before the kernel image is considered part of the header
        .long   stext - efi_head                // SizeOfHeaders
@@ -216,7 +216,7 @@ section_table:
        .byte   0
        .byte   0
        .byte   0                       // end of 0 padding of section name
-       .long   _edata - stext          // VirtualSize
+       .long   _end - stext            // VirtualSize
        .long   stext - efi_head        // VirtualAddress
        .long   _edata - stext          // SizeOfRawData
        .long   stext - efi_head        // PointerToRawData