diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-10-10 11:25:24 +0200 |
|---|---|---|
| committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-11-05 09:03:05 +0100 |
| commit | ea6bc80d1819f307d98c6562c8ebb2c6c1297d47 (patch) | |
| tree | 49f0983836e51ae3cc07ace02011e3766659ffae /arch/arm64/kernel/head.S | |
| parent | 95b395963fed02cca8849137b375528a5fc94e35 (diff) | |
arm64/efi: set PE/COFF section alignment to 4 KB
Position independent AArch64 code needs to be linked and loaded at the
same relative offset from a 4 KB boundary, or adrp/add and adrp/ldr
pairs will not work correctly. (This is how PC relative symbol
references with a 4 GB reach are emitted)
We need to declare this in the PE/COFF header, otherwise the PE/COFF
loader may load the Image and invoke the stub at an offset which
violates this rule.
Reviewed-by: Roy Franz <roy.franz@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 8c06c9d269d2..8ae84d8c2a8c 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -161,7 +161,7 @@ optional_header: extra_header_fields: .quad 0 // ImageBase - .long 0x20 // SectionAlignment + .long 0x1000 // SectionAlignment .long 0x8 // FileAlignment .short 0 // MajorOperatingSystemVersion .short 0 // MinorOperatingSystemVersion @@ -228,7 +228,15 @@ section_table: .short 0 // NumberOfRelocations (0 for executables) .short 0 // NumberOfLineNumbers (0 for executables) .long 0xe0500020 // Characteristics (section flags) - .align 5 + + /* + * EFI will load stext onwards at the 4k section alignment + * described in the PE/COFF header. To ensure that instruction + * sequences using an adrp and a :lo12: immediate will function + * correctly at this alignment, we must ensure that stext is + * placed at a 4k boundary in the Image to begin with. + */ + .align 12 #endif ENTRY(stext) |