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author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-10-08 16:11:27 +0200 |
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committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-11-05 09:02:59 +0100 |
commit | 95b395963fed02cca8849137b375528a5fc94e35 (patch) | |
tree | c782b65abaa9c71d124e9e19776c260dbf5fda23 /arch/arm64/kernel/efi-entry.S | |
parent | cac7f2429872d3733dc3f9915857b1691da2eb2f (diff) | |
download | linux-stable-95b395963fed02cca8849137b375528a5fc94e35.tar.gz linux-stable-95b395963fed02cca8849137b375528a5fc94e35.tar.bz2 linux-stable-95b395963fed02cca8849137b375528a5fc94e35.zip |
arm64/efi: efistub: jump to 'stext' directly, not through the header
After the EFI stub has done its business, it jumps into the kernel by
branching to offset #0 of the loaded Image, which is where it expects
to find the header containing a 'branch to stext' instruction.
However, the UEFI spec 2.1.1 states the following regarding PE/COFF
image loading:
"A UEFI image is loaded into memory through the LoadImage() Boot
Service. This service loads an image with a PE32+ format into memory.
This PE32+ loader is required to load all sections of the PE32+ image
into memory."
In other words, it is /not/ required to load parts of the image that are
not covered by a PE/COFF section, so it may not have loaded the header
at the expected offset, as it is not covered by any PE/COFF section.
So instead, jump to 'stext' directly, which is at the base of the
PE/COFF .text section, by supplying a symbol 'stext_offset' to
efi-entry.o which contains the relative offset of stext into the Image.
Also replace other open coded calculations of the same value with a
reference to 'stext_offset'
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'arch/arm64/kernel/efi-entry.S')
-rw-r--r-- | arch/arm64/kernel/efi-entry.S | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S index 619b1dd7bcde..a0016d3a17da 100644 --- a/arch/arm64/kernel/efi-entry.S +++ b/arch/arm64/kernel/efi-entry.S @@ -61,7 +61,8 @@ ENTRY(efi_stub_entry) */ mov x20, x0 // DTB address ldr x0, [sp, #16] // relocated _text address - mov x21, x0 + ldr x21, =stext_offset + add x21, x0, x21 /* * Flush dcache covering current runtime addresses |