efi/x86: Avoid using code32_start

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code32_start is meant for 16-bit real-mode bootloaders to inform the
kernel where the 32-bit protected mode code starts. Nothing in the
protected mode kernel except the EFI stub uses it.

efi_main() currently returns boot_params, with code32_start set inside it
to tell efi_stub_entry() where startup_32 is located. Since it was invoked
by efi_stub_entry() in the first place, boot_params is already known.
Return the address of startup_32 instead.

This will allow a 64-bit kernel to live above 4Gb, for example, and it's
cleaner as well.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200301230436.2246909-5-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-13-ardb@kernel.org

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Arvind Sankar 2020-03-08 09:08:43 +01:00 • committed by Ingo Molnar

parent 3fab43318f

commit 8acf63efa1

4 changed files with 8 additions and 10 deletions

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3

arch/x86/boot/compressed/head_32.S

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4

arch/x86/boot/compressed/head_64.S

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1

arch/x86/kernel/asm-offsets.c

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10

drivers/firmware/efi/libstub/x86-stub.c

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