x86/decompressor: Call trampoline directly from C code

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Instead of returning to the asm calling code to invoke the trampoline,
call it straight from the C code that sets it up. That way, the struct
return type is no longer needed for returning two values, and the call
can be made conditional more cleanly in a subsequent patch.

This means that all callee save 64-bit registers need to be preserved
and restored, as their contents may not survive the legacy mode switch.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20230807162720.545787-13-ardb@kernel.org

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Ard Biesheuvel 2023-08-07 18:27:09 +02:00 • committed by Borislav Petkov (AMD)

parent bd328aa01f

commit 64ef578b6b

2 changed files with 26 additions and 37 deletions

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31

arch/x86/boot/compressed/head_64.S

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32

arch/x86/boot/compressed/pgtable_64.c

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