efi/x86: Respect 32-bit ABI in efi32_pe_entry()
verify_cpu() clobbers BX and DI. In case we have to return error, we need to preserve them to respect the 32-bit calling convention. 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/20200301230436.2246909-3-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-11-ardb@kernel.org
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@ -660,7 +660,11 @@ SYM_DATA(efi_is64, .byte 1)
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SYM_FUNC_START(efi32_pe_entry)
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SYM_FUNC_START(efi32_pe_entry)
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pushl %ebp
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pushl %ebp
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pushl %ebx
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pushl %edi
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call verify_cpu // check for long mode support
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call verify_cpu // check for long mode support
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popl %edi
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popl %ebx
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testl %eax, %eax
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testl %eax, %eax
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movl $0x80000003, %eax // EFI_UNSUPPORTED
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movl $0x80000003, %eax // EFI_UNSUPPORTED
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jnz 3f
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jnz 3f
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