RE: [PATCH] objtool: fix objtool regression on x32 systems
From: David Laight
Date: Tue May 17 2022 - 04:27:48 EST
From: Peter Zijlstra
> Sent: 16 May 2022 22:25
...
> A quick look seems to suggest at least all the 'offset' fields should be
> u64 or something. The only reason that works is because -mcmodel=kernel
> keeps everything in the 2G range to make s32 immediates work. But it
> isn't right.
Offsets in instructions are only 8bit or 32bit.
The mod/reg/rm and SiB encodings don't support anything else.
If offsets might be large then they have to be loaded into
registers - which will slow things down.
Immediates can be 64bit (but not if the addressing mode
includes an offset).
David
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