Re: [edk2-devel] [PATCH] BaseTools/GenFw: Change opcode when converting ADR to ADRP

["Pedro Falcato" <pedro.falcato@gmail.com>]

On Thu, Oct 26, 2023 at 4:32 PM Jake Garver via groups.io
<jake=nvidia.com@groups.io> wrote:
>
> In the R_AARCH64_ADR_GOT_PAGE case on AARCH64, be sure to change the
> opcode to ADRP.  Prior to this change, we updated the address, but not
> the opcode.
>
> This resolves an issue experienced when building a StandaloneMm image
> with stack protection enabled on GCC 10.5.  This scenario generates an
> ADR where an ADRP is more common in other versions of GCC tested.  That
> explains the obscurity of the issue.  However, an ADR is valid and
> should be handled by GenFw.

Is this not a toolchain bug?
The aarch64 ELF ABI
(https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst)
says:
"Set the immediate value of an ADRP to bits [32:12] of X; check that
–232 <= X < 232"

So it mentions this relocation pointing *to an ADRP* specifically. And
AFAIK there's no way
    Page(G(GDAT(S+A)))-Page(P)

would ever make sense if we're looking at an adr and not an adrp.

Can you post the full disassembly for the function, plus relevant relocations?

-- 
Pedro


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