On Fri, Sep 27, 2024 at 11:18:38AM +0100, Mark Rutland wrote:

Certain portions of code always need to be position-independent
regardless of CONFIG_RELOCATABLE, including code which is executed in an
idmap or which is executed before relocations are applied. In some
kernel configurations the LLD linker generates position-dependent
veneers for such code, and when executed these result in early boot-time
failures.

Marc Zyngier encountered a boot failure resulting from this when
building a (particularly cursed) configuration with LLVM, as he reported
to the list:

Heh, I admire the "particularly cursed" bit.

I've tested with GNU LD 2.30 to 2.42 inclusive and LLVM 13.0.1 to 19.1.0
inclusive, using the kernel.org binaries from:

* https://mirrors.edge.kernel.org/pub/tools/crosstool/
* https://mirrors.edge.kernel.org/pub/tools/llvm/

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Marc Zyngier <maz@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <redacted>
Cc: Will Deacon <will@kernel.org>

Thanks for the patch!

Reviewed-by: Nathan Chancellor <nathan@kernel.org>