On Tue, Jan 12, 2021 at 10:23:12AM +0000, Mark Rutland wrote:

On Fri, Jan 08, 2021 at 09:39:53PM +0100, Peter Zijlstra wrote:

quoted

On Fri, Jan 08, 2021 at 09:32:58AM +0000, Will Deacon wrote:

quoted

Hi Arnd,

On Fri, Jan 08, 2021 at 10:19:56AM +0100, Arnd Bergmann wrote:

quoted

From: Arnd Bergmann <arnd@arndb.de>

With UBSAN enabled and building with clang, there are occasionally
warnings like

WARNING: modpost: vmlinux.o(.text+0xc533ec): Section mismatch in reference from the function arch_atomic64_or() to the variable .init.data:numa_nodes_parsed
The function arch_atomic64_or() references
the variable __initdata numa_nodes_parsed.
This is often because arch_atomic64_or lacks a __initdata
annotation or the annotation of numa_nodes_parsed is wrong.

for functions that end up not being inlined as intended but operating
on __initdata variables. Mark these as __always_inline, along with
the corresponding asm-generic wrappers.

Hmm, I don't fully grok this. Why does it matter if a non '__init' function
is called with a pointer to some '__initdata'? Or is the reference coming
from somewhere else? (where?).

FWIW the x86 atomics are __always_inline in part due to the noinstr
crud, which I imagine resulted in much the same 'fun'.

FWIW, I was planning on doing the same here as part of making arm64
noinstr safe, so I reckon we should probably do this regardless of
whether it's a complete fix for the section mismatch issue.

Fair enough:

Acked-by: Will Deacon <will@kernel.org>

Will

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