[PATCH v2 2/3] powerpc/64: Convert patch_instruction() to patch_u32()

Naveen N Rao naveen at kernel.org
Thu Nov 30 21:31:18 AEDT 2023

On Mon, Oct 16, 2023 at 04:01:46PM +1100, Benjamin Gray wrote:
> This use of patch_instruction() is working on 32 bit data, and can fail
> if the data looks like a prefixed instruction and the extra write
> crosses a page boundary. Use patch_u32() to fix the write size.
> Fixes: 8734b41b3efe ("powerpc/module_64: Fix livepatching for RO modules")
> Link: https://lore.kernel.org/all/20230203004649.1f59dbd4@yea/
> Signed-off-by: Benjamin Gray <bgray at linux.ibm.com>
> ---
> v2: * Added the fixes tag, it seems appropriate even if the subject does
>       mention a more robust solution being required.
> patch_u64() should be more efficient, but judging from the bug report
> it doesn't seem like the data is doubleword aligned.

That doesn't look to be the case anymore due to commits 77e69ee7ce07 
("powerpc/64: modules support building with PCREL addresing") and 
7e3a68be42e1 ("powerpc/64: vmlinux support building with PCREL 

- Naveen

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