[PATCH v5 8/8] powerpc/mm: Disable set_memory() routines when strict RWX isn't enabled

[Andrew Donnellan]

On 26/2/20 5:35 pm, Russell Currey wrote:
> There are a couple of reasons that the set_memory() functions are
> problematic when STRICT_KERNEL_RWX isn't enabled:
> 
>   - The linear mapping is a different size and apply_to_page_range()
> 	may modify a giant section, breaking everything
>   - patch_instruction() doesn't know to work around a page being marked
>   	RO, and will subsequently crash
> 
> The latter can be replicated by building a kernel with the set_memory()
> patches but with STRICT_KERNEL_RWX off and running ftracetest.
> 
> Reported-by: Jordan Niethe <jniethe5 at gmail.com>
> Signed-off-by: Russell Currey <ruscur at russell.cc>

Can we squash this in earlier in the series for the sake of bisectability?

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd at linux.ibm.com             IBM Australia Limited