Christophe Leroy <[email protected]> writes:
> set_memory_p() and set_memory_np() can fail.
>
> As mentioned in linux/mm.h:
>
> /*
> * To support DEBUG_PAGEALLOC architecture must ensure that
> * __kernel_map_pages() never fails
> */
>
> So panic in case set_memory_p() or set_memory_np() fail
> in __kernel_map_pages().
>
> Link: https://github.com/KSPP/linux/issues/7
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> arch/powerpc/include/asm/book3s/64/hash.h | 2 +-
> arch/powerpc/mm/book3s64/hash_utils.c | 3 ++-
> arch/powerpc/mm/pageattr.c | 10 +++++++---
> 3 files changed, 10 insertions(+), 5 deletions(-)
>
..
> diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
> index 16b8d20d6ca8..62b678585878 100644
> --- a/arch/powerpc/mm/pageattr.c
> +++ b/arch/powerpc/mm/pageattr.c
> @@ -106,17 +106,21 @@ int change_memory_attr(unsigned long addr, int numpages, long action)
> #ifdef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC
> void __kernel_map_pages(struct page *page, int numpages, int enable)
> {
> + int err;
> unsigned long addr = (unsigned long)page_address(page);
>
> if (PageHighMem(page))
> return;
>
> if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled())
> - hash__kernel_map_pages(page, numpages, enable);
> + err = hash__kernel_map_pages(page, numpages, enable);
> else if (enable)
> - set_memory_p(addr, numpages);
> + err = set_memory_p(addr, numpages);
> else
> - set_memory_np(addr, numpages);
> + err = set_memory_np(addr, numpages);
> +
> + if (err)
> + panic("%s: set_memory_%sp() failed\n", enable ? "" : "n");
This doesn't compile, it's missing __func__ I guess.
Seems like we could keep it simpler though, it should hopefully never
happen anyway, eg:
panic("%s: changing memory protections failed\n", __func__);
cheers