Re: [PATCH v6 21/38] powerpc: Implement the new page table range API

From: Matthew Wilcox
Date: Thu Aug 03 2023 - 23:50:34 EST

On Thu, Aug 03, 2023 at 04:38:14PM -0700, Nathan Chancellor wrote:
> > -EXPORT_SYMBOL(flush_dcache_icache_page);
> Apologies if this has already been fixed or reported, I searched lore
> and did not find anything. The dropping of this export in combination
> with the conversion above appears to cause ARCH=powerpc allmodconfig to
> fail with:
> ERROR: modpost: "flush_dcache_icache_folio" [arch/powerpc/kvm/kvm-pr.ko] undefined!
> I don't know if this should be re-exported or not but that does
> obviously resolve the issue.

Well, that was clumsy of me. I (and the Intel build bot) did test several
build combos, but clearly didn't manage to find a config that showed
this problem. Andrew, a fix patch for you to integrate, if you would:

diff --git a/arch/powerpc/mm/cacheflush.c b/arch/powerpc/mm/cacheflush.c
index 8760d2223abe..15189592da09 100644
--- a/arch/powerpc/mm/cacheflush.c
+++ b/arch/powerpc/mm/cacheflush.c
@@ -172,6 +172,7 @@ void flush_dcache_icache_folio(struct folio *folio)
flush_dcache_icache_phys((pfn + i) * PAGE_SIZE);

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)