mm/highmem: prepare for overriding set_pte_at()

The generic kmap_local() map function uses set_pte_at(), but MIPS requires
set_pte() and PowerPC wants __set_pte_at().

Provide arch_kmap_local_set_pte() and default it to set_pte_at().

Link: https://lkml.kernel.org/r/20210112170411.056306194@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/highmem.c b/mm/highmem.c
index c3a9ea7875ef86856e1a50967fc2bf363fdfb09c..874b732b120ce2c81945c8582971f645fba5a9f8 100644 (file)
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -473,6 +473,11 @@ static inline void *arch_kmap_local_high_get(struct page *page)
 }
 #endif
 
+#ifndef arch_kmap_local_set_pte
+#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \
+       set_pte_at(mm, vaddr, ptep, ptev)
+#endif
+
 /* Unmap a local mapping which was obtained by kmap_high_get() */
 static inline bool kmap_high_unmap_local(unsigned long vaddr)
 {
@@ -515,7 +520,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
        BUG_ON(!pte_none(*(kmap_pte - idx)));
        pteval = pfn_pte(pfn, prot);
-       set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval);
+       arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte - idx, pteval);
        arch_kmap_local_post_map(vaddr, pteval);
        current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
        preempt_enable();