+ mm-highmem-prepare-for-overriding-set_pte_at.patch added to -mm tree

+ mm-highmem-prepare-for-overriding-set_pte_at.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/highmem: prepare for overriding set_pte_at()
has been added to the -mm tree.  Its filename is
     mm-highmem-prepare-for-overriding-set_pte_at.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-highmem-prepare-for-overriding-set_pte_at.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-highmem-prepare-for-overriding-set_pte_at.patch

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------------------------------------------------------
From: Thomas Gleixner <tglx@linutronix.de>
Subject: 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>
---

 mm/highmem.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/mm/highmem.c~mm-highmem-prepare-for-overriding-set_pte_at
+++ a/mm/highmem.c
@@ -473,6 +473,11 @@ static inline void *arch_kmap_local_high
 }
 #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 lon
 	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();
_

Patches currently in -mm which might be from tglx@linutronix.de are

sparc-mm-highmem-flush-cache-and-tlb.patch
mm-highmem-prepare-for-overriding-set_pte_at.patch
mips-mm-highmem-use-set_pte-for-kmap_local.patch
powerpc-mm-highmem-use-__set_pte_at-for-kmap_local.patch