mips: fix HIGHMEM initialization

Commit 6faea3422e3b ("arch, mm: streamline HIGHMEM freeing") overzealously
removed mem_init_free_highmem() function that beside freeing high memory
pages checked for CPU support for high memory as a prerequisite.

Partially restore mem_init_free_highmem() with a new highmem_init() name
and make it discard high memory in case there is no CPU support for it.

Link: https://lkml.kernel.org/r/20251231105701.519711-1-rppt@kernel.org
Fixes: 6faea3422e3b ("arch, mm: streamline HIGHMEM freeing")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reported-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Jonas Jelonek <jelonek.jonas@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index a673d3d68254bde4c15386939cab21c898c835e8..8986048f9b110b0bb6bb6d4fc4e853163485c45c 100644 (file)
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -425,6 +425,28 @@ void __init paging_init(void)
 static struct kcore_list kcore_kseg0;
 #endif
 
+static inline void __init highmem_init(void)
+{
+#ifdef CONFIG_HIGHMEM
+       unsigned long tmp;
+
+       /*
+        * If CPU cannot support HIGHMEM discard the memory above highstart_pfn
+        */
+       if (cpu_has_dc_aliases) {
+               memblock_remove(PFN_PHYS(highstart_pfn), -1);
+               return;
+       }
+
+       for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
+               struct page *page = pfn_to_page(tmp);
+
+               if (!memblock_is_memory(PFN_PHYS(tmp)))
+                       SetPageReserved(page);
+       }
+#endif
+}
+
 void __init arch_mm_preinit(void)
 {
        /*
@@ -435,6 +457,7 @@ void __init arch_mm_preinit(void)
 
        maar_init();
        setup_zero_pages();     /* Setup zeroed pages.  */
+       highmem_init();
 
 #ifdef CONFIG_64BIT
        if ((unsigned long) &_text > (unsigned long) CKSEG0)