kernel_5.10 no rt

hc

2023-12-11 6778948f9de86c3cfaf36725a7c87dcff9ba247f

 kernel/arch/x86/mm/highmem_32.c
..
..
@@ -4,6 +4,65 @@
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 #include <linux/swap.h> /* for totalram_pages */
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 #include <linux/memblock.h>
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+void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
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+{
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+	unsigned long vaddr;
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+	int idx, type;
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+
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+	type = kmap_atomic_idx_push();
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+	idx = type + KM_TYPE_NR*smp_processor_id();
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+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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+	BUG_ON(!pte_none(*(kmap_pte-idx)));
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+	set_pte(kmap_pte-idx, mk_pte(page, prot));
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+	arch_flush_lazy_mmu_mode();
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+
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+	return (void *)vaddr;
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+}
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+EXPORT_SYMBOL(kmap_atomic_high_prot);
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+
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+/*
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+ * This is the same as kmap_atomic() but can map memory that doesn't
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+ * have a struct page associated with it.
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+ */
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+void *kmap_atomic_pfn(unsigned long pfn)
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+{
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+	return kmap_atomic_prot_pfn(pfn, kmap_prot);
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+}
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+EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
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+
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+void kunmap_atomic_high(void *kvaddr)
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+{
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+	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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+
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+	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
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+	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
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+		int idx, type;
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+
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+		type = kmap_atomic_idx();
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+		idx = type + KM_TYPE_NR * smp_processor_id();
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+
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+#ifdef CONFIG_DEBUG_HIGHMEM
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+		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
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+#endif
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+		/*
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+		 * Force other mappings to Oops if they'll try to access this
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+		 * pte without first remap it.  Keeping stale mappings around
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+		 * is a bad idea also, in case the page changes cacheability
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+		 * attributes or becomes a protected page in a hypervisor.
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+		 */
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+		kpte_clear_flush(kmap_pte-idx, vaddr);
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+		kmap_atomic_idx_pop();
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+		arch_flush_lazy_mmu_mode();
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+	}
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+#ifdef CONFIG_DEBUG_HIGHMEM
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+	else {
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+		BUG_ON(vaddr < PAGE_OFFSET);
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+		BUG_ON(vaddr >= (unsigned long)high_memory);
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+	}
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+#endif
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+}
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+EXPORT_SYMBOL(kunmap_atomic_high);
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+
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 void __init set_highmem_pages_init(void)
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 {
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 	struct zone *zone;