v4.19.13 snapshot.
diff --git a/arch/x86/mm/physaddr.c b/arch/x86/mm/physaddr.c
new file mode 100644
index 0000000..7f9acb6
--- /dev/null
+++ b/arch/x86/mm/physaddr.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bootmem.h>
+#include <linux/mmdebug.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+
+#include <asm/page.h>
+
+#include "physaddr.h"
+
+#ifdef CONFIG_X86_64
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+unsigned long __phys_addr(unsigned long x)
+{
+ unsigned long y = x - __START_KERNEL_map;
+
+ /* use the carry flag to determine if x was < __START_KERNEL_map */
+ if (unlikely(x > y)) {
+ x = y + phys_base;
+
+ VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
+ } else {
+ x = y + (__START_KERNEL_map - PAGE_OFFSET);
+
+ /* carry flag will be set if starting x was >= PAGE_OFFSET */
+ VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x));
+ }
+
+ return x;
+}
+EXPORT_SYMBOL(__phys_addr);
+
+unsigned long __phys_addr_symbol(unsigned long x)
+{
+ unsigned long y = x - __START_KERNEL_map;
+
+ /* only check upper bounds since lower bounds will trigger carry */
+ VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
+
+ return y + phys_base;
+}
+EXPORT_SYMBOL(__phys_addr_symbol);
+#endif
+
+bool __virt_addr_valid(unsigned long x)
+{
+ unsigned long y = x - __START_KERNEL_map;
+
+ /* use the carry flag to determine if x was < __START_KERNEL_map */
+ if (unlikely(x > y)) {
+ x = y + phys_base;
+
+ if (y >= KERNEL_IMAGE_SIZE)
+ return false;
+ } else {
+ x = y + (__START_KERNEL_map - PAGE_OFFSET);
+
+ /* carry flag will be set if starting x was >= PAGE_OFFSET */
+ if ((x > y) || !phys_addr_valid(x))
+ return false;
+ }
+
+ return pfn_valid(x >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
+#else
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+unsigned long __phys_addr(unsigned long x)
+{
+ unsigned long phys_addr = x - PAGE_OFFSET;
+ /* VMALLOC_* aren't constants */
+ VIRTUAL_BUG_ON(x < PAGE_OFFSET);
+ VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
+ /* max_low_pfn is set early, but not _that_ early */
+ if (max_low_pfn) {
+ VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
+ BUG_ON(slow_virt_to_phys((void *)x) != phys_addr);
+ }
+ return phys_addr;
+}
+EXPORT_SYMBOL(__phys_addr);
+#endif
+
+bool __virt_addr_valid(unsigned long x)
+{
+ if (x < PAGE_OFFSET)
+ return false;
+ if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
+ return false;
+ if (x >= FIXADDR_START)
+ return false;
+ return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
+#endif /* CONFIG_X86_64 */