Commit 69660fd7 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds

x86, mm: introduce _PAGE_DEVMAP

_PAGE_DEVMAP is a hardware-unused pte bit that will later be used in the
get_user_pages() path to identify pfns backed by the dynamic allocation
established by devm_memremap_pages.  Upon seeing that bit the gup path
will lookup and pin the allocation while the pages are in use.

Since the _PAGE_DEVMAP bit is > 32 it must be cast to u64 instead of a
pteval_t to allow pmd_flags() usage in the realmode boot code to build.
Signed-off-by: default avatarDan Williams <>
Cc: Thomas Gleixner <>
Cc: Ingo Molnar <>
Cc: "H. Peter Anvin" <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 6d8113c7
......@@ -24,7 +24,9 @@
#define _PAGE_BIT_HIDDEN _PAGE_BIT_SOFTW3 /* hidden by kmemcheck */
#define _PAGE_BIT_SOFT_DIRTY _PAGE_BIT_SOFTW3 /* software dirty tracking */
#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
#define _PAGE_BIT_SOFTW4 58 /* available for programmer */
#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
/* If _PAGE_BIT_PRESENT is clear, we use these: */
/* - if the user mapped it with PROT_NONE; pte_present gives true */
......@@ -83,8 +85,11 @@
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
#define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX)
#define _PAGE_DEVMAP (_AT(u64, 1) << _PAGE_BIT_DEVMAP)
#define _PAGE_NX (_AT(pteval_t, 0))
#define _PAGE_DEVMAP (_AT(pteval_t, 0))
#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment