[patch 38/60] x86/fixmap: Move cpu entry area into a separate PMD

[Thomas Gleixner]

From: Andy Lutomirski <luto@xxxxxxxxxx>

This allows the cpu entry area PMDs to be shared between the kernel and
user space page tables.

[ tglx: Fixed bottom of by one and added guards so other fixmaps can be
  	added later ]

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
 arch/x86/include/asm/fixmap.h |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -134,16 +134,22 @@ enum fixed_addresses {
 #ifdef CONFIG_PARAVIRT
 	FIX_PARAVIRT_BOOTMAP,
 #endif
-	FIX_TEXT_POKE1,	/* reserve 2 pages for text_poke() */
-	FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
 #ifdef	CONFIG_X86_INTEL_MID
 	FIX_LNW_VRTC,
 #endif
-	/* Fixmap entries to remap the GDTs, one per processor. */
+	FIX_TEXT_POKE1,	/* reserve 2 pages for text_poke() */
+	FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
+
+	/*
+	 * Fixmap entries to remap the IDT, and the per cpu entry areas.
+	 * Aligend to a PMD boundary.
+	 */
+	FIX_USR_SHARED_TOP = round_up(FIX_TEXT_POKE0 + 1, PTRS_PER_PMD),
 	FIX_CPU_ENTRY_AREA_TOP,
 	FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
+	FIX_USR_SHARED_BOTTOM  = round_up(FIX_CPU_ENTRY_AREA_BOTTOM + 2, PTRS_PER_PMD) - 1,
 
-	__end_of_permanent_fixed_addresses,
+	__end_of_permanent_fixed_addresses = FIX_USR_SHARED_BOTTOM,
 
 	/*
 	 * 512 temporary boot-time mappings, used by early_ioremap(),